M. M. Romine1,2, A. Gullick1,2, M. Morris1,2, L. Goss1,2, D. Chu1,2 1University Of Alabama at Birmingham,Gastrointestinal Surgery,Birmingham, Alabama, USA 2VA Birmingham HealthSystem,General Surgery,Birmingham, AL, USA
Introduction:
Controversy exists on the association of Body Mass Index (BMI) with SSI in patients with IBD. Previous conclusions have been limited by single-institution studies and inclusion of both Crohn’s disease (CD) and Ulcerative Colitis patients. In this study, we used a national dataset to investigate the association of BMI with SSI in patients with CD. We hypothesize that higher BMI is associated with higher risk for SSI in CD patients.
Methods:
Using the 2012-2014 ACS-NSQIP Procedure Targeted Database, we identified all patients with CD who underwent colectomy between 2012-2014. Patients with CD were stratified by weight status to underweight, normal weight, overweight and BMI class I (30-34.9), II (35-39.9) and III (>40). Patient demographics, preoperative comorbidities and surgical characteristics were compared. Primary outcomes were wound complications (SSI, organ space SSI, anastomotic leak) and secondary outcomes included other reported NSQIP-complications. Chi-square and Wilcoxon Rank Sums tests were used to determine differences among categorical and continuous variables, respectively. Stepwise backwards logistic regression analyses were performed to identify risk factors for SSI.
Results:
Of 3734 patients with CD, 12.29% were underweight, 43.92% were normal weight, 24.24% overweight, 12.35% BMI class I, 4.79% class II, and 2.41% class III. Overall, 24.4% of patients were smokers, 4.05% were diabetic and 62.94% were on steroids or other immunosuppressant. Patients with higher BMI class were more likely to have diabetes: 3.47% in class I, 6.7% in class II and 8.89% in class III (p value <0.001). A larger percentage of class III obese patients (27.45%) were classified as ASA 4-5 (p value <0.001). Higher BMI was associated with a greater rate of SSI: 6.75% in underweight, 6.4% in normal weight class, 10.06% in the overweight class, 8.89% in class I, 12.85% in class II and 16.67% in class III (p-value<0.001). Organ space SSI rates were highest in underweight patients 12.2%, 7.13% in the normal weight class, 6.85% in the overweight class, and 7.38%, 5.59%, and 2.22% in the BMI classes I, II and III, respectively (p-value<0.001). There was no significant difference in anastomotic leak rate (range 2.8-7.6%, p>0.05). Higher BMI was also associated with respiratory complications (class III 8.9% vs normal 2.2%, p=0.1) and Ileus (class III 20.2% vs 13.4% p=0.01). On multivariate analysis, BMI remained an independent predictor for SSI where BMI class III had highest odds of SSI infection (OR 2.8 CI 1.5-5.2) in addition to class II (OR 2.1 CI 1.3-4.5), class I (OR 1.4 CI 0.9-2), and overweight status (OR 1.5 CI 1.1-2.1) when compared to Normal weight individuals.
Conclusion:
Patients with CD and high BMI are at increased risk for SSI but not organ spaces SSI or anastomotic leak. Underweight CD patients are at increased risk for organ space SSI. Targeting BMI may be one actionable opportunity to reduce post-operative SSI rates.