Aveyard 2003.
Methods | Setting: 65 general practices, UK Recruitment: volunteers from random selection of smoking patients; not selected for motivation | |
Participants | 2471 smokers, 1373 in relevant arms, > 80% in pre‐contemplation or contemplation, 10% to 14% in preparation 54% female, average age 41, average cpd 20 | |
Interventions | No face‐to‐face contact ∙ Standard self‐help materials, single mailing ∙ Self‐help manual based on transtheoretical (SoC) model; expert system letter tailored on baseline questionnaire. Further questionnaires at 3 months and 6 months for additional letters (approximately 50% received 3 letters) | |
Outcomes | Abstinence at 12 months, sustained for 6 months Validation: saliva cotinine < 14.2 ng/mL | |
Notes | 2 vs 1; tailored self‐help vs standard self‐help | |
Risk of bias | ||
Bias | Authors' judgement | Support for judgement |
Random sequence generation (selection bias) | Low risk | Randomisation using minimisation to balance SoC, addiction, and socioeconomic status |
Allocation concealment (selection bias) | Low risk | Baseline questionnaires read optically and data transferred automatically to the Access database, which performed the minimisation |
Blinding (performance bias and detection bias) All outcomes | Low risk | Interventions of similar intensity 12 months: abstinence "was confirmed with salivary cotinine, so that we had unconfirmed and confirmed prevalence of quitting" Confirmed figures used in analysis |
Incomplete outcome data (attrition bias) All outcomes | Low risk | 24% of self‐help and 24% of control lost to follow‐up Included in ITT analysis here; sensitivity analyses allowing for differential dropout did not change findings |