Table 4.
Adjusted multivariate Poisson regression modeling post-operative infectious complications
| IRR (95% CI) | P-value | |
|---|---|---|
| Pre-operative UTI | 2.88 (2.25–3.70) | <0.001 |
| Age, years | ||
| <65 | 1 [ref.] | |
| ≥65 | 1.15 (1.10–1.21) | <0.001 |
| Female sex | 1.03 (0.98–1.08) | 0.208 |
| Race | ||
| White | 1 [ref.] | |
| Black | 1.02 (0.94–1.10) | 0.704 |
| Other | 1.11 (0.96–1.28) | 0.144 |
| BMI, kg/m2 | ||
| Normal: 18.5–24.9 | 1 [ref.] | |
| Underweight: <18.5 | 1.06 (0.82–1.37) | 0.657 |
| Overweight: 25–29.9 | 0.95 (0.89–1.02) | 0.152 |
| Obese: 30–34.9 | 1.01 (0.94–1.08) | 0.838 |
| Morbidly obese: ≥35 | 1.39 (1.29–1.49) | <0.001 |
| ASA Class | ||
| 1 or 2 | 1 [ref.] | |
| 3 | 1.64 (1.55–1.73) | <0.001 |
| 4 or 5 | 2.20 (1.99–2.43) | <0.001 |
| Inpatient | 1.84 (1.71–1.98) | <0.001 |
| Pre-op Labs | ||
| Hemoglobin <10 g/dL | 1.38 (1.29–1.47) | <0.001 |
| Albumin <3.5 g/dL | 1.49 (1.37–1.62) | <0.001 |
| Surgical specialty | ||
| Orthopedic surgery | 1 [ref.] | |
| Neurosurgery | 1.05 (1.00–1.10) | 0.067 |
| Emergency case | 1.62 (1.45–1.81) | <0.001 |
| Operative time ≥4 hrs | 1.82 (1.73–1.92) | <0.001 |
| Spine surgery type | ||
| Laminectomy | 1 [ref.] | |
| Spinal fusion | 0.86 (0.81–0.92) | <0.001 |
| Laminectomy & Fusion | 1.07 (1.01–1.13) | 0.032 |
| Spinal stimulator | 0.69 (0.49–0.97) | 0.034 |
Abbreviations: IRR= Incidence Rate Ratio, CI = Confidence Interval, UTI = Urinary Tract Infection, BMI = Body Mass Index, ASA = American Society of Anesthesiologists