Factors associated with progression of diabetic nephropathy in Japanese elderly patients with type 2 diabetes: Sub‐analysis of the Japanese Elderly Diabetes Intervention Trial

Abstract

Diabetic nephropathy is a serious complication in patients with type 2 diabetes. The aim of this study was to explore the factors associated with the progression of this complication in elderly patients with type 2 diabetes. This retrospective study of a subgroup of patients registered with the Japanese Elderly Diabetes Intervention Trial included 621 Japanese patients with type 2 diabetes mellitus (age ≥ 65 years, 346 with normoalbuminuria, 190 with microalbuminuria and 85 with overt proteinuria). Multivariate Cox proportional hazard regression model with a backward stepwise procedure was applied to select factors with significant effects on worsening of nephropathy stage and the doubling of serum creatinine. During the follow up (median 52 months), 21% of patients progressed from normoalbuminuria and microalbuminuria to a worse nephropathy stage. Aging, female sex and high-density lipoprotein cholesterol were identified as independent and significant factors that worsen nephropathy stage. Also, 6.1% of patients showed doubling of serum creatinine during follow up. A positive history of cardiovascular disease, hyperuricemia and conventional therapy were identified as significant factors involved in the doubling of serum creatinine. The cumulative incidence of the doubling of serum creatinine was significantly lower in the intensive therapy group than the conventional therapy group (P = 0.016), although that of progression of nephropathy stage was similar in the two groups. We identified several factors associated with the progression of diabetic nephropathy in elderly patients with type 2 diabetes. The results suggest that multiple risk factor intervention seems important in preventing deterioration of renal dysfunction.