Background: People trying to quit smoking can be helped with medication or by face-to-face behavioural support such as counselling and group therapy.
Objectives: We wanted to to find out whether support was also effective when it was provided by telephone.
Search methods: The most recent search for evidence was in May 2013. We identified 77 controlled trials with a total of almost 85,000 participants.
Results:This review identified trials evaluating the effect of any type of telephone counselling. We included trials where the participants had called helplines offering support for people trying to quit smoking (quitlines). We also included trials where people had received telephone calls from counsellors or other healthcare providers. Some of these compared telephone support with very minimal support such as self-help leaflets, and others looked at whether adding telephone calls was more helpful than just face-to-face support, or just providing a smoking cessation medication such as nicotine replacement therapy (NRT). Some trials only recruited people who were trying to stop smoking, whislt others offered support even if people were not actively planning to quit. Trials had to be randomized, and to follow up participants for at least six months.
A small number of trials were judged to be at risk of bias but we did not think that the overall results were likely to be biased. Trials in quitline populations were more likely to be unable to contact everyone for follow-up and generally relied on participants' self report of not smoking, rather than checking using biochemical tests. Trials used a wide range of numbers and lengths of calls, and there was some variation between the results of different trials which means that we cannot be certain that all types of counselling have the same effect.
Twelve trials involving over 30,000 people tested the effect of additional telephone calls from a counsellor for people who had called a quitline. When we pooled their results there was evidence that people receiving call-back counselling were more likely to have stopped smoking than those only sent self-help materials or given brief advice and support during the initial call. Calls increased the relative success by between 25% and 50%, but since the proportion quitting in the control groups was quite low this was equivalent to an absolute increase of only 2 to 4 percentage points.
Fifty-one trials involving over 30,000 people tested the effect of telephone counselling for people who had not called a quitline, some of whom might not have been actively planning to quit. Overall when pooled these showed a small benefit of the telephone calls, increasing the relative success by between 20% and 36%, equivalent to an absolute increase of 2 to 3 percentage points. In an analysis that took into account different characteristics of the trials (metaregression) there was evidence that offering a larger number of calls, and having participants who were interested in trying to quit, increased the effect. Trials which tested the additional benefit of telephone counselling for people who were using a smoking cessation medication had a slightly smaller relative benefit, but since people in these studies were benefitting from the medication the absolute benefit from adding telephone calls was about the same. Two trials that compared different numbers of calls detected a benefit of more calls compared to a single contact.
Six other trials tested other uses of telephone counselling including systems for referral of smokers to support. We did not pool these and none of them showed clear evidence of an effect.