Vitamin C Deficiency, High-Sensitivity C-Reactive Protein, and Cardiac Event-Free Survival in Patients with Heart Failure

Background: Vitamin C is related to lower levels of high-sensitivity C-reactive protein (hsCRP), an inflammatory biomarker that predicts cardiovascular disease. Whether vitamin C deficiency is associated with hsCRP and cardiac events in heart failure (HF) patients has not been examined. Purpose: The aim of this study is to determine the relationships among vitamin C intake, serum levels of hsCRP, and cardiac events. Methods: A total of 200 HF patients completed a 3-day food diary to determine vitamin C deficiency and provided blood to measure serum levels of hsCRP. Patients were followed for 2 years to obtain data on cardiac event-free survival. Moderation analyses with hierarchical logistic and Cox regressions were used for the data analysis. Results: Seventy-eight patients (39%) had vitamin C deficiency and 100 (50%) had an hsCRP level higher than 3 mg/L. Vitamin C deficiency was associated with an hsCRP level higher than 3 mg/L in the hierarchical logistic regression (odds ratio, 2.40; 95% confidence interval, [1.13-5.10]; P =.023). Vitamin C deficiency (hazard ratio, 1.68; 95% CI, 1.05-2.69, P =.029) and hsCRP level higher than 3 mg/L (hazard ratio, 1.79; 95% CI, 1.07-3.01; P =.027) predicted shorter cardiac event-free survival in hierarchical Cox regression. The interaction of hsCRP level higher than 3 mg/L and vitamin C deficiency produced a 2.3-fold higher risk for cardiac events (P =.002) in moderation analysis. Higher level of hsCRP predicted shorter cardiac event-free survival only in patients with vitamin C deficiency (P =.027), but not in those with vitamin C adequacy. Conclusion: Vitamin C deficiency moderated the relationship between inflammation and cardiac events in patients with HF. Future study is required to determine whether adequate intake of vitamin C could play a protective role against the impact of inflammation on cardiac events in HF patients.