The effect of market reform on racial differences in hospital mortality.

Objective: To determine whether racial differences in hospital mortality worsened after implementation of a New Jersey law in 1993 that reduced subsidies for uninsured hospital care and changed hospital payment from rate regulation to price competition.

Data Sources/study Setting: State discharge data for New Jersey and New York from 1990 to 1996.

Study Design: We used an interrupted time series design to compare risk-adjusted in-hospital mortality rates between states over time. Adjusting for patient characteristics, baseline interstate differences, and common intertemporal trends, we compared the effect sizes for whites and blacks in the following 4 groups: overall, uninsured, insured under age 65, and Medicare patients.

Data Collection/extraction Methods: The study sample included 1,357,394 patients admitted to New Jersey or New York hospitals between 1990 to 1996 with stroke, hip fracture, pneumonia, pulmonary embolism, congestive heart failure, or acute myocardial infarction (AMI).

Principal Findings: The increase in mortality in New Jersey versus New York was significantly larger among blacks than among whites for AMI (2.4% points vs 0.1% points, P-value for difference .026) but not for the other 6 conditions. In groupings of conditions for which hospital admission is non-discretionary and conditions in which admission is discretionary, we found qualitatively larger increases in mortality for blacks but no statistically significant racial differences among patients overall, uninsured patients, insured patients under age 65, or Medicare patients.

Conclusions: Market-based reform and reductions in subsidies for hospital care for the uninsured in New Jersey were associated with worsening racial disparities in in-hospital mortality for AMI but not for 6 other common conditions.