Serum uric acid levels and risk for vascular diseases in patients with metabolic syndrome.

Gout and increased serum uric acid (SUA) levels are often seen in patients with components of the metabolic syndrome. Increased SUA levels are associated with increased vascular risk, as is the metabolic syndrome. We investigated the association between SUA levels and the metabolic syndrome in a population of patients with manifest vascular disease to determine whether SUA levels convey an independent risk for vascular disease in patients with the metabolic syndrome.A nested case-cohort study of 431 patients with 220 cases with a new vascular event during followup, originating from the Second Manifestations of Arterial Disease (SMART) study. All patients had manifest vascular diseases, consisting of cerebral, coronary, or peripheral artery disease or abdominal aortic aneurysm. The relationship of SUA with the metabolic syndrome was analyzed with linear regression and adjusted for age, sex, creatinine clearance, and alcohol and diuretic use. The relationship of SUA levels with new vascular disease was investigated with Cox regression and adjusted for age and sex.The metabolic syndrome was present in 50% of patients. SUA levels were higher in 214 patients with the metabolic syndrome than in 217 patients without (0.36 +/- 0.08 mmol/l vs 0.32 +/- 0.09 mmol/l). SUA concentrations increased with the number of components of the metabolic syndrome (0.30 mmol/l to 0.38 mmol/l) adjusted for age, sex, creatinine clearance, and alcohol and diuretic use. Increased SUA concentrations were independently associated with risk for vascular events in patients without the metabolic syndrome (age and sex adjusted hazard ratio 2.4, 95% CI 1.0-5.5), in contrast to patients with the metabolic syndrome (adjusted hazard ratio 1.9, 95% CI 1.0-3.9).Elevated SUA levels are strongly associated with the metabolic syndrome, yet are not an independent risk factor for vascular disease in patients with the metabolic syndrome. In patients without the metabolic syndrome, elevated SUA levels are associated with increased risk for vascular disease.