Guay 2007.

Methods	Study design: ITS
Participants	Physicians Clinical speciality: not clear Level of training: fully trained Setting/country: outpatient (e.g., ambulatory care provided by hospitals/specialists)/Canada
Interventions	The PEM was the WHI trial, published on 17 July 2002, which concluded that overall health risks exceeded benefits from use of combined oestrogen plus progestin among healthy postmenopausal women
Outcomes	1 process outcome: total number of HRT prescriptions dispensed per month
Notes	‐
Risk of bias
Bias	Authors' judgement	Support for judgement
Intervention independent of other changes ‐ ITS	Unclear risk	No information was provided
Shape of Intervention effect pre‐specified ‐ ITS	Low risk	Quote, pg. 18: "from this perspective, the aim of our study is to evaluate the impact of the publication of the WHI study in the Quebecers population, and to estimate if the use of HRT did indeed change in accordance with the new guidelines"
Intervention unlikely to affect data collection ‐ ITS	Low risk	The intervention (WHI study) did not affect either the source or method of data collection
Blinding of outcome assessors (detection bias) ‐ ITS All outcomes	Low risk	The outcome was objective
Incomplete outcome data (attrition bias) ‐ ITS All outcomes	Low risk	The authors provide a thorough description of the proportions of patients removed from analysis by inclusion and exclusion criteria. There was a 10% difference between loss to follow‐up in pre‐WHI cohort (39% loss) and the post‐WHI cohort (49%), and the reasons for loss were similar. The cohorts were considerably different in absolute size, but this was attributable to the large difference in the time‐frame (16,560 patients, 3 years in pre‐WHI vs. 2067 women in 9 months post‐WHI)
Selective reporting (reporting bias) ‐ ITS	Low risk	All relevant outcomes in the methods section were reported in results section
Other bias ‐ ITS	Low risk	There was no evidence of other risks of bias