A longitudinal examination of a pay-for-performance program for diabetes care: evidence from a natural experiment.

BACKGROUND: Numerous studies have examined the impacts of pay-for-performance programs, yet little is known about their long-term effects on health care expenses.
OBJECTIVES: This study aimed to examine the long-term effects of a pay-for-performance program for diabetes care on health care utilization and expenses.
METHODS: This study represents a nationwide population-based natural experiment with a 4-year follow-up period under a compulsory universal health insurance program in Taiwan. The intervention groups consisted of 20,934 patients enrolled in the program in 2005, and 9694 patients continuously participated in the program for 4 years. Two comparison groups were selected by propensity score matching from patients seen by the same group of physicians. Generalized estimating equations were used to estimate differences-in-differences models to examine the effects of the pay-for-performance program.
RESULTS: Patients enrolled in the pay-for-performance program underwent significantly more diabetes specific examinations and tests after enrollment; the differences between the intervention and comparison groups declined gradually over time but remained significant. Patients in the intervention groups had a significantly higher number of diabetes-related physician visits in only the first year after enrollment and had fewer diabetes-related hospitalizations in the follow-up period. Concerning overall health care expenses, patients in the intervention groups spent more than the comparison group in the first year; however, the continual enrollees spent significantly less than their counterparts in the subsequent years.
CONCLUSIONS: The program seemed to achieve its primary goal in improving health care and providing long-term cost benefits.