Multicentre, randomised controlled trial of a smoking cessation text message intervention for pregnant smokers (MiQuit)

Abstract

Background: Text message cessation programmes have potential to change smoking behaviour during pregnancy but their effectiveness is unknown. This study aimed to estimate key parameters, including effectiveness and cost-effectiveness, for delivering a definitive effectiveness trial of a pregnancy specific, theory-guided, tailored text message cessation intervention. Methods: Multicentre, single-blinded, randomised controlled trial. Pregnant smokers (<25 weeks gestation) were recruited from 16 antenatal screening clinics in England. Control participants received usual care and a smoking cessation leaflet. Intervention participants received the control components plus 12 weeks of individually-tailored, automated, interactive, cessation text messages (MiQuit). Key parameters to inform a full trial were recruitment and outcome ascertainment rates. 7 smoking outcomes were assessed; the planned primary outcome for the full trial was continuous abstinence from 4 weeks post-randomisation until 36 weeks gestation, validated biochemically. Estimated costs were modelled per quitter and per QALY. Findings: 407 participants (203 MiQuit, 204 control) were randomised, 39% of those eligible. At follow-up, similar proportions per group provided self-report smoking status and a validation sample. More MiQuit participants achieved validated continuous abstinence relative to controls (5.4% vs. 2.0%; odds ratio [adjusted for site and gestation] 2.7, 95% CI 0.93 to 9.35). Adjusted odds ratios on other smoking outcomes ranged from 1.03 to 3.28 in favour of MiQuit. Incremental costs per quitter/QALY were £140.91 (95% CI -£192.87 to £617.96)/£3,623.09 (-£4,926.56 to £16,197.20), respectively, at the end of pregnancy. Discussion: Findings imply that this low-cost text message intervention is likely to be effective and cost-effective. A full trial is warranted.