Prognostic Significance of Serum Uric Acid in Patients Admitted to the Department of Medicine

Background: Hyperuricemia has been linked to proatherogenic processes, including increased oxidative stress and leukocyte activation, and was shown to predict adverse prognosis in heart failure, renal failure, and hypertension. Recently, serum uric acid (SUA) was shown to be an independent predictor of long-term mortality in patients with cardiovascular diseases. However, the prognostic significance of SUA for the short-term outcome of admitted medical patients is unknown.

Methods: Initial SUA, together with epidemiological, clinical, and laboratory data, was analyzed for a prospective cohort of 650 consecutive adult patients admitted to the department of internal medicine during a 3-month period.

Results: The mean, median, and range of SUA at admission were 6.1 +/- 2.7, 5.6, and 1.2 to 24 mg/dL, respectively. Increased SUA was significantly correlated with age, gender, comorbidities (coronary heart disease, heart failure, hypertension, diabetes, renal failure, and gout), use of diuretics, and current admission for cardiovascular diseases but not with current diagnosis of infection, malignancy, or inflammatory diseases, nor with C-reactive protein. However, SUA significantly correlated with mortality (7.7 versus 6 mg/L, P < 0.025) and was an independent predictor of mortality in a multivariate regression analysis (odds ratio: 1.11; confidence interval: 1.003-1.218; P = 0.04), with a significant difference in mortality between normal SUA (<6 mg/dL) with 5% mortality and high SUA (>12 mg/dL) with 27% mortality.

Conclusions: Initial SUA is an independent predictor of mortality in admitted medical patients. Whether significant asymptomatic hyperuricemia should be treated remains to be determined in further studies.