Supplementary Material for: Region of Birth Differences in Medication Adherence Among Patients with Stroke or Transient Ischemic Attack

Background and Purpose: Cultural and language barriers may affect quality of care, such as adherence to medications. We examined whether adherence to prevention medications within the year after stroke/transient ischemic attack (TIA) differed by region of birth. Methods: An observational study of adults with stroke/TIA admitted to hospitals in the Australian Stroke Clinical Registry (Queensland, Victoria; 2012-2016; n=45 hospitals), with linked administrative data. Region of birth was categorized into 10 groups (Australia, Other Oceania, North-West Europe, Southern/Eastern Europe, North Africa/Middle East, South-East Asia, North-East Asia, Southern/Central Asia, Americas, Sub-Saharan Africa). Analysis was limited to those with a first-ever stroke/TIA who were dispensed an antihypertensive, lipid-lowering, or antithrombotic medication within 1-year post-discharge. Medication adherence was calculated based on the proportion of days covered until 1 year immediately post-discharge/death. Associations between region of birth and being adherent (PDC ≥80%) was determined using multivariable logistic regression (adjusted for age, sex, stroke type, ability to walk on admission, discharge destination, socioeconomic position, main language spoken, comorbidity score). Results: Among 24,236 eligible participants (median age 74 years, 44% female, 68% Australian-born), 54% were adherent to antihypertensive medications, 56% to lipid-lowering medications, and 49% to antithrombotic medications. Compared to Australian-born participants, those born in Other Oceania (4.0%) were less likely to be adherent to lipid-lowering medications (OR 0.78, 95% CI 0.67-0.90) and antithrombotic (OR 0.84, 95% CI 0.72-0.97). Compared to Australian-born participants, those born in Southern and Central Asia (1.4%) were less likely to be adherent to lipid-lowering medications (odds ratio [OR]: 0.76, 95% CI 0.58-0.99) and antithrombotic (0.55, 95% CI 0.40-0.76). No significant differences were found with other regions. Conclusions: Disparities by the region of birth were observed in medication adherence after stroke/TIA for participants born in Asia and Oceania. Targeted education to improve medication adherence, specific to the needs of these groups, is warranted.