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National and international kidney failure registries: characteristics, commonalities, and contrasts

  • Monica S.Y. Ng
    Affiliations
    Department of Nephrology, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia

    Kidney Health Service, Royal Brisbane and Women’s Hospital, Herston, Queensland, Australia

    Faculty of Medicine and Institute for Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
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  • Vivek Charu
    Affiliations
    Department of Pathology, Stanford University School of Medicine, Palo Alto, California, USA
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  • David W. Johnson
    Affiliations
    Department of Nephrology, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia

    Translational Research Institute, Brisbane, Queensland, Australia

    Centre for Kidney Disease Research, University of Queensland, Brisbane, Queensland, Australia
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  • Michelle M. O’Shaughnessy
    Affiliations
    Department of Renal Medicine, Cork University Hospital, Wilton, Cork, Ireland
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  • Andrew J. Mallett
    Correspondence
    Correspondence: Andrew J. Mallett, Townsville Hospital and Health Service, 100 Angus Smith Drive, Douglas, QLD 4814, Australia.
    Affiliations
    Faculty of Medicine and Institute for Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia

    Department of Renal Medicine, Townsville University Hospital, Townsville, Queensland, Australia

    College of Medicine and Dentistry, James Cook University, Townsville, Queensland, Australia
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Open AccessPublished:November 01, 2021DOI:https://doi.org/10.1016/j.kint.2021.09.024
      Registries are essential for health infrastructure planning, benchmarking, continuous quality improvement, hypothesis generation, and real-world trials. To date, data from these registries have predominantly been analyzed in isolated “silos,” hampering efforts to analyze “big data” at the international level, an approach that provides wide-ranging benefits, including enhanced statistical power, an ability to conduct international comparisons, and greater capacity to study rare diseases. This review serves as a valuable resource to clinicians, researchers, and policymakers, by comprehensively describing kidney failure registries active in 2021, before proposing approaches for inter-registry research under current conditions, as well as solutions to enhance global capacity for data collaboration. We identified 79 kidney-failure registries spanning 77 countries worldwide. International Society of Nephrology exemplar initiatives, including the Global Kidney Health Atlas and Sharing Expertise to support the set-up of Renal Registries (SharE-RR), continue to raise awareness regarding international healthcare disparities and support the development of universal kidney-disease registries. Current barriers to inter-registry collaboration include underrepresentation of lower-income countries, poor syntactic and semantic interoperability, absence of clear consensus guidelines for healthcare data sharing, and limited researcher incentives. This review represents a call to action for international stakeholders to enact systemic change that will harmonize the current fragmented approaches to kidney-failure registry data collection and research.

