Betson 1998.
Methods | Setting: government outpatient clinic, Hong Kong Recruitment: smokers aged < 65 | |
Participants | 865 smokers, 92% male, 49% smoking > 10 cpd | |
Interventions | ∙ No intervention ∙ Self‐help materials (Chinese translation of American Cancer Society booklet) ∙ Physician advice (1 minute, based on 4 As) ∙ Physician advice and self‐help booklet | |
Outcomes | Abstinence at 1 year (sustained from 3 months) Validation: poor response to request for urine specimen, so data based on self‐report | |
Notes | 2 vs 1, self‐help with face‐to‐face contact 4 vs 3, self‐help as adjunct to advice Full paper provided by Professor Lam | |
Risk of bias | ||
Bias | Authors' judgement | Support for judgement |
Random sequence generation (selection bias) | Unclear risk | Table of random numbers used to allocate questionnaires to 4 groups placed in sealed numbered envelopes |
Allocation concealment (selection bias) | Unclear risk | "Every doctor was given a set of sealed envelopes" Considerable imbalance in numbers in each group; unclear whether this was due to randomisation procedure or selection bias |
Blinding (performance bias and detection bias) All outcomes | Unclear risk | Abstract only; unclear if participants were aware of what other arms received, but within comparisons in this review, interventions varied by intensity |
Incomplete outcome data (attrition bias) All outcomes | Low risk | 36% lost to follow‐up, included in ITT analysis |