DECREASED URINARY ALBUMIN EXCRETION ASSOCIATED WITH THE NORMALIZATION OF THE CIRCADIAN BLOOD PRESSURE PATTERN BY ANGIOTENSIN RECEPTOR BLOCKADE: PP.15.48

Objectives: Administration of angiotensin-receptor blockers (ARB) at bedtime as opposed to upon wakening increases the sleep-time relative blood pressure (BP) decline and their efficacy in lowering nocturnal BP. Urinary albumin excretion in non-dippers has been shown to be significantly greater than in dippers, although the potential effects on renal function of reverting the non-dipping pattern have not been clearly elucidated. Accordingly, we evaluated the administration-time-dependent effects on urinary albumin excretion of treatment with ARB in subjects with essential hypertension. Methods: We studied 815 untreated non-proteinuric hypertensive subjects (321 men), 48.7 ± 13.5 years of age, assigned to receive an ARB in monotherapy either on awakening or at bedtime. BP was measured at 20-min intervals from 07:00 to 23:00 h and at 30-min intervals at night for 48 h before and after 12 weeks of treatment. The subjects collected their urine during the first 24 h of each BP monitoring session. Results: The reduction in awake BP was similar for both treatment-times. Treatment at bedtime, however, was significantly more efficient in reducing asleep BP (17.2 versus 11.2 mmHg after morning treatment; P < 0.001). The sleep-time relative BP decline was increased towards a more dipping pattern only after bedtime dosing (P < 0.001). Urinary albumin excretion was significantly reduced after treatment, and to a significant larger extent after bedtime dosing (P = 0.032). This albumin reduction was independent of the change in awake BP after treatment, but highly correlated with both the decrease in asleep BP and the increase in sleep-time relative BP decline (r = 0.321; P < 0.001), independently of treatment-time. Conclusions: Bedtime administration of ARB provides higher efficacy, as compared to morning treatment, in reducing the asleep BP mean, and improves the sleep-time relative BP decline towards a more dipper profile. This might be clinically relevant, as nighttime BP is a better prognostic marker of cardiovascular mortality than awake BP. Most important, the normalization of the circadian BP pattern towards a more dipper profile is associated with a significant decrease in urinary albumin excretion.