Abstract
BACKGROUND: The effect of low serum uric acid (sUA) levels on kidney function is unclear. This study aimed to clarify the relationship between low sUA levels and the rapid decline in kidney function. METHODS: We examined the relationship between sUA levels and kidney function decline in health check-up examinees. A total of 10,547 participants were enrolled using data from the Yuport Medical Checkup Center Study between 1998 and 2002 for baseline and data from 2002 to 2006 as the follow-up period in Japan. According to sUA level (mg/dL), we classified the participants into the following six groups: (1) 2.0-2.9 (n = 247), (2) 3.0-3.9 (n = 1457), (3) 4.0-4.9 (n = 2883), (4) 5.0-5.9 (n = 2899), (5) 6.0-6.9 (n = 2010), and (6) 7.0-7.9 (n = 1,051). The relationship between sUA level and rapid decline in estimated glomerular filtration rate (ΔeGFR ≥ 3 mL/min/1.73 m(2)/year) was examined using a logistic regression model. RESULTS: During study period (5.4 ± 1.6 years), the incidence of rapid eGFR decline for the respective sUA groups (2.0-2.9, 3.0-3.9, 4.0-4.9, 5.0-5.9, 6.0-6.9, 7.0-7.9) were as follows: 4.5%, 4.0%, 2.4%, 3.3%, 3.1%, 3.4%. The crude and adjusted odds ratios (OR) for rapid eGFR decline were significantly higher in the 2.0-2.9 (OR:1.93 and 1.86) and 3.0-3.9 (OR:1.72 and 1.73) groups than in the 4.0-4.9 groups (reference). Stratified analysis of age differences revealed that the detrimental effect of low sUA was not evident in older adults (age ≥ 65 years). CONCLUSION: A lower normal sUA level is related to an increased risk for a rapid decline in kidney function.