Cardiovascular events in elderly patients with isolated systolic hypertension. A subgroup analysis of treatment strategies in STOP-Hypertension-2

Abstract

Objective: To perform a subgroup analysis on those patients in STOP-Hypertension-2 who had isolated systolic hypertension.

Design and methods: The STOP-Hypertension-2 study evaluated cardiovascular mortality and morbidity in elderly hypertensives comparing treatment with conventional drugs (diuretics, beta-blockers) with that of newer ones [angiotensin-converting enzyme (ACE) inhibitors, calcium antagonists]. In all, 6614 elderly patients with hypertension (mean age 76.0 years, range 70-84 years at baseline) were included in STOP-Hypertension-2. In the present subgroup analysis of STOP-Hypertension-2, isolated systolic hypertension was defined as systolic blood pressure at least 160 mmHg and diastolic blood pressure below 95 mmHg, in accordance with the Syst-Eur and Syst-China study criteria. In total, 2280 patients in STOP-Hypertension-2 met these criteria. In the study, patients were randomized to one of three treatment groups: "conventional" antihypertensive therapy with beta-blockers or diuretics (atenolol 50 mg, metoprolol 100 mg, pindolol 5 mg, or fixed-ratio hydrochlorothiazide 25 mg plus amiloride 2.5 mg daily); ACE inhibitors (enalapril 10 mg or lisinopril 10 mg daily); or calcium antagonists (felodipine 2.5 mg or isradipine 2.5 mg daily). Analysis was by intention to treat.

Results: The blood pressure lowering effect in patients with systolic hypertension was similar with all three therapeutic regimens: 35/13 mmHg in the conventional group (n=717), 34/12 mmHg in the ACE inhibitor group (n = 724), and 35/13 mmHg in the calcium antagonist group (n=708). Prevention of cardiovascular mortality, the primary endpoint of the study, did not differ between the three treatment groups. All stroke events, i.e. fatal and non-fatal stroke together, were significantly reduced by 25% in the newer-drugs group compared with the conventional group (95% CI 0.58-0.97; p=0.027). This difference was attributable to reduction of non-fatal stroke while fatal stroke events did not differ between groups. New cases of atrial fibrillation were significantly increased by 43% (95% CI 1.02-1.99; p=0.037) on "newer" drugs compared with "conventional" therapy, mainly attributable to the calcium antagonists. There were no significant differences between the three treatment groups with respect to the risks of myocardial infarction, sudden death or congestive heart failure.

Conclusions: The analysis demonstrated that "newer" therapy (ACE inhibitors/calcium antagonists) was significantly better (25%) than "conventional" (diuretics/beta-blockers) in preventing all stroke in elderly patients with isolated systolic hypertension.