INFLUENCE OF TIME OF DAY OF ANTIHYPERTENSIVE TREATMENT ON PLASMA FIBRINOGEN IN SUBJECTS WITH ESSENTIAL HYPERTENSION: PP.15.47

Objectives: Several studies have consistently documented differences in blood pressure (BP)-lowering efficacy, duration of action, safety profile and/or effects on the circadian BP pattern depending on the administration-time of antihypertensive medication. Clinical trials and epidemiological observations have also indicated that elevated fibrinogen is strongly correlated with an increased frequency of vascular events. Accordingly, we investigated the potential influence of time of day of antihypertensive treatment on the relationship between fibrinogen and ambulatory BP (ABPM) in subjects with essential hypertension. Methods: We studied 5000 hypertensive subjects (2392 men), 53.2 ± 13.6 years of age. Among them, 1672 patients were untreated at the time of the study, 1963 were treated with all drugs on awakening, and 1365 were receiving treatment at bedtime. BP was measured every 20-min from 07:00 to 23:00 h and every 30-min at night for 48 h. Blood samples were obtained in the early morning after nocturnal fasting, within the same week before starting ABPM. Results: For all three groups of subjects, independently of treatment scheme, plasma fibrinogen was comparable between extreme-dippers and dippers, but significantly elevated in non-dippers and, to a larger extent, in risers (P < 0.001 compared to all other groups). Compared with untreated subjects (315 mg/dl), fibrinogen was much higher among those treated with all drugs on awakening (330 mg/dl) than among those receiving treatment at bedtime (323 mg/dl). On the contrary, the sleep-time relative BP decline was significantly lower in subjects treated with all drugs on awakening (8.4%) compared to untreated subjects (10.9%, P < 0.001), and was highest among subjects treated with all drugs at bedtime (11.1%). Conclusions: Plasma fibrinogen is significantly correlated with the progressive loss in asleep BP regulation towards a more non-dipper or even riser profile. Compared with subjects receiving all their prescribed antihypertensive medication on awakening, treatment at bedtime was associated with higher sleep-time relative BP decline, significantly lower prevalence of non-dipping, and, simultaneously, lower plasma fibrinogen levels, what could all provide a diminished cardiovascular risk.