Relationship between serum uric acid levels and urinary albumin excretion in patients with heart failure

OBJECTIVES: Hyperuricaemia is a constant finding in patients with heart failure (HF). Upregulated xanthine-oxidase activity seems to contribute to progression of the disease through the production of oxidative stress and the development of vascular and endothelial dysfunction. On this basis we speculated that in HF serum uric acid levels correlated with a reliable marker of endothelial dysfunction as urinary albumin excretion. METHODS: Fifty-three patients with HF underwent assessment of serum uric acid, N-terminal probrain natriuretic peptide (NT-proBNP), glomerular filtration rate (GFR), other metabolic parameters and determination of urinary albumin concentration (UAC) in a morning urine sample. RESULTS: In univariate analysis there is a direct correlation between serum uric acid levels and log UAC (r = 0.43, P < 0.01); uric acid correlates also positively with log NT-proBNP (r = 0.31, P < 0.05) and negatively with log-GFR (r = -0.38, P < 0.01). In stepwise regression analysis serum uric acid emerged as the only predictor of increased UAC (standardized coefficient = 0.42, P = 0.001) independent of other clinical determinants and metabolic factors. CONCLUSION: Serum uric acid represents the strongest predictor of elevated UAC in HF. Regression of albuminuria may be a simple target to verify the efficacy of xanthine-oxidase inhibition in these patients.