Impact of payment method on behaviour of primary care physicians: a systematic review.

OBJECTIVE: To review the impact of payment systems on the behaviour of primary care physicians.
METHODS: All randomised trials, controlled before and after studies, and interrupted time series studies that compared capitation, salary, fee-for-service or target payments (mixed or separately) that were identified by computerised searches of the literature. Methodological quality assessment and data extraction were undertaken independently by two reviewers using a data checklist. Study results were qualitatively analysed.
RESULTS: Six studies met the inclusion criteria. There was considerable variation in the quality of reporting, study setting and the range of outcomes measured. Fee-for-service resulted in a higher quantity of primary care services provided compared with capitation but the evidence of the impact on the quantity of secondary care services was mixed. Fee-for-service resulted in more patient visits, greater continuity of care, higher compliance with a recommended number of visits, but lower patient satisfaction with access to a physician compared with salary payment. The evidence of the impact of target payment on immunisation rates was inconclusive.
CONCLUSIONS: There is some evidence to suggest that how a primary care physician is paid does affect his/her behaviour but the generalisability of these studies is unknown. Most policy changes in the area of payment systems are inadequately informed by research. Future changes to doctor payment systems need to be rigorously evaluated.