Effects of smoking and different BMI cutoff points on surgical site infection after elective open ventral hernia repair.

Abstract

BMI > 40kg/m2 and smoking have been identified as risk factors for surgical site infections (SSIs) after ventral hernia repair, however, the relationship with lower BMI values has not been described. The objective of this study was to analyze the relationship between different BMI thresholds, smoking, and SSI after open ventral hernia repair. All patients who underwent an elective non-emergent open ventral hernia repair with mesh were extracted from the 2011 to 2016 NSQIP database. Bivariate, multivariate logistic regression, and Classification and Regression Tree (CART) analyses were used. Of 55,240 patients, 2,620 (4.7%) developed SSIs (superficial: 58.5%, deep:27%, organ-space: 16%). BMI (OR: 1.035; 95% CI:1.03-1.04; p < 0.001) and smoking (OR:1.51; 95% CI:1.37-1.67; p < 0.001) were identified in logistic regression analysis as the two most modifiable risk factors independently associated with SSIs. CART analysis demonstrated that the lowest SSI rate belonged to non-smokers with BMI < 24.2kg/m2 (1.9%), and the highest SSI to smokers with BMI > 42.3kg/m2 (12%). Between these values, there was a stepwise increase in SSI rate as BMI increased, while smoking added additional risk in each group. Following open hernia repair, the association between SSI and being overweight starts at a BMI of 24.2, a threshold lower than previously described. The risk of SSI increases in a stepwise fashion as BMI increases and is augmented by smoking. Future studies are needed to determine if SSI reduction can be achieved with a combination of smoking cessation and weight loss using these BMI thresholds.