Patient selection and the assessment of blood pressure in clinical trials

A new method for selecting patients with mild-to-moderate hypertension who are appropriate for entry into clinical trials and a technique for assessing small but statistically significant decreases in diastolic blood pressure resulting from drug therapy are described. In this method, mild-to-moderate hypertension is defined to exclude subjects whose diastolic blood pressure decreases while they are taking placebo and to exclude subjects with highly variable diastolic blood pressure. A subject receives placebo for four weeks, during which time diastolic blood pressure while supine is measured three times on a single day of each week, the time between measurements not being less than 30 minutes. With the 12 measurements obtained during the four-week placebo period, the following calculations are made: an average of the 12 measurements; and average of the three measurements obtained on a given day, yielding the average diastolic blood pressure per week; and the range of the 12 measurements. Subjects are selected for study if their average diastolic blood pressure per week for the four-week placebo period is neither below 95 nor above 115 mmHg, if their average diastolic blood pressure per week does not decrease successively from week 1 to week 4, and if the range of the 12 measurements of diastolic blood pressure recorded over the four-week placebo period does not exceed 28 mmHg (equivalent to a standard deviation of 8.5). Use of the method is demonstrated in the selection of 63 patients for a double-blind study of two antihypertensive drugs.(ABSTRACT TRUNCATED AT 250 WORDS)