title: Methodology used in studies reporting chronic kidney disease prevalence: a systematic literature review.
abstract: BACKGROUND
  Many publications report the prevalence of chronic kidney disease (CKD) in the general population. Comparisons across studies are hampered as CKD prevalence estimations are influenced by study population characteristics and laboratory methods.
  
  
  METHODS
  For this systematic review, two researchers independently searched PubMed, MEDLINE and EMBASE to identify all original research articles that were published between 1 January 2003 and 1 November 2014 reporting the prevalence of CKD in the European adult general population. Data on study methodology and reporting of CKD prevalence results were independently extracted by two researchers.
  
  
  RESULTS
  We identified 82 eligible publications and included 48 publications of individual studies for the data extraction. There was considerable variation in population sample selection. The majority of studies did not report the sampling frame used, and the response ranged from 10 to 87%. With regard to the assessment of kidney function, 67% used a Jaffe assay, whereas 13% used the enzymatic assay for creatinine determination. Isotope dilution mass spectrometry calibration was used in 29%. The CKD-EPI (52%) and MDRD (75%) equations were most often used to estimate glomerular filtration rate (GFR). CKD was defined as estimated GFR (eGFR) <60 mL/min/1.73 m(2) in 92% of studies. Urinary markers of CKD were assessed in 60% of the studies. CKD prevalence was reported by sex and age strata in 54 and 50% of the studies, respectively. In publications with a primary objective of reporting CKD prevalence, 39% reported a 95% confidence interval.
  
  
  CONCLUSIONS
  The findings from this systematic review showed considerable variation in methods for sampling the general population and assessment of kidney function across studies reporting CKD prevalence. These results are utilized to provide recommendations to help optimize both the design and the reporting of future CKD prevalence studies, which will enhance comparability of study results.
authors.affiliation: ERA-EDTA Registry, Amsterdam Medical Center, Amsterdam, The Netherlands.
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authors.lastname: Brück
authors.affiliation: ERA-EDTA Registry, Amsterdam Medical Center, Amsterdam, The Netherlands.
authors.forename: Kitty J
authors.initials: KJ
authors.lastname: Jager
authors.affiliation: Department of Nephrology, Medical School, University of Ioannina, Ioannina, Greece.
authors.forename: Evangelia
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authors.affiliation: Department of Internal Medicine III/Nephrology, Medical University, Vienna, Austria.
authors.forename: Alexander
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authors.affiliation: Epidemiology and Population Health, LSHTM and UCL Centre for Nephrology, London, UK.
authors.forename: Dorothea
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authors.affiliation: Department of Medical Sciences/Molecular Epidemiology, Uppsala University, Uppsala, Sweden.
authors.forename: Johan
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authors.affiliation: Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany.
authors.forename: Dietrich
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authors.affiliation: Department of Epidemiology & Public Health, University College Cork, Ireland.
authors.forename: Gemma
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authors.affiliation: Unità Opaerativa di Cardiologia ed UTIC, Mercato S. Severino Hospital, Mercato S. Severino, Italy.
authors.forename: Vincenzo
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authors.lastname: Capuano
authors.affiliation: Nephrology and Dialysis, Columbus-Gemelli University Hospital, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Pietro Manuel
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authors.affiliation: Department of Cardiology, Toulouse University School of Medicine, Rangueil Hospital, Toulouse, France.
authors.forename: Jean
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authors.lastname: Ferrieres
authors.affiliation: Nephrology and Dialysis, Columbus-Gemelli University Hospital, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Giovanni
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authors.affiliation: Unit of Population Epidemiology, Division of primary care medicine, Department of Community Medicine, Primary Care and Emergency Medicine, Geneva University Hospital, Geneva, Switzerland.
authors.forename: Idris
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authors.lastname: Guessous
authors.affiliation: Department of Nephrology, St Olav Hospital, Norway/Faculty of Medicine, The Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
authors.forename: Stein
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authors.affiliation: Finnish Medicines Agency, Kuopio/National Institute for Health and Welfare, Helsinki, Finland.
authors.forename: Mika
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authors.affiliation: Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, Groningen, The Netherlands.
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authors.affiliation: Department of Nephrology, University Hospital of Ourense, Ourense, Spain.
authors.forename: Alfonso Otero
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authors.lastname: Gonzalez
authors.affiliation: Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Luigi
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authors.lastname: Palmieri
authors.affiliation: Department of Nephrology, Levanger Hospital, Health Trust Nord-Trøndelag/The Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
authors.forename: Solfrid
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authors.lastname: Romundstad
authors.affiliation: Department of Nephrology, Dialysis and Transplantation Unit, CNR-IFC, Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Reggio Calabria, Italy.
authors.forename: Belinda
authors.initials: B
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authors.affiliation: Research Centre in Epidemiology and Population Health, Inserm Unit 1018, Villejuif, France.
authors.forename: Benedicte
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authors.lastname: Stengel
authors.affiliation: Department of Nephrology, Freeman Hospital, Newcastle upon Tyne, UK.
authors.forename: Charles
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authors.lastname: Tomson
authors.affiliation: Department of Nephrology, Dialysis and Transplantation Unit, CNR-IFC, Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Reggio Calabria, Italy.
authors.forename: Giovanni
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authors.lastname: Tripepi
authors.affiliation: Institute for Community Medicine, University Medicine Greifswald, Greifswald, Germany.
authors.forename: Henry
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authors.lastname: Völzke
authors.affiliation: Departement of Nephrology, Transplantology and Internal Diseases, Faculty of Medicine in Katowice, Medical University of Silesia in Katowice, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Wiȩcek
authors.affiliation: Department of Nephrology/Graduate School of Medical Sciences, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Ron
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authors.lastname: Gansevoort
authors.affiliation: Division of Clinical Epidemiology and Ageing Research, German Cancer Research, Heidelberg, Germany.
authors.forename: Ben
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authors.lastname: Schöttker
authors.affiliation: Department of Nephrology, University Hospital Würzburg, Würzburg, Germany.
authors.forename: Christoph
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authors.lastname: Wanner
authors.affiliation: Department of Nephrology, Setubal Hospital Centre, Setubal, Portugal.
authors.forename: Jose
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authors.affiliation: Department of Nephrology, Dialysis and Transplantation Unit, CNR-IFC, Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Reggio Calabria, Italy.
authors.forename: Carmine
authors.initials: C
authors.lastname: Zoccali
authors.affiliation: Department of Nephrology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Van Biesen
authors.affiliation: ERA-EDTA Registry, Amsterdam Medical Center, Amsterdam, The Netherlands.
authors.forename: Vianda S
authors.initials: VS
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mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis*; D002138:Calibration; D005060:Europe / Q000453:epidemiology; D005919:Glomerular Filtration Rate; D006801:Humans; D015995:Prevalence; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology* / Q000503:physiopathology*; D012494:Sampling Studies
chemical_list: D015415:Biomarkers
keywords: CKD; CKD-EPI equation; MDRD; epidemiology; systematic review