Background Previous studies have suggested that gout increases the risk for the development of urolithiasis (uric acid stone or calcium-containing stone). However, the association between the prevalence of clinical or subclinical urinary stone disease and uric acid (UA) level has not been evaluated.
Objectives The purpose of this study is to evaluate the association between the rate of urinary stone on ultrasonography (USG) and UA level.
Methods We retrospectively reviewed radiographic and laboratory data from a tertiary hospital in Korea from 2010 to 2013. We included 13964 adult (≥20 years old) cases in which both abdominal or kidney ultrasonography and laboratory test have been performed for any purpose during these periods. We used calculated mean serum UA and creatinine levels for each case and stratified all cases by UA level and age. The risk of urinary stone on USG was analysed in association with uric acid level by multiple logistic regression analysis with adjustment for age, sex, body mass index, creatinine and known underlying diseases including diabetes mellitus and hypertension.
Results Among 6743 men (48%) and 7221 women (52%), mean age was 51.3±13.5 (range, 20-95), mean uric acid level was 4.5±2.1 mg/dL (range, 0.4-21.8), and mean creatinine level was 2.1±2.2 mg/dL (range, 0.4-18.9). Hyperuricemia (UA level above 7.0 mg/dL in men or 6.0 mg/dL in women) was found in 1750 cases (13%). Urinary stone on USG was detected in 608 cases (4.4%). The detection rates of urolithiasis in individuals with hyperuricemia and normal UA level were 5.9% and 4.1%, respectively (P=0.001). The overall detection rate of urolithiasis increased proportionally to serum UA level (Fig. 1A). In multiple logistic regression analysis, individuals with higher serum UA level had significantly higher risk of urolithiasis (adjusted odds ratio (OR)=1.136, 95% confidence interval (CI), 1.087-1.188, P<0.001), and these relationship was more prominent in men (OR=1.174, 95% CI, 1.108-1.243, P<0.001 in men; OR=1.106, CI, 1.023-1.196, P=0.011 in women) (Fig. 1B).
Conclusions This study suggested that individuals with higher serum uric acid level had higher risk of clinical or subclinical urolithiasis, especially in men.
Disclosure of Interest None declared