Evaluation of the role of serum and 24-hour urinary fetuin-A levels in patients with urolithiasis

Background: Urolithiasis is a common urinary tract disorder with a substantial risk of recurrence. Fetuin-A (α2-Heremans-Schmid glycoprotein) is a systemic inhibitor of ectopic calcification and may influence urinary crystal formation. This study compared serum and 24-hour urinary fetuin-A concentrations in patients with urolithiasis and controls and examined their relationship with stone radiopacity and composition. Methods: This prospective case-control study included 40 patients with urolithiasis and 40 controls matched for age, sex, and weight. Serum and 24-hour urine fetuin-A concentrations were measured using an ELISA. Stone radiopacity and chemical composition were assessed. Continuous variables were compared using independent-samples t-tests, with p < 0.05 considered statistically significant. Results: Mean serum fetuin-A concentrations were lower in patients with urolithiasis than in controls (35.06 ± 12.90 vs 41.31 ± 8.89 ng/mL; p = 0.0137). Mean 24-hour urinary fetuin-A concentrations were also lower (26.42 ± 10.15 vs 36.90 ± 18.31 ng/mL; p = 0.0022). Neither serum nor urinary fetuin-A differed significantly between patients with radiolucent and radio-opaque stones. Calcium oxalate, including mixed calcium oxalate-containing stones, was present in 31 of 40 cases (77.5%). Conclusion: Patients with urolithiasis had lower serum and urinary fetuin-A concentrations than controls. These findings demonstrate an association but do not establish causality. Larger studies are needed to determine whether fetuin-A has a role in stone formation or recurrence.