This 2020 study assessed blood NAD⁺ levels in elderly patients (aged 75–101) hospitalized for decompensated heart failure compared to healthy donors (aged 19–68). Results showed significantly lower NAD⁺ concentrations in the elderly heart failure group (mean 20.7 μmol/L) versus healthy controls (mean 23.4 μmol/L). The decline in NAD⁺ was independent
