Clinical Implications of the Change in Glomerular Filtration Rate with Adrenergic Blockers in Patients with Morning Hypertension: The Japan Morning Surge-1 Study

Background. The aim of this study was to clarify the relationship between the change in estimated glomerular filtration rate (eGFR) and urinary albumin by antihypertensive treatment. Methods. We randomized 611 treated patients with morning hypertension into either an added treatment group, for whom doxazosin was added to the current medication, or a control group, who continued their current medications. We compared the change in eGFR and urinary albumin creatinine ratio (UACR) between the groups. Results. The extent of the reduction in eGFR was significantly greater in the added treatment group than in the control group (−3.83 versus −1.08 mL/min/1.73 m(2), P = 0.001). In multivariable analyses, the change in eGFR was positively associated with the change in UACR in the added treatment group (β = 0.20, P = 0.001), but not in the control group (β = −0.002, P = 0.97). When the changes in eGFR were divided by each CKD stage, eGFR was significantly more decreased in stage 1 than in the other stages in the added treatment group (P < 0.001), but no differences were seen in the control group (P = 0.44). Conclusion. The reduction of eGFR could be seen only in the early stage of CKD, and this treatment appeared to have no negative effect on renal function.