title: Validation study of medicare claims to identify older US adults with CKD using the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study.
abstract: BACKGROUND
  Health care claims data may provide a cost-efficient approach for studying chronic kidney disease (CKD).
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  We compared characteristics and outcomes for individuals with CKD defined using laboratory measurements versus claims data from 6,982 REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study participants who had Medicare fee-for-service coverage.
  
  
  METHODS
  Presence of CKD as defined by both the REGARDS Study (CKDREGARDS) and Medicare data (CKDMedicare), presence of CKDREGARDS but not CKDMedicare, and presence of CKDMedicare but not CKDREGARDS, and absence of both CKDREGARDS and CKDMedicare.
  
  
  RESULTS
  Mortality and incident end-stage renal disease (ESRD).
  
  
  METHODS
  The research study definition of CKD (CKDREGARDS) included estimated glomerular filtration rate (eGFR) < 60mL/min/1.73m(2) or albumin-creatinine ratio > 30mg/g at the REGARDS Study visit. CKD in Medicare (CKDMedicare) was identified during the 2 years before each participant's REGARDS visit using a claims-based algorithm.
  
  
  RESULTS
  Overall, 32% of participants had CKDREGARDS and 6% had CKDMedicare. Sensitivity, specificity, and positive and negative predictive values of CKDMedicare for identifying CKDREGARDS were 15.5% (95% CI, 14.0%-17.1%), 97.7% (95% CI, 97.2%-98.1%), 75.6% (95% CI, 71.4%-79.5%), and 71.5% (95% CI, 70.4%-72.6%), respectively. Mortality and ESRD incidence rates, expressed per 1,000 person-years, were higher for participants with versus without CKDMedicare (mortality: 72.5 [95% CI, 61.3-83.7] vs 33.3 [95% CI, 31.5-35.2]; ESRD: 16.4 [95% CI, 11.2-21.6] vs 1.3 [95% CI, 0.9-1.6]) and with versus without CKDREGARDS (mortality: 59.9 [95% CI, 55.4-64.4] vs 25.5 [95% CI, 23.6-27.4]; ESRD: 6.8 [95% CI, 5.4-8.3] vs 0.1 [95% CI, 0.0-0.3]). Among participants with CKDREGARDS, those with abdominal obesity, diabetes, anemia, lower eGFR, more outpatient visits, hospitalization, and a nephrologist visit in the 2 years before their REGARDS visit were more likely to have CKDMedicare.
  
  
  CONCLUSIONS
  CKDREGARDS relied on eGFR and albuminuria assessed at a single visit.
  
  
  CONCLUSIONS
  CKD, whether defined in claims or through research study measurements, was associated with increased mortality and ESRD. However, individuals with CKD identified in claims may represent a select high-risk population.
authors.affiliation: Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL. Electronic address: pmuntner@uab.edu.
authors.forename: Paul
authors.initials: P
authors.lastname: Muntner
authors.affiliation: Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL; Department of Medicine, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Orlando M
authors.initials: OM
authors.lastname: Gutiérrez
authors.affiliation: Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhao
authors.affiliation: National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA; Department of Endocrinology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
authors.forename: Caroline S
authors.initials: CS
authors.lastname: Fox
authors.affiliation: Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Nicole C
authors.initials: NC
authors.lastname: Wright
authors.affiliation: Department of Medicine, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Curtis
authors.affiliation: Department of Epidemiology, Emory University, Atlanta, GA.
authors.forename: William
authors.initials: W
authors.lastname: McClellan
authors.affiliation: Department of Emergency Medicine, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Henry
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Healthcare Organization and Policy, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Meredith
authors.initials: M
authors.lastname: Kilgore
authors.affiliation: Department of Medicine, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: David G
authors.initials: DG
authors.lastname: Warnock
authors.affiliation: Atlanta VA Medical Center, Atlanta, GA; Department of Medicine, Emory University, Atlanta, GA.
authors.forename: C Barrett
authors.initials: CB
authors.lastname: Bowling
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007344:Insurance Claim Reporting / Q000592:standards*; D008297:Male; D006278:Medicare / Q000592:standards*; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods; D011446:Prospective Studies; D044469:Racial Groups / Q000208:ethnology*; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis / Q000191:economics / Q000208:ethnology*; D020521:Stroke / Q000175:diagnosis / Q000191:economics / Q000208:ethnology*; D014481:United States / Q000208:ethnology
keywords: Chronic kidney disease (CKD); albuminuria; claims-based algorithm; end-stage renal disease (ESRD); estimated glomerular filtration rate (eGFR); health care claims data; predictive value; sensitivity; specificity