Stopping smoking shortly before surgery and postoperative complications: a systematic review and meta-analysis

Abstract

Objective: To examine existing smoking studies that compare surgical patients who have recently quit smoking with those who continue to smoke to provide an evidence-based recommendation for front-line staff. Concerns have been expressed that stopping smoking within 8 weeks before surgery may be detrimental to postoperative outcomes. This has generated considerable uncertainty even in health care systems that consider smoking cessation advice in the hospital setting an important priority. Smokers who stop smoking shortly before surgery (recent quitters) have been reported to have worse surgical outcomes than early quitters, but this may indicate only that recent quitting is less beneficial than early quitting, not that it is risky.

Design: Systematic review with meta-analysis.

Data sources: British Nursing Index (BNI), The Cochrane Library database, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Medline, PsycINFO to May 2010, and reference lists of included studies.

Study selection: Studies were included that allow a comparison of postoperative complications in patients undergoing any type of surgery who stopped smoking within 8 weeks prior to surgery and those who continued to smoke.

Data extraction: Two reviewers independently screened potential studies and assessed their methodologic quality. Data were entered into 3 separate meta-analyses that considered all available studies, studies with a low risk of bias that validated self-reported abstinence (to assess possible benefits), and studies of pulmonary complications only (to assess possible risks). Results were combined by using a random-effects model, and heterogeneity was evaluated by using the I(2) statistic.

Results: Nine studies met the inclusion criteria. One found a beneficial effect of recent quitting compared with continuing smoking, and none identified any detrimental effects. In meta-analyses, quitting smoking within 8 weeks before surgery was not associated with an increase or decrease in overall postoperative complications for all available studies (relative risk [RR], 0.78; 95% confidence interval [CI], 0.57-1.07), for a group of 3 studies with high-quality scores (RR, 0.57; 95% CI, 0.16-2.01), or for a group of 4 studies that specifically evaluated pulmonary complications (RR, 1.18; 95% CI, 0.95-1.46).

Conclusions: Existing data indicate that the concern that stopping smoking only a few weeks prior to surgery might worsen clinical outcomes is unfounded. Further larger studies would be useful to arrive at a more robust conclusion. Patients should be advised to stop smoking as early as possible, but there is no evidence to suggest that health professionals should not be advising smokers to quit at any time prior to surgery.