Objective: To compare the management of mild diastolic hypertension (90 to 104 mm Hg) using a nonpharmacologic intervention with that using propranolol or placebo.
Design: Randomized, placebo-controlled trial with a 2 x 2 factorial design.
Setting: University-based ambulatory care center.
Participants: Two hundred seven men and 105 women, 22 to 59 years of age, 73% white, who had mild diastolic hypertension untreated for at least eight weeks.
Interventions: 1) a multicomponent lifestyle modification intervention (lifestyle focus group, or LFG) administered in eight weekly meetings + placebo, 2) LFG + propranolol, 3) propranolol alone, and 4) placebo alone, followed for 12 months.
Measurements: Systolic blood pressure (SBP), diastolic blood pressure (DBP), and self-reported adverse effects at each of nine follow-up visits; fasting total cholesterol, triglycerides, and glucose at baseline and 12 months; 24-hour urine sodium (Na+) and potassium (K+), three-day food records and physical activity questionnaire at three and 12 months; and a quality of life questionnaire at 12 months.
Main results: The mean decreases in DBP at 12 months were: 8.5 mm Hg in the LFG + propranolol group; 7.7 mm Hg in the propranolol-only group; 5.9 mm Hg in the placebo-only group; and 5.4 mm Hg in the LFG + placebo group. Repeated-measures analysis of covariance showed that level of baseline DBP (p < 0.0001), time of follow-up (p < 0.0001), and propranolol use (p < 0.0001) were significantly associated with a decrease in DBP at 12 months. Despite reductions in urinary Na+ (-35 mEq; 95% CI = -50, -19), dietary Na+ (-521 mg; 95% CI = -710, -332), total calories ingested (-238; 95% CI = -335, -140), and weight (-1.4 lb; 95% CI = -3.7, +0.8), and significant increases in dietary K+ (+294 mg; 95% CI = +107, +480) and in mets-minutes of exercise (+43; 95% CI = +20, +67) at three months, assignment to the LFG intervention had no effect on DBP at three or 12 months. The subjects assigned to take propranolol more frequently reported fatigue during ordinary activities, sleep disturbance, decrease in sexual activity, and depressed feelings, when compared with the subjects taking placebo, but the numbers of study withdrawals did not differ by drug assignment. No significant difference in total cholesterol and glucose levels was observed by group assignment. Triglycerides increased significantly in the subjects assigned to propranolol (mean difference = +20 mg/dL; 95% CI of difference +1.5, +39). There was no difference in the responses to 21 quality of life items between the subjects assigned to propranolol and those assigned to placebo.
Conclusions: This multicomponent lifestyle modification intervention was unable to promote persistent behavior changes and thus was inferior to propranolol therapy for the treatment for mild diastolic hypertension. Future research should focus on single modifiable factors to lower blood pressure.