Impact of medical reimbursement revision on ambulance transport of self‐inflicted injury patients: a nationwide study in Japan

AIM: Self‐inflicted injury, as one reason to visit the emergency department, is an important issue in emergency medicine around the world. However, the impact of changes in social systems, such as medical reimbursement revision, on ambulance transport for self‐inflicted injury remains unclear. The aim of this study was to assess the impact of medical reimbursement revision on the emergency transport of self‐inflicted injury patients using nationwide ambulance records. METHODS: This was a retrospective observational study from April 2012 to March 2016. We analyzed nationwide ambulance records in Japan, and included self‐inflicted injury, drug poisoning, and drug overdose patients transported to hospitals by ambulance. The primary outcome of this study was age‐adjusted number of self‐inflicted injury patients transported by ambulance in each month per 1 million standard populations. To assess the impact of the medical reimbursement revision in 2014, we calculated the R (2), regression coefficients and 95% confidence interval (CI) using interrupted time series analysis. RESULTS: This study included 148,873 patients. The R (2) for the interrupted time series model was 0.821. The regression coefficient for the time trend before the medical reimbursement revision was 0.167 (95% CI, 0.090 to 0.244; p < 0.001), that for the time trend after the medical reimbursement revision was −0.226 (95% CI, −0.327 to −0.125, p < 0.001), and that of the medical reimbursement revision was −2.165 (95% CI, −3.730 to −0.601, p = 0.008). CONCLUSION: In Japan, the medical reimbursement revision in April 2014 helped to decrease the number of self‐inflicted injury patients transported to hospitals by ambulance.