Adherence and medication utilisation patterns of fixed-dose and free combination of angiotensin receptor blocker/thiazide diuretics among newly diagnosed hypertensive patients: a population-based cohort study

OBJECTIVE: The study aimed to compare the adherence and persistence among newly diagnosed hypertensive patients using fixed-dose (FDC) and free combinations (FC) of angiotensin receptor blocker (ARB)/thiazide diuretic using Taiwan's National Health Insurance Research Database. METHODS: General linear regression and Kaplan-Meier analyses were used to estimate the impact of FDC on adherence [measured by medication possession ratio (MPR)] and persistence (time from day of initiation to treatment discontinuation) of ARB/thiazide diuretic. RESULTS: The adjusted MPRs were all significantly higher among FDC group compared with FC group (6 months: 66.55% vs. 63.86%; 1 year: 52.58% vs. 46.73%, 1.5 year: 46.30% vs. 38.07%; 2 year: 42.06% vs. 32.45%, all p < 0.001). Patients received FDC therapy were less likely to discontinue their therapy [adjusted hazard ratio (HR) 0.79, 95% CI = 0.74-0.85]. CONCLUSIONS: Our findings suggest that use of FDC is associated with higher adherence and persistence rates than use of FC in newly diagnosed hypertensive patients.