Comment: The quality of evidence is downgraded by study limitations (lack of blinding in half of the studies and selective reporting) and by inconsistency (unexplained variability in results).
A Cochrane review [Abstract] 1 included 19 studies with a total of 14 890 subjects. Three studies 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). Results from interventions using the same delivery modes but different content 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; 1 trial, n=521), 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; 1 trial, n=1862). Comparing unrestricted vs restricted number of phone calls to reach potential participants resulted in better recruitment (RR 1.87, 95% CI 1.61 to 2.18; 1 trial, n=1444). Finally, 10 studies investigated the effect of adding a recruitment mode to existing recruitment strategies. 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; 1 trial, n=937 and RR 29.07, 95% CI 1.74 to 485.70; 1 trial, n=811, 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; 1 trial, n=469); 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). Out of the 19 included studies, only 4 reported on the effect of recruitment strategy on smoking cessation at 6 months or longer. Only one of them showed a significant difference in the levels of smoking cessation that favoured the enhanced recruitment strategy.
In an RCT 2 smokers planning to quit (n=1070) were randomly assigned to 27 tailored cessation emails (deluxe), 3 to 4 tailored emails with links to downloadable booklets (basic) or a single non-tailored email (single). Self-reported 7-day point-prevalence abstinence was assessed at 1 month, 3 months and 6 months postenrolment.Across follow-ups, abstinence was significantly greater for smokers in the deluxe proup (34%) compared with the single group (25.8%; OR=1.47, 95% CI 1.07 to 2.02, p=0.02) but there was no difference between the basic (30.8%) and the single group (p=0.13). Results were independent of baseline cigarettes per day, interest in quitting, smoker in household, use of nicotine replacement therapy (NRT) or varenicline, and gender.
Date of latest search: 2020-04-12
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