Table 2. Multivariable Analysis for Possible Confounding Variables.
| Procedure | No. of SSIs/No. of Procedures (%) | Difference (95% CI) | Unadjusted Odds Ratio (95% CI)b | P Value | Adjusted Odds Ratio (95% CI)b | P Value | |
|---|---|---|---|---|---|---|---|
| Preintervention (n = 29 098)a | Postintervention (n = 30 911)a | ||||||
| All procedures and SSIs | 252 (0.87) | 256 (0.83) | −0.04 (−0.18 to 0.11) | 0.96 (0.80 to 1.14) | .61 | 0.85 (0.71 to 1.01)c | .07 |
| CABG-CD | 54/2512 (2.15) | 26/2661 (0.98) | −1.17 (−1.85 to −0.49) | 0.45 (0.28 to 0.72) | <.001 | 0.36 (0.22 to 0.60)d | <.001 |
| CABG-C | 2/458 (0.44) | 10/529 (1.89) | 1.45 (0.15 to 2.76) | 4.39 (0.96 to 20.15) | .06 | NE | NA |
| Craniotomy | 24/1771 (1.36) | 37/2230 (1.66) | 0.30 (−0.45 to 1.06) | 1.23 (0.73 to 2.06) | .43 | NE | NA |
| Spinal fusion | 41/4514 (0.91) | 61/5233 (1.17) | 0.26 (−0.14 to 0.66) | 1.29 (0.86 to 1.92) | .21 | 1.05 (0.69 to 1.60)e | .82 |
| Hip prosthesis | 46/6569 (0.70) | 60/7189 (0.83) | 0.13 (−0.16 to 0.43) | 1.19 (0.81 to 1.76) | .37 | 1.17 (0.80 to 1.73)e | .42 |
| Abdominal hysterectomy | 2/220 (0.91) | 3/340 (0.88) | −0.03 (−1.63 to 1.57) | 0.97 (0.16 to 5.85) | .97 | NE | NA |
| Knee prosthesis | 49/7787 (0.63) | 41/9013 (0.45) | −0.17 (−0.40 to 0.05) | 0.72 (0.48 to 1.09) | .12 | 0.68 (0.44 to 1.03)f | .07 |
| Laminectomy | 34/5267 (0.65) | 18/3716 (0.48) | −0.16 (−0.47 to 0.15) | 0.75 (0.42 to 1.33) | .32 | NE | NA |
Abbreviations: CABG-CD, coronary artery bypass graft with chest and donor site incisions; CABG-C, coronary artery bypass graft with chest incision only; NA, not applicable; NE, not examined (because of low SSI rate); SSI, surgical site infection.
The preintervention period is from January 1, 2014, through February 29, 2016, and the postintervention period is from June 1, 2016, through July 31, 2018.
Reference for odds ratio is preintervention group.
Confounders in the multivariable model included facility, procedure type, American Society of Anesthesiologists class, emergency procedure, endoscopic approach, trauma, diabetes, age, and duration of surgery.
Confounders in the multivariable model included facility, emergency procedure, endoscopic approach, diabetes, age, and duration of surgery.
Confounders in the multivariable model included facility, American Society of Anesthesiologists class, emergency procedure, endoscopic approach, trauma, diabetes, age, and duration of surgery.
Confounders in the multivariable model included facility, American Society of Anesthesiologists class, emergency procedure, trauma, diabetes, age, and duration of surgery.