Background: Zinc is an essential cofactor for energy transfer and physiological heart function, has antioxidant properties, and is involved in multiple signaling pathways. We aimed to investigate the associations between serum zinc levels with prognosis, as well as underlying cardiac function and exercise capacity, in patients with heart failure (HF).
Methods and results: We measured serum zinc levels in 968 consecutive hospitalized patients with decompensated HF, who were divided into 3 groups based on serum zinc levels (µg/dL): first (zinc ≥75, n = 323), second (62≤ zinc <75, n = 322), and third (zinc <62, n = 323) tertiles. We examined cardiac function and exercise capacity and followed up on all patients. Although cardiac function did not differ among the 3 groups, peak oxygen consumption was significantly lower in the third tertile than in the first and second tertiles (peak oxygen consumption, 14.2 vs 15.9 and 15.2 mL/kg/min, P = .010). In the Kaplan-Meier analysis (mean duration of follow-up 1103 days), cardiac and all-cause mortality was highest in the third tertile compared with the first and second tertiles. In the Cox proportional hazard analysis, serum zinc level was a predictor of cardiac and all-cause mortality. In the subgroup analysis, there were no interactions concerning associations between serum zinc levels with prognosis and other important variables, including age, gender, comorbidities, medications, other micronutrient levels, B-type natriuretic peptide, and left ventricular ejection fraction. The associations between zinc levels with mortality were consistent in all subgroups.
Conclusion: Decreased serum zinc levels are associated with high mortality, accompanied by impaired exercise capacity.
Keywords: Serum zinc levels; cardiac function; exercise capacity; prognosis.
Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.