Background: Vitamin C deficiency is prevalent in adults with heart failure (HF). Little is known about the relationship of dietary vitamin C deficiency with health outcomes in adults with HF.
Objective: The study's aim was to determine the relationships of vitamin C deficiency measured at baseline with health-related quality of life (HRQOL) and cardiac event-free survival in patients with HF measured 1 year later.
Method: A total of 251 patients with HF completed a 4-day food diary. Dietary vitamin C deficiency was defined as daily intake less than the estimated average requirement from the Institute of Medicine of 75 mg/d for men and 60 mg/d for women. Health-related quality of life was assessed using the Minnesota Living with Heart Failure Questionnaire at 12 months. Patients were followed for a median of 1 year to determine time to the first event of cardiac-related hospitalization or death. Data were analyzed by hierarchical linear and Cox proportional hazards regressions.
Results: One hundred patients (40%) had vitamin C deficiency. Dietary vitamin C deficiency was associated with poorer HRQOL at 12 months (β = 0.16, P = .02) after controlling for demographic and clinical variables. During the follow-up period, 59 patients (24%) had cardiac events. In Cox regression, vitamin C deficiency predicted shorter cardiac event-free survival after adjusting for the same covariates (hazards ratio, 1.95; 95% confidence interval, 1.08-3.51).
Conclusion: Vitamin C deficiency was associated with poorer HRQOL and shorter cardiac event-free survival in patients with HF. The findings suggest that encouraging patients with HF to consume a diet rich in fruits/vegetables to prevent vitamin C deficiency may lead to better health outcomes.