The impact of smoking cessation prior to surgery on postoperative complications:
A systematic review and meta-analysis

Authors:
Ian Lockhart, Edward Mills and Steven Kelly

Presenter:
Ian Lockhart
Evidence-based Medicine Manager, Pfizer Ltd, Tadworth, UK

Abstract
Objectives: To investigate the effect of preoperative smoking cessation on postoperative complications and to determine if there is an optimal smoking cessation duration.

Methods: A systematic review identified all RCTs evaluating smoking cessation impact on postoperative complications and observational studies evaluating risk of complications among past and current smokers undergoing surgery. Ten electronic database searches were conducted and two reviewers independently selected relevant studies and extracted data. A random-effects meta-analysis of RCTs was conducted, with meta-regression used to examine the impact of time in weeks on the magnitude of effect. For observational studies, proportions of past versus current smokers were pooled.

Results: Six RCTs and 15 observational studies were identified. The pooled RCTs (all chemically verified cessation) had a Relative Risk Reduction [RRR] of 41% (95% CI, 15 – 59%, p = 0.01) for prevention of postoperative complications. Each week of cessation increased the magnitude of effect by 19%. Trials of at least 4 weeks cessation had a significantly larger treatment effect than shorter trials (p = 0.04). Observational studies (cessation mostly self-reported) demonstrated that smoking cessation significantly decreased total (P = <0.0001, I2 = 15%), wound healing (P = 0.0006. I2 = 0%) and pulmonary complications (P=0.003. I2 = 7%).

Conclusions: Increasing smoking cessation duration prior to surgery significantly decreases the incidence of postoperative complications.

Source of funding: Study sponsored by Pfizer Ltd.

Declaration of interest: Ian Lockhart and Steven Kelly are employees of Pfizer Ltd. Edward Mills received funding from Pfizer Ltd. to conduct the review.