Incomplete benefit of antihypertensive therapy on stroke reduction in older hypertensives with abnormal nocturnal blood pressure dipping (extreme-dippers and reverse-dippers)

Abstract

To determine whether the benefits of antihypertensive treatment vary according to dipper status, 811 asymptomatic elderly Japanese hypertensives underwent 24-h ambulatory blood pressure monitoring. During a mean follow-up period of 41 months, 32 stroke events were observed in patients who remained nonmedicated (n = 385), and in 27 patients in the medicated group (n = 426), indicating a 24% lower rate of stroke as a result of antihypertensive therapy. Patients were divided into a white-coat hypertensive (WCHT) group (ambulatory blood pressure <130/80 mm Hg; n = 236) and a sustained hypertensive (SHT) group (n = 575). Sixty-one percent of SHT and 32% of WCHT patients were being medicated. In the SHT group, the stroke rates were 12.4% in nonmedicated and 7.4% in medicated group (P =.04), whereas in the WCHT group the stroke rates were 2.5% in nonmedicated and 1.3% in medicated group (P = not significant). The SHT were further classified according to their nocturnal systolic blood pressure (BP) decrease, as follows: 97 extreme-dippers with >20% nocturnal systolic BP decrease; 230 dippers with >10% but <20% decrease; 185 nondippers with >0% but <10% decrease; 63 reverse-dippers with <0% decrease. In the dipping groups of SHT, the stroke rates were similar according to medication versus no-medication in extreme-dippers (12% v 13%), and reverse-dippers (23% v 22%), but in nondippers there was a significantly lower rate (by 65%, P =.038) in the medicated (4.4%) than the nonmedicated (13%) groups. In dippers, the stroke rate was also lower in the medicated than the nonmedicated patients (4.7% v 8.8%), a decrease of 47% (P =.217), although the difference was not significant. In conclusion, in older SHT subjects, antihypertensive therapy using clinic BP may be less effective for the groups with extremely abnormal diurnal BP patterns (extreme-dippers and reverse-dippers) than those with relatively normal patterns (dippers and nondippers). Patients with WCHT also showed no benefit.