Predictors of blood pressure increases after withdrawal of antihypertensive therapy.

We examined possible predictors of the recurrence of high blood pressure (BP) in patients who remained normotensive after withdrawal of drug therapy. Thirty untreated male patients with WHO stage I essential hypertension (mean age 43 +/- 6 years) were randomly allocated to oxprenolol or nitrendipine groups. Before therapy, BP at rest, during mental arithmetic (MA) and during the cold pressor (CP) test was assessed. After 6 months of effective monotherapy, all drugs were withdrawn and casual BP was followed up for 5 months. Two weeks after cessation of therapy 26% were hypertensive again, after 4 weeks 28%, after 12 weeks 48% and after 21 weeks 74%. The two therapeutic groups did not differ in their BP increase after discontinuation of therapy. Predictors for the return of high BP were age, pretreatment BP, systolic and diastolic BP increase to the CP test. Analyses of covariance for age and pretreatment BP confirmed that reactivity to the CP test was a predictor of the return of hypertension.