title: Can managed care plans reliably infer the quality of cardiac surgeons' outcomes?
abstract: OBJECTIVE
  To assess whether managed care plans can reliably infer the quality of cardiac surgeons' outcomes.
  
  
  METHODS
  Evaluation of administrative discharge data and reported health plan enrollments.
  
  
  METHODS
  We analyzed 221,327 coronary artery bypass graft (CABG) admissions performed by 398 cardiac surgeons in 75 state-regulated hospitals in Florida between 1998 and 2006. For our outcomes quality measure, we constructed surgeon-level risk-adjusted mortality rates using demographic and comorbidity data. We also obtained managed care plan enrollments in Florida in 2005 to discern the number of patient outcomes possibly seen by any individual plan. Finally, we constructed a confidence interval around any particular surgeon's CABG outcomes quality and tested whether the surgeon's quality could reliably be found to be worse than benchmarks using normal approximations and exact binomial limits.
  
  
  RESULTS
  Even if a plan had as high as a 50% share of a county's managed care-insured CABG patients, then of 86 surgeons in the 5 largest counties in Florida, no surgeon could confidently be judged to be of poorer than average quality.
  
  
  CONCLUSIONS
  In cardiac surgeons' outcomes quality monitoring, individual managed care plans face a "law of small numbers." Insufficient patient volume by contracted surgeons, inadequate variation in outcomes, and low levels of adverse outcomes combine to make true quality almost impossible to infer. Some mitigation may be possible through more effective use of data (more measures and pooling over time) and through more effective interorganizational sharing of data (leveraging specialist society quality data and statewide pooling).
authors.affiliation: Department of Community and Family Medicine, Duke University, Box 90120, Durham, NC 27708, USA. m.huesch@duke.edu
authors.forename: Marco D
authors.initials: MD
authors.lastname: Huesch
mesh_terms: D016001:Confidence Intervals; D001026:Coronary Artery Bypass / Q000401:mortality / Q000592:standards*; D005431:Florida / Q000453:epidemiology; D006801:Humans; D008329:Managed Care Programs / Q000458:organization & administration*; D010351:Patient Discharge; D019984:Quality Indicators, Health Care; D015203:Reproducibility of Results; D016896:Treatment Outcome; D014481:United States