De novo diabetic nephropathy on renal allografts

Posttransplant diabetes mellitus (PTDM) is a well-recognized clinical problem following renal transplantation. Long-term risks of PTDM are similar to those of diabetes mellitus in general population. The aim of our study was to identify de novo diabetic nephropathy (DN) in our group of patients with PTDM.

Thirty-four patients with PTDM were reviewed retrospectively. Light microscopy, immunofluorescence, and electron microscopy techniques were performed in 10 of 21 patients with graft biopsy.

Five patients (four women, one man), aged 47.4 years (range, 29 to 58), four of whom received cadaveric grafts, were found to have de novo DN. Their serum creatinine was 211.4 micromol/L (range, 140 to 294). Three patients were slightly proteinuric (0.3 to 0.5 g/L). PTDM was diagnosed 2.4 months after transplantation (range, 1 to 6). Histologic diagnosis of de novo DN was made, on average, 52.6 months after transplantation (range, 8 to 115), and 50.2 months (range, 2 to 114) after PTDM. De novo DN presented as diffuse diabetic glomerulosclerosis in four patients and nodular diabetic sclerosis in one patient, and combined with transplant glomerulopathy in all five patients. The mean graft survival time for this group of patients was equivalent with a control group. Although the difference in slopes of serum creatinine between the studied groups was clinically relevant, it was not statistically significant.

In view of our findings, when histologic de novo DN was found in 5 out of 10 patients, one could conclude that de novo DN could be a frequent complication of PTDM.