Histopathological Changes with Urinary Escherichia coli Infection and Glycemic Control in Patients with Long-Standing Diabetes Mellitus

Abstract

Background: Chronic diabetes mellitus is accompanied by renal structural injury and a higher risk of urinary tract infections. The relationship between glycemic control, urinary Escherichia coli infection and renal histopathological changes is still of clinical significance. Objective: To determine the relationship between renal histopathological changes, urinary E. coli infection, and glycemic control in patients with long-standing diabetes mellitus. Methods: The study was prospective observational analytical study with 100 diabetic patients with diabetes mellitus for more than 10 years who had renal biopsy performed clinically. The research period was from January, 2026 to June 2026. Demographic and clinical data were collected. HbA1c was used to evaluate glycemic control and urine culture was done for the presence of E. coli. The renal biopsy specimens were examined for glomerular, tubular, interstitial and vascular changes. Results: Diabetic glomerulosclerosis was seen in 72% of the patients, followed by mesangial expansion (55%), tubular atrophy/interstitial fibrosis (48%), vascular changes (46%) and interstitial inflammation (39%). 34% of patients had urinary E. coli infection. Infection was more frequent among patients with HbA1c ≥7% than those with HbA1c <7% (44.1% vs. 12.5%, p=0.001). Interstitial inflammatory changes were also more common in culture positive patients (58.8% vs. 28.8%, p=0.003). Conclusion: Long-standing diabetes was associated with increased renal histopathological abnormalities, with poor glycemic control and urinary E. coli infection.