      Keywords

      Kidney-failure registries play key roles in health infrastructure planning, benchmarking, continuous quality improvement, hypothesis generation, and the conduct of real-world trials (Figure 1). From a public health perspective, kidney-failure registries serve to quantify disease burden, thus informing preventative strategy development and health infrastructure planning.
      • Lim T.-O.
      • Goh A.
      • Lim Y.-N.
      • et al.
      Review article: use of renal registry data for research, health-care planning and quality improvement: What can we learn from registry data in the Asia–Pacific region?.
      Additionally, kidney-failure registries enable clinicians and healthcare management organizations to audit practice patterns and evaluate service quality, supporting benchmarking across jurisdictions and regulatory oversight.
      • Lim T.-O.
      • Goh A.
      • Lim Y.-N.
      • et al.
      Review article: use of renal registry data for research, health-care planning and quality improvement: What can we learn from registry data in the Asia–Pacific region?.
      Taiwan Society of Nephrology
      2019 annual report on kidney disease in Taiwan.
      • Tan J.
      Renal replacement therapy in Brunei Darussalam: comparing standards with international renal registries.
      Kidney-failure registries also are utilized increasingly to support epidemiologic,
      • Hedgeman E.
      • Lipworth L.
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      • et al.
      International burden of chronic kidney disease and secondary hyperparathyroidism: a systematic review of the literature and available data.
      • Schena F.P.
      Epidemiology of end-stage renal disease: international comparisons of renal replacement therapy.
      • Stewart J.H.
      • McCredie M.R.E.
      • Williams S.M.
      ESRD Incidence Study Group
      Geographic, ethnic, age-related and temporal variation in the incidence of end-stage renal disease in Europe, Canada and the Asia-Pacific region, 1998–2002.
      health-outcomes,
      • Allen P.J.
      • Chadban S.J.
      • Craig J.C.
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      Recurrent glomerulonephritis after kidney transplantation: risk factors and allograft outcomes.
      • McDonald S.P.
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      Long-term survival of children with end-stage renal disease.
      • Vajdic C.M.
      • McDonald S.P.
      • McCredie M.R.E.
      • et al.
      Cancer incidence before and after kidney transplantation.
      • O’Shaughnessy M.M.
      • Liu S.
      • Montez-Rath M.E.
      • et al.
      Kidney transplantation outcomes across GN subtypes in the United States.
      and health-economics
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      • Whitlock R.H.
      • Bamforth R.J.
      • et al.
      Cost-utility of dialysis in Canada: hemodialysis, peritoneal dialysis, and nondialysis treatment of kidney failure.
      research (Figure 2). Such findings predominantly can be described as either (i) hypothesis generating, thus supporting the future design of interventional trials,
      • Clayton P.
      • McDonald S.
      • Chadban S.
      Steroids and recurrent IgA nephropathy after kidney transplantation.
      or (ii) prognostic, thus guiding patient counselling and clinical decision making, as well as public health interventions.
      • Allen P.J.
      • Chadban S.J.
      • Craig J.C.
      • et al.
      Recurrent glomerulonephritis after kidney transplantation: risk factors and allograft outcomes.
      • McDonald S.P.
      • Craig J.C.
      Long-term survival of children with end-stage renal disease.
      • Vajdic C.M.
      • McDonald S.P.
      • McCredie M.R.E.
      • et al.
      Cancer incidence before and after kidney transplantation.
      • O’Shaughnessy M.M.
      • Liu S.
      • Montez-Rath M.E.
      • et al.
      Kidney transplantation outcomes across GN subtypes in the United States.
      ,
      • De La Mata N.L.
      • Clayton P.A.
      • Kelly P.J.
      • et al.
      Survival in living kidney donors: an Australian and New Zealand cohort study using data linkage.
      • Oniscu G.C.
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      • Sørensen V.R.
      • Heaf J.
      • Wehberg S.
      • et al.
      Survival benefit in renal transplantation despite high comorbidity.
      • Bray B.D.
      • Boyd J.
      • Daly C.
      • et al.
      Vascular access type and risk of mortality in a national prospective cohort of haemodialysis patients.
      • Majak G.B.
      • Reisæter A.V.
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      • et al.
      The effect of pregnancy on the long-term risk of graft loss, cardiovascular disease, and death in kidney transplanted women in Norway: a retrospective cohort study.
      The strength of registry-based research is that it provides the ability to study population-based cohorts under real-world conditions, with longitudinal follow-up, overcoming some of the limitations of single-center reports (uncertain generalizability) and randomized controlled trials (highly selected patient cohorts, shorter follow-up). Registries also enable the study of rare diseases, such as Fabry disease
      • Thadhani R.
      • Wolf M.
      • West M.L.
      • et al.
      Patients with Fabry disease on dialysis in the United States.
      and Alport Syndrome.
      • Mallett A.
      • Kearey P.
      • Cameron A.
      • et al.
      The Ckd. Qld fabRy Epidemiology (aCQuiRE) study protocol: identifying the prevalence of Fabry disease amongst patients with kidney disease in Queensland, Australia.
      Figure thumbnail gr1
      Figure 1Graph of the number of kidney-failure registry studies published and indexed on PubMed between January 2000 and December 2020, showing a steady increase in the annual number of reports.
      Figure thumbnail gr2
      Figure 2Key roles of kidney-failure registries.
      Benefits of registry research can be amplified by utilizing data from multiple registries,thus improving statistical power and generalizability, while enabling comparisons among jurisdictions. However, the majority of studies have been restricted to single registries (Nadeau-Fredette A-C, Sukul N, Lambie M, et al. Risk factors for early mortality after switch from peritoneal dialysis to hemodialysis: a multinational registry study [abstract]. J Am Soc Nephrol. 2019;30(suppl):579. Abstract FR-PO536).
      • Hedgeman E.
      • Lipworth L.
      • Lowe K.
      • et al.
      International burden of chronic kidney disease and secondary hyperparathyroidism: a systematic review of the literature and available data.
      • Schena F.P.
      Epidemiology of end-stage renal disease: international comparisons of renal replacement therapy.
      • Stewart J.H.
      • McCredie M.R.E.
      • Williams S.M.
      ESRD Incidence Study Group
      Geographic, ethnic, age-related and temporal variation in the incidence of end-stage renal disease in Europe, Canada and the Asia-Pacific region, 1998–2002.
      ,
      • Caskey F.J.
      • Kramer A.
      • Elliott R.F.
      • et al.
      Global variation in renal replacement therapy for end-stage renal disease.
      • Caskey F.J.
      • Stel V.S.
      • Elliott R.F.
      • et al.
      The EVEREST study: an international collaboration.
      • Kim S.J.
      • Schaubel D.E.
      • Fenton S.S.A.
      • et al.
      Mortality after kidney transplantation: a comparison between the United States and Canada.
      • De Meyer V.
      • Abramowicz D.
      • De Meester J.
      • et al.
      Variability in the incidence of renal replacement therapy over time in Western industrialized countries: a retrospective registry analysis.
      • Donovan K.
      • Ford D.
      • van Schalkwyk D.
      • Ansell D.
      UK Renal Registry 12th annual report: chapter 16: international comparisons with the UK RRT programme.
      • Ivory S.E.
      • Polkinghorne K.R.
      • Khandakar Y.
      • et al.
      Predicting 6-month mortality risk of patients commencing dialysis treatment for end-stage kidney disease.
      • Kramer A.
      • Stel V.S.
      • Caskey F.J.
      • et al.
      Exploring the association between macroeconomic indicators and dialysis mortality.
      • Merion R.M.
      • Goodrich N.P.
      • Johnson R.J.
      • et al.
      Kidney transplant graft outcomes in 379 257 recipients on 3 continents.
      • Pladys A.
      • Bayat S.
      • Couchoud C.
      • et al.
      Daily hemodialysis practices in Australia/New Zealand and in France: a comparative cohort study.
      • Stel V.S.
      • Awadhpersad R.
      • Pippias M.
      • et al.
      International comparison of trends in patients commencing renal replacement therapy by primary renal disease.
      • Stewart J.H.
      • McCredie M.R.
      • Williams S.M.
      Geographic, ethnic, age-related and temporal variation in the incidence of end-stage renal disease in Europe, Canada and the Asia-Pacific region, 1998-2002.
      • Wakasugi M.
      • Kazama J.J.
      • Narita I.
      Age- and gender-specific incidence rates of renal replacement therapy in Japan: an international comparison.
      The few inter-registry studies that have been performed have described predominantly the basic epidemiology of kidney failure
      • Schena F.P.
      Epidemiology of end-stage renal disease: international comparisons of renal replacement therapy.
      ,
      • Caskey F.J.
      • Kramer A.
      • Elliott R.F.
      • et al.
      Global variation in renal replacement therapy for end-stage renal disease.
      ,
      • Caskey F.J.
      • Stel V.S.
      • Elliott R.F.
      • et al.
      The EVEREST study: an international collaboration.
      ,
      • De Meyer V.
      • Abramowicz D.
      • De Meester J.
      • et al.
      Variability in the incidence of renal replacement therapy over time in Western industrialized countries: a retrospective registry analysis.
      ,
      • Donovan K.
      • Ford D.
      • van Schalkwyk D.
      • Ansell D.
      UK Renal Registry 12th annual report: chapter 16: international comparisons with the UK RRT programme.
      ,
      • Kramer A.
      • Stel V.S.
      • Caskey F.J.
      • et al.
      Exploring the association between macroeconomic indicators and dialysis mortality.
      ,
      • Stel V.S.
      • Awadhpersad R.
      • Pippias M.
      • et al.
      International comparison of trends in patients commencing renal replacement therapy by primary renal disease.
      • Stewart J.H.
      • McCredie M.R.
      • Williams S.M.
      Geographic, ethnic, age-related and temporal variation in the incidence of end-stage renal disease in Europe, Canada and the Asia-Pacific region, 1998-2002.
      • Wakasugi M.
      • Kazama J.J.
      • Narita I.
      Age- and gender-specific incidence rates of renal replacement therapy in Japan: an international comparison.
      (Supplementary Table S1). Other studies have investigated risk factors for mortality after transition from peritoneal dialysis (PD) to hemodialysis (HD), (Nadeau-Fredette A-C, Sukul N, Lambie M, et al. Risk factors for early mortality after switch from peritoneal dialysis to hemodialysis: a multinational registry study [abstract]. J Am Soc Nephrol. 2019;30(suppl):579. Abstract FR-PO536) or compared post-transplant mortality
      • Kim S.J.
      • Schaubel D.E.
      • Fenton S.S.A.
      • et al.
      Mortality after kidney transplantation: a comparison between the United States and Canada.
      and daily HD practices
      • Pladys A.
      • Bayat S.
      • Couchoud C.
      • et al.
      Daily hemodialysis practices in Australia/New Zealand and in France: a comparative cohort study.
      between jurisdictions. Ivory et al. used data from the Australian and New Zealand Dialysis and Transplant Registry (ANZDATA), to develop a point tool for predicting patient mortality in early stages of dialysis, and from the United Kingdom Renal Registry (UKRR), for external validation.
      • Ivory S.E.
      • Polkinghorne K.R.
      • Khandakar Y.
      • et al.
      Predicting 6-month mortality risk of patients commencing dialysis treatment for end-stage kidney disease.
      Barriers to inter-registry research are multidimensional and complex, involving ethico-legal, technical, financial, political, motivational, and sociocultural arenas.
      • Geneviève L.D.
      • Martani A.
      Mallet MC Factors influencing harmonized health data collection, sharing and linkage in Denmark and Switzerland: a systematic review.
      As a result, international calls to improve access to registry information and collaborative research
      • Pisani E.
      • AbouZahr C.
      Sharing health data: Good intentions are not enough.
      have been difficult to answer, as these require a coordinated, multifaceted approach across oftentimes resource-limited settings. This review aims to address these barriers to inter-registry research by first characterizing the status quo of kidney-failure registries and then proposing strategies to overcome these barriers, citing examples and lessons relating to research on other conditions that can be applied to kidney-failure registries.

       Identification and characterization of existing kidney-failure registries

      In preparing this review, we searched PubMed for publications describing kidney-failure registries, using the following search string: “(registry) AND ((kidney failure) OR (end stage kidney disease) OR (ESKD) OR (end stage renal disease) OR (ESRD) or (renal replacement therapy) or (RRT) or (kidney replacement therapy) OR (KRT)) Filters: humans, from 1 January, 2000 to 7 June, 2021.” A list of kidney-failure registries was then compiled from publications describing registry designs, registry-based studies, and registry reports. Registry staff contact details were garnered from registry websites and corresponding authors on registry studies and/or reports. Registry staff members were contacted electronically, with questions regarding founding year, population coverage, funding body, patient enrollment criteria, data-collection methods, and data availability for research. Copies of registry data-collection sheets were also requested from registry staff. The above information was sought from registry reports, publications, and studies, in cases in which registry staff were not available. Figure 3 indicates the main sources of information used to gather information regarding each registry when preparing this review. Registries were classified as being active if they had an up-to-date website, had at least one publication within the past 5 years, or had contributed data to a secondary registry within the past 5 years. Registries were defined as being developing if they were initiated within the past 5 years and had not yet published any reports. Registries were defined as being inactive or unknown if the registry was reported to have ceased functioning, registry staff were uncontactable, the most recent report was published >10 years ago, or the registry was only mentioned in passing in a literature review. When summarizing the characteristics of individual registries (e.g., percentage collecting data on a particular variable), only active registries were included in the denominator population.
      Figure thumbnail gr3
      Figure 3A world map identifying countries with a kidney-failure registry and the method by which information regarding this registry was obtained. Color coding depicts the primary data source used to extract registry information for this review; registries for which limited data were publically available were designated as having developing, inactive, or uncertain status.

