A slight increase within the normal range of serum uric acid and the decline in renal function: associations in a community-based population

Hyperuricemia is a risk factor for adverse renal outcomes in patients with chronic kidney disease. This study investigated the effect of uric acid on renal function in a community-based population. We used a nationwide database of 165 847 subjects (aged 29-74, male 40%) who participated in the annual 'Specific Health Check and Guidance in Japan' checkup between 2008 and 2010; we examined the relationship between serum uric acid levels at baseline and 2-year change in the estimated glomerular filtration rate (eGFR) obtained by using the Japanese equation. After adjusting for possible confounders, the eGFR change was inversely correlated with uric acid at baseline. In the multivariable analysis, the decline in eGFR was significantly more rapid in subjects with the slight increase in uric acid (males a parts per thousand yen5.7 mg/dL, females a parts per thousand yen4.4 mg/dL), and the risk for incidental renal insufficiency (eGFR < 60 mL/min/1.73 m(2)) was increased at uric acid of a parts per thousand yen6.3 mg/dL in males and a parts per thousand yen5.5 mg/dL in females, compared with the lowest quintile. The multiple linear regression analysis revealed that the effect of uric acid on eGFR changes was significant, especially in females, those with proteinuria and diabetes and those without alcohol consumption. This study showed that serum uric acid is independently associated with a more rapid decline of eGFR and incident renal insufficiency, and that a slight increase within the normal range of serum uric acid might be a risk for renal damage in the general population.