Renal histologic changes and the outcome in patients with diabetic nephropathy

BACKGROUND: The progression of diabetic nephropathy (DN) is frequently determined by clinical parameters; however, the predictive value of histologic lesions remains largely unknown. Our aim was to evaluate the relationship between histologic changes and renal outcome in patients with type 2 diabetes mellitus (T2DM). METHODS: A total of 396 patients with T2DM and biopsy-proven DN who received follow-up for at least 1 year were recruited. The severity of different histologic lesions was assessed using the pathologic classification established by the Renal Pathology Society. Renal outcomes were defined by progression to end-stage renal disease and doubling of serum creatinine. The influence of histologic findings on renal outcomes was assessed using univariate and multivariate Cox regression. RESULTS: A univariate Cox regression showed that the severity of glomerular and interstitial lesions had a significant impact on renal outcomes (P < 0.001). Scores of vascular lesions demonstrated no association with renal outcomes (P > 0.05). A multivariate COX analysis demonstrated that the glomerular classes and scores of interstitial fibrosis and tubular atrophy were significantly associated with renal outcomes when adjusting for baseline proteinuria, mean arterial pressure and estimated glomerular filtration rate (P < 0.05). The glomerular and interstitial lesions correlated significantly among each other. However, in several patients, the severity of interstitial lesions did not correlate with glomerular lesions. CONCLUSION: These findings indicated that the severity of glomerular and interstitial lesions were significantly associated with renal outcomes in patients with DN, whereas the vascular indexes did not have any impact on renal outcomes.