       The status quo of kidney-failure registries

      In total, we identified 61 active, national kidney-failure registries (Supplementary Table S2), 3 active, international registries consisting of amalgamated information (Supplementary Table S3), 15 registries with inactive or uncertain status (Supplementary Table S4), and 2 developing registries. Together, these registries enrolled patients from 77 countries across 6 continents (Supplementary Table S5). Notably, 1 of the registries covers 6 countries, and some countries had multiple kidney-failure registries. These numbers are higher than those reported in the Global Kidney Health Atlas (75 dialysis registries, 68 transplant registries), a cross-sectional survey of kidney-failure registries conducted in 2019,
      • Bello A.
      • Levin A.
      • Lunney M.
      • et al.
      Global Kidney Health Atlas: A Report by the International Society of Nephrology on the Global Burden of End-stage Kidney Disease and Capacity for Kidney Replacement Therapy and Conservative Care across World Countries and Regions.
      a difference likely explained by the fact that, in preparing this current review, contact of registry staff was used to support data obtained from publications.
      We identified 3 major types of kidney failure registry, as follows: (i) registries aiming for complete capture of the target population within a defined country or region (Supplementary Table S2); (ii) multinational databases that source primary data from existing national registries (n = 3; Supplementary Table S3); and (iii) research registries that include data from multiple geographic regions but have incomplete capture of contributing country populations, typically owing to inclusion of data from only a sample of centers or dialysis units (e.g., the Dialysis Outcomes and Practice Patterns Study, the North American Pediatric Renal Trials and Collaborative Studies). This review focuses predominantly on the former 2 types (i and ii) of registries.

       Funding sources

      We identified 9 categories of registry funding, as follows: government (43%), national society (38%), kidney medicine department (3%), industry (3%), academic institution (2%), charity (2%), other (2%), and unfunded (13%; Supplementary Table S2). These percentages are similar to results from a global survey of kidney health surveillance systems completed by Hole et al.
      • Hole B.D.
      • Evans K.M.
      • Pyart R.
      • et al.
      International collaborative efforts to establish kidney health surveillance systems.

       Inclusion criteria

      We identified variability with respect to inclusion criteria for kidney-failure registry enrollment (Table 1). People could be enrolled at the time of dialysis initiation
      Annual report 2014.
      • Kolesnyk I.
      • Noordzij M.
      • Kolesnyk M.
      • et al.
      Renal replacement therapy in Ukraine: epidemiology and international comparisons.
      Indonesian Renal Registry
      11th Report of Indonesian Renal Registry (2018).
      or up to 90 days after dialysis initiation.
      • Couchoud C.
      • Stengel B.
      • Landais P.
      • et al.
      The renal epidemiology and information network (REIN): a new registry for end-stage renal disease in France.
      US Renal Data System (USRDS)
      2020 Researcher’s Guide to the USRDS Database.
      Norwegian Renal Registry
      Annual report 2019.
      Some registries include kidney-failure patients on conservative care pathways who are not receiving dialysis or a kidney transplant.,
      • Couchoud C.
      • Stengel B.
      • Landais P.
      • et al.
      The renal epidemiology and information network (REIN): a new registry for end-stage renal disease in France.
      ,
      National Registry of Diseases OfficeSingapore Government
      Chronic kidney failure notification.
      ERA-EDTA Registry
      ERA-EDTA Registry Annual Report 2017.
      National Quality Registry for Renal Failure (SNR/SRR).
      • Soyibo A.K.
      • Barton E.N.
      Report from the Caribbean renal registry, 2006.
      Indian Society of Pediatric Nephrology (ISPN)
      Chronic kidney disease form.
      However, enrollment is typically incomplete for patients on conservative care pathways (e.g., 58% in the Norwegian Renal Registry,
      ERA-EDTA Registry
      ERA-EDTA Registry Annual Report 2017.
      60% in the Svenskt Njurregister [SNR]
      National Quality Registry for Renal Failure (SNR/SRR).
      ), as these patients may have reduced interaction with kidney-disease services and may be primarily treated by non–kidney-disease specialists (e.g., those in general practice, internal medicine, or palliative care). The Renal Registry of Hong Kong and the Brunei Dialysis and Transplant Registry record data only from patients treated in the public healthcare systems. This does not alter inclusivity in the latter case, as the public healthcare system covers 100% of kidney replacement therapy (KRT) costs.
      Department of Renal Services (DORS)
      Table 1Variability in patient population enrolled in kidney-failure registries
      Inclusion criteriaKidney-failure registries
      Timing of enrollment
       At time of KRT startANZDATA, Cyprus, Russia, Serbia, Ukraine, UKRR, Indonesia
       ≥45 d after KRT startREIN
       ≥60 d after KRT startUSRDS
       ≥90 d after KRT startCORR, Norwegian Renal Registry, DNSL
      Includes conservative careSingapore Renal Registry, Norwegian Renal Registry, REIN, UKRR, SNR, Caribbean Renal Registry, ISPN CKD registry
      Includes public patients onlyRenal registry of Hong Kong, Brunei Dialysis and Transplant Registry
      ANZDATA, Australia and New Zealand Dialysis and Transplant Registry; CORR, Canadian Organ Replacement Registry; DNSL, Danish Nephrological Society National Register; ISPN CKD, Indian Society of Pediatric Nephrology Chronic Kidney Disease Registry; KRT, kidney replacement therapy; REIN, Le Reseau Epidemiologie et Information en Nephrologie; SNR, Svenskt Njurregister; UKRR, United Kingdom Renal Registry; USRDS, US Renal Data System.

