An α-adrenergic blocker titrated by self-measured blood pressure recordings lowered blood pressure and microalbuminuria in patients with morning hypertension:: the Japan Morning Surge-1 Study

Background The impact on microalbuminuria of strict treatment aimed at lowering of self-measured morning blood pressure using an adrenergic blockade is unclear. Methods We conducted an open-label multicenter trial, the Japan Morning Surge-1 Study, that enrolled 611 hypertensive patients, whose self-measured morning systolic blood pressure levels were more than 135 mmHg while taking antihypertensive drugs. These were randomly allocated to an experimental group, whose members received bedtime administration of 1-4 mg doxazosin (doxazosin group) or a control group whose members continued without any add-on medication (control group). The urinary albumin/creatinine ratio was investigated at the baseline and 6 months after the randomization. Results Both the morning and evening blood pressures and urinary albumin/creatinine ratio (-3.4 vs. 0.0 mg/gCr for urinary albumin/creatinine ratio; P<0.001) were more markedly reduced in the doxazosin group than in the control group. This difference in the urinary albumin/creatinine ratio between the two groups was more marked in the patients with microalbuminuria (n=238, -27.9 vs. -8.1 mg/gCr, P<0.001). The reduction of urinary albumin/creatinine ratio was significantly associated with the use of doxazosin, and the change in all self-measured blood pressures (morning, evening, the average morning-evening), and these associations were independent of each other (P<0.001). Conclusion Adding a bedtime dose of an a-adrenergic blocker titrated by self-measured morning blood pressure in treated hypertensive patients with uncontrolled morning hypertension significantly reduced blood pressure and urinary albumin excretion rate, particularly in those with microalbuminuria.