Secades Villa 2009.

Study characteristics
Methods	Design: 3‐group cluster‐randomized controlled trial Setting: 3 primary care centers in Asturias, Spain Recruitment: Opportunistic recruitment of people who smoked attending the practice
Participants	89 adults who smoked (> 10 cpd) ready to quit. 61% F, 22 cpd, av.age 43
Interventions	Intervention 1: participants received a 7‐minute brief counseling in which they set a quit date, self‐help materials and 4 follow‐up telephone calls from a general practitioner or a primary care nurse Intervention 2: participants received 1 x 20‐min counseling session weekly for 5 weeks, delivered by a clinical psychologist Control: participants received a 7‐minute brief counseling and self‐help materials
Outcomes	Continuous abstinence at 12m Validation: Expired CO ≤ 4 ppm
Funding Source	Supported by research grant no. MB‐02‐506‐2 from the University of Oviedo (Spain)
Author's declarations of interest	Not reported
Notes	Strategy: Adjunctive counseling Level: Patient Comparison type: Single 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 status biochemically validated
Incomplete outcome data All outcomes	Low risk	At 6‐month follow‐up, 100% of participants were located
Recruitment bias (cluster RCTs only)	Low risk	Participants were affiliated with the practice before randomization
Balanced baseline characteristics? (cluster RCTs only)	High risk	There were statistically significant differences among the groups (P < .05) on 2 characteristics: age and years smoking
Adjustment for clustering in analysis? (cluster RCTs only)	Unclear risk	No details reported