Relationship of Uric Acid With Progression of Kidney Disease

Background

Uric acid levels are increased in patients with kidney dysfunction. We tested the hypothesis that uric acid may be associated with kidney disease progression.

Study Design

Cohort study.

Setting & Participants

5,808 participants of the Cardiovascular Health Study.

Predictor

Uric acid levels.

Outcomes & Measurements

Kidney disease progression was defined as a decrease in estimated glomerular filtration rate (GFR) of 3 mL/min/1.73 m² per year or greater (≥0.05 mL/s) and as incident chronic kidney disease (CKD). Measures of kidney function were estimated GFR using the Modification of Diet in Renal Disease Study equation.

Results

Higher quintiles of uric acid levels were associated with greater prevalences of estimated GFR less than 60 mL/min/1.73 m² (<1.00 mL/s) of 7%, 14%, 12%, 25%, and 42% for quintiles 1 (≤4.41 mg/dL [≤262 μmol/L]), 2 (4.41 to 5.20 mg/dL [262 to 309 μmol/L]), 3 (5.21 to 5.90 mg/dL [310 to 351 μmol/L]), 4 (5.91 to 6.90 mg/dL [352 to 410 μmol/L]), and 5 (>6.90 mg/dL [>410 μmol/L]), respectively. In comparison, there was only a modest, but significant, association between quintiles of uric acid levels and progression of kidney function decrease, with adjusted odds ratios of 1.0, 0.88 (95% confidence interval [CI], 0.64 to 1.21), 1.23 (95% CI, 0.87 to 1.75), 1.47 (95% CI, 1.04 to 2.07), and 1.49 (95% CI, 1.00 to 2.22) for quintiles 1 through 5, respectively. No significant association was found between uric acid level and incident CKD (adjusted odds ratio, 1.00; 95% CI, 0.89 to 1.14).

Limitations

Measurements of albuminuria were not available.

Conclusions

Uric acid levels are associated strongly with prevalent CKD. In comparison, greater uric acid levels had a significant, but much weaker, association with progression of kidney disease.

Index Words: Uric acid, kidney function, chronic kidney disease