Borderline hypertension discovered during screening: effect of twelve months' treatment.

The frequency of borderline hypertension (diastolic BP 95 to 109 mm Hg) is described in 5,877 men and 1,125 women attending a screening clinic. Borderline hypertension is more frequent in each 5-year age group in men than women. The results of the initial 12 months treatment show a greater fall in mean systolic and diastolic pressures in those on active treatment in comparison with placebo. Over the same 12 months the sum of selected ECG precordial lead voltages shows a significant fall in those on active treatment as compared with those on placebo.