title: Use of Medicare data to identify coronary heart disease outcomes in the Women's Health Initiative.
abstract: BACKGROUND
  Data collected as part of routine clinical practice could be used to detect cardiovascular outcomes in pragmatic clinical trials or clinical registry studies. The reliability of claims data for documenting outcomes is unknown.
  
  
  RESULTS
  We linked records of Women's Health Initiative (WHI) participants aged ≥65 years to Medicare claims data and compared hospitalizations that had diagnosis codes for acute myocardial infarction or coronary revascularization with WHI outcomes adjudicated by study physicians. We then compared the hazard ratios for active versus placebo hormone therapy based solely on WHI-adjudicated events with corresponding hazard ratios based solely on claims data for the same hormone trial participants. Agreement between WHI-adjudicated outcomes and Medicare claims was good for the diagnosis of myocardial infarction (κ, 0.71-0.74) and excellent for coronary revascularization (κ, 0.88-0.91). The hormone:placebo hazard ratio for clinical myocardial infarction was 1.31 (95% confidence interval, 1.03-1.67) based on WHI outcomes and 1.29 (95% confidence interval, 1.00-1.68) based on Medicare data. The hazard ratio for coronary revascularization was 1.09 (95% confidence interval, 0.88-1.35) based on WHI outcomes and 1.10 (95% confidence interval, 0.89-1.35) based on Medicare data. The differences between hazard ratios derived from WHI and Medicare data were not significant in 1000 bootstrap replications.
  
  
  CONCLUSIONS
  Medicare claims may provide useful data on coronary heart disease outcomes among patients aged ≥65 years in clinical research studies.
  
  
  BACKGROUND
  URL: www.clinicaltrials.gov. Unique identifier: NCT00000611.
authors.affiliation: Stanford University School of Medicine, Stanford, CA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hlatky
authors.forename: Roberta M
authors.initials: RM
authors.lastname: Ray
authors.forename: Dale R
authors.initials: DR
authors.lastname: Burwen
authors.forename: Karen L
authors.initials: KL
authors.lastname: Margolis
authors.forename: Karen C
authors.initials: KC
authors.lastname: Johnson
authors.forename: Anna
authors.initials: A
authors.lastname: Kucharska-Newton
authors.forename: JoAnn E
authors.initials: JE
authors.lastname: Manson
authors.forename: Jennifer G
authors.initials: JG
authors.lastname: Robinson
authors.forename: Monika M
authors.initials: MM
authors.lastname: Safford
authors.forename: Matthew
authors.initials: M
authors.lastname: Allison
authors.forename: Themistocles L
authors.initials: TL
authors.lastname: Assimes
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Bavry
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Berger
authors.forename: Rhonda M
authors.initials: RM
authors.lastname: Cooper-DeHoff
authors.forename: Susan R
authors.initials: SR
authors.lastname: Heckbert
authors.forename: Wenjun
authors.initials: W
authors.lastname: Li
authors.forename: Simin
authors.initials: S
authors.lastname: Liu
authors.forename: Lisa W
authors.initials: LW
authors.lastname: Martin
authors.forename: Marco V
authors.initials: MV
authors.lastname: Perez
authors.forename: Hilary A
authors.initials: HA
authors.lastname: Tindle
authors.forename: Wolfgang C
authors.initials: WC
authors.lastname: Winkelmayer
authors.forename: Marcia L
authors.initials: ML
authors.lastname: Stefanick
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014487:Centers for Medicare and Medicaid Services, U.S. / Q000706:statistics & numerical data*; D003327:Coronary Disease / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy*; D004967:Estrogens / Q000627:therapeutic use; D005260:Female; D020249:Hormone Replacement Therapy / Q000706:statistics & numerical data; D006801:Humans; D007345:Insurance Claim Review; D006278:Medicare / Q000706:statistics & numerical data*; D009203:Myocardial Infarction / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D063868:Patient Outcome Assessment; D062645:Percutaneous Coronary Intervention / Q000706:statistics & numerical data; D011372:Progestins / Q000627:therapeutic use; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome; D014481:United States; D016387:Women's Health / Q000706:statistics & numerical data*
chemical_list: D004967:Estrogens; D011372:Progestins
keywords: myocardial infarction; patient outcome assessment; pragmatic clinical trials; randomized controlled trials; validation studies