Systolic Hypertension in China Trial - Syst-China

Description:

Syst-China is a placebo controlled trial to investigate whether antihypertensive drug treatment could reduce the incidence of fatal and nonfatal stroke in older Chinese patients with isolated systolic hypertension.

Hypothesis:

Active treatment can reduce the incidence of stroke and other cardiovascular complications in older patients with isolated systolic hypertension. 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.

Study Design

Study Design:

Patients Enrolled: 2394
Mean Patient Age: 66.5 +/- 5.5 years
Female: 36%

Patient Populations:

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

Primary Endpoints:

Blood pressure Mortality Cardiovascular mortality Stroke non-fatal MI

Drug/Procedures Used:

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.

Principal Findings:

At entry, sitting blood pressure averaged 170.5 mmHg systolic and 86.0 mmHg diastolic, age averaged 66.5 years and total serum cholesterol was 5.1 mmol/l. After 2 years of follow-up, sitting systolic and diastolic blood pressures had fallen by 10.9 mmHg and 1.9 mmHg in the placebo group and by 20.0 mmHg and 5.0 mmHg in the active treatment group. The intergroup differences were 9.1 mmHg systolic (95% confidence interval 7.6-10.7 mmHg ) and 3.2 mmHg diastolic (95% confidence interval 2.4-4.0). Active treatment reduced total strokes by 38% (from 20.8 to 13.0 endpoints per 1000 patient-years, P=0.01), all-cause mortality by 39% (from 28.4 to 17.4 endpoints per 1000 patient-years, P=0.003), cardiovascular mortality by 39% (from 15.2 to 9.4 endpoints per 1000 patient-years, P=0.03), stroke mortality by 58% (from 6.9 to 2.9 endpoints per 1000 patient-years, P=0.02), and ail fatal and nonfatal cardiovascular endpoints by 37% (from 33.3 to 21.4 endpoints per 1000 patient-years, P=0.004). 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 .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.

Interpretation:

Antihypertensive treatment is associated with lower rates of stroke and other cardiovascular complications in older Chinese patients with isolated systolic hypertension. Treatment of 1000 Chinese patients for 5 years might be associated with a reduction in 55 deaths, 39 strokes or 59 major cardiovascular endpoints. 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.

References:

Archives of Internal Medicine 2000;160: J Hypertens.1998;16:1823-1829.

Clinical Topics: Dyslipidemia, Prevention, Lipid Metabolism, Nonstatins, Statins, Hypertension, Smoking

Keywords: Stroke, Follow-Up Studies, Diuretics, Captopril, Calcium Channel Blockers, Smoking, Cholesterol, Nitrendipine, Drug Combinations, Hydrochlorothiazide, Confidence Intervals, Hypertension, Diabetes Mellitus


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