Association between serum soluble TNFα receptors and renal dysfunction in type 2 diabetic patients without proteinuria

Aim The aim of our study was to investigate whether serum levels of soluble tumor necrosis factor α receptor (sTNFR) 1 and 2 are markers for renal dysfunction in type 2 diabetic patients without overt proteinuria. Methods Japanese type 2 diabetic patients without overt proteinuria (n = 168) enrolled in the prospective observational follow-up study in 2001 were retrospectively analyzed. At baseline, the serum levels of sTNFR1 and sTNFR2 were measured by sandwich ELISA. The associations between these markers and change in estimated glomerular filtration rate (eGFR) after 5 years were evaluated. Results The levels of sTNFR1 and sTNFR2 closely correlated. At baseline, sTNFR1 and sTNFR2 associated inversely with eGFR. After 5 years, patients with high level of both sTNFR1 and sTNFR2 showed a greater decline in eGFR (−13.8 ± 15.5% versus −8.5 ± 11.8%, P = 0.027) and a 4-fold higher risk for a GFR decline of ≥25% than those with high level of only one receptor or low level of both receptors. These associations were enhanced in diabetic women. Conclusions The higher levels of sTNFR1 and sTNFR2 were associated with a greater decline in eGFR in type 2 diabetic patients without proteinuria, especially in diabetic women.