Table 2: Logistic regression models for predicting 30-day mortality.

VariableModel 1—entire sampleModel 2—diabetics with general surgery subgroupModel 3—diabetics with vascular surgery subgroup
Model R-square
0.3330.3000.165
Odds ratio (95% CI)Odds ratio (95% CI)Odds ratio (95% CI)

Diabetes
 NondiabeticReference category
 Diabetic—oral0.78 (0.70, 0.86)*Reference categoryReference category
 Diabetic—insulin0.83 (0.75, 0.92)*1.18 (1.00, 1.39)1.06 (0.83, 1.35)
Anesthesia technique
 GeneralReference categoryReference categoryReference category
 Epidural0.46 (0.24, 0.91)*0.00 (0.00, α)0.85 (0.34, 2.11)
 Spinal0.87 (0.68, 1.09)0.25 (0.06, 1.01)1.25 (0.85, 1.82)
 Regional0.48 (0.30, 0.76)*1.08 (0.14, 8.16)0.29 (0.11, 0.79)
 Local0.43 (0.19, 0.95)*0.00 (0.00, α)0.09 (0.003, 2.33)
 Monitored anesthesia care0.78 (0.64, 0.96)*0.97 (0.62, 1.51)0.96 (0.62, 1.49)
 Other1.06 (0.46, 2.44)1.14 (0.15, 8.69)0.00 (0.00, α)
 None3.60 (1.03, 12.6)*0.00 (0.00, α)0.00 (0.00, α)
Surgical specialty: vascular1.57 (1.42, 1.72)*
Male gender0.99 (0.92, 1.06)1.15 (0.98, 1.35)0.92 (0.75, 1.16)
Ventilator dependent2.19 (1.93, 2.49)*2.13 (1.63, 2.79)*3.54 (2.13, 5.88)*
COPD1.61 (1.47, 1.76)*1.54 (1.26, 1.88)*1.54 (1.17, 2.02)*
Cardiac risk factors1.57 (1.43, 1.72)*1.18 (0.91, 1.152)1.49 (0.87, 2.53)
On dialysis1.39 (1.24, 1.56)*1.85 (1.46, 2.35)*1.88 (1.46, 2.42)*
Steroid use1.31 (1.16, 1.48)*1.29 (0.98, 1.70)1.15 (0.73, 1.8)
10% weight loss2.81 (2.45, 3.22)*2.73 (1.98, 3.77)*2.25 (1.24, 4.08)*
Sepsis
 NoneReference categoryReference categoryReference category
 Sepsis2.62 (2.32, 2.96)*2.49 (1.92, 3.23)*1.84 (1.26, 2.68)*
 Septic shock3.39 (2.93, 3.94)*3.89 (2.85, 5.34)*3.42 (1.91, 6.14)*
 SIRS2.30 (2.08, 2.55)*2.13 (1.67, 2.73)*1.80 (1.29, 2.53)*
Emergent case2.33 (2.15, 2.53)*2.09 (1.73, 2.53)*2.35 (1.78, 3.11)*
ASA class
 No ASA class assignedReference category0.00 (0.00, α)Reference category
 No disturbance0. 44 (0.014, 0.14)*0.00 (0.00, α)0.00 (0.00, α)
 Mild disturbance0.20 (0.08, 0.49)*0.06 (0.033, 0.107)*0.21 (0.005, 8.64)*
 Severe disturbance1.53 (0.62, 3.78)0.20 (0.13, 0.32)*0.41 (0.11, 15.2)*
 Life threatening5.40 (2.19, 13.2)*0.64 (0.42, 0.99)*0.89 (0.024, 33.0)*
 Moribund13.6 (5.44, 33.9)*Reference category**5.37 (0.13, 217.5)*
Wound classification
 CleanReference categoryReference categoryReference category
 Clean/contaminated2.01 (1.82, 2.22)*2.40 (1.87, 3.09)*2.03 (1.39, 2.96)*
 Contaminated1.88 (1.66, 2.14)*2.45 (1.80, 3.33)*1.34 (0.89, 2.02)
 Dirty/infected1.78 (1.58, 1.99)*2.37 (1.76, 3.18)*0.99 (0.71, 1.40)

Values expressed as odds ratios (95% confidence intervals x, y). *Significance at . **Moribund category is used as the reference category as there were no cases designated as “not assigned” or “no disturbance” and odds ratios could not be calculated in reference to these categories. COPD: chronic obstructive pulmonary disease, ASA: American Society of Anesthesiologists, SIRS: systemic inflammatory response syndrome, and CI: confidence interval.