Background: Hypertension is a common complication in autosomal dominant polycystic kidney disease (ADPKD). This prospective randomized double-blind study was performed to compare the renal and cardiac effects of the ACE inhibitor ramipril and the beta-blocker metoprolol as first line therapy in ADPKD patients with hypertension.
Methods: Forty-six hypertensive ADPKD patients were randomized to either ramipril (n = 23) or metoprolol (n = 23). Twenty-four hour (24-h) ambulatory blood pressure (BP), glomerular filtration rate (GFR) as calculated by the Cockcroft and Gault formula, urinary albumin excretion (albumin/creatinine ratio), and left ventricular mass index (LVMI) were established at baseline and at yearly intervals. The total follow-up was 3 years. Baseline characteristics were similar in both groups.
Results: Mean arterial pressure (MAP) decreased significantly in both the ramipril and the metoprolol group (-8 +/- 2 and -6 +/- 2 mmHg; both P < 0.01). There was a significant decline in renal function during follow-up which was similar in patients treated with ramipril or metoprolol (-2.5 +/- 0.7 vs -2.9 +/- 0.8 ml/min/year; P = NS). After the 3 years follow-up, no differences in GFR, LVMI and urinary albumin excretion were observed between the ramipril and the metoprolol group (80.7 +/- 10.7 vs 78.0 +/- 7.6 ml/min, 102.6 +/- 6.8 vs 100.3 +/- 5.4 g/m(2); and 42.6 +/- 12.3 vs 70.3 +/- 32.5 mg/g, respectively; all P = NS). A post-hoc analysis evaluating the effects of BP control, revealed that LVMI increased in patients with standard BP control while it remained stable in patients with rigorous BP control with a significant difference in LVMI between the groups after 3 years of follow-up (110.5 +/- 6.3 vs 90.9 +/- 4.7 g/m(2); P = 0.017). Also, by the end of the study albuminuria was lower in patients with rigorous vs standard BP control (23.5 +/- 6.7 vs 94.8 +/- 35.4 mg/g; P = 0.05).
Conclusions: In our study population of hypertensive ADPKD patients, no differences in renal function, urinary albumin excretion and LVMI were detected between those treated with ramipril or metoprolol, respectively, during a 3 years follow-up. Rigorous BP control prevented an increase in LVMI and reduced urinary albumin excretion, suggesting a crucial role of BP control for slowing progression of cardiac and renal organ damage in ADPKD.