Impact of coordinated care on adherence to antihypertensive medicines among adults experiencing polypharmacy in Australia

Abstract

Background: Adherence to antihypertensives is key for blood pressure control. Most people with hypertension have several comorbidities and require multiple medicines, leading to complex care pathways. Strategies for coordinating medicine use can improve adherence, but cumulative benefits of multiple strategies are unknown. Methods: Using dispensing claims for a 10% sample of eligible Australians, we identified adult users of antihypertensives during July 2018–June 2019 who experienced polypharmacy (≥5 unique medicines). We measured medicine use reflecting coordinated medicine management in 3 months before and including first observed dispensing, including: use of simple regimens for each cardiovascular medicine; prescriber continuity; and coordination of dispensings at the pharmacy. We measured adherence (proportion of days covered) to antihypertensive medicines in the following 12 months, and used logistic regression to assess independent associations and interactions of adherence with these measures of care. Results: We identified 202 708 people, of which two-thirds (66.6%) had simple cardiovascular medicine regimens (one tablet per day for each medicine), two-thirds (63.3%) were prescribed >75% of medicines from the same prescriber, and two-thirds (65.5%) filled >50% of their medicine on the same day. One-third (28.4%) of people experienced all three measures of coordinated care. Although all measures were significantly associated with higher adherence, adherence was greatest among people experiencing all three measures (odds ratio = 1.63; 95% confidence interval: 1.55–1.72). This interaction was driven primarily by effects of prescriber continuity and dispensing coordination. Conclusions: Coordinating both prescribing and dispensing of medicines can improve adherence to antihypertensives, which supports strategies consolidating both prescribing and supply of patients’ medicines.