High-Dose Intravenous Vitamin C Treatment: A 10-Year Prospective Cohort Study

Full abstract

Read the full abstract

Background: Oxidative stress is increasingly recognized as a key factor in diseases such as cancer, infections, and chronic pain. High-dose intravenous vitamin C (IVC) increases plasma levels more than oral intake and is gaining attention as a potential therapy. However, the effects and tolerability of IVC in routine clinical practice remain poorly understood. Methods: This 10-year multicenter observational High-Dose Intravenous Vitamin C Treatment Cohort (HIVITC) study (2012–2022) included 5721 patients who received an average of 7.5 g of IVC per week for vitamin C deficiency. The study assessed underlying diseases (UDs), symptom changes, and adverse events in accordance with Good Clinical Practice (GCP), the guideline for Strengthening the reporting of observational studies in epidemiology (STROBE), and the Declaration of Helsinki. Results: The concentration of vitamin C (Vit C) was below an adequate level (<50 μmol/L) in 83% of 1295 patients with laboratory-verified Vit C status. Patients with low plasma Vit C concentrations (≤22.9 μmol/L) reported significantly higher symptom intensity. During the IVC treatment period, the prevalence of Vit C deficiency and hypovitaminosis decreased from 36.6% to 7% in a subgroup of 142 patients. The most common UDs were linked to infections. Significant reductions in sum scores were observed for non-specific symptoms (tiredness/fatigue, sleep disorders, depression, lack of concentration), pain, and the most common disease-specific symptoms by the end of the treatment period (p < 0.0001). Safety data showed very good tolerability (99.1%), with only 17 non-serious adverse events reported. Conclusions: This study provides a robust body of real-world data (RWD) demonstrating the excellent safety profile of high-dose IVC and the association of this therapy with symptom improvement in the general population with various UDs.