Plasma renin predicts success of antihypertensive drug withdrawal.

This study examined the relationship of plasma renin activity (PRA) to the likelihood of maintaining blood pressure control after discontinuation of antihypertensive medication. Patients whose blood pressure was previously treated and controlled in the Hypertension Detection and Follow-up Program were enrolled in the Dietary Intervention Study of Hypertension. After stratification by obesity, patients were randomized to discontinue medication with no dietary intervention, sodium restriction, or weight reduction for the obese. Among 496 subjects in the Dietary Intervention Study of Hypertension, 75 were randomly selected for PRA measurement at 4 months after intervention, and all had their blood pressure under control at that time. Patients were followed up for 56 weeks after randomization. The endpoint was return to antihypertensive medication due to elevated diastolic blood pressure. Kaplan-Meier survival analysis showed that subjects with PRA < or = 53.3 ng/100 mL/h, the median level, had a lower cumulative success rate for remaining off antihypertensive drug than those with PRA above the median (P = .046). In Cox regression analysis controlling for 24-h urinary sodium level, baseline diastolic blood pressure, age, sex, race, obesity, and dietary intervention group, a unit decrease in log PRA was associated with a 2.78-fold increase in risk of returning to drug (P = .006); this inverse relationship was independent of dietary intervention and change in diastolic blood pressure in the first 4 months before PRA was measured. The data indicate that patients with low PRA are less likely to maintain blood pressure control without drugs than patients with high PRA.