AHRQ Report: ACEIs, ARBs Show Similar Effects on Blood Pressure

More than 65 million adults in the United States have high blood pressure, making it one of the most common conditions family physicians are likely to encounter in everyday practice. Two common classes of medications used to manage essential hypertension -- angiotensin-converting enzyme inhibitors, or ACEIs, and angiotensin receptor blockers, or ARBs (also known as angiotensin II receptor antagonists) -- have been studied extensively. Now, the Agency for Healthcare Research and Quality, or AHRQ, has published a report comparing the effectiveness and other aspects of these two types of drugs.

The report, "Comparative Effectiveness of Angiotensin-Converting Enzyme Inhibitors (ACEIs) and Angiotensin II Receptor Antagonists (ARBs) for Treating Essential Hypertension," (73-page PDF; About PDFs) which analyzed the results of 61 studies on various outcome measures, asked three key questions:

The AHRQ researchers found solid evidence suggesting that ACEIs and ARBs have similar long-term effects on blood pressure control among adults with essential hypertension, although outcomes were confounded to some extent by additional treatments and varying dose-adjustment protocols. Limited data on mortality and major cardiovascular events in the included studies precluded researchers from discerning any differential effect of ACEIs versus ARBs on those health outcomes.

No differences in general quality of life measures were noted between the two types of drugs, although the strength of evidence for this finding was low. The researchers also found no difference in comparative rates of treatment success based on use of a single antihypertensive agent in either class.

There were no consistent differential effects between ACEIs and ARBs on other potentially important clinical outcomes, including lipid levels, presence or absence of various markers of carbohydrate metabolism/diabetes control, progression to type 2 diabetes, and progression of renal disease.

Differences were observed between the two types of drugs when assessing safety, adverse events, tolerability, persistence and adherence. ACEIs have consistently been shown to be associated with greater risk of cough than ARBs. In the AHRQ analysis, a dry cough was reported by approximately 1.7 percent of patients who took ACEIs compared with about 0.6 percent of those who took ARBs. Angioedema was reported only in patients treated with ACEIs, but because it was rarely explicitly reported in the included studies, it was not possible to estimate its frequency in the overall study population, said the researchers.

ACEIs and ARBs showed similar rates of adherence based on pill counts, but the researchers questioned whether that finding would be applicable outside of the clinical trial setting. Somewhat more patients continued therapy with ARBs than with ACEIs, but researchers found the magnitude of this effect difficult to quantify.

The researchers were unable to reach any conclusions regarding the comparative rates of effectiveness, adverse events or tolerability of ACEIs and ARBs in particular patient subgroups. They recommended further research in this area, especially among subgroups of special importance, such as patients with essential hypertension and certain comorbidities, including diabetes mellitus, congestive heart failure, chronic kidney disease and dyslipidemia. They also recommended that future studies follow patient outcomes for several years, and that more studies include such groups as the elderly and ethnic and racial minorities.