Table 5.
Multivariate logistic regression models selected by stepwise logistic regression for symptomatic intracranial haemorrhage and functional outcome at 6 months
|
OHS score 0–2 versus OHS score 3–6 |
Symptomatic intracranial haemorrhage |
|||
|---|---|---|---|---|
| Odds ratio (95% CI) | p | Odds ratio (95% CI) | p | |
| Age (years) | 0·96 (0·95–0·97) | <0·0001 | 0·99 (0·98–1·01) | 0·556 |
| NIHSS score | 0·83 (0·82–0·85) | <0·0001 | 1·07 (1·04–1·10) | 0·0001 |
| Time to randomisation (h) | 1·04 (0·96–1·13) | 0·288 | 0·98 (0·83–1·15) | 0·798 |
| Alteplase versus control | 1·12 (0·94–1·34) | 0·196 | 6·71 (3·93–11·46) | <0·0001 |
| Antiplatelets at the time of stroke versus none | .. | .. | 1·60 (1·07–2·38) | 0·021 |
| Small or medium lesion versus no lesion | 0·85 (0·67–1·07) | 0·173 | .. | .. |
| Large or very large lesion versus no lesion | 0·54 (0·39–0·74) | 0·0001 | .. | .. |
| Hyperattenuated artery versus none | 0·71 (0·55–0·92) | 0·009 | 1·61 (1·07–2·42) | 0·023 |
| Old infarct versus none | .. | .. | 1·67 (1·13–2·46) | 0·009 |
| Mild leukoaraiosis versus none | 0·76 (0·62–0·93) | 0·009 | .. | .. |
| Severe leukoaraiosis versus none | 0·59 (0·45–0·79) | 0·0003 | .. | .. |
Numbers of patients in each category are shown in table 1. Odds ratios indicate the increased or decreased odds of the clinical factor being present for a 1 year increase in age, a 1 point increase in NIHSS score, or a 1 h increase in time to randomisation. Models selected by stepwise logistic regression from full models shown in table 4. Additional time windows are shown in the appendix (pp 8–9). The first four variables were forced into all models. We used p≤0·05 as criteria for both forward and backward steps. Blank cells represent variables that were dropped as non-significant during stepwise selection. The final nominal p values take no account of model selection. Age, NIHSS score, and time to randomisation were entered into the model as continuous variables; thus the odds ratio for age represents the estimated change in odds of the outcome for a 1 year increase in age, with all other variables unchanged. The units for NIHSS score are points on a scale from 0 to 37 (maximum observed in this trial). Factors with three levels were either retained or excluded at each step; the method did not permit separate consideration of the individual 1 df contrasts comprising the three-level factors. NIHSS=National Institutes of Health Stroke Scale. OHS=Oxford Handicap Scale.