Physicochemical indicators and recurrence of urolithiasis in patients with hyperuricemia: a predictive model

Abstract

Abstract Objective To identify metabolic predictors of urolithiasis recurrence and investigate whether the predictive value of urinary citrate differs across metabolic subgroups, with the aim of developing a subgroup-specific prediction model. Methods We retrospectively analyzed patients who experienced a first episode of urolithiasis between 2013 and 2015 and subsequently underwent metabolic evaluation at the Department of Urology of our institution. Baseline assessment included demographic characteristics, blood biochemical parameters, and 24-h urinary metabolic indices. Follow-up data on stone recurrence were collected through standardized telephone interviews conducted between 2023 and 2025. Multivariable logistic regression and subgroup analyses were performed to identify predictors of recurrence. A prediction model for patients with hyperuricemia was developed using stepwise logistic regression and internally validated by tenfold cross-validation. Results A total of 184 patients were included. Multivariable logistic regression identified 24-h urinary citrate as the only metabolic parameter independently associated with stone recurrence ( P = 0.04). Correlation analysis demonstrated significant associations between urinary citrate and serum uric acid, urinary calcium, urinary oxalate, and age. Subgroup analysis showed that the inverse association between urinary citrate and recurrence remained significant only among patients with hyperuricemia ( P = 0.03), whereas similar trends in other metabolic subgroups did not reach statistical significance. The interaction between serum uric acid and urinary citrate was not statistically significant ( P = 0.40). A preliminary prediction model incorporating urinary citrate, age, BMI, triglycerides, and parathyroid hormone demonstrated moderate discriminative performance, with a mean cross-validated AUC of 0.747. Conclusion Urinary citrate was independently associated with urolithiasis recurrence, with this association being particularly evident among patients with hyperuricemia. These findings suggest that the predictive value of urinary citrate may vary across different metabolic backgrounds and support further investigation of metabolically stratified approaches to recurrence risk assessment. External validation in larger prospective cohorts is warranted.