Effects of Aliskiren Monotherapy versus Amlodipine Monotherapy in Hypertensive Patients with Obesity or Type 2 Diabetes Mellitus

<b><i>Introduction:</i></b> Renin-angiotensin system inhibitors have been reported to exert protective effects against organ damage and failure; however, the impact of the direct renin inhibitor as monotherapy has not been assessed. Here, we investigated the effects of 24-week monotherapy with aliskiren compared to amlodipine in hypertensive patients with type 2 diabetes or obesity. <b><i>Methods:</i></b> In this randomized intervention study, 62 adult hypertensive patients with visceral obesity (defined as a body mass index [BMI] greater than 25 kg/m² and a visceral adipose tissue area [VFA] greater than 100 cm²) or type 2 diabetes mellitus (age 57 ± 13, 65% men, BMI 28.8 ± 4.8 kg/m², VFA 134.8 ± 47.0 cm², blood pressure 141 ± 16/86 ± 13 mm Hg) were randomized to receive 24-week treatment with aliskiren (max. 300 mg) or amlodipine (max. 10 mg). The primary outcome was the change in VFA at 24 weeks post-treatment. <b><i>Results:</i></b> Change in VFA did not differ significantly from baseline in either group. Systolic blood pressure significantly decreased at 12 weeks (−10 mm Hg, <i>p</i> = 0.001) and 24 weeks (−10 mm Hg, <i>p</i> = 0.001) in the amlodipine group and at 24 weeks (−11 mm Hg, <i>p</i> = 0.001) in the aliskiren group. Diastolic blood pressure significantly decreased at 24 weeks (−6 mm Hg, <i>p</i> = 0.009) only in the amlodipine group. Although the estimated glomerular filtration rates did not significantly change in either group, the logarithm of urinary albumin excretion significantly decreased at 24 weeks only in the aliskiren group (−0.60, <i>p</i> &lt; 0.001). The 24-week changes in the urinary albumin excretion significantly correlated with the changes in the plasma renin activity in the aliskiren group (<i>r</i> = 0.51, <i>p</i> = 0.008). <b><i>Conclusion:</i></b> Aliskiren monotherapy did not show any superiority to amlodipine monotherapy on VFA, estimated glomerular filtration rates, or urinary albumin excretion in obese or type 2 diabetic hypertensive patients.