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 α-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.