Table 2.
Interrupted time series (ITS) analyses for total expenditure per case, length of stay, and in-hospital mortality of hospitalized insured patients before and after the DIP reform
| Indicators | Baseline monthly slope (β1) | Step change (β2) | Monthly slope change (β3) | Constant (β0) | ||||
|---|---|---|---|---|---|---|---|---|
| Estimate (95%CI) | P value | Estimate (95%CI) | P value | Estimate (95%CI) | P value | Estimate (95%CI) | P value | |
| All hospitals | ||||||||
| ln (Total expenditure per case) | -0.006 (-0.009, -0.003) | 0.000 | 0.059 (0.025, 0.093) | 0.001 | 0.011 (0.007, 0.014) | 0.000 | 9.309 (8.296, 10.322) | 0.000 |
| Length of stay | -0.052 (-0.074, -0.031) | 0.000 | 0.371 (0.128, 0.615) | 0.004 | 0.009 (-0.017, 0.037) | 0.492 | -1.707 (-10.943, 7.528) | 0.709 |
| In-hospital mortality rate | -0.009 (-0.020, 0.002) | 0.091 | 0.016 (-0.107, 0.140) | 0.788 | -0.003 (-0.015, 0.009) | 0.622 | -6.910 (-10.687, -3.133) | 0.001 |
| Hospital ownership | ||||||||
| Public hospitals | ||||||||
| ln (Total expenditure per case) | -0.006 (-0.009, -0.003) | 0.000 | 0.056 (0.021, 0.092) | 0.003 | 0.011 (0.008, 0.014) | 0.000 | 9.690 (8.757, 10.623) | 0.000 |
| Length of stay | -0.060 (-0.079, -0.042) | 0.000 | 0.309 (0.060, 0.558) | 0.016 | 0.022 (0.001, 0.043) | 0.041 | -1.163 (-8.101, 5.775) | 0.736 |
| In-hospital mortality rate | -0.011 (-0.020, -0.002) | 0.017 | -0.017 (-0.129, 0.095) | 0.766 | 0.001 (-0.009, 0.010) | 0.901 | -6.787 (-9.621, -3.953) | 0.000 |
| Private hospitals | ||||||||
| ln (Total expenditure per case) | 0.003 (0.000, 0.007) | 0.038 | 0.020 (-0.118, 0.157) | 0.773 | -0.003 (-0.010, 0.003) | 0.322 | 8.601 (7.599, 9.602) | 0.000 |
| Length of stay | 0.053 (-0.007, 0.113) | 0.084 | 0.624 (-2.791, 4.039) | 0.713 | -0.141 (-0.290, 0.008) | 0.062 | -9.917 (-37.460, 17.627) | 0.469 |
| In-hospital mortality rate | 0.005 (-0.019, 0.028) | 0.697 | -0.236 (-1.183, 0.712) | 0.617 | -0.083 (-0.133, -0.032) | 0.002 | 1.589 (-4.179, 7.357) | 0.579 |
| Hospital level | ||||||||
| Tertiary hospitals | ||||||||
| ln (Total expenditure per case) | -0.002 (-0.005, -0.000) | 0.033 | 0.074 (0.036, 0.113) | 0.000 | 0.006 (0.004, 0.008) | 0.000 | 9.597 (8.326, 10.869) | 0.000 |
| Length of stay | -0.050 (-0.068, -0.032) | 0.000 | 0.051 (-0.254, 0.355) | 0.737 | -0.013 (-0.032, 0.005) | 0.165 | 4.974 (-4.817, 14.764) | 0.309 |
| In-hospital mortality rate | -0.009 (-0.015, -0.003) | 0.006 | 0.034 (-0.087, 0.154) | 0.573 | -0.003 (-0.010, 0.005) | 0.452 | -7.106 (-12.306, -1.906) | 0.009 |
| Secondary hospitals | ||||||||
| ln (Total expenditure per case) | -0.000 (-0.002, 0.001) | 0.899 | -0.049 (-0.092, -0.007) | 0.025 | 0.004 (0.000, 0.008) | 0.047 | 7.807 (7.328, 8.286) | 0.000 |
| Length of stay | -0.005 (-0.033, 0.023) | 0.729 | 0.296 (-0.433, 1.025) | 0.414 | -0.048 (-0.105, 0.009) | 0.095 | 12.784 (5.292, 20.276) | 0.001 |
| In-hospital mortality rate | 0.005 (-0.006, 0.015) | 0.349 | -0.144 (-0.416, 0.129) | 0.291 | -0.037 (-0.059, -0.014) | 0.002 | -4.148 (-6.841, -1.455) | 0.004 |
| Primary hospitals | ||||||||
| ln (Total expenditure per case) | -0.005 (-0.011, 0.001) | 0.113 | 0.064 (0.020, 0.109) | 0.006 | 0.009 (0.000, 0.018) | 0.039 | 9.373 (8.651, 10.095) | 0.000 |
| Length of stay | -0.100 (-0.262, 0.063) | 0.222 | 1.096 (-0.167, 2.360) | 0.087 | 0.235 (0.022, 0.449) | 0.032 | 7.788 (-19.674, 35.251) | 0.568 |
| In-hospital mortality rate | -0.026 (-0.076, 0.023) | 0.291 | -0.261 (-0.609, 0.087) | 0.137 | 0.066 (-0.010, 0.141) | 0.088 | -9.395 (-17.074, -1.716) | 0.018 |
DIP denoted the Diagnosis-Intervention Packet payment reform; CI the confidence interval. Total expenditure was adjusted to 2019 considering inflation using the annual consumer price index of China. Total expenditure per case was logarithmically transformed in the ITS model. ITS analyses controlled for the number of discharge cases, age, sex, Charlson Comorbidity Index of patients, and seasonality, with robust standard errors