The effect of high-dose parenteral vitamin D3 on COVID-19-related inhospital mortality in critical COVID-19 patients during intensive care unit admission: an observational cohort study

Eur J Clin Nutr. 2021 Sep;75(9):1383-1388. doi: 10.1038/s41430-021-00984-5. Epub 2021 Jul 23.


Background: In many studies, vitamin D has been found to be low in COVID-19 patients. In this study, we aimed to investigate the relationship between clinical course and inhospital mortality with parenteral administration of high-dose vitamin D3 within the first 24 h of admission to patients who were hospitalized in the intensive care unit (ICU) because of COVID-19 with vitamin D deficiency.

Methods: This study included 175 COVID-19 patients with vitamin D deficiency [25(OH) D <12 ng/mL] who were hospitalized in the ICU. Vitamin D3 group (n = 113) included patients who received a single dose of 300,000 IU vitamin D3 intramuscularly. Vitamin D3 was not administered to the control group (n = 62).

Results: Median C-reactive protein level was 10.8 mg/dL in the vitamin D3 group and 10.6 mg/dL in the control group (p = 0.465). Thirty-nine percent (n = 44) of the patients in the vitamin D3 group were intubated endotracheally, and 50% (n = 31) of the patients in the control group were intubated endotracheally (p = 0.157). Parenteral vitamin D3 administration was not associated with inhospital mortality by multivariate logistic regression analysis. According to Kaplan-Meier survival analysis, the median survival time was 16 d in the vitamin D3 group and 17 d in the control group (log-rank test, p = 0.459).

Conclusion: In this study, which was performed for the first time in the literature, it was observed that high-dose parenteral vitamin D3 administration in critical COVID-19 patients with vitamin D deficiency during admission to the ICU did not reduce the need for intubation, length of hospital stay, and inhospital mortality.

Publication types

  • Observational Study

MeSH terms

  • COVID-19*
  • Cholecalciferol
  • Cohort Studies
  • Hospital Mortality
  • Humans
  • Intensive Care Units
  • SARS-CoV-2
  • Vitamin D
  • Vitamin D Deficiency* / drug therapy


  • Vitamin D
  • Cholecalciferol