Relationships among Non-Neoplastic Histopathological Features, Kidney Function, Proteinuria, and Other Clinical Factors in Patients Undergoing Nephrectomy.

Introduction: The non-neoplastic kidney parenchyma from nephrectomies is often overlooked in routine examinations. We aimed to evaluate the associations between global glomerulosclerosis (GS), interstitial fibrosis (IF), or arteriosclerosis (AS) and estimated glomerular filtration rate (eGFR), dipstick proteinuria, and other clinical factors.

Methods: We performed a cross-sectional analysis of 781 patients with nephrectomy. We used regression models with and without interaction factors. The tested exposures were GS, IF, or AS, and the outcome measures were GFR and dipstick proteinuria.

Results: In multivariable analyses, increasing degrees of GS, IF, or AS were significantly associated with lower eGFR and proteinuria (p < 0.05 for each). Obesity and hypertension (HTN) modified the association between eGFR and degrees of GS, whereas proteinuria and cardiovascular disease (CVD) modified the association between eGFR and degrees of AS (p for interaction <0.05). Compared with GS <10%, GS >50% was associated with lower eGFR in patients with (-45 mL/min/1.73 m²) than without (-19 mL/min/1.73 m²) obesity, and GS >50% was associated with lower eGFR in patients with (-31 mL/min/1.73 m²) than without (-16 mL/min/1.73 m²) HTN. Compared with AS <26%, AS >50% was associated with lower eGFR in patients with (-11 mL/min/1.73 m²) than without (-6 mL/min/1.73 m²) proteinuria, and AS >50% was associated with lower eGFR in patients with (-23 mL/min/1.73 m²) than without (-7 mL/min/1.73 m²) CVD.

Conclusion: Greater degrees of each GS, IF, and AS are independently associated with proteinuria and lower eGFR. Obesity, HTN, proteinuria, and CVD modify the relationship between eGFR and specific histopathological features of nephrosclerosis.