Association between asymptomatic hyperuricemia and kidney stones.

BACKGROUND

Nephrolithiasis is commonly observed in patients with gout; however, the role of asymptomatic hyperuricemia in stone formation remains unclear. This study evaluated the association between serum uric acid levels and nephrolithiasis in a large health screening population.

METHODS

We conducted a cross-sectional analysis of 31,198 Korean adults who underwent health checkups between 2010 and 2020. Clinical parameters included anthropometric measures, blood pressure, serum uric acid, renal and hepatic function markers, lipid profiles, glycemic indices, inflammatory biomarkers, serum calcium, and vitamin D3 levels. Nephrolithiasis was defined as the presence of at least one renal stone ≥5 mm detected by ultrasonography and/or kidney-ureter-bladder radiography. Hierarchical logistic regression models (unadjusted, age- and BMI-adjusted, and fully adjusted) were used to assess associations separately in men and women.

RESULTS

Median serum uric acid concentrations were 6.0 mg/dL in men and 4.4 mg/dL in women. In men, higher serum uric acid levels were associated with nephrolithiasis across hierarchical models. In fully adjusted analyses, serum uric acid remained significantly associated with stone prevalence, and men in the highest uric acid quartile (≥6.9 mg/dL) had higher odds compared with those in the lowest quartile (adjusted OR: 3.546; 95% CI: 1.240-10.144). No statistically significant association was observed in women.

CONCLUSIONS

Higher serum uric acid levels were associated with nephrolithiasis in men but not in women in this cross-sectional analysis. These findings contribute to the epidemiologic understanding of sex-specific differences in stone risk; prospective studies are needed to clarify causality and potential clinical implications.