Purpose: To investigate patterns of initial drug therapy for the treatment of hypertension and to evaluate treatment persistence and change of treatment during a 4-year period in patients receiving thiazides (TZs) and/or angiotensin II-receptor blockers (ARBs) as first-line treatment.
Methods: All initial users of antihypertensive drugs in 2005 and 2009 registered in the Norwegian Prescription Database were included. Treatment on five index dates at 1-year intervals was recorded. A patient was considered to be under treatment on an index date if a drug had been dispensed within the previous 180 days and to have maintained treatment persistence if he/she was on any antihypertensive treatment on the index date and all previous index dates.
Results: Among 78,453 new users of antihypertensives in 2005, women started more often with TZs than men (30 vs. 25 %) and less often with ARBs (22 vs. 25 %). In men, the hazard of non-persistence with antihypertensive treatment was significantly lower among initial ARB users than among TZ users (hazard ratio 0.87, 95 % confidence interval 0.81-0.94); in women no significant difference was found. After 4 years, 49 % of the men and 51 % of the women who had started with plain TZs were still using TZs, whereas 65 % of the male ARB users and 60 % of the female ARB users were still using ARBs.
Conclusion: TZs and ARBs were the most widely used first-line antihypertensives. Among the men enrolled in the study, ARB users had a somewhat better persistence with antihypertensive treatment than TZ users. Among both genders, continuation on ARBs was more common than continuation on TZs.