Table 2.
Stepwise regression sensitivity analysis and bootstrap variable-selection stability.
| Model | Adjustment variables | OR | 95% CI | p-value | AUC | Brier score | AIC |
|---|---|---|---|---|---|---|---|
| Panel A. Association of rSIG across the primary and stepwise sensitivity models | |||||||
| Model 1 | Unadjusted | 2.212 | 1.970–2.483 | <0.001 | 0.828 | 0.060 | 882.9 |
| Model 2 | Age, sex, and onset-to-admission time | 2.063 | 1.830–2.326 | <0.001 | 0.849 | 0.055 | 826.9 |
| Model 3 | Model 2 plus hypertension and diabetes mellitus | 2.078 | 1.842–2.344 | <0.001 | 0.851 | 0.055 | 829.6 |
| Model 4 | Model 3 plus cerebral herniation, PLT, Hb, BG, INR, and APTT | 1.783 | 1.560–2.038 | <0.001 | 0.867 | 0.053 | 809.5 |
| Stepwise model | Onset-to-admission time, cerebral herniation, RBC, and BG | 1.746 | 1.534–1.988 | <0.001 | 0.864 | 0.053 | 797.1 |
| Variable | Effect scale | Beta | SE | aOR | 95% CI | p-value |
|---|---|---|---|---|---|---|
| Panel B. Complete results of the final backward stepwise logistic regression model | ||||||
| rSIG | Per 5-point decrease | 0.557 | 0.066 | 1.746 | 1.534–1.988 | <0.001 |
| Onset-to-admission time | Per 100-min increase | 0.052 | 0.007 | 1.053 | 1.039–1.067 | <0.001 |
| Cerebral herniation | Coded 1 vs. 0 | 0.638 | 0.278 | 1.893 | 1.098–3.262 | 0.022 |
| RBC | Per 1 × 10^12/L increase | −0.582 | 0.133 | 0.559 | 0.430–0.726 | <0.001 |
| BG | Per 1 mmol/L increase | 0.073 | 0.032 | 1.076 | 1.010–1.146 | 0.024 |
| Variable | Retained in original model | Selection frequency, % | Direction consistency, % |
|---|---|---|---|
| Panel C. Bootstrap variable-selection frequencies | |||
| Onset-to-admission time | Yes | 100.0 | 100.0 |
| rSIG | Yes | 100.0 (forced) | 100.0 |
| RBC | Yes | 79.8 | 99.9 |
| Cerebral herniation | Yes | 78.7 | 100.0 |
| BG | Yes | 73.8 | 100.0 |
| Lymphocytes | No | 54.2 | — |
| Cr | No | 54.2 | — |
| Temp | No | 39.4 | — |
| Ca | No | 32.0 | — |
| TC | No | 28.7 | — |
| Hb | No | 26.5 | — |
| LDL-C | No | 25.3 | — |
| INR | No | 23.2 | — |
| Alb | No | 23.0 | — |
| APTT | No | 21.3 | — |
| UA | No | 17.9 | — |
| TBil | No | 16.9 | — |
| HDL-C | No | 16.9 | — |
| AST | No | 14.9 | — |
| ALP | No | 11.6 | — |
AIC, Akaike information criterion; APTT, activated partial thromboplastin time; Alb, albumin; ALP, alkaline phosphatase; aOR, adjusted odds ratio; AST, aspartate aminotransferase; AUC, area under the receiver operating characteristic curve; BG, blood glucose; Ca, calcium; CI, confidence interval; Cr, creatinine; GCS, Glasgow Coma Scale; Hb, hemoglobin; HDL-C, high-density lipoprotein cholesterol; HR, heart rate; INR, international normalized ratio; LDL-C, low-density lipoprotein cholesterol; OR, odds ratio; RBC, red blood cell count; rSIG, reverse shock index multiplied by Glasgow Coma Scale score; SBP, systolic blood pressure; SE, standard error; TBil, total bilirubin; TC, total cholesterol; Temp, body temperature; UA, uric acid.