an increasing trendP = 0.002
The average BMI reimbursement per hospitalization showed an increasing trend before the reform, with an upward slope of 1.7% per month ( β 1 = 0.017, P = 0.002), and fell by 41.2% in the month of the reform ( β 2 = −0.412, P < 0.001), and the monthly trend decreased by 2% ( β 3 = −0.020, P = 0.037).