Effects of the circadian time of antihypertensive treatment on the ambulatory blood pressure pattern of hypertensive patients with type 2 diabetes

Abstract

A blunted nocturnal decline in blood pressure (BP) is frequent in hypertensive patients with type 2 diabetes mellitus (DM). The actual prevalence of a non-dipping pattern in DM is, however, highly variable among different studies. Recent results have also indicated that non-dipping in treated hypertensive patients treated with single morning doses is markedly related to the absence of 24-hour therapeutic coverage [J Hypertens. 2002;20:1097–1104]. Accordingly, we studied the impact of antihypertensive treatment and the time of therapy on the circadian pattern of BP in hypertensive patients with DM. We studied 585 hypertensive patients with DM (328 men), 60.4±11.2 years of age. Among them, 142 patients were untreated at the time of the study, 236 patients were receiving all their antihypertensive medication upon awakening, and 207 were taken one antihypertensive drug at bedtime. BP was measured at 20-min intervals from 07:00 to 23:00 hours and at 30-min intervals at night for 48 consecutive hours. Physical activity was simultaneously monitored every minute by wrist actigraphy to accurately calculate the diurnal and nocturnal means of BP on a per subject basis. Among untreated patients, 64.1% were non-dippers. In treated patients, BP was reduced during diurnally active hours, but not during nocturnal sleep, as compared to untreated patients (P<0.001). Thus, the percentage of non-dippers among treated patients was increased to 69.8%. Most important, 25% of the treated patients were risers (nocturnal BP mean above the diurnal mean). As a function of the circadian time of treatment, 73.3% of the patients with all drugs on awakening were non-dippers. This percentage was reduced to 64.7% in patients who received one antihypertensive drug at bedtime (P=0.041). Results from this study indicate the high prevalence of an altered circadian BP pattern in DM. The extremely high prevalence of risers among treated patients with DM indicates the need to establish a proper chronotherapeutic scheme that could allow not only to reduce BP but also to modify the altered circadian profile into a dipper BP pattern, associated to a lower cardiovascular risk.