Smoking Cessation Before Surgery May Not Increase Post-Op Complications

Laurie Barclay, MD

March 22, 2011

March 22, 2011 — Stopping smoking a few days before surgery is not associated with increased postoperative complications, according to the results of a systematic review and meta-analysis reported online March 14 in the Archives of Internal Medicine.

"Concerns have been expressed that stopping smoking within 8 weeks before surgery may be detrimental to postoperative outcomes," write Katie Myers, MSc, CPsychol, from the Queen Mary University of London, Barts, and The London School of Medicine and Dentistry in London, England, and colleagues.

"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."

Assessment of Studies

The goal of the study was to assess smoking studies comparing surgical patients who have recently quit smoking vs those who continue to smoke to generate an evidence-based recommendation for front-line staff.

The reviewers searched British Nursing Index, The Cochrane Library database, Cumulative Index to Nursing and Allied Health Literature, EMBASE, MEDLINE, PsycINFO to May 2010, and bibliographies of included studies to identify studies allowing a comparison of postoperative complications in patients undergoing any type of surgery who stopped smoking within 8 weeks preceding surgery and those who continued smoking.

Methodologic quality was independently evaluated by 2 reviewers. Three separate meta-analyses were performed: (1) all available studies; (2) studies with a low risk for bias and confirmation of self-reported abstinence, to determine possible benefits; and (3) studies of pulmonary complications only, to determine possible risks. A random-effects model allowed combination of the data, and the I2 statistic was used to assess heterogeneity.

Of 9 studies meeting the selection criteria, one showed a benefit of recent quitting vs continuing to smoke, and none showed any harms. For all available studies, meta-analyses showed that stopping smoking within 8 weeks preoperatively was not associated with an increase or decrease in overall postoperative complications (relative risk [RR], 0.78; 95% confidence interval [CI], 0.57 - 1.07). Findings were similar, for a group of 3 studies with high-quality scores (RR, 0.57; 95% CI, 0.16 - 2.01) and for a group of 4 studies that specifically assessed pulmonary complications (RR, 1.18; 95% CI, 0.95 - 1.46).

"Existing data indicate that the concern that stopping smoking only a few weeks prior to surgery might worsen clinical outcomes is unfounded," the study authors write. "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."

Limitations of this study include the relatively small number of available studies, results based on observational data, inclusion only of studies published in English, and substantial heterogeneity in 2 of the meta-analyses.

Review Not Definitive

In an accompanying invited commentary, Clara K. Chow, MBBS, PhD, from the University of Sydney and The George Institute for Global Health in Sydney, NSW, Australia, and P. J. Devereaux, MD, PhD, from the Population Health Research Institute, McMaster University in Hamilton, Ontario, Canada, note that the review does not definitively answer the question raised.

"Physicians should ideally try to get their patients to stop smoking several months prior to their surgery," Drs. Chow and Devereaux write. "The appropriate advice regarding the optimal timing of smoking cessation for patients seen close to their scheduled surgery awaits further research. The magnitude of the problem (ie, upwards of 70 million adult smokers worldwide undergo major surgery annually) highlights the need for large, high-quality, perioperative tobacco use studies."

One of the study authors (Hayden McRobbie, MBChB, PhD) is supported by the UK Centre for Tobacco Control Studies, a UKCRC Public Health Research Centre of Excellence. Coauthor Peter Hajek, PhD, and Dr. McRobbie have received research funds from and provide consultancies to the following makers of smoking cessation medications: GlaxoSmithKline, Novartis, Pfizer Global, and Johnson & Johnson. Drs. Chow and Devereaux have disclosed no relevant financial relationships.

Arch Intern Med. Published online March 14, 2011. Full text Full text

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