Do public hospitals respond to changes in DRG price regulation? The case of birth deliveries in the Italian NHS

We study how changes in Diagnosis-Related Group price regulation affect hospital behaviour in quasi-markets with exclusive provision by public hospitals. Exploiting a quasi-natural experiment, we use a difference-in-differences approach to test whether public hospitals respond to an exogenous change in Diagnosis-Related Group tariffs by increasing C-section rates and/or by upcoding. Controlling for a detailed set of mother characteristics, we find that price changes did not affect the probability of a C-section. We do however find evidence of upcoding: Conditional on the birth delivery method (either a C-section or a vaginal delivery), public hospitals experiencing the largest price change exhibit a higher probability of treating patients coded as complicated. This finding suggests that even public hospitals may be sensitive to market incentives.