Table 3 Variables considered for the baseline adjustment

Demographic variables

• age at index date

• gender

• year of hospital discharge

Condition-related variables

• type of index diagnosis (ACS only, ACS plus revascularization)

• duration of index hospitalization

• number of days between index date and first dispensation of statin

Therapy-related factors

• filling at least one prescription for specific cardiovascular medication (s) during the first year post-index including (beta-blockers; angiotensin converting enzyme-inhibitor (ACEI) or angiotensin receptor-blockers (ARB); calcium channel blockers (CCBs); diuretics; anticoagulants; antiplatelet; nitrates; or other lipid drugs - yes/no for each) (Appendix 3)

• filling at least one prescription with a quantity of 28 tablets as an evidence of unit-of-use packaging

• receiving a high (versus low) statin dose on first prescription post index

• the statin used on first prescription following the index date (atorvastatin versus others)

• burden of medications defined as the total number of distinct medications’ therapeutic groups dispensed to the individual

Patient-related factors

• socio-economic status (SES) assessed by the deprivation index (DI) developed by Pampalon et al. This was identified by mapping individuals’ residential postal codes to geographic-level statistics for the Statistics Canada census.

• comorbidities calculated by Deyo-adapted Charlson score method using hospitalizations data

• specific comorbid conditions of diabetes, and hypertension reported in any physician claim or hospitalization in the year prior to the index date (Appendix 4)

Health system-related factors

• specialty of prescribing physician for the first statin dispensation (general practitioner (GP), cardiologist, general internist, cardiac surgeon, other)

• number of physician billing claims in the first 3 months following the first statin dispensation

• any prior hospitalization in the year prior to the index date.