Background: In severe chronic heart failure (CHF) elevated serum levels of uric acid (UA) predict poor survival. This study investigates whether hyperuricaemia (defined as serum UA level > or = 6.5 mg/dL) extends its prognostic value on population with less advanced CHF.
Methods: We studied 119 consecutive patients with stable, mild-moderate CHF (88 men, age: 64+/-11 years, NYHA class I/II/III: 9/65/45, LVEF: 32+/-8%).
Results: Serum UA level (mean: 6.2+/-2.0 mg/dL, range: 2.0-16.2 mg/dL) increased in parallel to CHF severity expressed as NYHA class (4.9+/-1.1 vs. 5.7+/-1.5 vs. 7.2+/-2.4 mg/dL, NYHA I vs. II vs. III; NYHA I, II vs. III, p<0.01), inversely correlated with peak oxygen consumption (r=-0.39, p<0.01) and LVEF (r=-0.31, p<0.01), but not with renal function (expressed as creatinine clearance calculated from Cockcroft-Gault formula; r=-0.14, p>0.1), and predicted inflammatory status as evidenced by the correlation with C-reactive protein (r=0.31, p=0.003). Hyperuricaemia was detected in 48 (40%) patients. During follow-up (mean: 580+/-209 days, > 18 months in all survivors), 27 (23%) patients died. Hyperuricaemia was related to impaired survival in univariate (HR 2.8, 95%CI: 1.3-6.1, p=0.01) and multivariate analyses (adjusted for NYHA class and impaired renal function--the only mortality predictors in this population; p<0.05). The 18-month survival for CHF patients with hyperuricaemia was 71% (95% CI: 58-84%) vs. 89% (95% CI: 81-96%) in those with normal UA level (p=0.01).
Conclusion: In patients with mild-moderate CHF, hyperuricaemia predicts exercise intolerance and inflammatory activation and is strongly and independently related to poor prognosis. Whether elevated serum UA level may become a novel therapeutic target in CHF, deserves further studies.