Objective: To examine the association between preventable hospitalization rates and proportions of managed care enrollment at the primary care service area level.
Study design: Multivariate design.
Methods: The study used the Healthcare Cost and Utilization Project State Inpatient Data from the Agency for Healthcare Research and Quality for Arizona, Massachusetts, and New York for the years 1995 and 2005 to examine the association between preventable hospitalization rates and proportions of managed care enrollment in 1995 and 2005. The period 1995-2005 was marked by the beginning and end of several legislative and policy initiatives causing changes in elderly hospitalization patterns as well as Medicare managed care enrollment patterns. The study used ordinary least squares regressions, adjusting for heteroscedasticity. A cross-sectional analysis was used to examine the association each year. A pooled sample analysis over years tested the changes in relative contributions of managed care over time.
Results: Preventable hospitalization rates were inversely associated with Medicare managed enrollment in both years. This association was, however, found to be weaker in 2005 than in 1995. The decline in contributions of managed care was also statistically significant.
Conclusions: Despite increased managed care enrollment, the role of Medicare managed care in explaining declines in preventable hospitalization rates diminished over time. The results could be explained by the growth of private fee-for-service types of managed care plans and the resultant decline in emphasis on care coordination relative to health maintenance organization plans.