Chinese Trial on Isolated Systolic Hypertension in the Elderly

Abstract

BACKGROUND: In 1988, the Systolic Hypertension in China (Syst-China) Collaborative Group initiated the placebo-controlled Syst-China trial to investigate whether antihypertensive drug treatment could reduce the incidence of fatal and nonfatal stroke in older Chinese patients with isolated systolic hypertension. OBJECTIVES: To explore (1) whether the benefits of active treatment were evenly distributed across 4 strata, prospectively defined according to sex and previous cardiovascular complications, and (2) whether the morbidity and mortality results were influenced by age, level of systolic or diastolic blood pressure (BP), smoking or drinking habits, or diabetes mellitus at enrollment. METHODS: Eligible patients had to be 60 years or older with a sitting systolic BP of 160 to 219 mm Hg and diastolic BP less than 95 mm Hg. After stratification for center, sex, and previous cardiovascular complications, 1253 patients were assigned to active treatment starting with nitrendipine (10-40 mg/d), with the possible addition of captopril (12.5-50.0 mg/d), and/or hydrochlorothiazide (12.5-50 mg/d). In the 1141 control patients, matching placebos were used similarly. RESULTS: Male sex, previous cardiovascular complications, older age, higher systolic BP or lower diastolic BP, living in northern China, smoking, and diabetes mellitus significantly and independently increased the risk of 1 or more of the following end points: total or cardiovascular mortality, all fatal and nonfatal cardiovascular end points, all strokes, and all cardiac end points. In the placebo-control group diabetes raised the risk of all end points 2- to 3-fold (P< or =.05). However, active treatment reduced the excess risk associated with diabetes to a nonsignificant level (P values ranging from .12-.86) except for cardiovascular mortality (P = .04). Cox regression with adjustments applied for significant covariates suggested that active treatment may reduce total mortality more (P = .06) in women and stroke more (P = .07) in men and that it may provide better protection against cardiac end points in nonsmokers than smokers (P = .04). Otherwise, the benefits of active treatment were equally manifest, regardless of the enrollment characteristics of the patients, and regardless of whether active treatment consisted of only nitrendipine or of nitrendipine associated with other active drugs. CONCLUSIONS: In elderly Chinese patients with isolated systolic hypertension, stepwise antihypertensive drug treatment, starting with the dihydropyridine calcium channel blocker nitrendipine, improved prognosis. The benefit was particularly evident in diabetic patients; for cardiac end points it tended to be larger in nonsmokers. Otherwise, the benefit of active treatment was not significantly influenced by the characteristics of the patients at enrollment in the trial.