Initial antihypertensive prescription and switching: a 5 year cohort study from 250,851 patients.

Abstract

PurposeAdverse effects of antihypertensive therapy incur substantial cost. We evaluated whether any major classes of antihypertensive drugs were significantly associated with switching as a proxy measure of medication side effects in a large Chinese population in Hong Kong.MethodsFrom a clinical database, all adult patients newly prescribed an antihypertensive mono-therapy in Hong Kong between the years 2001-2003 and 2005 were included. Those who paid only one visit, died or stayed in the cohort for ResultsFrom 250,851 subjects, 159,813 patients were eligible. A total of 6,163 (3.9%) switched their medications within 180 days. Patients prescribed thiazide diuretics had the highest switching rate (5.6%), followed by ACEIs (4.5%), CCBs (4.4%) and beta-blockers (3.2%). When compared with ACEIs, patients on thiazide diuretics were significantly more likely to be switchers (adjusted odds ratio [AOR] 1.49, 95% C.I. 1.31-1.69, pConclusionsThe higher rates of switching among thiazide diuretics in this study might raise a probably greater incidence of their adverse effects in this Chinese population, yet other factors might also influence switching rates. Patients prescribed thiazide diuretics for longer term should be observed for their intolerability.