Impact of smoking on the surgical outcome of Crohn's disease: A propensity-score matched National Surgical Quality Improvement Program analysis

Aim: Smoking is known to have a deleterious effect on Crohn's disease (CD). The present study addressed the specific impact of smoking on the outcome of surgery for CD. Method: A review of the National Surgical Quality Improvement Program (NSQIP) database (2005-2012) identified 7631 patients with CD who underwent surgical resection. Patients were stratified based on smoking status and were compared with univariate statistical tests. Generalized linear regression and multiple logistic regressions were used to model the impact of smoking on the surgical outcome [length of stay (LOS), mortality, postoperative complications and readmission]. To confirm the validity of the regression models and to evaluate the influence of smoking in comparable patient cohorts, a propensity score match was also performed. Results: There were 2047 (26.8%) patients with CD identified as current smokers, and 5584 (74.2%) identified as non- or ex-smokers. Smokers were more likely to have a pulmonary comorbidity, preoperative weight loss and a higher American Society of Anesthesiologists classification. No differences in mortality were observed between smokers and non- or ex-smokers in univariate analysis. In multivariate analysis, smoking status was not significantly associated with LOS. Morbidity (OR 1.20, P = 0.003), particularly infectious (OR 1.30, P < 0.001) and pulmonary (OR 1.87, P < 0.001) complications, and readmission (OR 1.58, P = 0.004) were significantly associated with smoking status. These findings were validated on propensity-score matching analysis. Conclusion: In patients with CD, the detrimental effects of smoking on surgical outcomes are driven by infectious and pulmonary complications, and by an increased likelihood of readmission.