Table 3. A multivariate model for predicting the natural logarithm of LOS in benzodiazepine overdose.

Predictor	Coefficient	95% CI
Constant	1.96	1.82, 2.09
Drug
Alprazolam	0.24	0.04, 0.43
Diazepam	−0.03	−0.12, 0.06
TCAs	0.60	0.46, 0.75
Anticonvulsants	0.40	0.16, 0.63
Antipsychotics	0.33	0.17, 0.50
Age (10 years increase)	0.17	0.14, 0.20
DDDs Taken (10 unit increase)	0.03	0.01, 0.05

The benzodiazepine drug variable had three categories (other benzodiazepine, alprazolam and diazepam) and other was used as the reference. Age was a continuous variable but the coefficient applied to 10 years increments (i.e. the coefficient of the ln[LOS] with an increase of age by 10 years). All other variables were dichotomous. The reference for co-ingested drugs was the absence of that co-ingested drug.