A Cochrane review [Abstract] 1 included 37 studies with over 15 000 smokers. Most trials recruited a population without regard to their intention to quit. Trials were conducted in 1 to 12 sessions, with the total duration ranging from 5 to 315 minutes. Most trials used supportive telephone contacts, and supplemented the counselling with self-help materials. Interventions were delivered by primary care physicians, hospital clinicians, nurses or counsellors. Enhancing existing smoking cessation support with additional motivational interviewing (MI) compared with existing support alone, showed a trend towards better effect (RR 1.07, 95% CI 0.85 to 1.36; 12 trials, n=4167; I²=47%), and MI compared with other forms of smoking cessation support gave an RR of 1.24 (95% CI 0.91 to 1.69; 12 trials, n=5192, I²=54%).
Another Cochrane review [Abstract] 2 included 83 studies with 29 563 smokers. Studies were pooled to compare more versus less support. There was a benefit of behavioural support in addition to pharmacotherapy. When all studies of additional behavioural therapy were pooled, there was a statistically significant benefit from additional support (RR 1.15, 95% CI 1.08 to 1.22; 65 trials, n=23 331, I²=8%) for abstinence at longest follow-up, and this effect was not different when we compared subgroups by type of pharmacotherapy or intensity of contact. Increasing the amount of behavioural support increased the chance of success by about 10% to 20%. This effect was similar in the subgroup of 8 studies in which the control group received no behavioural support (RR 1.20, 95% CI 1.02 to 1.43; n=4018, I²=20%). 17 studies compared interventions matched for contact time but that differed in terms of the behavioural components or approaches employed.
Comment: The quality of evidence is downgraded by variable shortcomings in study quality.
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