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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.

Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

Interventions in the preoperative clinic for long term smoking cessation: a quantitative systematic review

A Zaki, A Abrishami, J Wong, and FF Chung.

Review published: 2008.

Link to full article: [Journal publisher]

CRD summary

The authors concluded that preoperative smoking interventions, including counselling and pharmacotherapy, can increase the chance of abstinence by up to 60% within three to six months following surgery. The authors' cautious conclusion appears appropriate in view of the limited evidence identified.

Authors' objectives

To assess the efficacy of interventions delivered in the preoperative clinic to promote long-term (at least three months) smoking cessation following surgery.


The Cochrane Library (Tobacco Addiction Group, Central Register of Controlled Trials and DARE), MEDLINE, EMBASE and CINAHL were searched to September 2007. Search terms were reported. Reference lists of retrieved articles were handsearched. Authors of relevant articles and experts in the field were contacted.

Study selection

Parallel-group randomised controlled trials (RCTs) that evaluated the effects of smoking-cessation interventions (initiated in the preoperative clinic) on quitting rates three, six and 12 months after elective surgery were eligible for inclusion. Eligible interventions included advice or more intensive behavioural therapy with or without pharmacotherapy and post-discharge follow-up. Studies that compared nicotine replacement therapy (NRT) or other pharmacotherapy versus placebo, usual care or less intensive programmes were considered. Observational studies and trials that focused only on preoperative smoking cessation or postoperative surgical outcomes were excluded.

The included studies were conducted in Canada and USA. Interventions assessed included counselling and pharmacotherapy (bupropion or NRT), stress reduction aids and computer-assisted counselling programmes or counselling sessions followed by postoperative telephone follow-up. Pharmacotherapy was provided in all studies as part of the multi-component smoking cessation programmes in the preoperative clinic. Duration of NRT varied among included studies (range one week to 30 days). Mean patient age ranged from 42.5 to 50 years. The proportion of enrolled patients in preparation stage ranged from 10% to 50%. The proportion of patients with previous quitting attempts varied among studies (range 25% to 87%). Outcomes measured included prevalence of abstinence, number of cigarettes smoked per day, change in the smoker's readiness for change and incidence of treatment-related complications (for pharmacotherapy interventions).

Three reviewers independently selected studies for inclusion; discrepancies were resolved by a fourth reviewer.

Assessment of study quality

Study quality was assessed according to the methods described in the Cochrane Handbook for Systematic Reviews of Interventions. Key criteria assessed were randomisation, concealment of treatment allocation, blinding, completeness of follow-up and intention-to-treat analyses.

Three reviewers independently assessed the quality of included studies; disagreements were resolved by a fourth reviewer.

Data extraction

Two reviewers independently extracted data on outcomes to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Authors of included studies were contacted for any missing data. The authors did not state how any disagreements were resolved.

Methods of synthesis

Pooled odds ratios and 95% CIs were calculated using both fixed-effect and random-effects meta-analysis; random-effects estimates of effects were presented. Sensitivity analysis considered the effect on the pooled estimate of using fixed-effect and random-effects methods and exclusion of trials with high drop-out rates and by intention-to-treat analysis. Heterogeneity was assessed using X2 and I2 statistics. Subgroup analysis was based on study quality. A funnel plot was not drawn due to the small number of included studies.

Results of the review

Four RCTs (n=610 patients, range 47 to 237 patients) were included. Follow-up periods ranged from three weeks to 12 months; only one RCT followed patients for up to one year. Randomisation, allocation concealment, blinding and outcome assessment were adequate in all included studies. Follow-up was not complete in any trials. All trials performed intention-to-treat analyses.

Interventions were associated with a higher cessation rate at the three- to six-month follow-up period compared to controls (OR 1.58, 95% 1.02 to 2.45, I2=0%; n=520 patients, four RCTs).

There was no significant difference between intervention and control groups in the only trial with a longer follow-up period of 12 months (OR 1.05, 95% CI 0.53 to 2.09; n=169 patients, one RCT).

Sensitivity analyses did not change the overall effects.

Authors' conclusions

Preoperative smoking interventions, including counselling and pharmacotherapy, can increase the chance of abstinence by up to 60% within three to six months following surgery.

CRD commentary

The review question was clearly stated. Several relevant databases were searched. Attempts were made to search for unpublished studies. Review processes were conducted in duplicate, which reduced risks of error and bias. Study quality was assessed using appropriate criteria and the results were used to inform the synthesis. Appropriate approaches were used to combine study results; there was no evidence of statistical heterogeneity. The authors acknowledged potential for publication bias and the limitations of few studies with small sample sizes.

The authors' cautious conclusion appears appropriate in view of the limited evidence identified.

Implications of the review for practice and research

Practice: The authors stated that anti-smoking interventions that involved use of the preoperative clinic as a teachable moment (for example, by anaesthesiologists) in an organised multifaceted programme might reduce rates of postoperative complications and increase the likelihood of permanent smoking cessation in the long term.

Research: The authors stated that further high-quality randomised controlled trials with at least 12 months' follow-up after surgery were needed to evaluate the possibility of longer abstinence. Further studies were warranted to demonstrate the feasibility and efficacy of preoperative smoking-cessation interventions in routine practice. The authors recommended further studies to evaluate the feasibility of multifaceted programmes in which anaesthesiologists provided anti-smoking interventions in the preoperative phase.


None stated.

Bibliographic details

Zaki A, Abrishami A, Wong J, Chung FF. Interventions in the preoperative clinic for long term smoking cessation: a quantitative systematic review. Canadian Journal of Anesthesia 2008; 55(1): 11-21. [PubMed: 18166743]

Indexing Status

Subject indexing assigned by NLM


Adult; Counseling /methods /statistics & numerical data; Female; Follow-Up Studies; Humans; Male; Middle Aged; Postoperative Period; Preoperative Care /methods; Randomized Controlled Trials as Topic /statistics & numerical data; Smoking /drug therapy /psychology /therapy; Smoking Cessation /methods /statistics & numerical data; Time; Treatment Outcome



Database entry date


Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.

CRD has determined that this article meets the DARE scientific quality criteria for a systematic review.

Copyright © 2014 University of York.

PMID: 18166743


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