Effects of the per diem prospective payment system with DRG-like grouping system (DPC/PDPS) on resource usage and healthcare quality in Japan

Abstract

Objectives: In 2003, Japan introduced the prospective payment system (PPS) with diagnosis-related groups (DRG) rearranged grouping system called the diagnostic procedure combination/per-diem payment system (DPC/PDPS). Even after eight years, little is known about the effects of DPC/PDPS. The purpose of this study was to examine the effects of DPC/PDPS on resource usage and healthcare quality.

Methods: Using 2001-2009 (fiscal year) administrative data of acute myocardial infarction patients, four indices, including inpatient total accumulated medical charges, length of stay (LOS), mortality rate, and readmission rate, were compared between patients reimbursed by DPC/PDPS or by fee-for-service.

Results: DPC/PDPS significantly reduced total accumulated medical charges by $1061 (95% confidence interval [CI], -2007, -116) and LOS by 2.29 days (95% CI, -3.71, -0.88) after risk adjustment. However, mortality rate (Odds ratio [OR], 0.94; 95% CI, 0.73, 1.21) was unchanged. Furthermore, DPC/PDPS increased the readmission rate (OR, 1.37; 95% CI, 1.03, 1.82).

Conclusions: This study showed that DPC/PDPS was associated with reduced resource usage, but not improved healthcare quality, as with DRG/PPSs in other countries. To achieve successful healthcare reform, further discussion on additional motives will be required.