Olano Espinosa 2013.

Study characteristics
Methods	Design: Cluster‐ randomized controlled trial Setting: Healthcare centres in Area 11 of the Spanish Madrid Health System, Spain Recruitment: Participants selected from computerized clinic records
Participants	405 nurses and 425 doctors from the 35 clinics 5910 adults who smoked. av.age 43, 53% F, av. cpd not reported
Interventions	Intervention: professionals received 4 x 90‐minute training sessions on smoking cessation Control: professionals were offered the training after finishing the follow‐up period
Outcomes	Continuous abstinence at 6m Validation: Salivary cotinine < 13 ng/ml
Funding Source	Spanish Public Health Investigations Fund, with no role in the study
Author's declarations of interest	QUOTE: "Two authors (FJA and EOE) work as directors of Cantabria University Tobacco Control Master"
Notes	Strategy: Provider training Level: Provider Comparison type: Single component vs. standard care
Risk of bias
Bias	Authors' judgement	Support for judgement
Sequence Generation	Low risk	QUOTE: "...randomly selected 15 patients for each quota by using number combinations generated with EPIDAT 2.0 software"
Allocation concealment	Low risk	QUOTE: "An independent research assistant assigned the 35 health care centers randomly using SPSS v.12 software...". No further detail provided.
Blinding of outcome assessors All outcomes	Low risk	Abstinence biochemically validated
Incomplete outcome data All outcomes	Unclear risk	Not reported
Recruitment bias (cluster RCTs only)	Low risk	Participants were affiliated with the practice before randomization
Balanced baseline characteristics? (cluster RCTs only)	Low risk	QUOTE: "No significant differences were found between both groups with respect to profession, age, sex, professional experience, percentage of smokers, and previous training in treating tobacco addiction"
Adjustment for clustering in analysis? (cluster RCTs only)	High risk	Not apparent