Table 4.
Difference-in-Differences Logistic Regression Results: Heterogeneous SIM Effect on 30-Day Hospital Readmissions among Adults with Diabetes by State
| No pre-treatment trends adjustment (Model 4) | Pre-treatment trends adjustment (Model 5) | |||||
|---|---|---|---|---|---|---|
| Variable | aOR | P-value | 95% Confidence Interval | aOR | P-value | 95% Confidence Interval |
| AR × Post | 0.951** | 0.040 | 0.907, 0.998 | 1.072* | 0.099 | 0.987, 1.164 |
| MA × Post | 0.970* | 0.077 | 0.938, 1.003 | 1.054** | 0.012 | 1.011, 1.097 |
| VT × Post | 1.021 | 0.771 | 0.887, 1.174 | 0.867 | 0.258 | 0.676, 1.111 |
| AR × year trend | 0.961*** | 0.001 | 0.939, 0.985 | |||
| MA × year trend | 0.973*** | 0.000 | 0.961, 0.986 | |||
| VT × year trend | 1.073 | 0.179 | 0.968, 1.189 | |||
| Race/ethnicity | ||||||
| Black | 0.941*** | 0.000 | 0.924, 0.957 | 0.941*** | 0.000 | 0.924, 0.957 |
| Hispanic | 0.885*** | 0.000 | 0.862, 0.909 | 0.886*** | 0.000 | 0.863, 0.909 |
| Other | 0.840*** | 0.000 | 0.814, 0.866 | 0.840*** | 0.000 | 0.815, 0.866 |
| Age | 1.003*** | 0.000 | 1.002, 1.004 | 1.003*** | 0.000 | 1.002, 1.004 |
| Female | 0.917*** | 0.000 | 0.906, 0.927 | 0.917*** | 0.000 | 0.906, 0.927 |
| Length of stay | 1.037*** | 0.000 | 1.035, 1.039 | 1.037*** | 0.000 | 1.035, 1.039 |
| ED admission | 1.216*** | 0.000 | 1.190, 1.241 | 1.215*** | 0.000 | 1.190, 1.241 |
| Comorbidity count | 1.140*** | 0.000 | 1.135, 1.145 | 1.140*** | 0.000 | 1.135, 1.145 |
| Payer | ||||||
| Medicaid | 1.051*** | 0.000 | 1.024, 1.078 | 1.050*** | 0.000 | 1.024, 1.078 |
| Medicare-Medicaid | 1.107*** | 0.000 | 1.087, 1.129 | 1.107*** | 0.000 | 1.086, 1.128 |
| Private | 0.739*** | 0.000 | 0.725, 0.753 | 0.739*** | 0.000 | 0.725, 0.753 |
| Uninsured | 0.682*** | 0.000 | 0.644,0.722 | 0.682*** | 0.000 | 0.644, 0.722 |
| Other | 0.816*** | 0.000 | 0.790, 0.843 | 0.815*** | 0.000 | 0.790, 0.842 |
| Goodness of Fit | ||||||
| AIC | 1394744 | 1394701 | ||||
| BIC | 1395096 | 1395105 | ||||
Note: Models are estimated by using four-group propensity score weighting; models include year and hospital indicators (not shown). Standard errors are estimated by clustering at the hospital level. aOR: adjusted odds ratio; for interaction terms, it is the ratio of two adjusted odds ratios. AR: Arkansas; MA: Massachusetts; VT: Vermont AIC: Akaike’s information criterion; BIC: Bayesian information criterion; Post: post-SIM. Reference group for race/ethnicity is white and for payer is Medicare. Source: Authors’ analysis of Healthcare Cost and Utilization Project’s State Inpatient Databases
p<0.10
p<0.05
p<0.01