Multicenter,Randomized,Parallel Study of Spherical Adsorptive Carbon (KREMEZIN) in Patients with Early Stage Chronic Kidney Disease of Nephropathy due to Type 2 Diabetes

INTERVENTION: Angiotensin converting enzyme inhibitor and/or Angiotensin II receptor blockade and Kremezin Angiotensin converting enzyme inhibitor and/or Angiotensin II receptor blockade CONDITION: Early‐stage renal failure due to type 2 diabetic nephropathy PRIMARY OUTCOME: Doubling of the serum creatinine concentration. More than 15 mL/min of the decrement of estimated GFR. The need for long‐term dialysis. Renal transplantation. Death. SECONDARY OUTCOME: Hospitalization from cardiovascular causes. The changes in the level of estimated GFR, serum creatinine and proteinuria. INCLUSION CRITERIA: 1) outpatient 2) age over 20 3) estimated GFR (eGFR), calculated by MDRD equation, is between 30 mL/min and 60 mL/min. the ratio of latest eGFR (eGFR2) and eGFR over 3 months before the day of eGFR2 measurement (eGFR1) is under 0.95 (eGFR2/eGFR1 <= 0.95) 4) over excretion of proteinuria (+‐ <= using paper test, or 30 mg/dL <= the concentration of proteinuria) 5) therapy with Angiotensin converting enzyme inhibitor and/or Angiotensin II receptor blockade continuously 6) periodical diet therapy 7) diabetic retinopathy