Austin 2003.

Methods	Study design: ITS
Participants	Physicians Clinical speciality: not clear Level of training: fully trained Setting/country: not clear/Canada
Interventions	2 PEMs were studied, but only 1 respected our inclusion criteria for ITS studies that more than 3 points need to be available before and after the intervention, and that PEM was the HERS. The HERS study was published in 1998 and demonstrated that the risks associated with hormone therapy outweighed the benefits for women taking continuous oestrogen and progestin regimens
Outcomes	2 process outcomes (prescribing): the proportion women older than 65 years who filled a prescription for ERT in Ontario (prevalence of use of ERT) the number of prescriptions filled by women who had not filled a prescription for ERT in the previous 365 days (proportion of incident users of ERT)
Notes	‐
Risk of bias
Bias	Authors' judgement	Support for judgement
Intervention independent of other changes ‐ ITS	Unclear risk	No information is provided
Shape of Intervention effect pre‐specified ‐ ITS	Unclear risk	Quote, pg. 3241: "we examined patterns of prescriptions for estrogen replacement therapy (ERT) before and after publication of the Women's Health Initiative (WHI) study on July 17, 2002. We also examined trends around the publication of the Heart and Estrogen/progestin Replacement Study (HERS) in 1998"
Intervention unlikely to affect data collection ‐ ITS	Low risk	COMMENT: the intervention (publication of the WHI study in 2002) 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	Quote, pg. 3241: "we studied claims for ERT to Ontario's universal Drug Benefit program for seniors (ODB), which tracks medication use by all 1.3 million residents of Ontario older than 65 years"
Selective reporting (reporting bias) ‐ ITS	Low risk	All relevant outcomes in the methods section were reported in the results section
Other bias ‐ ITS	Low risk	There was no evidence of other risks of bias