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The SNAP trial: a randomised placebo-controlled trial of nicotine replacement therapy in pregnancy – clinical effectiveness and safety until 2 years after delivery, with economic evaluation

Cooper, Sue; Lewis, Sarah; Thornton, Jim; Marlow, Neil; Watts, Kim; Britton, John; Grainge, Matthew J.; Taggar, Jaspal; Essex, Holly; Parrott, Steve; Dickinson, Anne; Whitemore, Rachel; Coleman, Tim

Authors

JIM THORNTON jim.thornton@nottingham.ac.uk
Professor of Obstetrics and Gynaecology

Neil Marlow

Kim Watts

John Britton

Matthew J. Grainge

Dr JASPAL TAGGAR Jaspal.Taggar@nottingham.ac.uk
Clinical Associate Professor and Headof Primary Care Undergraduate Education

Holly Essex holly.essex@york.ac.uk

Steve Parrott

ANNE DICKINSON anne.dickinson@nottingham.ac.uk
Clinical Trial Research Assistant

Rachel Whitemore

TIM COLEMAN tim.coleman@nottingham.ac.uk
Professor of Primary Care



Abstract

BACKGROUND:
Smoking during pregnancy causes many adverse pregnancy and birth outcomes. Nicotine replacement therapy (NRT) is effective for cessation outside pregnancy but efficacy and safety in pregnancy are unknown. We hypothesised that NRT would increase smoking cessation in pregnancy without adversely affecting infants.
OBJECTIVES:
To compare (1) at delivery, the clinical effectiveness and cost-effectiveness for achieving biochemically validated smoking cessation of NRT patches with placebo patches in pregnancy and (2) in infants at 2 years of age, the effects of maternal NRT patch use with placebo patch use in pregnancy on behaviour, development and disability.
DESIGN:
Randomised, placebo-controlled, parallel-group trial and economic evaluation with follow-up at 4 weeks after randomisation, delivery and until infants were 2 years old. Randomisation was stratified by centre and a computer-generated sequence was used to allocate participants using a 1 : 1 ratio. Participants, site pharmacies and all study staff were blind to treatment allocation.
SETTING:
Seven antenatal hospitals in the Midlands and north-west England.
PARTICIPANTS:
Women between 12 and 24 weeks' gestation who smoked ≥ 10 cigarettes a day before and ≥ 5 during pregnancy, with an exhaled carbon monoxide (CO) reading of ≥ 8 parts per million (p.p.m.).
INTERVENTIONS:
NRT patches (15 mg per 16 hours) or matched placebo as an 8-week course issued in two equal batches. A second batch was dispensed at 4 weeks to those abstinent from smoking.
MAIN OUTCOME MEASURES:
PARTICIPANTS:
self-reported, prolonged abstinence from smoking between a quit date and childbirth, validated at delivery by CO measurement and/or salivary cotinine (COT) (primary outcome). Infants, at 2 years: absence of impairment, defined as no disability or problems with behaviour and development. Economic: cost per 'quitter'.
RESULTS:
One thousand and fifty women enrolled (521 NRT, 529 placebo). There were 1010 live singleton births and 12 participants had live twins, while there were 14 fetal deaths and no birth data for 14 participants. Numbers of adverse pregnancy and birth outcomes were similar in trial groups, except for a greater number of caesarean deliveries in the NRT group. Smoking: all participants were included in the intention-to-treat (ITT) analyses; those lost to follow-up (7% for primary outcome) were assumed to be smoking. At 1 month after randomisation, the validated cessation rate was higher in the NRT group {21.3% vs. 11.7%, odds ratio [OR], [95% confidence interval (CI)] for cessation with NRT, 2.05 [1.46 to 2.88]}. At delivery, there was no difference between groups' smoking cessation rates: 9.4% in the NRT and 7.6% in the placebo group [OR (95% CI), 1.26 (0.82 to 1.96)]. Infants: at 2 years, analyses were based on data from 888 out of 1010 (87.9%) singleton infants (including four postnatal infant deaths) [445/503 (88.5%) NRT, 443/507 (87.4%) placebo] and used multiple imputation. In the NRT group, 72.6% (323/445) had no impairment compared with 65.5% (290/443) in placebo (OR 1.40, 95% CI 1.05 to 1.86). The incremental cost-effectiveness ratio for NRT use was £4156 per quitter (£4926 including twins), but there was substantial uncertainty around these estimates.
CONCLUSIONS:
Nicotine replacement therapy patches had no enduring, significant effect on smoking in pregnancy; however, 2-year-olds born to women who used NRT were more likely to have survived without any developmental impairment. Further studies should investigate the clinical effectiveness and safety of higher doses of NRT.
TRIAL REGISTRATION:
Current Controlled Trials ISRCTN07249128.
FUNDING:
This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 54. See the NIHR Journals Library programme website for further project information.

Journal Article Type Article
Publication Date Aug 1, 2014
Journal Health Technology Assessment
Print ISSN 1366-5278
Electronic ISSN 1366-5278
Publisher NIHR Journals Library
Peer Reviewed Peer Reviewed
Volume 18
Issue 54
APA6 Citation Cooper, S., Lewis, S., Thornton, J., Marlow, N., Watts, K., Britton, J., …Coleman, T. (2014). The SNAP trial: a randomised placebo-controlled trial of nicotine replacement therapy in pregnancy – clinical effectiveness and safety until 2 years after delivery, with economic evaluation. Health Technology Assessment, 18(54), doi:10.3310/hta18540
DOI https://doi.org/10.3310/hta18540
Publisher URL http://www.journalslibrary.nihr.ac.uk/hta/volume-18/issue-54#abstract
Copyright Statement Copyright information regarding this work can be found at the following address: http://eprints.nottingh.../end_user_agreement.pdf

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Copyright Statement
Copyright information regarding this work can be found at the following address: http://eprints.nottingham.ac.uk/end_user_agreement.pdf





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