Lindsay 1989.

Study characteristics
Methods	Design: 3‐group cluster‐randomized controlled trial Setting: Primary care practices, Canada Recruitment: Receptionists identified people who smoked while visiting provider for routine appointment
Participants	83 providers 1942 people who smoked aged > 16 years, 64% smoked at least 20 cpd, av. age not reported, av. cpd not reported
Interventions	Intervention 1: Gum only • Physicians were cued by a project document indicating the participant's agreement to participate. Physicians in this group were instructed to advise the participant to quit smoking • Participants were advised to use nicotine gum (at their own cost) by their physician Intervention 2: Gum plus • Physicians attended a training session on smoking cessation. Flow sheet provided to them to help them deliver intervention. Physicians in this group were instructed to advise the participant to quit smoking • Participants received self‐help materials and were advised to use nicotine gum (at their own cost) by their physician Control: usual care. QUOTE: "If it was part of their usual practice to address the smoking issue with patients, this occurred. We gave no instructions to patients about whether they should mention their agreement to participate to their physician, and we had no way of assessing whether this, in fact, occurred"
Outcomes	3m continuous abstinence measured at 12 months Validation: Salivary cotinine < 0.057 umol/L Quit attempts Measures of provider implementation: Ask, Advise, Assist, Assist‐Meds, Assist‐Self‐help, Assist‐Quit Date, Arrange
Funding Source	National Institute of Health (USA) and Canadian National Research and Development Program
Author's declarations of interest	Not reported
Notes	Strategy: Provider training + flow sheet Level: Provider + Practice Comparison type: Multi‐component vs. standard care
Risk of bias
Bias	Authors' judgement	Support for judgement
Sequence Generation	Unclear risk	No details reported
Allocation concealment	Unclear risk	No details reported
Blinding of outcome assessors All outcomes	Low risk	Smoking abstinence was validated by cotinine
Incomplete outcome data All outcomes	Unclear risk	Authors reported that 21.3% (n = 129/606) of participants in the gum‐plus group attended 4 or 5 follow‐up visits and that no data were available for gum‐only group. No further details reported
Recruitment bias (cluster RCTs only)	Low risk	Participants were affiliated with the practice before randomization. QUOTE: "patients entered the study when they visited their physician for a routine office appointment"
Balanced baseline characteristics? (cluster RCTs only)	Low risk	QUOTE: "we observed no differences on physician characteristics among experimental groups"; "we observed some difference in motivation levels among groups and the main analyses of outcome adjusted for these differences"
Adjustment for clustering in analysis? (cluster RCTs only)	Low risk	QUOTE: "treatment effect was assessed using analysis of covariance; the unit of analysis being the practice"