CPIT III trial. Cessation of smoking in pregnancy incentives trial (Phase III)

Aim(s):

To examine the effectiveness and cost-effectiveness of offering financial incentives to pregnant smokers to quit.

Research questions:

  1. How effective is the addition of up to £400 of financial incentives to usual NHS smoking cessation services in terms of cotinine-validated abstinence in late pregnancy and six months after birth?
  2. Is this strategy cost-effective both in terms of cost per extra quitter, and potential lifetime cost per Quality Adjusted Life Year (QALY) gained?
  3. What effect does demographic diversity and differences in smoking cessation service configuration have on observed outcomes?
  4. What are the barriers and facilitators to trial recruitment, retention and implementation in different areas with different population groups?

Summary:

Annually, in the UK, smoking causes 5000 early miscarriages, 100 stillbirths and 200 infant deaths. Smoking increases prematurity, low birth weight, asthma, attention deficit disorder and learning difficulties, adding substantial costs to health care.  One in four UK women smoke for part and one in eight throughout pregnancy.  Smoking cessation services offer counselling plus free Nicotine Replacement Therapy (NRT), however only 10% of pregnant smokers use these services and as few as 3% stop.  Systematic reviews including those undertaken as part of the NIHR HTA funded BIBS study led by Pat Hoddinott [HBC02.1] show promise for financial incentives and NICE have put forward a research recommendation for a definitive trial of financial incentives. BIBS surveyed the public and relevant health professionals, conducted a discrete choice experiment on women with a smoking history and interviewed a range of stakeholders on types, acceptability and levels of incentive. More than 85% of the general public found vouchers valued up to £40 per month acceptable. Vouchers above £20 per month were required, and higher values would increase the likelihood of quitting.

CPIT III is a multi-centre randomised controlled trial at 4 centres, with a parallel process evaluation led by the Unit’s Pat Hoddinott and Fiona Harris, who have internationally recognised methodological expertise in qualitative methods applied to trials. It follows an efficacy trial (CPIT II) undertaken in Glasgow.  It incorporates the findings from the BIBS platform study for incentive trials.  The four trial sites have different smoking cessation service and maternity care configurations.  The mixed methods process evaluation will investigate how CPIT III integrates at the four sites.  In particular, qualitative interviews and observations will help to understand any differences in recruitment rates or engagement in the trial and the fit with local context.

Principal Investigator: University of Stirling and University of Glasgow

NMAHP Research Unit Collaborators: Professor Pat Hoddinott

Funder: CRUK