IMPACT OF THE COVID-19 PANDEMIC ON ADHERENCE TO CARDIOVASCULAR MEDICATIONS AMONG CHRONICALLY TREATED PATIENTS IN ALBERTA

Background: Some studies have suggested that the COVID-19 pandemic negatively impacted patient adherence with chronic therapies. We designed this study to explore whether cardiovascular drug adherence patterns changed in chronically treated patients during the COVID-19 pandemic. Methods: Retrospective cohort study examining drug dispensation data for all Alberta residents older than 18 years who were chronic users of at least one cardiovascular drug class, defined as receiving at least one prescription per annum for any agent in that drug class from March 15, 2017 to March 14, 2023 and 2 or more prescriptions within 365 days during either the pre-pandemic phase (March 15, 2018 to March 14, 2020) or the pandemic phase (March 15, 2020 to March 14, 2022). We calculated the proportion of days covered (PDC) for each drug class per patient and used generalized estimating equation logistic regression to estimate the effect of time period (pandemic versus pre-pandemic) on achievement of good adherence (PDC>0.8) after adjusting for age, sex, socioeconomic status, and comorbidities. Results: We evaluated 548,601 chronic users of at least one cardiovascular drug class between March 15, 2018 and March 14, 2022. The most frequently dispensed cardiovascular drug classes were ACEi/ARB (67.6%), statins (53.8%), beta-blockers (21.0%), and calcium channel blockers (20.7%); the most frequent diagnoses were hypertension (77.2%), diabetes mellitus (30.6%), and ischemic heart disease (19.6%), although 55.4% of the patients had Charlson Comorbidity Index scores of 0. The mean PDC for cardiovascular drug use in our cohort was 85.7% (median 93%) pre-pandemic and 87.0% (median 94%) during the pandemic. The proportion exhibiting good adherence (PDC>0.8) increased from 72.8% pre-pandemic to 75.4% during the pandemic (p<0.001). During the pandemic, users of cardiovascular drugs were more likely to exhibit good adherence (PDC>0.8) than they were in the pre-pandemic period: aOR ranged from 1.05 (95%CI 1.00-1.11) for mineralocorticoid receptor antagonists to 1.16 (1.15-1.17) for statins. Conclusion: Chronic users of cardiovascular drugs exhibited higher adherence measures during the COVID-19 pandemic than prior to the pandemic.