Uric acid and prognosis in angiography-proven coronary artery disease

Abstract

Background: The optimal uric acid (UA) level associated with the lowest mortality and the strength of association between UA and mortality in various subgroups of patients with coronary artery disease (CAD) are unknown.

Materials and methods: This study included 13 273 patients with angiographic confirmation of CAD and UA measurements available. The primary outcome analysis was 1-year mortality.

Results: Based on the receiver operating characteristic curve analysis, the best cut-off of UA for mortality prediction was 7·11 mg/dL. Using this cut-off, patients were divided into two groups: the group with UA ≤ 7·11 mg/dL (n = 9075) and the group with UA > 7·11 mg/dL (n = 4198). Cardiac mortality was 6·3% (256 deaths) in patients with UA > 7·11 mg/dL and 2·3% (201 deaths) in patients with UA ≤ 7·11 mg/dL [hazard ratio (HR) = 2·82, 95% confidence interval (CI) 2·36-3·36; P < 0·001]. After adjustment for cardiovascular risk factors, UA remained an independent correlate of cardiac mortality (HR = 1·20, 95% CI 1·08-1·34; P = 0·001, for each standard deviation increase in the logarithmic scale of UA). The relationship between cardiac or all-cause mortality and UA showed a J-shaped pattern with lowest mortality in patients with UA between 5·17 and 6·76 mg/dL. UA predicted mortality across all subgroups of patients, with strongest association in women and patients without arterial hypertension.

Conclusions: UA predicted an increased risk of cardiac mortality across all subgroups of patients with CAD. The association between UA and cardiac or all-cause mortality had a 'J-shaped' pattern with lowest risk of death in patients with UA levels between 5·17 and < 6·76 mg/dL.