Long-term persistence and adherence to blood pressure lowering agents among older Australians

Poor adherence and persistence to blood pressure lowering (BPL) agents leads to increased risk of morbidity and mortality. The aim of this study was to investigate the long-term adherence, persistence, and re-initiation of BPL agents among older Australians (aged ≥65 years).

We utilised the Pharmaceutical Benefits Scheme data covering a 10% random sample of Australians. We identified 31 088 older Australians (mean age, 75.4 years; 56% females) with newly initiated BPL therapy from 2008 to 2016. Adherence was assessed using the proportion of days covered (PDC) at 6-month intervals. Discontinuation was defined as ≥90 days without BPL coverage. Cox regression was applied to compare the time till the first discontinuation of BPL agents across different BPL categories and among various subgroups.

Over a mean follow-up of 3.8 years, 40% to 70% of older Australians received a BPL agent discontinued it. The median time to discontinuation ranged from 159 to 373 days. Persistence with fixed dose combinations was the best (68%, 58%, and 41% at 6, 12, and 36 months respectively), followed by angiotensin II receptor blockers (69%, 58%, and 40%), beta-blockers (67%, 54%, and 36%), angiotensin converting enzyme inhibitors (62%, 51%, and 34%), calcium channel blockers (57%, 47%, and 31%), and diuretics (59%, 41%, and 23%). Among those who discontinued, 30% to 50% re-initiated, with median days to re-initiation ranging from 177 to 302. Only 21% to 42% of the study population maintained "good" adherence (PDC ≥ 0.8) to BPLs over 3 years.

Compliance to BPL agents is poor among older Australians. Interventions to enhance adherence and persistence to BPL agents are needed.