Assessment of the introduction of DRG-based reimbursement in Switzerland: Evidence on the short-term effects on length of stay compliance in university hospitals

The implementation of a nationwide diagnosis-related groups (DRG) reimbursement system in 2012 marked an important step in increasing the transparency and efficiency of hospital services in Switzerland. However, no clear evidence exists to date on the response of hospitals to the introduction of SwissDRG. Using administrative data on inpatient stays in Swiss university hospitals and the length of stay compliance (LOSC) as a measure of hospital performance, we find a significant short-term reduction in LOSC for hospitals that experienced a change from retrospective per diem to prospective DRG reimbursement, compared to hospitals with a prospective payment system already before 2012. LOSC can be interpreted as a performance indicator because it compares the actual length of stay with a benchmark value, taken from the yearly DRG catalogue. The reduction in LOSC implies that hospitals in the treatment group on average had an increase in LOS relative to the benchmark compared to the control hospitals. This may be interpreted as a negative effect of SwissDRG on hospital performance, at least in the short-run, and we provide supporting evidence that hospitals that worked under DRG already before adapted more quickly and efficiently.