title: Prevalence of reduced kidney function and albuminuria in older adults: the Berlin Initiative Study.
abstract: BACKGROUND
  Although CKD is said to increase among older adults, epidemiologic data on kidney function in people ≥70 years of age are scarce. The Berlin Initiative Study (BIS) aims to fill this gap by evaluating the CKD burden in older adults.
  
  
  METHODS
  The BIS is a prospective population-based cohort study whose participants are members of Germany's biggest insurance company. This cross-sectional analysis (i) gives a detailed baseline characterization of the participants, (ii) analyses the representativeness of the cohort's disease profile, (iii) assesses GFR and albuminuria levels across age categories, (iv) associates cardiovascular risk factors with GFR as well as albuminuria and (v) compares means of GFR values according to different estimating equations with measured GFR.
  
  
  RESULTS
  A total of 2069 participants (52.6% female, mean age 80.4 years) were enrolled: 26.1% were diabetic, 78.8% were on antihypertensive medication, 8.7% had experienced a stroke, 14% a myocardial infarction, 22.6% had cancer, 17.8% were anaemic and 26.5% were obese. The distribution of comorbidities in the BIS cohort was very similar to that in the insurance 'source population'. Creatinine and cystatin C as well as the albumin:creatinine ratio (ACR) increased with increasing age. After multivariate adjustments, reduced GFR and elevated ACR were associated with most cardiovascular risk factors. The prevalence of a GFR <60 mL/min/1.73 m 2 ranged from 38 to 62% depending on the estimation equation used.
  
  
  CONCLUSIONS
  The BIS is a very well-characterized, representative cohort of older adults. Participants with an ACR ≥30 had significantly higher odds for most cardiovascular risk factors compared with an ACR <30 mg/g. Kidney function declined and ACR rose with increasing age.
authors.affiliation: Institute of Public Health, Charité University Medicine, Campus Virchow, Berlin, Germany.
authors.forename: Natalie
authors.initials: N
authors.lastname: Ebert
authors.affiliation: Institute for Biostatistics and Clinical Epidemiology, Charité University Medicine, Campus Benjamin Franklin, Berlin, Germany.
authors.forename: Olga
authors.initials: O
authors.lastname: Jakob
authors.affiliation: Department of Nephrology, Charité University Medicine, Campus Mitte Berlin, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Gaedeke
authors.affiliation: Department of Nephrology, Charité University Medicine, Campus Benjamin Franklin, Berlin, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: van der Giet
authors.affiliation: Department of Nephrology, Vivantes Klinikum im Friedrichshain, Berlin, Germany.
authors.forename: Martin K
authors.initials: MK
authors.lastname: Kuhlmann
authors.affiliation: Institute of Clinical Epidemiology and Medical Biostatistics, Friedrich Karls-University, Tübingen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Martus
authors.affiliation: Institute of Public Health, Charité University Medicine, Campus Virchow, Berlin, Germany.
authors.forename: Nina
authors.initials: N
authors.lastname: Mielke
authors.affiliation: Department of Nephrology, Charité University Medicine, Campus Benjamin Franklin, Berlin, Germany.
authors.forename: Mirjam
authors.initials: M
authors.lastname: Schuchardt
authors.affiliation: Department of Nephrology, Charité University Medicine, Campus Benjamin Franklin, Berlin, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Tölle
authors.affiliation: AOK-Nordost - die Gesundheitskasse, Berlin, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Wenning
authors.affiliation: Institute of Public Health, Charité University Medicine, Campus Virchow, Berlin, Germany.
authors.forename: Elke S
authors.initials: ES
authors.lastname: Schaeffner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000419:Albuminuria / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D001604:Berlin / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology / Q000503:physiopathology; D015897:Comorbidity; D003404:Creatinine / Q000097:blood; D003430:Cross-Sectional Studies; D055316:Cystatin C / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D015995:Prevalence; D011446:Prospective Studies; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D012307:Risk Factors
chemical_list: D055316:Cystatin C; D003404:Creatinine
keywords: GFR; albuminuria; chronic kidney disease; cohort; older adults