Renal tubulointerstitial lesions: a prognostic marker in idiopathic membranous nephropathy.

To evaluate the impact of renal tubulointerstitial lesions (TIL) on clinical and pathologic outcomes and prognosis in patients with idiopathic membranous nephropathy. A retrospective cohort study was performed on 582 patients with idiopathic membranous nephropathy. Patients were divided into two groups based on the presence or absence of TIL as determined by renal biopsy: TIL- (258 cases) and TIL+ (324 cases). Kaplan-Meier survival curves and Cox regression models were used to analyze the influence of TIL on renal prognosis. Logistic regression models were used to further identify risk factors associated with the development of TIL. Patients in the TIL+ group were predominantly male, older, and had a higher prevalence of hypertension, hyperlipidemia, nephrotic syndrome, microscopic hematuria, and immunosuppressive therapy compared to the TIL- group. In addition, triglycerides, blood urea nitrogen, and 24-hour urine protein were significantly higher in the TIL+ group, while albumin and estimated glomerular filtration rate were lower (p < 0.05). Pathologic staging revealed more severe glomerulosclerosis lesions and renal artery intimal thickening in the TIL+ group. After a median follow-up of 45 months, IMN patients in the TIL+ group had a lower disease remission rate and worse renal prognosis as demonstrated by Kaplan-Meier survival curves and Cox regression modeling. Logistic regression modeling identified hypertension, globular/segmental glomerulosclerosis, and intimal thickening of small renal arteries as independent risk factors for TIL in patients with idiopathic membranous nephropathy. TIL is frequently associated with idiopathic membranous nephropathy, with more severe clinical manifestations and pathologic features, and idiopathic membranous nephropathy patients with TIL have a lower disease remission rate and worse overall renal prognosis. Hypertension, globular/segmental glomerulosclerosis, and intimal thickening of small renal arteries are independent risk factors for the development of TIL in patients with idiopathic membranous nephropathy.