| Methods |
Country: USA
Setting: 7 pediatrics and family practice departments in Health Maintenance Organization medical centres in Oregon and Washington State
Study design: RCT (prevention and cessation). Blocked randomization method, using sealed envelopes |
| Participants |
Participants: 448 adolescent smokers selected from 2524 recruits attending clinic appointments.
Age range: 14‐17 years
Criteria for inclusion: those who were willing to stay after consultation at clinic and had no intention of leaving geographical area within 1 year
Follow‐up method: mailed questionnaires and telephone interviews
Inducements to enter study: none
Pre‐study smoking status assessment: self‐reported 30‐day smoking status
Non‐significant demographic differences between arms of trial at level of P < 0.05 except for small difference in positive at depression screen (P < 0.01) |
| Interventions |
Intervention: 3 sequential interventions plus maximum of 2 boosters:
(1) clinical message encouraging quitting or not starting, (2) 10‐12 min individual, multi‐media interactive computer‐delivered expert system tailored to stage of change of individual (3) 3‐5 min of motivational counselling by trained health counsellors. Boosters were delivered at clinic attendance (computer programme and motivation counselling) or by telephone (motivational counselling only). Repeated attempts were made to deliver boosters.
Theoretical basis of intervention: prompts to clinicians to give brief advice, TTM and MI
Control: dietary advice (5‐a‐day fruit and vegetables); theoretical basis of intervention: brief advice ‐ 3‐5 min motivational counselling |
| Outcomes |
Measurement: 30‐day PPA; follow‐up periods: > 3 months, 1 year and 2 years
No verification
Losses to follow‐up: 6% at 12 months and 12% at 24 months |
| Notes |
This systematic review uses definition of smoking of 1 cpw for ≥ 6 months to define a regular smoker. Hollis et al confirm that their definition of 'smokers' most closely fits this criterion.
We have only used the data for smokers, although the trial included separate smoking uptake prevention results. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
"blocked over time and stratified according to medical centre and 30‐day cigarette smoking status," method of sequence generation not specified |
| Allocation concealment (selection bias) |
Low risk |
"Study staff members not involved in recruitment or randomization printed the stratified allocation assignments on index cards and concealed the cards in envelopes." |
| Blinding of participants and personnel (performance bias)
All outcomes |
Unclear risk |
Not specified |
| Blinding of outcome assessment (detection bias)
All outcomes |
High risk |
Assessor blinded, but no biochemical validation used. Differential misreport possible |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Loss to follow‐up at 2 years higher in treatment group (14.3%) than in control group (10.1%). 6 types of analyses to model missing data, including ITT analysis, in which participants lost to follow‐up counted as smokers. "Conclusions were largely consistent among the various missing‐data procedures." |
