Validation of the interstitial fibrosis and tubular atrophy on the new pathological classification in patients with diabetic nephropathy: A single-center study in China

Objectives: The association between interstitial fibrosis and tubular atrophy (IFTA) and the clinical outcomes in diabetic nephropathy (DN) remains unclear. This study is to evaluate the clinical predictors and renal prognosis of IFTA score in patients with DN.

Methods: 52 cases with DN with renal biopsy were divided into three groups according to IFTA score. The χ2 test or Fisher's exact test, Mann-Whitney U-test, Kruskal-Wallis H-test and Spearman's correlation analysis were used in this subject. Ordinal regression mode was utilized to evaluate which clinical factors might be the predictors of IFTA score.

Results: Compared to IFTA score 1 group, the patients in score 3 were younger and have greatly lower level of eGFR and hemoglobin and higher serum creatinine (p<0.01). A close relationship between the clinical findings and IFTA was observed, such as IFTA with eGFR(r=-0.58, P<0.01), triglyceride(r=-0.29, P=0.04), Hb (r=-0.38, P<0.01), systolic blood pressure (r=0.29, P=0.04) and urinary protein level (r=0.46, P<0.01); in addition, eGFR (OR 0.31 (95%Cl -1.883 to -0.485) p=0.001) showed statistical significance with IFTA. The 5-year renal survival rate was estimated as 100% in IFTA score 0, 88.9% in score 1, 76.9% in score 2, and 20.0% in score 3. Furthermore, greatly lower level of eGFR, and higher serum creatinine and BUN in the glomerular class IV were seen (p<0.01 vs class II), with positive correlation with IFTA (r=0.51, P<0.01).

Conclusion: The renal pathologic diagnosis in IFTA score was a good predictor for renal prognosis in type II DM. eGFR might be a predictor of IFTA in patients with DN.