Is Vitamin D an Effective Treatment Method in Reducing Mortality in patients who have Cardiovascular Disease?

OBJECTIVE: The objective of this selective EBM review is to determine whether or not vitamin D is an effective treatment method in reducing mortality due to cardiovascular disease. STUDY DESIGN: A review of two double blind, randomized controlled trials (RCTs) and one randomized open-label study published in the English language after 2008. The articles compared oral, intramuscular, or oil drops of vitamin D to a placebo group. DATA SOURCES: One double-blind randomized controlled trial, one randomized control trial that was not blinded, and one randomized open-label study were found using PubMed, Medline, Embase, or Cochrane. The articles were selected based on their correlation to the specified topic, date of publications, and their evaluation of POEMs. OUTCOMES MEASURED: The effect of vitamin D supplementation on reducing mortality in patients with cardiovascular disease will be measured. Mortality was measured by main cause of death from death registrations, Rankin scales, repeated contacts with the participants, contact with family physicians, regular review of medical records, and consultation of the respective registration office. RESULTS: Two studies used in this review showed no significant improvement in vitamin D allocation in the reduction of mortality due to cardiovascular disease while one found clinical significance in the allocation of vitamin D. Avenell et al. and Zittermann et al.’s studies were not able to demonstrate an improvement in vascular mortality or all-cause mortality respectively with vitamin D supplementation. Gupta et al. reported a potential benefit in ischemic stroke survivors with vitamin D insufficiency or deficiency with the supplementation of vitamin D and calcium. This is the only RCT that did not separate calcium and vitamin D supplementation and instead combined both which showed a trend towards reduction in mortality. CONCLUSIONS: The results of these studies showed no significant improvement in vitamin D allocation alone to reducing cardiovascular death. Although Gupta et al. reported a statistically significant lower mortality rate in the treatment arm compared to the placebo, it did not separate vitamin D allocation from calcium therefore we cannot assume that vitamin D supplementation alone reduced death from cardiovascular disease. Future studies should be conducted when vitamin D supplementation is given before a major cardiovascular event such as a stroke or heart failure