Effect of a Carbonaceous Oral Adsorbent on the Progression of CKD: A Multicenter, Randomized, Controlled Trial

Background: The carbonaceous oral adsorbent AST-120 slows the deterioration of kidney function in patients with advanced chronic kidney disease (CKD). However, information about AST-120 in patients with less severe stages of CKD is lacking. Study Design: Randomized controlled trial. Setting & Participants: 75 medical facilities, 460 patients with CKD with serum creatinine (sCr) concentrations less than 5.0 mg/dL (not undergoing dialysis). Intervention: Random assignment to either a low-protein diet and anti hypertensive medication in the control group or that treatment combined with AST-120 (6 g/d). Outcomes & Measurements: Composite primary end point: doubling of sCr level, increase in sCr level to 6.0 mg/dL or more, need for dialysis or transplantation, or death. Secondary outcomes: adverse events and changes in estimated creatinine clearance (CCr) rate, proteinuria (protein in milligrams per day), and quality of life. Results: Mean sCr level was 2.66 mg/dL and estimated CCr was 22.4 mL/min in both groups. During 56 weeks, numbers of primary end-point events (43 for control versus 42 for AST-120) and event-free survival (P = 0.9) did not differ between groups. Gastrointestinal adverse events were less common in the control group than the AST-120 group (2 versus 32 events). Estimated CCr decreased more in the control group than in the AST-120 group (-0.15 versus -0.12 mL/min/y; P = 0.001). Median proteinuria changed from protein of 1,162 to 1,167 mg/d in the control group versus 1,102 to 906 mg/d in the AST-120 group (P = 0.2). Limitation: Infrequent primary end-point events. Conclusion: AST-120 did not substantially slow the progression of kidney disease in patients with moderate to severe CKD during 1 year. Am J Kidney Dis 54:459-467. (C) 2009 by the National Kidney Foundation, Inc.