Association between peripheral blood eosinophil count and kidney replacement therapy initiation risk in patients with nephrosclerosis.

Eosinophils are implicated in cardiovascular risk and chronic kidney disease progression. However, prior cohorts included patients with heterogeneous etiologies, making it unclear whether eosinophils independently predict kidney prognosis in nephrosclerosis, a condition characterized by vascular injury. Therefore, we investigated whether the peripheral eosinophil count is associated with kidney prognosis in patients with biopsy-proven nephrosclerosis. This retrospective multicenter cohort study included 202 patients with biopsy-proven nephrosclerosis who underwent kidney biopsy between 2010 and 2024. Patients were categorized into low and high eosinophil groups according to the median peripheral eosinophil count. The primary outcome was kidney replacement therapy initiation. Missing data were handled using multiple imputations with chained equations. Multivariable Cox proportional hazards models were used to assess associations, and Least Absolute Shrinkage and Selection Operator regression was applied to identify relevant covariates. Sensitivity analyses treated eosinophil count as a continuous variable. During a median follow-up of 28.5 months, kidney replacement therapy was initiated in 31 patients (15.3%). The high eosinophil group had a significantly higher incidence of kidney replacement therapy initiation (p = .005) and demonstrated an independent association with increased risk in multivariable analysis (hazard ratio 3.09; 95% confidence interval 1.06-8.95). This association remained significant in sensitivity analyses, treating eosinophil count as a continuous variable (hazard ratio per standard deviation increase 1.47; 95% confidence interval 1.01-2.14). Elevated peripheral eosinophil counts were independently associated with adverse kidney outcomes in patients with nephrosclerosis, suggesting their potential prognostic value.