Title:
Interventions for recruiting smokers into cessation programmes.

Abstract:
Tobacco control is a top public health priority around the globe due to the high prevalence of cigarette smoking and its associated morbidity and mortality. Much effort has been focused on establishing the effectiveness of different smoking cessation strategies. This review, however, aims to address the initial challenge faced by smoking cessation programmes: recruitment of smokers.
The primary objective of this review was to determine the effectiveness of different strategies for recruiting smokers into cessation programmes. The secondary objective was to determine the impact that these strategies had on smoking cessation rates at least six months after enrolment into a cessation programme.
We searched the specialised register of the Cochrane Tobacco Addiction Group using a search strategy which included the terms ('recruit$', 'invit$', 'enter', 'entry', 'enrolment') combined with ('smok$', 'cigarette', 'smoking cessation', 'tobacco') in the title, abstract or keyword fields. We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), and registers of current and ongoing trials. We also searched the reference lists of included studies.
We included randomised controlled trials and cluster randomised controlled trials that compared at least two different methods of recruiting current smokers into a smoking cessation programme. We also included those studies which focused on the effectiveness of a smoking cessation programme as long as the study involved multiple recruitment methods and reported results of the recruitment phase.
From each included study, we extracted data on the type of participants, type of recruitment strategies (i.e., setting, mode of communication used, intensity and duration) and comparisons, and on randomisation, allocation concealment, and blinding procedures.Our primary outcome was the proportion of smokers successfully recruited to each cessation programme compared to alternative modalities of recruitment. Our secondary outcome was smoking cessation for at least six months. Given the substantial heterogeneity across recruitment interventions and participants, we adopted a narrative synthesis approach for summarising results.
This review includes 19 studies with a total of 14,890 participants. We categorised the included studies according to the modes used to deliver the recruitment strategy: head to head comparison of individual recruitment strategies; comparison of the same delivery mode but with different content or intensity; and the addition of another mode to an existing recruitment method.We identified three studies that made head-to-head comparisons of different types of recruitment strategies. Of these, only one study detected a significant effect, finding that a personal phone call was more effective than a generic invitation letter (RR 40.73, 95% CI 2.53 to 654.74). Five studies compared interventions using the same delivery modes but different content. Results showed that tailored messages through an interactive voice response system resulted in a higher recruitment rate than assessment of smoking status alone using the same system (RR 8.64, 95% CI 4.41 to 16.93), and that text messages indicating scarcity of places available were more effective than generic text message reminders (RR 1.45, 95% CI 1.07 to 1.96). One study compared interventions using the same delivery mode but different intensity and found that allowing for more phone call attempts to reach potential participants can result in better recruitment (RR 1.87, 95% CI 1.61 to 2.18). Finally, 10 studies investigated the effect of adding a recruitment mode to existing recruitment strategies. Findings showed that: adding a text message reminder or real quotes from participants to a personal phone call improved recruitment of participants (RR 3.38, 95% CI 1.26 to 9.08 and RR 29.07, 95% CI 1.74 to 485.70, respectively); that adding a personal phone call to an existing newsletter can also increase recruitment rates (RR 65.12, 95% CI 4.06 to 1045.4]); that a reactive-proactive recruitment phase is more effective than a proactive phase alone (63.8% versus 47.5%, RR not available); and that active recruitment at schools is more effective than passive recruitment (p < 0.001, denominator not available for calculation of RR). Additionally, a number of studies in this category showed that providing incentives can effectively increase the number of participants recruited into smoking cessation programmes.Out of the 19 included studies, only four reported on the effect of recruitment strategy on smoking cessation at six months or longer. Three of these studies compared strategies that used the same delivery mode with different content. Their results were non-significant. The remaining three studies evaluated adding an additional mode to an existing recruitment intervention. Only one of them showed a significant difference in the levels of smoking cessation that favoured the enhanced recruitment strategy, but this may have reflected the offer of incentives once in the programme rather than the recruitment strategy itself (RR at 15 or 18 months 2.60, 95% CI 1.48 to 4.56).
The substantial heterogeneity across the included studies restricts our ability to draw firm conclusions about the effectiveness of different recruitment strategies in relation to recruitment of participants into smoking cessation programmes or levels of smoking cessation. The limited evidence, however, suggests that the following elements may improve the recruitment of smokers into cessation programmes: personal, tailored interventions; recruitment methods that are proactive in nature; and more intensive recruitment strategies (i.e., those strategies that require increased contact with potential participants).