Objectives: To assess trends in prescriptions, determinants and timing of treatment discontinuation and/or changes in antihypertensive drug therapy in a cohort of hypertensive patients living in Pavia, a city in the north of Italy.
Methods: The cohort included 61 493 patients aged ≥18 years who received their first antihypertensive drug prescription (monotherapy, fixed or extemporaneous combination) during the period 2003-6. Patients were classified as 'persistent' if 12 months after the beginning of treatment they were still taking a regular therapy (same drug = 'same therapy users', added one or more drugs = 'add-on therapy users', different drug = 'switchers'). Otherwise, they were classified as 'non-persistent' (stopping therapy after the first prescription = 'occasional users'; stopping treatment early = 'stoppers'; taking medicines in an erratic fashion = 'intermittent users').
Results: ACE inhibitors were the most frequently prescribed drugs (22.8%), followed by β-adrenoceptor antagonists (β-blockers) [14.3%], diuretics (13.9%), Ca(2+) antagonists (11.4%) and angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]) [9.3%]. After 12 months, persistent patients were only 11.2% (same therapy users 6.7%, switchers 3.2%, add-on therapy users 1.3%). Non-persistent patients were 88.8% (35.3% occasional users, 20.6% stoppers, 32.8% intermittent users). Patient-related predictors of persistence were older age, male sex, concomitant treatment with antidiabetic and hypolipidaemic drugs and previous hospitalizations for cardiovascular events. Highest level of persistence was seen in patients starting with ARBs (18.8%), followed by ACE inhibitors (11.4%), β-blockers (11.0%), Ca(2+) antagonists (10.8%) and diuretics (3.0%). Among ARBs, considering separately monotherapy and fixed-combination therapy, highest level of persistence was observed in patients starting with candesartan, irbesartan, valsartan and telmisartan given in monotherapy, and with valsartan and telmisartan given in fixed-dose combination.
Conclusions: Persistence to antihypertensive treatment at 12 months is only 11.2%, being the lowest with diuretics (3.0%) and the highest with ARBs (18.8%).