Do well-publicized risk-adjusted outcomes reports affect hospital volume?

Abstract

Report cards on hospital performance are common but have uncertain impact. The objective of this study was to determine whether hospitals recognized as performance outliers experience volume changes after publication of a report card. Secondary objectives were to test whether favorable outliers attract more patients with related conditions, or from outside their catchment areas; and whether disadvantaged groups are less responsive to report cards. We used a time-series analysis using linear and autoregressive models. We studied patients admitted to nonfederal hospitals designated as outliers in reports on coronary bypass surgery (CABG) mortality in New York, acute myocardial infarction (AMI) mortality in California, and postdiskectomy complications in California. We studied observed versus expected hospital volume for topic and related conditions and procedures, by month/quarter after a report card, with and without stratification by age, race/ethnicity, insurance, and catchment area. Potential confounders included statewide prevalence, prereport hospital volume and market share, and unrelated volume. In California, low-mortality and high-mortality outliers did not experience changes in AMI volume after adjusting for autocorrelation. Low-complication outliers for lumbar diskectomy experienced slightly increased volume in autoregressive models. No other cohorts demonstrated consistent trends. In New York, low-mortality outliers experienced significantly increased CABG volume in the first month after publication, whereas high-mortality outliers experienced decreased volume in the second month. The strongest effects were among white patients and those with HMO coverage in California, and among white or other patients and those with Medicare in New York. Volume effects were modest, transient, and largely limited to white Medicare patients in New York.