A retrospective cohort study on the pathology and outcomes of type 2 diabetic patients with renal involvement

Objective To investigate the association of clinical and histological characteristics and the development of ESRD in T2DM patients with renal involvement. Methods We conducted a retrospective analysis of clinical and pathologic data from T2DM patients who underwent renal biopsy (n = 120). Results The mean age, duration of diabetes, and eGFR were 50.9 +/- 11.2 years, 92.8 +/- 41.3 months, 55.1 +/- 42.3 mL/min/1.73 m(2), respectively. Among these patients, 57 (47.5%) were diagnosed with diabetic nephropathy (DN), and 63 (52.5%) with non-diabetic renal disease (NDRD). The most common subtype of NDRD is membranous nephropathy. Compared with the NDRD group, the DN group had a longer duration of diabetes, worse renal function, and a higher proportion of diabetic retinopathy. Kaplan-Meier analysis showed that the 5-year renal survival rate of the DN group was only 41%, whereas that of the NDRD group was 84%. ESRD was defined as eGFR below 15 mL/min/1.73 m(2). After multivariate adjustment, the risk of ESRD in DN patients was 3.81 times higher than that in NDRD patients. According to Glomerular Class, the 5-year renal survival rate of type IIA, IIB, III, and IV in the DN group was 88, 56, 28, and 15%, respectively. Kaplan-Meier analysis showed that there was a significant difference in renal survival among different glomerular classes or different interstitial fibrosis and tubular atrophy (IFTA) scores. But Cox proportional hazards analysis indicated that only IFTA score (HR 2.75, 95% CI 1.37-5.51,P = 0.001), but not the glomerular class (HR 1.21, 95% CI 0.73-2.00,P = 0.465), could predict renal outcome when adjusting for multivariate. Conclusion The prognosis of DN patients is significantly worse than that of NDRD patients. Compared with glomerular lesions, tubulointerstitial lesions were associated with higher risk for renal death in DN patients.