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Table 3 Variables considered for the baseline adjustment

From: Does the association between adherence to statin medications and mortality depend on measurement approach? A retrospective cohort study

Variable category Included variables
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.