title: International Network of Chronic Kidney Disease cohort studies (iNET-CKD): a global network of chronic kidney disease cohorts.
abstract: Chronic kidney disease (CKD) is a global health burden, yet it is still underrepresented within public health agendas in many countries. Studies focusing on the natural history of CKD are challenging to design and conduct, because of the long time-course of disease progression, a wide variation in etiologies, and a large amount of clinical variability among individuals with CKD. With the difference in health-related behaviors, healthcare delivery, genetics, and environmental exposures, this variability is greater across countries than within one locale and may not be captured effectively in a single study.
  
  
  
  Studies were invited to join the network. Prerequisites for membership included: 1) observational designs with a priori hypotheses and defined study objectives, patient-level information, prospective data acquisition and collection of bio-samples, all focused on predialysis CKD patients; 2) target sample sizes of 1,000 patients for adult cohorts and 300 for pediatric cohorts; and 3) minimum follow-up of three years. Participating studies were surveyed regarding design, data, and biosample resources.
  
  
  
  Twelve prospective cohort studies and two registries covering 21 countries were included. Participants age ranges from >2 to >70 years at inclusion, CKD severity ranges from stage 2 to stage 5. Patient data and biosamples (not available in the registry studies) are measured yearly or biennially. Many studies included multiple ethnicities; cohort size ranges from 400 to more than 13,000 participants. Studies' areas of emphasis all include but are not limited to renal outcomes, such as progression to ESRD and death.
  
  
  
  iNET-CKD (International Network of CKD cohort studies) was established, to promote collaborative research, foster exchange of expertise, and create opportunities for research training. Participating studies have many commonalities that will facilitate comparative research; however, we also observed substantial differences. The diversity we observed across studies within this network will be able to be leveraged to identify genetic, behavioral, and health services factors associated with the course of CKD. With an emerging infrastructure to facilitate interactions among the investigators of iNET-CKD and a broadly defined research agenda, we are confident that there will be great opportunity for productive collaborative investigations involving cohorts of individuals with CKD.
authors: Department of Nephrology and Hypertension, University of Erlangen-Nürnberg, Erlangen, Germany.
authors: Thomas
authors: T
authors: Dienemann
authors: Department of Biostatistics and Epidemiology, Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
authors: Naohiko
authors: N
authors: Fujii
authors: Department of Biostatistics and Epidemiology, Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
authors: Paula
authors: P
authors: Orlandi
authors: Department of Biostatistics and Epidemiology, Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
authors: Lisa
authors: L
authors: Nessel
authors: Division of Pediatric Nephrology, Children's Hospital of Philadelphia, Philadelphia, USA.
authors: Susan L
authors: SL
authors: Furth
authors: Centre for Chronic Disease, School of Medicine, University of Queensland, Brisbane, Queensland, Australia.
authors: Wendy E
authors: WE
authors: Hoy
authors: Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors: Seiichi
authors: S
authors: Matsuo
authors: Nephrology and Hypertension, Innsbruck Medical University, Innsbruck, Austria.
authors: Gert
authors: G
authors: Mayer
authors: School of Clinical Sciences, University of Bristol, Southmead Hospital, Westbury-on-Trym, Bristol, UK.
authors: Shona
authors: S
authors: Methven
authors: Division of Pediatric Nephrology, Center for Pediatrics and Adolescent Medicine, University of Heidelberg, Heidelberg, Germany.
authors: Franz
authors: F
authors: Schaefer
authors: Institute of Public Health, Charite University Medicine, Berlin, Germany.
authors: Elke S
authors: ES
authors: Schaeffner
authors: Directora Division Epidemiologia, DIGESA-Ministerio Salud Publica, Montevideo, Uruguay.
authors: Laura
authors: L
authors: Solá
authors: Université Paris-Saclay, Univ Paris-Sud, UVSQ, CESP, Centre for Research in Epidemiology and Population Health, Inserm, F-CRIN-INI-CRCT, Villejuif, France.
authors: Bénédicte
authors: B
authors: Stengel
authors: Department of Internal Medicine I, Division of Nephrology, University of Würzburg, Würzburg, Germany.
authors: Christoph
authors: C
authors: Wanner
authors: Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, China.
authors: Luxia
authors: L
authors: Zhang
authors: Division of Nephrology, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors: Adeera
authors: A
authors: Levin
authors: Department of Nephrology and Hypertension, University of Erlangen-Nürnberg, Erlangen, Germany.
authors: Kai-Uwe
authors: KU
authors: Eckardt
authors: Department of Biostatistics and Epidemiology, Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA. hfeldman@mail.med.upenn.edu.|Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, USA. hfeldman@mail.med.upenn.edu.
authors: Harold I
authors: HI
authors: Feldman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D035843:Biomedical Research / Q000193:education / Q000458:organization & administration; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005500:Follow-Up Studies; D014943:Global Health; D006801:Humans; D007391:International Cooperation; D007676:Kidney Failure, Chronic / Q000453:epidemiology / Q000503:physiopathology; D008875:Middle Aged; D064887:Observational Studies as Topic; D011446:Prospective Studies; D012042:Registries; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology* / Q000401:mortality / Q000503:physiopathology; D012107:Research Design; D012720:Severity of Illness Index; D060756:Social Networking; D055815:Young Adult
keywords: CKD; Cohort study; Diversity; Epidemiology; Network