Effect of combined treatment of oral sorbent with protein-restricted diet on change of reciprocal creatinine slope in patients with CRF.

BACKGROUND: Low-protein diet (LPD) is one therapy and AST-120, an oral carbon adsorbent, is the other therapy to reduce blood levels of indoxyl sulfate in patients with chronic renal failure (CRF). Based on the different mechanisms of reducing indoxyl sulfate levels, the addition of AST-120 to an LPD was investigated.

METHODS: Seven hundred twenty-two patients with chronic glomerulonephritis (CGN) and 162 patients with diabetic nephropathy (DN) were stratified by protein intake: less than 0.50 g/kg/d (0.50-g/kg/d group), 0.51 to 0.65 g/kg/d (0.65-g/kg/d group), and 0.66 to 0.80 g/kg/d (0.80-g/kg/d group). To analyze the effect of combined AST-120 therapy (6 g/d) in patients on LPD therapy, the slope of the reciprocal of serum creatinine (1/Cr slope), which represents progression of CRF, was applied.

RESULTS: (1) In patients with CGN, the addition of AST-120 with an LPD was as follows: the 1/Cr slope in the 0.50-g/kg/d (n = 152), 0.65-g/kg/d (n = 318), and 0.80-g/kg/d (n = 252) groups changed significantly from -430 x 10(-5) to -83 x 10(-5), -333 x 10(-5) to -102 x 10(-5), and -431 x 10(-5) to -116 x 10(-5) dL/mg/wk. (2) In patients with DN, the addition of AST-120 with an LPD was as follows: the 1/Cr slope in the 0.65-g/kg/d (n = 74) and 0.80-g/kg/d (n = 68) groups changed significantly from -602 x 10(-5) to -125 x 10(-5) and -646 x 10(-5) to -185 x 10(-5) dL/mg/wk.

CONCLUSION: It is suggested that the addition of AST-120 to a mild LPD provides the comparable effect with a strict LPD in the point of suppressing the progress of CRF.