       Data collection

      All registries collect data at least annually (Supplementary Table S2). Comorbidities may be recorded at patient enrollment only (e.g., United States Renal Data System [USRDS]
      US Renal Data System (USRDS)
      2020 Researcher’s Guide to the USRDS Database.
      ) or updated regularly (e.g., ANZDATA-
      Australia and New Zealand Dialysis and Transplant Registry (ANZDTR)
      Data forms.
      ). Event notifications, such as those for change in dialysis modality, kidney transplantation, peritoneal dialysis (PD) peritonitis, acute rejection, graft failure, and death, may be made in real time (e.g., ANZDATA,
      Australia and New Zealand Dialysis and Transplant Registry (ANZDTR)
      Data forms.
      Singapore Renal Registry, Korean Renal Data System,
      • Jin D.-C.
      Dialysis registries in the world: Korean Dialysis Registry.
      and USRDS
      US Renal Data System (USRDS)
      2020 Researcher’s Guide to the USRDS Database.
      ) or at prespecified time intervals (e.g., the Japanese Society for Dialysis Therapy Renal Data Registry [JRDR]
      • Masakane I.
      • Taniguchi M.
      • Nakai S.
      • et al.
      Annual Dialysis Data Report 2016, JSDT RenalData Registry.
      and the Colombia Renal Registry
      • Gómez R.A.
      Renal disease in Colombia.
      ).
      Data collected by registries can be broadly divided into demographic, comorbidity, dialysis, transplant, and outcome categories (Figure 4). Variables reported in greater than 50% of registries include the following: current treating center (70%), age (95%), gender (93%), cause of kidney failure (95%), hepatitis status (54%), date of KRT initiation (80%), KRT modality (93%), hemodialysis (HD) access type (66%), hemoglobin (56%), erythropoiesis-stimulating agent use (52%), date of kidney transplant (82%), donor type (56%), mortality rate (86%), and cause of death (89%).
      Figure thumbnail gr4
      Figure 4Summary of variables reported with the highest frequency by kidney-failure registries. Percentages are calculated by dividing the number of registries that record each variable by the number of primary kidney-failure registries with active status multiplied by 100. CMV, cytomegalovirus; ESA, erythropoiesis-stimulating agent; HD, hemodialysis; HLA, human leukocyte antigen; HTN, hypertension; IS, immunosuppression; KRT, kidney replacement therapy; PD, peritoneal dialysis; PET, postitron emission tomography; PRA, panel-reactive antibody.
      Disease definitions vary significantly among registries (Table 2). For example, coronary artery disease is recorded as coronary artery disease, ischemic heart disease, myocardial infarction, and angina pectoris (Table 2). Le Registre de Dialyse Peritoneale de Langue Francaise (RDPLF) and the Danish Nephrological Society National Registry (DNSL) both record comorbidities using the Charlson comorbidity score—an index that can be used to predict 10-year survival in people with multiple comorbidities. Some registries do not collect comorbidity data, including the Renal Registry of Bosnia and Herzegovina, the Croatian Registry of Renal Replacement Therapy (CRRRT), and the Dutch Renal Function Replacement Registry (RENINE).
      Table 2Examples of challenges to semantic interoperability
      Disease termKidney-failure registries
      Coronary artery disease
       Coronary artery diseaseANZDATA, SNR, Singapore Renal Registry, Finnish Registry for Kidney Diseases, REIN, Swiss Renal Registry
       Ischemic heart diseaseJRDR, RDPLF, MDTR, Singapore Renal Registry, TWRDS, RIDT/SIN, SNR, Norwegian Renal Registry, USRDS, UKRR, Uruguayan Dialysis Registry
       Myocardial infarctionFinnish Registry for Kidney Diseases, REIN, Swiss Renal Registry, Argentina Renal Registry, CORR, RDPLF, UKRR, Swiss Renal Registry
       Angina pectorisFinnish Registry for Kidney Diseases, UKRR
      Peripheral vascular disease
       Peripheral vascular diseaseANZDATA, OEDTR, Belgian Society of Nephrology (Dutch-speaking) Renal Registry, Finnish Registry for Kidney Diseases, RIDT/SIN, SNR, Norwegian Renal Registry, Swiss Renal Registry, UKRR, Brazilian Dialysis Registry, Uruguayan Dialysis Registry, Argentina Renal Registry, Puerto Rico Renal Registry, Lebanon National Kidney Registry, USRDS, CORR
       Limb amputationOEDTR, Belgian Society of Nephrology (Dutch-speaking) Renal Registry, Finnish Registry for Kidney Diseases, Swiss Renal Registry, UKRR, Brazilian Dialysis Registry, Argentina Renal Registry, Puerto Rico Renal Registry, USRDS, CORR
       Limb claudicationUKRR
       Symptomatic peripheral vascular diseaseUSRDS, RDPLF
      Kidney disease coding
       Free textSingapore Renal Registry
       ICD-10ANZDATA, Czech Republic Registry of Dialysis Patients, Finnish Registry for Kidney Diseases, Ukrainian National Renal Registry, Brazilian Dialysis Registry, Puerto Rico Renal Registry, USRDS
       ERA-EDTAOEDTR, Croatian Registry for Renal Replacement Therapy, DNSL, RENINE, Finnish Registry for Kidney Diseases, Greek Renal Registry, RIDT/SIN, SNR, Norwegian Renal Registry, Spanish Renal Disease Registry, Swiss Renal Registry, UKRR, South African Renal Registry
       BespokeMDTR, Renal Registry of Hong Kong, Korean Renal Data System, Brunei Dialysis and Transplant Registry, Indian Society of Paediatric Nephrology Chronic Kidney Disease Registry, Indonesia Renal Registry, REIN, North Macedonia Renal Registry, Portuguese Society of Nephrology Renal Registry, Caribbean Renal Registry, Uruguayan Dialysis Registry, Argentina Renal Registry, TRDS
       UnknownJRDR, Chinese Scientific Registry of Kidney Transplantation, Chinese Renal Data System, TRT, TWRDS, Iceland Renal Registry, Latvia Renal Patient Registry, Lithuania Renal Registry, RRR, SRR, Serbia Renal Registry, Slovenia RRT Registry, Chilean Society of Nephrology Dialysis Register, Colombia Renal Registry, Israel National Registry of Renal Replacement Therapy, Iran Renal Registry, Lebanon National Kidney Registry, CORR, RDPLF, Belgian Society of Nephrology (Dutch-Speaking) Renal Registry, Renal Registry of Bosnia and Herzegovina, Cyprus Renal Registry, Estonia Renal Registry
      ANZDATA, Australia and New Zealand Dialysis and Transplant Registry; CORR, Canadian Organ Replacement Registry; DNSL, Danish Nephrological Society National Register; ERA-EDTA, European Renal Association–European Dialysis and Transplant Association Registry; ICD-10, International Statistical Classification of Diseases and Related Health Problems, 10th Revision; JRDR, Japanese Society for Dialysis Therapy Renal Data Registry; MDTR, Malaysian Dialysis and Transplant Registry; OEDTR, Austrian Dialysis and Transplantation Register; RDPLF, Le Registre de Dialyse Peritoneale de Langue; REIN, Le Reseau Epidemiologie et Information en Nephrologie; RENINE, Dutch Renal Function Replacement Registration; RIDT/SIN, Italian Registry of Dialysis and Transplantation; RRR, Romania Renal Registry; RRT, renal replacement therapy; SNR, Svenskt Njurregister; SRR, Scottish Renal Registry; TRDS, Turkish Renal Data System; TRT, Thailand Renal Replacement Therapy Registry; TWRDS, Taiwan Renal Data System; UKRR, United Kingdom Renal Registry; USRDS, US Renal Data System.
      The cause of kidney failure is occasionally recorded in a free-text format, but it is more typically based on disease-classification systems, such as that in the International Statistical Classification of Diseases and Related Health Problems 10th Revision [ICD-10], the European Renal Association – European Dialysis and Transplant Association Registry (ERA-EDTA) disease codes, or internally bespoke coding systems (Table 2). Only 30% of registries record whether kidney disease diagnoses are biopsy-proven, either as part of the disease classification or via an extra question (Figure 4).
      The registries show tremendous variability in data granularity and format. The comprehensiveness of KRT modality data varies, with some registries using only 3 categories (HD, PD, transplant), whereas others have additional categories for home HD, in-center HD, self HD, hemodiafiltration, continuous ambulatory PD, and automated PD. The 26% of registries that report a reason for changing KRT modality specify reasons only for changing from PD to HD.
      National Registry of Diseases OfficeSingapore Government
      Chronic kidney failure notification.
      ,
      • Badal H.P.
      • Ortiz M.
      40th Chronic Haemodialysis Report in Chile (as of August 31, 2020).
      ,
      • Heaf J.
      The Danish Nephrology Registry.
      PD peritonitis is documented variably, with 4 different measures of incidence utilized; reporting of clinical findings, causative organism, drug treatment, PD solution at time of infection, hospitalization requirements, and response to treatment is more limited (Figure 5). Similar variability is observed across all data categories (Supplementary Table S2).
      Figure thumbnail gr5
      Figure 5Variability in the reporting of peritoneal dialysis (PD) peritonitis episodes across kidney-failure registries. Percentages are calculated by dividing the number of registries that record each variable by the number of primary active registries reporting on PD peritonitis.

