Methods	Cluster RCT, with the primary care physician as the unit of randomisation
Participants	480 adults with coronary heart disease from 252 practices in Edmonton and Calgary; Opinion leader statement: n= 165; Unsigned statement:n=158 and Control: n=157 Country: Canada Type of targeted behaviour: General management of a problem (secondary care for CHD statin management
Interventions	Opinion Leader endorsed /signed evidence summary Unsigned evidence summary Method of OL identification: Sociometric Proportion of Social Network that nominated OL: UNCLEAR Single OL or OL teams identified: single OL OL disseminated information: Formal (Faxed evidence summaries) OL frequency of involvement:action taken at one time-point Control: No intervention (physicians only received a coronary chart for their patients, which is considered somewhat more than standard care in this region)
Outcomes	Improvement in statin management (new start or dose increase) 6 months post-catheterisation
Notes
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	p.898/Col 2/Para 1 “Randomizationtookplace 1:1:1 following the completion of the patients angiogram using a computer-generated central randomization system with concealment of the randomization list.”
Allocation concealment (selection bias)	Low risk	p.898/Col 2/Para 1 Although primary care physicians were not blinded to allocation status, both allocation concealment and blinding were achieved for investigators, patients, outcome assessors, and analysts
Blinding (performance bias and detection bias) All outcomes	Low risk	Although primary care physicians were not blinded to allocation status, both allocation concealment and blinding were achieved for investigators, patients, outcome assessors, and analysts p.900/Col 2/Para 2 Follow-up data was collected by independent and blinded outcome assessors, clinical events were independently adjudicated by two blinded investigators (FAM and SRM) who then met to resolve discrepancies, and statistical analyses were conducted by a statistician blinded to allocation status
Incomplete outcome data (attrition bias) All outcomes	Low risk	p.901/Col 2/Para 1 We evaluated the status of 466 patients (97%) after six months (2 patients were lost to follow up, 6 withdrew consent, 3 died and 3 were excluded due to protocol violations
Selective reporting (reporting bias)	Low risk	All outcomes mentioned in the methods section were also presented in the results
Other bias	Low risk
Similar baseline outcome measures?	Low risk	p.28 /Table 1 At baseline, there were no statistically significant differences between groups (Table 1)
Similar baseline characteristics?	Low risk	p.28/Table 1. At baseline, there were no statistically significant differences between groups
Protection against contamination?	Low risk	This was a randomized clinical trial clustered at the level of the primary care physician to avoid contamination