Histopathologic and clinical features of diabetic nephropathy alone and with concomitant nondiabetic renal diseases

Abstract

Background and objective: Diabetic nephropathy (DN) is a major complication of diabetes mellitus (DM) and one of the leading causes of end-stage kidney disease. The aim of the present study was to evaluate the histomorphological and clinical profiles of DN and associated non-diabetic renal dieases (NDRD) in diabetic patients. Materials and methods: The study was carried out at the Department of Histopathology, Armed Forces Institute of Pathology (AFIP), Dhaka, from July 2019 to December 2020. Renal biopsy samples from known diabetic patients were included in the study. The formalin-fixed tissues were stained with haematoxylene & eosin (H&E), Periodic acid Schiff (PAS), Masson Trichrome (MT) and Jones Methanamine Silver (JMS) stains. Tissues were stained for IgG, IgA, IgM, C3, C1q, kappa and lambda for direct immunofluorescence (DIF) study. DN was histologically classified according to Tervaert classification system. Interstitial fibrosis and tubular atrophy (IFTA) as well as arteriolar hyalinization scoring was also done. Clinical information was retrieved from the patient’s information sheet. Results: Total 46 biopsy samples from DN cases were included in the study. The mean age of the cases was 46.76+10.63 years, including 36 males and 10 females. The most common clinical presentation was nephritic range proteinuria (n=32, 69.56%). Among all, 27 (58.69%) patients had haematuria. The mean serum creatinine level was 4.28+2.61 mg/dl, and 80.43% had serum creatinine levels >1.5 mg/dl. Histopathologic examinatiom revealed type III DN in 26 (56.5%) and type IV DN in 11 (23.9%) cases. IFTA score 1 (<25%) was seen in 20 (43.5%), score 2 (25-50%) in 19 (41.3%) and score 3 (>50%) in 7 (15.2%). Vascular hyalinization score-2 in 25 (54.3%), score-1 in 14 (30.4%) and score-0 in 7 (15.2%). DN class II, III and IV were associated with high urinary total protein (UTP) and serum creatinine levels. Among the histologic changes, percentage of glomerular sclerosis, the mean IFTA score and vascular hyalinization score were found to be highest in class IV DN, and all were significantly associated with histologic glomerular DN classes (p= <0.05). Of the total cases, 21 (45.65%) were found with nondiabetic renal diseases (NDRD), the most common feature was focal segmental glomerulosclerosis (FSGS) (26.57%), followed by IgA nephropathy and post-infectious glomerulonephritis (PIGN). Among 46 cases, one post-transplant biopsy was included, which revealed class II DN along with features of calcineurin inhibitor toxicity. Conclusion: Tervaert’s histologic classification of our cases revealed class III DN lesions as the predominant one, and the classes had a significant association with age of the patient, serum creatinine level, mean IFTA, arteriolar hyalinization and NDRD. Among the NDRD, FSGS was the most common pathology. IMC J Med Sci. 2023; 17(1): 003. DOI: https://doi.org/10.55010/imcjms.17.003 *Correspondence: Sk Md Jaynul Islam, Department of Histopathology, Armed Forces Institute of Pathology, Dhaka Cantonment, Dhaka, Bangladesh. Email: jaynul.islam@gmail.com