Do Medicare Advantage enrollees tend to be admitted to hospitals with better or worse outcomes compared with fee-for-service enrollees?

Bernard Friedman, H. Joanna Jiang

The hospitals selected by or for Medicare beneficiaries might depend on whether the patient is enrolled in a Medicare Advantage (MA) plan. A theoretical model of profit maximization by MA plans takes into account the tradeoffs of consumer preferences for annual premium versus outcomes of care in the hospital and other attributes of the plan. Hospital discharge databases for 13 states in 2006, maintained by the Agency for Healthcare Research and Quality, are the main source of data. Risk-adjusted mortality rates are available for all non-maternity adult patients in each of 15 clinical categories in about 1,500 hospitals. All-adult postoperative safety event rates covering 9 categories of events are calculated for surgical cases in about 900 hospitals. Instrumental variables are used to address potential endogeneity of the choice of a MA plan. The key findings are these: enrollees in MA plans tend to be treated in hospitals with lower resource cost and higher risk-adjusted mortality compared to Fee-for-Service (FFS) enrollees. The risk-adjusted mortality measure is about 1.5 percentage points higher for MA plan enrollees than the overall mean of 4%. However, the rate of safety events in surgical patients favors MA plan enrollees--the rate is 1 percentage point below the average of 3.5%. These discrepant results are noteworthy and are plausibly due to greater discretion by the health plan in approving patients for elective surgery and as well as selecting hospitals for surgical patients. Emergency patients are generally excluded for the safety outcome measures. In addition, the current mortality measures may not adequately represent all surgical patients. Such caveats should be prominently highlighted when presenting comparative data. With that proviso, the study justifies informing Medicare beneficiaries about the mortality and safety outcome measures for hospitals being used by a MA plan compared to hospitals used by FFS enrollees.