| Methods |
Setting: hospital or chest clinic in UK.
Recruitment: Volunteers selected by motivation. |
| Participants |
New patients with smoking‐related disease but not pregnant, terminally or psychiatrically ill.
1392 patients, smoke at least 1cpd, mean 17cpd.
Therapists: physicians. |
| Interventions |
1. Advice.
2. Advice plus signed agreement.
3. Advice plus letters of support.
4. Advice plus letters plus signed agreement.
Intervention level: intensive vs minimal.
Aids used: yes. Follow‐up visits: none. |
| Outcomes |
Sustained at 12 m (& 6m).
Validation: expired CO. |
| Notes |
The use of supportive letters was classified as intensive, so 3 & 4 compared to 1 & 2 in the intensive vs minimal comparison; (two studies are reported in the same paper). |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
"Patients were allocated at random."; method of sequence generation was not specified. |
| Allocation concealment (selection bias) |
Unclear risk |
Patients were randomised using "a sequence of sealed envelopes."; it is unclear whether envelopes were opaque. |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Similar numbers lost across all 4 groups. 1) 72/343; 2) 80/347; 3) 90/351; 4) 86/351); participants with missing data were considered smoking. |