       Approach to inter-registry research under current conditions

      Planning of any research using registries involves key steps, including study question conception, registry selection, and methods development. Registry selection, in turn, will depend on the study question, registry protocol, and data availability. Data availability is governed by various ethico-legal, political, and financial motivational factors.
      • Geneviève L.D.
      • Martani A.
      Mallet MC Factors influencing harmonized health data collection, sharing and linkage in Denmark and Switzerland: a systematic review.
      Key ethico-legal considerations include privacy, respect for autonomy, and data protection regulations.
      • Geneviève L.D.
      • Martani A.
      Mallet MC Factors influencing harmonized health data collection, sharing and linkage in Denmark and Switzerland: a systematic review.
      ,
      • van Panhuis W.G.
      • Paul P.
      • Emerson C.
      • et al.
      A systematic review of barriers to data sharing in public health.
      These issues can be addressed via official/legal approval of the study, ethical approval by a research ethics committee/institutional review board, legislation permitting data collection and sharing, health data anonymization, and confidentiality measures via data security audits. The majority of registries (70%) allow data requests for research, pending ethical and registry committee approvals (Supplementary Table S2). Several registries, such as the Austrian Dialysis and Transplant Registry (OEDTR), the Croatian Registry for Renal Replacement Therapy, and the Czech Republic Registry of Dialysis Patients require the applicant to be residing in the country or a member of the affiliated nephrology professional society. Even in the absence of such data-access restrictions, the authors of this review recommend collaborating with local investigators when considering inter-registry research, as their input is critical to navigating the local ethico-legal environment, as well as contextualizing study development and data interpretation in the setting of local practice patterns and resource availability.
      Navigating data protection regulations becomes more complex when datasets are transmitted across national boundaries—particularly because regulations vary considerably across countries.
      • Geneviève L.D.
      • Martani A.
      Mallet MC Factors influencing harmonized health data collection, sharing and linkage in Denmark and Switzerland: a systematic review.
      ,
      • Auffray C.
      • Balling R.
      • Barroso I.
      • et al.
      Making sense of big data in health research: towards an EU action plan.
      The General Data Protection Regulation (GDPR) attempts to harmonize fragmented policies across the European Union with provisions to facilitate research “designed to serve mankind” (Recital 4).
      • Chico V.
      The impact of the General Data Protection Regulation on health research.
      ,
      • Rumbold J.
      • Pierscionek B.
      The effect of the General Data Protection Regulation on medical research.
      However, legal uncertainty resulting from variable interpretation of the GDPR and various cantonal requirements continues to discourage researchers from sharing data in Europe.
      • Geneviève L.D.
      • Martani A.
      • Perneger T.
      • et al.
      Systemic fairness for sharing health data: perspectives from Swiss stakeholders.
      Parallel analyses of single-registry data, followed by comparison of aggregated results (without sharing of individual-level data), may offer a temporary solution until a clear legal framework to support data sharing across jurisdictions has been developed.
      Ethical issues can arise when managing data from vulnerable populations (e.g., minorities, Indigenous peoples, those residing in developing countries) and need to be considered carefully throughout the research process. Data sovereignty and community engagement in all research processes are paramount to respect sociocultural practices and ensure that generated results translate into tangible benefits that align with each group’s priorities and interest.
      • Tangcharoensathien V.
      • Boonperm J.
      • Jongudomsuk P.
      Sharing health data: developing country perspectives.
      ,
      • Walker J.D.
      • Pyper E.
      • Jones C.R.
      • et al.
      Unlocking First Nations health information through data linkage.
      Several guidelines are available regarding research approaches involving Indigenous peoples in Australia,
      Australian Institute of Aboriginal and Torres Strait Islander Studies (AIATSIS)
      AIATSIS Code of Ethics for Aboriginal and Torres Strait Islander Research.
      ,
      Australian Institute of Aboriginal and Torres Strait Islander Studies (AIATSIS)
      A Guide to Applying the AIATSIS Code of Ethics for Aboriginal and Torres Strait Islander Research.
      New Zealand,
      • Hudson M.
      • Milne M.
      • Reynolds P.
      • et al.
      Te Ara Tika Guidelines for Maori research ethics: A framework for researchers and ethics committee members.
      Canada,
      First Nations Child & Family Caring Society (FNCFCS)
      Guidelines for Ethical Research.
      ,
      Canadian Institutes of Health Research (CIHR)
      CIHR guidelines for health research involving Aboriginal People.
      and the US.
      National Congress of American Indians (NCAI)
      Research Regulation.
      The consolidated criteria for strengthening reporting of health research involving Indigenous peoples (CONSIDER) statement provides information for reporting of health research involving Indigenous peoples.
      • Huria T.
      • Palmer S.C.
      • Pitama S.
      • et al.
      Consolidated criteria for strengthening reporting of health research involving indigenous peoples: the CONSIDER statement.
      Medical research in developing countries is broadly guided by the Declaration of Helsinki, the Council for International Organisations of Medical Sciences guidelines, and the Guidance on Good Clinical Practice document.
      • Zumla A.
      • Costello A.
      Ethics of healthcare research in developing countries.
      The European Union and the Nuffield Council on Bioethics provide specific commentary pertaining to healthcare research in developing countries.
      European Group on Ethics in Science and New Technologies to the European Commission
      Opinion Nr 17 on ethical aspects of clinical research in developing countries.
      ,
      Nuffield Council on Bioethics (NCB)
      The Ethics of Research Related to Healthcare in Developing Countries.
      Research regarding vulnerable people should be community-driven, and researchers should actively seek input from all stakeholders. Inclusion of local and Indigenous peoples is key to creating equal partnerships, ensuring cultural competence, and developing local expertise.
      • Tangcharoensathien V.
      • Boonperm J.
      • Jongudomsuk P.
      Sharing health data: developing country perspectives.
      ,
      • Fitzpatrick E.F.M.
      • Martiniuk A.L.C.
      • D’Antoine H.
      • et al.
      Seeking consent for research with indigenous communities: a systematic review.
      Building capacity for registry research and maintaining local access to data should be critical components of any research project to level the playing field and provide lasting benefits to local communities.
      Data-sharing agreements can be used to address mistrust among stakeholders, data ownership issues, and institutional requirements. Lack of funding and research incentives have been cited as major barriers to conducting inter-registry studies, as data extraction, preparation, and annotation require extensive human and technical resources.
      • van Panhuis W.G.
      • Paul P.
      • Emerson C.
      • et al.
      A systematic review of barriers to data sharing in public health.
      This obstacle is particularly relevant for low-resource settings in which registry activities are unfunded and research is completed on top of full-time workloads. Incorporation of data from resource-limited countries into existing registries bears consideration, as exemplified by the intermittent contributions of North African countries to the ERA-EDTA and USRDS registries.
      • Pecoits-Filho R.
      • Okpechi I.G.
      • Donner J.-A.
      • et al.
      Capturing and monitoring global differences in untreated and treated end-stage kidney disease, kidney replacement therapy modality, and outcomes.
      Although some registries, such as the UKRR, charge fees for data requests in some circumstances,
      UK Kidney Association
      Apply to access United Kingdom Renal Registry data.
      in-kind remuneration (e.g., coauthorship, data-processing skill sharing, equipment, software, researcher time) could be considered when monetary payment is not possible due to resource constraints. The investigators of the Explaining the Variation in Epidemiology of RRT through Expert opinion, Secondary data sources and Trends over time (EVEREST) study reported that official study endorsements by the ERA-EDTA and the International Society of Nephrology (ISN) also improved study response rates.
      • Caskey F.J.
      • Stel V.S.
      • Elliott R.F.
      • et al.
      The EVEREST study: an international collaboration.
      Technical aspects of data sharing include data transfer, security, storage, and maintenance. The internet is the default standard for secure data transfer.
      • Gliklich R.
      • Dreyer N.
      • Leavy M.
      Registries for Evaluating Patient Outcomes: A User’s Guide.
      Various available methods for combining health data can be used, depending on whether data are collected prospectively or retrospectively. Prospective data collection from multiple registries can be facilitated using system integration software (e.g., the PINNACLE Registry),
      • Gliklich R.
      • Dreyer N.
      • Leavy M.
      Registries for Evaluating Patient Outcomes: A User’s Guide.
      creation of new registry interfaces (e.g., ERA-EDTA, Database of Databases),
      • Gliklich R.
      • Dreyer N.
      • Leavy M.
      Registries for Evaluating Patient Outcomes: A User’s Guide.
      ,
      • de Carvalho E.C.A.
      • Batilana A.P.
      • Simkins J.
      • et al.
      Application description and policy model in collaborative environment for sharing of information on epidemiological and clinical research data sets.
