Diabetic Nephropathy Remission and Regression Team Trial in Japan (DNETT-Japan): Rationale and study design

The prevalence of end-stage renal disease (ESRD) is uprising in the paralleled with the increase of chronic kidney disease (CKD) patients. Diabetic nephropathy (DN) is the most important underlying disease of CKD and a leading cause of ESRD in Japan. Intensified multifactorial intervention in patients with type 2 diabetes with microalbuminuria slows the progression to nephropathy, and progression of retinopathy and autonomic neuropathy. However, further studies are needed to establish the effect of intensified multifactorial treatment on DN with overt proteinuria. In this trial, doctors and co-medicals collaborate to treat the DN patients to prevent the deterioration of DN by multifactorial intensive therapy. Diabetic Nephropathy Remission and Regression Team Trial in Japan (DNETT-Japan) is an open, randomized controlled trial to evaluate the efficacy of renal protection of multifactorial intensive therapy in type 2 diabetes patients with overt proteinuria (urinary albumin-to-creatinine ratio ≥300mg/g creatinine). The study has a targeted enrollment of 600 Japanese patients, and divided into two protocols by renal insufficiency (protocol A: serum creatinine: <1.2mg/dl in male and <1.0mg/dl in female, and protocol B: serum creatinine: 1.2–2.5mg/dl in male and 1.0–2.5mg/dl in female). The patients were allocated standard treatment or intensive multifactorial treatment. Intensive treatment was a stepwise implementation of behavior modification, pharmacological therapy targeting hyperglycaemia, hypertension, dyslipidaemia, and proteinuria. The primary outcome is the proteinuria in protocol A and the composite endpoint of time to the first occurrence of doubling of serum creatinine, ESRD (the need for chronic dialysis, or renal transplantation) or death in protocol B. The follow-up period is 5 years and the study ends in 2014.