The London Exercise And Pregnant smokers (LEAP) trial: a randomised controlled trial of physical activity for smoking cessation in pregnancy with an economic evaluation

Abstract

BackgroundSmoking during pregnancy is the main preventable cause of poor birth outcomes. Improved methods are needed to help women to stop smoking during pregnancy. Pregnancy provides a compelling rationale for physical activity (PA) interventions as cessation medication is contraindicated or ineffective, and an effective PA intervention could be highly cost-effective.ObjectiveTo examine the effectiveness and cost-effectiveness of a PA intervention plus standard behavioural support for smoking cessation relative to behavioural support alone for achieving smoking cessation at the end of pregnancy.DesignMulticentre, two-group, pragmatic randomised controlled trial and economic evaluation with follow-up at the end of pregnancy and 6 months postnatally. Randomisation was stratified by centre and a computer-generated sequence was used to allocate participants using a 1 : 1 ratio.Setting13 hospitals offering antenatal care in the UK.ParticipantsWomen between 10 and 24 weeks’ gestation smoking five or more cigarettes a day before pregnancy and one or more during pregnancy.InterventionsParticipants were randomised to behavioural support for smoking cessation (control) or behavioural support plus a PA intervention consisting of supervised treadmill exercise plus PA consultations. Neither participants nor researchers were blinded to treatment allocation.Main outcome measuresThe primary outcome was self-reported, continuous smoking abstinence between a quit date and end of pregnancy, validated by expired carbon monoxide and/or salivary cotinine. Secondary outcomes were maternal weight, depression, birth outcomes, withdrawal symptoms and urges to smoke. The economic evaluation investigated the costs of the PA intervention compared with the control intervention.ResultsIn total, 789 women were randomised (n = 394 PA,n = 395 control). Four were excluded post randomisation (two had been enrolled twice in sequential pregnancies and two were ineligible and randomised erroneously). The intention-to-treat analysis comprised 785 participants (n = 392 PA,n = 393 control). There was no significant difference in the rate of abstinence at the end of pregnancy between the PA group (7.7%) and the control group (6.4%) [odds ratio for PA group abstinence 1.21, 95% confidence interval (CI) 0.70 to 2.10]. For the PA group compared with the control group, there was a 33% (95% CI 14% to 56%), 28% (95% CI 7% to 52%) and 36% (95% CI 12% to 65%) significantly greater increase in self-reported minutes of moderate- and vigorous-intensity PA from baseline to 1 week, 4 weeks and 6 weeks respectively. Accelerometer data showed that there was no significant difference in PA levels between the groups. There were no significant differences between the groups for change in maternal weight, depression, withdrawal symptoms or urges to smoke. Adverse events and birth outcomes were similar between the groups except for there being significantly more caesarean births in the control group than in the PA group (28.7% vs. 21.3%;p < 0.023). The PA intervention was less costly than the control intervention by £35 per participant. This was mainly attributable to increased health-care usage in the control group. However, there was considerable statistical uncertainty around this estimate.ConclusionsDuring pregnancy, offering an intervention combining supervised exercise and PA counselling does not add to the effectiveness of behavioural support for smoking cessation. Only 10% of participants had PA levels accessed by accelerometer and it is, therefore, unclear whether or not the lack of an effect on the primary outcome is the result of insufficient increases in PA. Research is needed to identify the smoking populations most suitable for PA interventions and methods for increasing PA adherence.Trial registrationCurrent Controlled Trials ISRCTN48600346.FundingThis project was funded by the NIHR Health Technology Assessment programme and will be published in full inHealth Technology Assessment; Vol. 19, No. 84. See the NIHR Journals Library website for further project information.

Factors associated with study attrition in a pilot randomised controlled trial to explore the role of exercise-assisted reduction to stop (EARS) smoking in disadvantaged groups

“…Another exercise counselling for smoking cessation among depressed women [43] reports slightly higher attrition rates of 35 % at 10 weeks with no difference between arms. A recent study using exercise to support pregnant smokers to quit reported 11 % attrition for unexplained reasons [44]. A study supporting homeless people to quit [45] reports 25 % attrition at 26 weeks with no difference between study arms.…”

Re-starting smoking in the postpartum period after receiving a smoking cessation intervention: a systematic review

“…We contacted ongoing trials investigators in August 2014 and March 2015, but no new studies were identified; we were unable to make contact for two trials , and no results were available for another . Four studies reported continuous abstinence only , seven reported both continuous and point‐prevalence abstinence and 16 reported point‐prevalence abstinence only The primary meta‐analysis contained 571 women from 11 studies , while the secondary meta‐analysis included 9262 women from 23 studies A summary of the characteristics of included studies can be found in Supporting information, file 2.…”

“…Twenty studies were randomized controlled trials (RCTs) with individual randomization , five were cluster‐randomized and two were quasi‐randomized Of the cluster‐randomized studies, all required participants to give consent to join the study, therefore no cluster RCTs were excluded from the review on the basis of not consenting women to join. Control groups received information booklets in 15 studies ; counselling (eight studies) ; placebo patches (three studies) ; one used non‐contingent vouchers (rewards given to participants for attending the clinic) ; and one did not report what the control intervention was Three studies used ‘usual care’ as a control, but did not define this , while one study reported using ‘usual care’ as provided by the UK NHS The control group received no intervention in one study . Fourteen studies reported using a single technique for the control intervention .…”

“…For the intervention groups, 17 studies reported using information booklets , 20 reported using counselling , four used nicotine replacement therapy (NRT) , three used social support interventions , two used motivational interviewing (MVI) techniques and two used financial incentives The following interventional approaches were employed in one study each: ‘stages of change’ , contingent vouchers (smoker rewarded for meeting certain criteria) , letters of support and physical activity . Only four studies used a single technique , with most trials utilizing combinations of intervention strategies.…”

Does aerobic exercise reduce postpartum depressive symptoms? a systematic review and meta-analysis

“…A correlation of 0.6 was used in the assumptions to estimate standard deviations of differences, based on a previous sample of postpartum women. 21 A random effects model was used throughout because of known clinical heterogeneity between populations and methodological heterogeneity between interventions.…”