Does vitamin D serum level affect prognosis of COVID-19 patients?

Background: Since the beginning of the Coronavirus disease 2019 (COVID-19) pandemic there have been contradictions and speculations about the relationship between vitamin D and COVID-19. Given that there is an association between vitamin D deficiency and some diseases-including cancer, autoimmune disease and some infectious diseases-a higher incidence and mortality rate in the vitamin-D-deficient COVID-19 population was not a surprise; conversely, some research would argue this relationship. Considering these contradictions, this study aimed to determine the relationship between prognosis and vitamin D level in cases with COVID-19. Methods: In this cross-sectional study, 329 confirmed cases of COVID-19-who were admitted to KamkarArabNia Hospital in Qom city, Iran from March-July 2020-were categorized into three groups according to vitamin D serum levels (ng/ml): sufficient (>30), insufficient (20-30) and deficient (<20). Prognosis was determined across the groups. Results: There was a significant difference in hospital stay between patients with sufficient and insufficient vitamin D levels (P = 0.007). Adjusting vitamin D levels for confounding variables, linear regression underscored significant differences in the association between length of hospitalization and lower vitamin D levels, with a longer stay noted in insufficient groups (P = 0.002). However, there was no significant difference in the time interval to return to normal oxygen level (from SpO2 < 93%) or death rate between groups (P > 0.05). Conclusion: There was a significant association between hospital stay and lower serum vitamin D levels. However, the relationship between vitamin D status and death rate or the time interval to return to normal oxygen levels was not significant. (c) 2021 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-ncnd/4.0/).

Automated summary

This study found a significant association between vitamin D levels and hospital stay in COVID-19 patients, but no significant relationship with death rate or time to return to normal oxygen levels.