Insulin Resistance as a Risk Factor for Metabolic Staghorn Calculi Development in Individuals without Diabetes

Background The incidence of metabolic staghorn calculi is rising, and while insulin resistance (IR) is an established risk factor for nephrolithiasis, its specific role in metabolic staghorn calculi remains underexplored. This study investigates the predictive value of IR indices for metabolic staghorn calculi. Methods In this retrospective analysis, clinical data from 1,199 stone formers (January 2022–December 2024) were reviewed. Patients were categorized into non-staghorn calculi (n = 970) and staghorn calculi (n = 229) groups. Seventy percent were randomly assigned to a training cohort. Imaging parameters were retrieved from workstation databases. Univariate and multivariate logistic regression identified significant risk factors. Model performance was assessed using calibration curves and receiver operating characteristic (ROC) analysis, with the remaining 30% serving as the validation cohort. Results Univariate analysis revealed significantly elevated TyG_WHtR (OR = 3.98, 95% CI: 3.21–4.99; p < 0.001), TG/HDL ratio (OR = 1.35, 95% CI: 1.29–1.42; p < 0.001), and VAT/SAT ratio (OR = 1.23, 95% CI: 1.12–1.35; p < 0.001) in the staghorn group versus non-staghorn calcium oxalate stone formers. The multivariate model demonstrated high discriminatory power (training cohort AUC = 0.89, 95% CI: 0.85–0.92; validation cohort AUC = 0.90, 95% CI: 0.85–0.95). Conclusion IR independently predicts metabolic staghorn calculi formation. The IR-based model exhibits robust diagnostic accuracy, offering a clinical tool for early identification of high-risk individuals.