ACE inhibitors versus diuretics: ALLHAT versus ANBP2

The ALLHAT (The Antihypertensive and Lipid-Lowering treatment to prevent Heart Attack Trial) trial enrolled hypertensive patients with at least one additional risk factor for coronary heart disease (CHD) to a comparison of the diuretic chlorthalidone, the calcium channel blocker, amlodipine, and the angiotensin-converting enzyme (ACE) inhibitor, lisinopril. Throughout the study, chlorthalidone decreased the systolic blood pressure to a slightly, but significantly greater extent (0.8-3.1 mmHg) than amlodipine or lisinopril. No significance differences were reported for amlodipine versus chlorthalidone or lisinopril versus chlorthalidone on the primary outcome of combined incidence of fatal CHD and nonfatal myocardial infarction. The findings of ALLHAT support the use of thiazide-type diuretics as first choice pharmacological therapy in at risk patients with hypertension. ANBP2 (The Second Australian National Blood Pressure Study) was also a comparison between diuretics (hydrochlorothiazide) and ACE inhibitors (enalapril) but was performed in older hypertensives that had few previous cardiovascular events. Diastolic blood pressure reduction was similar in both groups at all times. The risk of the primary outcome of all cardiovascular events or death from any cause was 11% lower in the ACE group than the diuretic group and the benefit was predominantly in men. Thus, ANBP2 suggests that in relatively healthy elderly hypertensive patients, ACE inhibitors should be preferred to diuretics.