Table 3

Final multivariate logistic model. Deviance values and p values are for sequential tests, adding each variable to a model containing all those above it. Odds ratios <1 are associated with a decreasing probability of survival. Odds ratios for continuous variables are for a difference of 5 units* or 1 unit as indicated. Age is fitted as a function with two linear parts; there is no effect on the odds of survival until the age of 50, but after this point the odds of survival decrease by a factor of 0.545 for each 5 year increase in age

Variablep ValueCategoriesOdds ratio(95% CI)
Age<0.0001Piecewise linear0.545* (0.43–0.69)
GCS total<0.0001Linear1.31 (1.12–1.53)
ISS score<0.0001Linear0.737* (0.60–0.91)
Pupils 0.004Both reacting1
Only one reacting0.599(0.18–2.00)
Neither reacting0.168(0.06–0.50)
CT 0.004Visible haematoma1
No visible haematoma3.53(1.43–8.73)