Superoxide dismutase activity as a predictor of adverse outcomes in patients with nonischemic dilated cardiomyopathy

Oxidative stress contributes to progression of heart failure (HF). The present study analyzed the efficacy of the activities of superoxide dismutase (SOD) and its isoenzymes (CuZnSOD and MnSOD) as prognostic factors in dilated cardiomyopathy. The usefulness of activities of total SOD, MnSOD, and CuZnSOD was assessed, taking into account clinical, echocardiographic, and laboratory parameters as risk predictors of long-term clinical outcomes (death, heart transplant, combined end point) in 109 patients with nonischemic dilated cardiomyopathy (NIDCM) in this study with a 5-year follow-up. Regression analysis showed that total serum SOD activity was a predictor of worse long-term clinical outcome even after adjustment for NT-proBNP, hemoglobin, sodium, creatinine clearance, left ventricular ejection fraction (LVEF), BMI, and NYHA class (LVEF: HR 1.059, 95% CI 1.007–1.114, P = 0.026; BMI: HR 1.073, 95% CI 1.021–1.126, P = 0.005; NYHA: HR 1.073, 95% CI 1.022–1.126, P = 0.005). MnSOD and CuZnSOD activities were also predictors of worse long-term clinical outcome even after adjustment for laboratory parameters and BMI or NYHA class; however, after adjustment for LVEF, a borderline statistical significance was achieved (LVEF: HR 1.054, 95% CI 0.993–1.119, P = 0.081 [MnSOD]; HR 1.092, 95% CI 0.989–1.297, P = 0.082 [CuZnSOD]). Increased activities of total serum SOD and its isoenzymes in NIDCM patients correspond with a poor prognosis and may have prognostic value in the prediction of long-term clinical outcomes. In conclusion, the present study shows that serum SOD activity may be a useful predictor of adverse outcome in HF.