      and health information exchanges (e.g., Oakland Southfield Physicians Quality Registry).
      • Auffray C.
      • Balling R.
      • Barroso I.
      • et al.
      Making sense of big data in health research: towards an EU action plan.
      ,
      • Vest J.R.
      • Gamm L.D.
      Health information exchange: persistent challenges and new strategies.
      These methods ultimately reduce the data-entry burden by allowing data from diverse registries to be periodically extracted from primary registries and mapped to a centralized registry. These tremendous undertakings require strong support from government and participating registries to provide the organizational, technical, and financial resources during the start-up, launch, and maintenance phases.
      • Gliklich R.
      • Dreyer N.
      • Leavy M.
      Registries for Evaluating Patient Outcomes: A User’s Guide.
      ,
      • Vest J.R.
      • Gamm L.D.
      Health information exchange: persistent challenges and new strategies.
      For one-off projects, anonymized retrospective data can be manually combined into an encrypted file for statistical analysis.
      • Caskey F.J.
      • Kramer A.
      • Elliott R.F.
      • et al.
      Global variation in renal replacement therapy for end-stage renal disease.
      ,
      • Kim S.J.
      • Schaubel D.E.
      • Fenton S.S.A.
      • et al.
      Mortality after kidney transplantation: a comparison between the United States and Canada.
      ,
      • Pladys A.
      • Bayat S.
      • Couchoud C.
      • et al.
      Daily hemodialysis practices in Australia/New Zealand and in France: a comparative cohort study.
      Atlhough this method is labour-intensive, it remains the most common approach utilized in inter-registry studies.
      Another challenge to inter-research research is the need for data harmonization—that is, the process of bringing together data with varying formats, naming conventions, and variable definitions into 1 cohesive dataset. Evaluation of harmonization potential starts with an assessment of all variables in each dataset and the extent to which each is present across datasets. Up-to-date and historical information regarding variable definitions and availability should be sought from each registry, as these factors are dynamic and change over time. For example, data on comorbidity, smoking status, and body mass index have been consistently collected in ANZDATA only since the mid-1990s.
      • Mallett A.
      • Tang W.
      • Clayton P.A.
      • et al.
      End-stage kidney disease due to Alport syndrome: outcomes in 296 consecutive Australia and New Zealand Dialysis and Transplant Registry cases.
      The JRDR recorded dialyzer membrane material and surface area in 2000, 2002, 2009, 2010, and 2017 only.
      Japanese Society for Dialysis Therapy (JSDT)
      An Overview of Regular Dialysis Treatment in Japan.
      The Le Reseau Epidemiologie et Information en Nephrologie (REIN) is considering changing from using its bespoke disease classification system to using ERA-EDTA disease codes for cause of kidney failure (personal communication, C. Couchoud, November 5, 2020).
      In some cases, variable categories may need to be collapsed into less-detailed categories or via a single binary (yes/no) variable. For example, peripheral vascular disease has been recorded in various registries as defined by each of the following: (i) peripheral vascular disease only; (ii) amputation only; (iii) peripheral vascular disease and amputation; and (iv) peripheral vascular disease, amputation, and claudication (Table 2). In a harmonized dataset, these data may be converted via a binary classification of peripheral vascular disease (yes/no), to maximize dataset inclusion. Desired information also can be inferred from collected variables. For example, dialyzer features have been recorded as (i) model and brand in ANZDATA and the Malaysian Dialysis and Transplant Registry and (ii) surface area and material in the JRDR and the Czech Republic Registry of Dialysis Patients. The latter 2 dialyzer features (ii) can be inferred from data from (i). Program extraction codes are then required to extract data from each individual dataset into the harmonized dataset. Care must be taken at each step to ensure consistent, adequate harmonization. Issues and questions should be discussed regularly amongst the harmonization team, local registry staff, and other stakeholders to ensure appropriate harmonization.
      The ISN strategic plan for integrated care of patients with kidney failure advocates for agreement on standardized minimum and progressive datasets, a scoping review of ethical issues for registries, development of an ISN “registry standards” document and “registry checklist” for publications, and appointment of local champions for recognition and networking.
      • Harris D.C.H.
      • Davies S.J.
      • Finkelstein F.O.
      • et al.
      Strategic plan for integrated care of patients with kidney failure.
      Moreover, data capture could potentially be improved and/or simplified by employing innovative approaches, such as mobile phone platforms or use of machine learning to automate data extraction from electronic health records or registries.
      • Pecoits-Filho R.
      • Okpechi I.G.
      • Donner J.-A.
      • et al.
      Capturing and monitoring global differences in untreated and treated end-stage kidney disease, kidney replacement therapy modality, and outcomes.
      In addition to supporting the local development and maintenance of regional registries, the hope is that these recommended approaches streamline data harmonization approaches and facilitate inter-registry research.
      Statistical analysis should be defined a priori to increase the transparency and validity of findings.
      • Hiemstra B.
      • Keus F.
      • Wetterslev J.
      • et al.
      DEBATE-statistical analysis plans for observational studies.
      Data reporting should conform to the Strengthening The Reporting of OBservational studies in Epidemiology (STROBE) statement,
      • Elm Ev
      • Altman D.G.
      • Egger M.
      • et al.
      Strengthening the reporting of observational studies in epidemiology (STROBE) statement: guidelines for reporting observational studies.
      the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines,
      • Stroup D.F.
      • Berlin J.A.
      • Morton S.C.
      • et al.
      Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis of Observational Studies in Epidemiology (MOOSE) group.
      or the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD)
      • Collins G.S.
      • Reitsma J.B.
      • Altman D.G.
      • et al.
      Transparent reporting of a multivariable prediction model for individual prognosis or diagnosis (TRIPOD): the TRIPOD Statement.
      guidelines, depending on study design. Data from different registries can be analyzed as a single dataset or separately in parallel. Caskey et al. combined data from 46 countries to examine associations among KRT incidence, national gross domestic product, and healthcare spending
      • Caskey F.J.
      • Kramer A.
      • Elliott R.F.
      • et al.
      Global variation in renal replacement therapy for end-stage renal disease.
      (Supplementary Table S1). This approach enhanced power by using a large study population and allowed head-to-head comparisons between countries. Nadeau-Fredette et al. analyzed data from ANZDATA, USRDS, the Canadian Organ Replacement Register (CORR), and ERA-EDTA separately and compared summary statistics to identify risk factors for mortality after PD-to-HD transition (Nadeau-Fredette A-C, Sukul N, Lambie M, et al. Risk factors for early mortality after switch from peritoneal dialysis to hemodialysis: a multinational registry study [abstract]. J Am Soc Nephrol. 2019;30(suppl):579. Abstract FR-PO536). This method allows the raw dataset to remain with each local investigator, overcoming ethico-legal barriers related to data transfer across national boundaries. The granularity of each dataset is also maintained, as the categorizations within each discrete variable do not need to be “harmonized” among registries. However, this method does not enable direct quantitative comparisons among datasets.
      The limitations of registry-based research, as compared to randomized controlled trials or prospective cohort studies, include the following: (i) exposures and treatments are not randomly assigned; (ii) data for some variables of interest might not be available; and (iii) data may be missing. As is the case with other retrospective cohort studies, registry-based studies are susceptible to bias and confounding, as exposures and treatments are not randomly assigned. Registry data collection also tends to focus on breadth rather than depth of knowledge, to reduce the administrative workload, particularly in the setting of stretched healthcare resources.
      • McDonald S.P.
      • Russ G.R.
      Australian registries—ANZDATA and ANZOD.
      As a result, some potentially confounding variables of interest might not be included in multivariable analyses. This impact of this effect can be ameliorated by requesting additional data from companion (e.g., transplant) registries or by performing data linkage with independent data sources.
      • Sypek M.P.
      • Dansie K.B.
      • Clayton P.
      • et al.
      Comparison of cause of death between Australian and New Zealand Dialysis and Transplant Registry and the Australian National Death Index.
      • Webster A.C.
      • Supramaniam R.
      • O’Connell D.L.
      • et al.
      Validity of registry data: agreement between cancer records in an end-stage kidney disease registry (voluntary reporting) and a cancer register (statutory reporting).
      • Iwagami M.
      • Tomlinson L.A.
      • Mansfield K.E.
      • et al.
      Validity of estimated prevalence of decreased kidney function and renal replacement therapy from primary care electronic health records compared with national survey and registry data in the United Kingdom.
      Incomplete data can introduce susceptibility to selection and information bias.
      • Tripepi G.
      • Jager K.J.
      • Dekker F.W.
      • et al.
      Selection bias and information bias in clinical research.
      In South Korea, 70% of the overall kidney-failure population is included in registry data, and individual-level data contribution was only 46% overall—49.2% from private clinics, 38.2% from general hospitals, and 66.7% from university hospitals.

