Table 2.
Multivariable Cox proportional hazards model of variables associated with reduced likelihood of survival
| Variable | Coefficient | Standard error | Hazard ratio | 95 % CI of the hazard ratio | p value |
|---|---|---|---|---|---|
| Packed cell volume on admission (%) | 0.032 | 0.014 | 1.033 | 1.004–1.06 | 0.024 |
| Heart rate on admission (beats/min) “the linear effect” | 0.014 | 0.005 | 1.014 | 1.004–1.024 | 0.008 |
| Duration of surgery (min) | 0.0066 | 0.0025 | 1.007 | 1.002–1.01 | 0.008 |
| Epiploic foramen entrapment | Ref | ||||
| No | −0.66 | 0.77 | 0.52 | 0.1–1.35 | 0.39 |
| Yes | |||||
| Surgery duration × EFE | 0.013 | 0.006 | 1.013 | 1.002–1.03 | 0.027 |
The data are from 318 horses that survived following laparotomy for treatment of small intestinal lesions; only 302 horses were included in the model due to missing data for some variables. The model is adjusted for the non-linear relationship between heart rate on admission and probability of survival. CI confidence interval, Re reference category