Significance of renal biopsy in patients with presumed diabetic nephropathy

Patients with diabetic nephropathy (DN) typically show varying degrees of proteinuria and renal impairment. Because these clinical signs are frequently observed in other glomerulopathies, renal biopsy is required to make a definitive diagnosis of DN. We carried out the present study to evaluate the significance of renal biopsy for patients who have been presumptively diagnosed with DN.

A total of 55 patients with type 2 diabetes mellitus (DM), and proteinuria, hematuria and/or renal impairment were enrolled in this study.

Renal biopsy showed that just 30 patients (54.5%) were histologically diagnosed with DN. Fasting plasma glucose and glycated hemoglobin levels were associated with the presence of DN, whereas baseline renal function showed no statistically significant relationship to DN. The duration of DM was not associated with the presence of DN. Patients with DN had a higher rate of diabetic retinopathy (DR) than those with non-DN (DN 18 patients vs non-DN three patients, P = 0.00029). DN patients with DR showed a more severe renal histology than those without.

These data suggest that, even for patients with long-term DM, renal biopsy should be carried out in patients with presumed DN. Because treatment options differ between DN and primary glomerulopathies, renal biopsy should especially be considered for presumed DN without DR.