The famous SHEP study conducted in the late 1980s and early

The famous SHEP study conducted in the late 1980\'s and early 1990\'s had as its purpose \"to assess the ability of antihypertensive drug treatment toreduce the risk of nonfatal and fatal (total) stroke in isolated systolichypertension.\" Treatment with chlorthalidone was compared with placebo in 4736 patients with hypertension (SHEP, 1991). 2365 received activetreatment, 2371 received placebo. The 5-year average systolic blood pressure was 155 mm Hg for theplacebo group and 143 mm Hg for the active treatment group, and the 5-yearaverage diastolic blood pressure was 72 and 68 mm Hg, respectively. The5-year incidence of total stroke was 5.2 per 100 participants for activetreatment and 8.2 per 100 for placebo. The relative risk for total stroke was 0.63. For the secondary endpoint of clinical nonfatal myocardial infarction plus coronary death, therelative risk was 0.73. Major cardiovascular events were reduced (relativerisk, 0.68). For deaths from all causes, the relative risk was 0.87.

The efficacy of the chlorthalidone intervention for the prevention of stroke may be expressed as:

0.37

0.25

1.58

0.63

Solution

The correct answer is: A

0.37