Pay-for-performance and continuity of care synergistically reduced amputation of lower extremity in patients with diabetes: a population-based cohort study

BACKGROUND: Diabetic foot is a common and costly complication of diabetes. No existing study has looked at the effect of continuity of care on amputations of diabetes (DM) patients while considering pay-for-performance (P4P) participation. We investigated the impact of the P4P program and the continuity of care index (COCI) on the incidence of lower extremity amputations (LEA) among diabetics in Taiwan. METHODS: This was a population-based cohort study using insurance claims data from 1997 to 2013. We selected 15,650 DM patients in the P4P program along with age- and sex-matched non-P4P participants at a 1:4 ratio. Time-weighted average (TWA) of the COCI was calculated and included in the time-dependent Cox proportional hazard models to examine the impact of P4P and COCI on the risk of LEA, while controlling for individual and area level characteristics. RESULTS: During four-year follow-up, 1816 subjects experienced LEA. The cumulative LEA hazard rate of the P4P group (n = 153) was significantly lower than that of the non-P4P group (n = 1663) (hazard ratio = 0.37, 95% CI = 0.31–0.43, p < 0.0001, by log-rank test). In the time-dependent Cox proportional hazard model, the adjusted hazard ratios (aHR) for the P4P group was 0.35, (p < 0.0001). With the low COCI (< 0.360) group as the reference, the aHR of LEA was 0.49 (p < 0.0001) for the middle COCI group, (p < 0.0001), and the aHR of LEA for the high COCI (≥0.643) group was 0.23 (p < 0.0001). CONCLUSIONS: Participating in the P4P program and increasing COCI might reduce the risk of amputation for DM patients, independently and synergistically. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12913-022-08075-2.