Institute of Epidemiology & Health Care


Study Design

Start 2 Quit

This randomised trial will be conducted in two stages.

We will recruit practices through the Primary Care Research Network initially in Camden (North London) and in Oxfordshire for the pilot phase, proceeding to a full trial in a further 96 practices in 16 NHS Stop Smoking Services (SSS) areas.

Target population

All smokers motivated to quit who have not previously or recently attended the SSS.


All smokers aged 16 and over will be identified from their medical records in participating practices. After screening by the GP to exclude unsuitable participants, these smokers will be sent a Participant Information Sheet - PDF, and a Smoking Questionnaire and Consent Form - PDF together with a cover letter from their GP. The data on the questionnaire will be used to assess the criteria for inclusion in the trial, to update their smoking status in their medical records, as well as to tailor the personal tailored risk information letter to the participants. All smokers returning the questionnaire and willing to participate will be randomised to the Control or Intervention group. Smokers will have the option of returning the questionnaire to update their records only.

  • The Control group will receive a standard generic letter advertising the SSS and inviting them to contact the service to make an appointment to see an advisor.
  • The Intervention group will receive a personal tailored letter from the GP offering risk information specific to the patient and an invitation and appointment to attend a 'Come and Try it' taster session to find out more about the services. The taster session will be run by advisors from the local service and will offer information about the services, a measurement of expired-air carbon monoxide (CO), a 10 minute video showing group and one-to-one sessions in progress, and the opportunity to ask questions about the service. Attendees will be encouraged to sign up to a group or one-to-one session at a convenient time. Participants who fail to attend will receive a further invitation and taster session appointment 3 months later to encourage attendance.

Evaluation and Outcomes

Research interviewers, independent of the service providers, will conduct follow-up interviews 6-months after the date of randomisation by telephone, to assess: attendance at the services, current smoking status, daily cigarette consumption, reasons for non-attendance and barriers to attendance in all participants.

Primary outcome measure:

i) The proportion of people entering the SSS (i.e. attending the first session of a 6-week course) over a period of 6 months from the receipt of the invitation letter. Self-reported attendance data will be validated by records of attendance at the SSS.

ii) 7-day point prevalent abstinence at the 6-month follow-up, validated by a salivary cotinine sample or an expired-air carbon monoxide (CO) measure for all participants reporting abstinence in both the Intervention and Control groups.

Secondary outcome measures:

i) Prolonged periods of abstinence of 7 days to 24 weeks measured by self-report.

ii) Self-reported changes in daily cigarette consumption, quit attempts, and changes in motivation and intention to quit in continuing smokers.

iii) Use of NRT, Zyban, Champix and other smoking cessation aids.

iv) The number completing the 6-week SSS course.

v) Process measures:
a. the number of smokers attending the "Come and Try It" taster session (Intervention group only)
b. perception of the personal tailored risk information letters
c. reasons for non-attendance at the "Come and Try It" taster session and barriers to attendance at the SSS

vi) Health Economic measures
a. cost of providing the interventions
b. patients' use of health and social care services
c. QALYs calculated from the EQ-5D

Sample size

We aim to recruit 4500 participants. Practices generally identify 13% to 22% of their patients as smokers, depending on the characteristics of the patient population, and the accuracy and completeness of the records.

Therefore we estimate that 6 practices in each of 18 SSS areas, with a list size of at least 4000, would give approximately 432,000 patients and, assuming an average smoking prevalence of 15%, 64800 smokers.

Based on an estimated response rate of 7% from smokers motivated to quit, we would secure 4500 participants.

In order to prevent any bias due to variability in the delivery of the intervention we will inflate the size of the Intervention group by a factor of 1.51.

Thus approximately 2707 will be randomised to the Intervention group to receive the tailored letter and taster session, and 1793 to the Control group.