Exhibit 3.
Predictors of Ambulance Diversion Using Hierarchical Hospital-level analysis* (n=202)
Source: Authors' analysis of California OSHPD, U.S. Census Bureau & Area Resource File data as cited above (references 26 & 27)
| Predictor | Multiplicative Increase for Unit Change in Predictor | 95%CI Lower Bound | 95%CI Upper Bound | p-value |
|---|---|---|---|---|
| Non-White (%) | 1.024 | 1.004 | 1.044 | 0.0193 |
| Other socioeconomic determinants of ED care | ||||
| Age (years) | 0.999 | 0.933 | 1.071 | 0.9833 |
| Gender – Male (%) | 0.999 | 0.891 | 1.119 | 0.9806 |
| Income (per $1000) | 0.988 | 0.948 | 1.028 | 0.5482 |
| Insurance (% Med-Cal + % Uninsured) | 0.963 | 0.941 | 0.985 | 0.0013 |
| Population Density (Log Scale) | 1.392 | 0.829 | 2.339 | 0.2219 |
| Supply of ED Care010 | ||||
| Ratio of ED Visits to ED Beds per Day | 1.261 | 1.041 | 1.527 | 0.0191 |
| Inpatient admissions to inpatient bed-days (%) | 1.022 | 1.004 | 1.041 | 0.0177 |
| Hospital Structural Characteristics | ||||
| Trauma status (Ref=No) | 2.874 | 1.306 | 6.325 | 0.0096 |
| Ownership (Ref=NFP) | 0.0988 | |||
| County | 2.153 | 0.457 | 10.14 | 0.3335 |
| For Profit | 0.576 | 0.314 | 1.057 | 0.0772 |
| Teaching status (Ref=No) | 1.339 | 0.451 | 3.971 | 0.6000 |
| Operating Margin | 0.994 | 0.978 | 1.010 | 0.4314 |
*
Hierarchical model with hospitals nested in county. Outcome is transformed annual diversion hours (log of annual diversion hours + 1)