Uric acid renal excretion and renal insufficiency in decompensated severe heart failure.

Objective: To evaluate uric acid renal excretion, hyperuricemia, renal dysfunction, and prognosis in patients with decompensated severe heart failure, as there are few data available.

Methods: One hundred and twenty-two patients, hospitalized for heart failure decompensation, in NYHA class IV, were classified into 3 groups as follows. Pilot group [ejection fraction (EF)0.45 and valvular dysfunction, n=16). The patients in groups 1 and 2 underwent assessment of creatinine and uric acid clearance before and after pyrazinamide, to estimate uric acid tubular secretion. Uric acid clearance <6.8 mL/min and secretion <170 microg/min were considered reduced. In groups 1 and pilot (n=106), mortality was analyzed by Cox regression model, and the prognostic value of hyperuricemia was assessed by ROC curve.

Results: In groups 1 and 2, respectively, serum uric acid was 511.7 and 422.5 micromol/L, and creatinine clearance was 46.7 and 61.4 mL/min. Uric acid clearance (3.2 vs. 3.9 mL/min) and tubular secretion (116 vs. 128 microg/min) were not different, but lower than normal values. In groups 1 and pilot, the 12-month mortality was 46.4% (CI 95%: 36.7%-56.0%). At end of follow-up, mortality was associated with impaired creatinine clearance (p<0.001), but not with hyperuricemia (p=0.236).

Conclusions: In patients with decompensated severe heart failure, the tubular secretion and the clearance of uric acid were reduced. Renal dysfunction was associated with mortality, but hyperuricemia was not.