      Korean Society of Nephrology. ESRD Registry Committee, current renal replacement therapy in Korea. Seoul, South Korea; 2019.

      In 2018, mean center participation per province in the Indonesian Renal Registry (IRR) was 76.4% (95% confidence interval 67.2%–85.7%).
      Indonesian Renal Registry
      11th Report of Indonesian Renal Registry (2018).
      In both cases, people who were “missing” from the registry may differ from included people, thereby limiting the generalizability of findings to the national population. Specific data components can also be underreported, despite complete population capture. For example, the Shanghai Dialysis Registry reported 100% population capture between 1999 and 2006.
      • Yao Q.
      • Zhang W.
      • Qian J.
      Peritoneal dialysis in Shanghai.
      However, dialysis adequacy was only reported in 57% of people on PD in 2006. Approaches to address missing data in research studies include complete case analysis, single imputation, and multiple imputation—all of which are susceptible to bias and confounding.
      • Shivasabesan G.
      • Mitra B.
      • O’Reilly G.M.
      Missing data in trauma registries: a systematic review.
      Sensitivity analyses are required to explore the potential effect of missing not-at-random data on estimated results.
      • Jakobsen J.C.
      • Gluud C.
      • Wetterslev J.
      • et al.
      When and how should multiple imputation be used for handling missing data in randomised clinical trials—a practical guide with flowcharts.
      However, despite these limitations, inter-registry studies have the major advantage of including large, nationally representative patient populations, which enhances the generalizability of study findings. However, populations not covered by registries, in particular those in lower-income countries, remain marginalized. People living in these countries might differ fundamentally from people living in countries with established kidney-failure registries, with respect to disease susceptibility, healthcare systems, and socioeconomic factors. However, not all the countries lacking a national registry have a low gross domestic product and limited healthcare services. For example, Germany and Luxembourg lack kidney-failure registries yet their gross domestic product per capita is among the highest in Europe and among universal healthcare systems.
      eurostat
      Gross domestic product at market prices.
      • Blümel M.
      • Spranger A.
      • Achstetter K.
      • Maresso A.
      • et al.
      European Observatory on Health Systems and Policies
      Germany: health system review. World Health Organization. Regional Office for Europe 2020.
      Organisation for Economic Co-operation and Development (OECD), European Observatory on Health Systems and Policies
      Luxembourg: Country Health Profile 2017, State of Health in the EU.
      Lack of a registry can be overcome by supplementing registry-derived data with data requested from countries without a registry. The EVEREST study was an international collaboration that examined associations between patient factors and kidney-failure outcomes across 46 countries.
      • Caskey F.J.
      • Kramer A.
      • Elliott R.F.
      • et al.
      Global variation in renal replacement therapy for end-stage renal disease.
      ,
      • Caskey F.J.
      • Stel V.S.
      • Elliott R.F.
      • et al.
      The EVEREST study: an international collaboration.
      Countries with no known kidney-failure registries (e.g., Germany) were approached for data to ensure coverage, thereby enhancing the generalizability of study findings.

       Proposed solutions to build capacity for registry research

      Key goals in building capacity for registry-based research should include the following: (i) the construction and maintenance of kidney-failure registries worldwide; (ii) enhancement of the sustainability, quality, and comprehensiveness of registry data; (iii) harmonization of data elements among registries; and (iv) development of international consensus, guidelines, and incentives for health registry collaboration (Figure 6).
      Figure thumbnail gr6
      Figure 6Proposed solutions to build capacity for inter-registry research.
      According to the Global Kidney Health Atlas, less than 1 in 4 low-income countries can estimate their incidence or prevalence of chronic kidney disease, owing to deficiencies in health information systems (HIS).
      • See E.J.
      • Bello A.K.
      • Levin A.
      • et al.
      Availability, coverage, and scope of health information systems for kidney care across world countries and regions.
      In Africa and South America, kidney-failure registries are often established by local nephrologists with little funding and poor participation from local centers, resulting in limited sustainability.
      • Davids M.R.
      • Eastwood J.B.
      • Selwood N.H.
      • et al.
      A renal registry for Africa: first steps.
      ,
      • Davids M.R.
      • Caskey F.J.
      • Young T.
      • et al.
      Strengthening renal registries and ESRD research in Africa.
      As a result, supporting the development and maintenance of kidney-failure registries in low-income countries is a key goal to improving information for advocacy, health infrastructure development, quality assurance monitoring, and research. To this end, Sharing Expertise to support the set-up of Renal Registries (SharE-RR) is an ISN initiative encouraging shared learning among countries with kidney-disease registries.
      • Hole B.D.
      • Evans K.M.
      • Pyart R.
      • et al.
      International collaborative efforts to establish kidney health surveillance systems.
      The initial objectives involved a global survey of kidney-disease registries and a workshop for registry conception.
      • Hole B.D.
      • Evans K.M.
      • Pyart R.
      • et al.
      International collaborative efforts to establish kidney health surveillance systems.
      Although this initiative can foster individual knowledge and skills, it does not address systemic barriers to HIS development in low- and middle-income countries.
      Establishing sustained and comprehensive HIS is an expensive, long-term endeavor that holds little appeal for decision-makers with short-term horizons.
      • AbouZahr C.
      • Boerma T.
      Health information systems: the foundations of public health.
      Decision-makers need to be shown return on investment, which may be achieved via increased emphasis by global aid providers on results-based management and performance-based funding—both of which require sound data generated through reliable and transparent systems. The shift toward “payment by results” programs by global aid providers represents the vanguard of this movement.
      • Savedoff W.
      • Perakis R.
      • Schwanke B.
      Shifting the Foreign Aid Paradigm — Paying for Outcomes.
      ,
      Department for International Development
      Designing and delivering payment by results programmes: a DFID smart guide.
      Resource allocation guided by real-world data improves spending efficacy and efficiency, thereby allowing countries to maximize net income. A learning healthcare system driven by sound data delivers additional returns with each successive correction.
      • Nataatmadja M.
      • Cho Y.
      • Johnson D.W.
      Continuous quality improvement initiatives to sustainably reduce peritoneal dialysis-related infections in Australia and New Zealand.
      The next step involves harmonizing fragmented and overlapping HIS funding by global organizations. Active between 2005 and 2013, the Health Metrics Network was a global partnership hosted by the World Health Organization that sought to provide coordinated support to strengthen HIS.
      Organisation for Economic Cooperation and Development
      A road map for a country-led data revolution, 2015.
      The network is credited with HIS-driven improvements in mortality rates and cost effectiveness.
      • Ashraf H.
      Countries need better information to receive development aid.
      The Partnership in Statistics for Development in the 21st Century (PARIS21) initiative continues the effort to build statistical capacity for data production, maintenance, and analysis in developing countries.
      Organisation for Economic Cooperation and Development
      A road map for a country-led data revolution, 2015.
      Enhancing sustainability, quality, and comprehensiveness of registry data is key for effective inter-registry collaboration. Efforts to maintain data sustainability need to be driven locally, and tailored to available infrastructure, technological, and financial capacities.
      • Ashraf H.
      Countries need better information to receive development aid.
      For example, paper-based HIS may be more appropriate than electronic HIS in countries with unreliable electricity supply, limited internet access, and low computer literacy. Databases that can be understood and used by policymakers are more likely to be continuously funded. Sustained funding and center engagement require policymakers to recognize the value of evidence-driven healthcare and incentivize service providers. As a result, the majority of longstanding kidney-failure registries are funded by government subsidy or kidney health societies (Supplementary Table S2).
      The collection and curation of high-quality data should be the modus operandi of all registries. In practice, many kidney-failure registries lack systematic internal data-quality audits, owing to resource limitations.
      • McDonald S.P.
      • Russ G.R.
      Australian registries—ANZDATA and ANZOD.
      Data errors can arise at various stages in the registry process.
      • Arts D.G.T.
      • De Keizer N.F.
      • Scheffer G.-J.
      Defining and improving data quality in medical registries: a literature review, case study, and generic framework.
      Examples include incompleteness regarding data source, nonadherence to data definitions, calculation errors, programming errors in extraction software, transcription error, incomplete transcription, and typing errors. Methods to address these issues include extensive training and selection of motivated data collectors, routine completeness checks and site visits, clear data definitions, use of closed questions, and regular feedback on results and recommendations to resolve data errors.
      • Hoeijmakers F.
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      • et al.
      National quality registries: how to improve the quality of data?.
      Data comprehensiveness is beneficial to maximizing capacity to control for confounders and maximizing data potential for secondary use. Endeavors to increase data comprehensiveness need to be balanced against feasibility in the setting of finite healthcare resources. Direct upload from electronic health records may ameliorate data-entry burden, although this solution is only available to jurisdictions with electronic health records. Furthermore, large-scale developments to create syntactic and semantic interoperability are required across fragmented and diverse electronic health records before this aspiration can be realized.
      Harmonization of data elements would reduce the amount of data synthesis required for inter-registry research. Initially, we propose that this would involve a universal shift toward collecting individual-level data. Ultimately, a carefully defined core set of variables should be collected in a standardized way by all registries, allowing datasets to be merged seamlessly (e.g., unit of measure for PD peritonitis = number of PD peritonitis episodes per year at risk). Core variables should be established through partnership with all stakeholders, including patients, caregivers, health professionals, database managers, biostatisticians, and policymakers. The Standardised Outcomes in Nephrology (SONG) initiative exemplifies optimal processes for establishing core outcome domains in clinical research and engaging consumers as partners. This method utilizes multimodal approaches, such as nominal group techniques, Delphi surveys, and consensus workshops, to ensure that selected variables are relevant and important to all stakeholders, and feasible to implement.
      Standardised Outcomes in Neprology (SONG) initiative
      The SONG Handbook.
      In 1997, the International Federation of Renal Registries (IFRR) was organized to standardize kidney-disease registries with respect to terminology, data collection, and data analysis protocols.
      • Schena F.P.
      Report on the first meeting of the Chairmen of the National and International Registries.
      The outcomes of this initiative are unknown, as no further reports have been generated since 1997 after their first meeting. More recently, the Nephrology QUality European Studies (NephroQUEST) project was initiated by the ERA-EDTA to provide a consensus on quality performance indicators (Table 3) to be included in European kidney-disease registries.
      • Jager K.
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      ,
      • van der Veer S.N.
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      Measuring the quality of renal care: things to keep in mind when selecting and using quality indicators.
      Selected variables are skewed significantly toward hemodialysis populations with limited variables relevant to peritoneal dialysis and kidney transplant cohorts. Additionally, this initiative had no patient or caregiver input and was limited to the European continent. Other initiatives to improve semantic interoperability include the Kidney Health Initiative—data harmonization in kidney transplantation,
      Data harmonization in kidney transplantation. Washington DC: Kidney Health Initiative.
      the Kidney Disease: Improving Global Outcomes (KDIGO) consensus on kidney-failure reporting in clinical trial outcomes,
      • Levin A.
      • Agarwal R.
      • Herrington W.G.
      • et al.
      International consensus definitions of clinical trial outcomes for kidney failure: 2020.
      and the Clinical Data Interchange Standards Consortium (CDISC) guidelines for reporting in diabetic kidney disease, kidney transplant, and polycystic kidney disease.
      Clinical Data Interchange Standards Consortium (CDISC)
      Therapeutic areas.
      Ironically, work designed to harmonize data has been fragmented across disease subtypes and/or locations, highlighting the need for coordinated consensus approaches.
      Table 3Final proposed ERA-EDTA registry dataset developed by the NephroQUEST project
      DomainVariable
      DemographicAge

