Meta-Analysis: Impact of Drug Class on Adherence to Antihypertensives

Study Questions:

Does drug class influence adherence to antihypertensives?


This was a meta-analysis of English language articles published until February 2009. Studies were included which provided information on adherence to antihypertensive medications using medication refill data with enough detail to calculate measures of relative risk for adherence and associated variance on at least two or more distinct antihypertensive drug classes. Participants of these studies were all community-dwelling adults, ages 18 years or older.


A total of 935,920 participants (mean age 61.7 years, 53.1% women) were included from 17 studies that met inclusion criteria. The pooled mean adherence by drug class ranged from 28% for beta-blockers to 65% for angiotensin II receptor blockers (ARBs). Adherence rates for ARBs were higher than adherence rates for angiotensin-converting enzyme inhibitors (ACE inhibitors) (hazard ratio [HR], 1.33; 95% confidence interval [CI], 1.13-1.57). Adherence for ARBs was also better than that observed for diuretics (HR, 1.95; 95% CI, 1.73-2.20), and beta-blockers (HR, 2.09; 95% CI, 1.14-3.85). Adherence to diuretics was lower than adherence to other antihypertensive drug classes. After publication bias was accounted for, there were no longer significant differences in adherence between ARBs and ACE inhibitors, or between diuretics and beta-blockers.


The investigators concluded that adherence differs by antihypertensive class, with the lowest adherence observed for diuretics and beta-blockers. The highest rates of adherence were observed for ARBs and ACE inhibitors.


Adherence to medications is an important concern and is a frequent reason for poorly controlled blood pressure. For many cardiac medications, including antihypertensive medications, adherence drops significantly in the year following drug initiation. Providers must learn to assess adherence at every visit and address patient concerns and/or barriers to adherence in order to improve long-term compliance.

Keywords: Risk, Diuretics, Blood Pressure Determination

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