Impact of Baseline Renal Function on the Efficacy and Safety of Aliskiren Added to Losartan in Patients With Type 2 Diabetes and Nephropathy

OBJECTIVE Proteinuric diabetic patients with reduced glomerular filtration rate (GFR) are at high risk of renal and cardiovascular disease progression and treatment-related adverse events. This post hoc analysis assessed the efficacy and safety of aliskiren added to the maximal recommended dose of losartan according to baseline estimated GFR (eGFR) (stage 1-3 chronic kidney disease [CKD]). RESEARCH DESIGN AND METHODS In the Aliskiren in the Evaluation of Proteinuria in Diabetes (AVOID) study, 599 hypertensive patients with type 2 diabetes and nephropathy received 6 months of aliskiren (150 mg daily titrated to 300 mg daily after 3 months) or placebo added to 100 mg losartan and optimal antihypertensive therapy. Exclusion criteria included eGFR<30 ml/min per 1.73 m2 and serum potassium>5.1 mmol/l. RESULTS Baseline characteristics were similar between treatment groups in all CKD stages. The antiproteinuric effects of aliskiren were consistent across CKD stages (19, 22, and 18% reduction). In the stage 3 CKD group, baseline serum creatinine levels were equal, but renal dysfunction, prespecified as a postrandomization serum creatinine elevation>176.8 μmol/l (2.0 mg/dl) occurred more frequently in the placebo group (29.2 vs. 13.6%, P=0.032). Serum potassium elevations>5.5 mmol/l (based on a single measurement) were more frequent with aliskiren (22.5 vs. 13.6%) in stage 3 CKD. Adverse event rates were similar between treatments, irrespective of CKD stage. CONCLUSIONS Aliskiren added to losartan reduced albuminuria and renal dysfunction and was well tolerated, except for hyperkalemia (stage 3), independent of baseline CKD stage in patients with type 2 diabetes, hypertension, and nephropathy.