      Gender

      Dry weight

      Smoking status

      Primary renal disease
      ComorbidityAmputation

      Comorbidities at start of kidney replacement therapy
      Kidney replacement therapyTreatment modality

      Duration of kidney replacement therapy
      DialysisDialysis duration + frequency

      Vascular access type

      Treatment with erythropoietin-stimulating agents

      Urea clearance

      Creatinine clearance
      Vital signsBlood pressure
      BiochemistrySerum albumin

      C-reactive protein

      Total cholesterol

      High-density lipid cholesterol

      Triglycerides

      Hemoglobin

      Ferritin

      Serum calcium

      Serum phosphorus

      Serum parathyroid hormone
      TransplantSource of kidney donor

      Graft survival
      OutcomesSurvival on kidney replacement therapy
      ERA-EDTA, European Renal Association–European Dialysis and Transplant Association Registry; NephroQUEST, Nephrology QUality European Studies.
      International consensus, guidelines, and incentives are required to facilitate health registry collaboration. In a qualitative study, researchers identified legal uncertainty and lack of fair attribution mechanisms as major barriers to data sharing.
      • Geneviève L.D.
      • Martani A.
      • Perneger T.
      • et al.
      Systemic fairness for sharing health data: perspectives from Swiss stakeholders.
      Dialogue and consensus-building among stakeholders, including funders, researchers, institutions, journal editors, ethics committees, multinational agencies, and governments are essential to developing unified guidelines on global health data collaboration.
      • Whitworth J.
      Data sharing: reaching consensus.
      Such discussion could be facilitated by a nonpartisan third party, such as the World Health Organization or the Organisation for Economic Co-operation and Development. Furthermore, reliable citation of datasets is required to incentivize researchers to share datasets in the hypercompetitive research environment.
      • Pisani E.
      • AbouZahr C.
      Sharing health data: Good intentions are not enough.
      ,
      DataCite
      DataCite’s value.
      Other requisite reforms involve the development of searchable databases for metadata (e.g., DataCite), procedures for quality control of datasets, and standards governing data use, as seen in the fields of genomics and proteomics.
      • Pisani E.
      • AbouZahr C.
      Sharing health data: Good intentions are not enough.
      ,
      • Auffray C.
      • Balling R.
      • Barroso I.
      • et al.
      Making sense of big data in health research: towards an EU action plan.

       Conclusion

      Kidney-failure registries fulfill an important role in collecting data regarding disease burden, service provision, and patient characteristics and outcomes. This information drives advocacy efforts, health infrastructure development, preventative health polices, and service benchmarking. Increasingly, kidney-failure registries are used for epidemiologic and hypothesis-generating research. This review serves as an important resource that comprehensively describes the structure, funding, and content of kidney-failure registries globally in 2021, as well as suggested approaches to support inter-registry research. We are hopeful that this review, in conjunction with initiatives such as the Global Kidney Health Atlas, SharE-RR, and NephroQUEST, will provide a roadmap to guide and encourage future collaborative inter-registry research.

      Disclosure

      MSYN has received a Robert and Janelle Bird Postdoctoral Research Fellowship from the RBWH Foundation. DWJ has received grants from Baxter Healthcare, Fresenius Medical Care, and NHMRC; and consulting fees or honoraria from Baxter Healthcare, AstraZeneca, Bayer, Awak, Ono, BI & Lilly, and Amgen. AJM has received research grants from Sanofi Genzyme and participated in an Advisory Board for Otsuka. All the other authors declared no competing interests.

      Acknowledgments

      The authors thank and acknowledge all local registry staff who verified registry information: Mandy Farmer (ANZDATA); Chi Bon Leung (Hong Kong); Sandra Lim (Singapore); Yen-Chung Lin (Taiwan); Jackson Tan (Brunei); Reinhard Kramar, Julia Kerschbaum (Austria); Johan De Meester (Belgium); Halima Resic (Bosnia and Herzegovina); Svjetlana Cala (Croatia); Kyriakos Ioannou (Cyprus); Helle Thiesson, Kristine Hommel (Denmark); Lara Heuveling (the Netherlands); Mai Rosenberg (Estonia); Jaakko Helve (Finland); Cécile Couchoud (France, REIN), Christian Verger (France, RDPLF); Aurelio Limido (Italy); Helena Rydell (Sweden); Nikola Gjorgjievski (North Macedonia); Anna Varberg Reisæter (Norway); Ana Galvão (Portugal); Liliana Garneata (Romania); Chrissie Watters (Scotland); Angela Magaz, Beatriz Mahillo, Óscar Zurriaga, Pablo Castro de la Nuez (Spain); Rebecca Winzeler (Switzerland); Natalia Stepanova (Ukraine); Katharine Evans (United Kingdom); Ricardo Sesso, Jocemir Lugon, Thiago Quintas Camara (Brazil); María Carlota González Bedat (Uruguay); Liliana Bisigniano (Argentina); Rafael Alberto Gomez Acevedo (Colombia); Jorge Huertas (Ecuador); Guillermo García García (Mexico); Angela M. Díaz (Puerto Rico); Gültekin Süleymanlar (Turkey); Beth Forrest (USA); Michael Manno (Canada); Anneke Kramer (ERA-EDTA). Sources of funding for this work include a Robert and Janelle Bird Postdoctoral Research Fellowship, Royal Brisbane, and the Women’s Hospital Foundation.

      Supplementary Material

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