Differences in inpatient performance of public general hospitals following implementation of a points-counting payment based on diagnosis-related group: a robust multiple interrupted time series study in Wenzhou, China

ObjectivesThis study measures the differences in inpatient performance after a points-counting payment policy based on diagnosis-related group (DRG) was implemented. The point value is dynamic; its change depends on the annual DRGs’ cost settlements and points of the current year, which are calculated at the beginning of the following year.DesignA longitudinal study using a robust multiple interrupted time series model to evaluate service performance following policy implementation.SettingTwenty-two public general hospitals (8 tertiary institutions and 14 secondary institutions) in Wenzhou, China.InterventionThe intervention was implemented in January 2020.Outcome measuresThe indicators were case mix index (CMI), cost per hospitalisation (CPH), average length of stay (ALOS), cost efficiency index (CEI) and time efficiency index (TEI). The study employed the means of these indicators.ResultsThe impact of COVID-19, which reached Zhejiang Province at the end of January 2020, was temporary given rapid containment following strict control measures. After the intervention, except for the ALOS mean, the change-points for the other outcomes (p