Aim: Glomerular filtration rate (GFR) is commonly calculated using the modification of diet in renal disease (MDRD) and Cockroft-Gault (CG) formulas and recently by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) algorithm and not directly measured, so that the real impact of antihypertensive therapy on GFR could not be well defined. In this study, the effect of Aliskiren on the GFR measured by radionuclide clearance of 99mTc-diethylene triamine penta-acetic acid (DTPA) was investigated.
Methods: In 106 hypertensive subjects (53% men) aged 61.9±12.7 years with uncontrolled blood pressure (BP) receiving at least 2 antihypertensive medications, Aliskiren was added once-daily at a dose of 150-300 mg for 12 months. Clinic BP measurements were taken at every follow-up visit (1st, 6th and 12th month), while 24-hours ambulatory BP and GFR (in mL/min/1.73 m2) were evaluated at baseline and at the end of the follow-up. Analysis of variance for repeated measures of BP, GFR and microalbuminuria was provided.
Results: With the use of Aliskiren a significant reduction of BP and microalbuminuria was found (P<0.0001). Only in male population, a significant reduction in GFR calculated with CKD-EPI (82.4±15 vs. 78.6±18.2, P<0.01) and CG (81.6±29.5 vs. 74.2±28.4, P<0.0001) formulas was observed. This impairment of GFR was not found either with MDRD formula (70.5±19.6 vs. 68.3±23.4) or by radionuclide clearance (62.4±18.6 vs. 61.4±20.5).
Conclusion: This study seems to demonstrate that the efficacy on BP control of Aliskiren is not accompanied by an impairment of GFR. In order to evaluate the effect of Aliskiren on GFR scintigraphy technique or MDRD formula resulted to be the most accurate methods.