Food Sci Nutr. 2021 Sep 19;9(11):6307-6313. doi: 10.1002/fsn3.2591. eCollection 2021 Nov.
Considering the high prevalence of vitamin D deficiency worldwide and its relationship with immune response to viral infections, this study attempted to identify the predictive power of serum vitamin D for poor outcomes among the COVID-19 patients. This retrospective cohort study included all patients with confirmed COVID-19 hospitalized between February 20, 2020, and April 20, 2020, at a designated COVID-19 hospital, located in Tehran province, Iran. General characteristics, medical history and clinical symptoms were recorded by trained physicians. Blood parameters including complete blood count, creatinine, lactate dehydrogenase, creatine phosphokinase, erythrocyte sedimentation rate, C-reactive protein and vitamin D were tested. This study included 290 hospitalized patients with COVID-19 (the mean age [SD]: 61.6 [16.9], 56.6% males), of whom 142 had vitamin D concentrations less than 20 ng/ml, defined as vitamin D deficiency. COVID-19 patients with vitamin D deficiency were more likely to die (Crude OR [95% CI]: 2.30 [1.25-4.26]), require ICU (2.06 [1.22-3.46]) and invasive mechanical ventilation (2.03 [1.04-3.93]) based on univariate logistic regression results. Although, after adjusting for potentials confounders such as gender and age, the association between vitamin D and need to invasive mechanical ventilation lost its significance, adjusted values for the risk of death and ICU requirement were still statistically significant. Vitamin D deficiency can be considered as a predictor of poor outcomes and mortality in COVID-19 patients. Therefore, checking serum 25 (OH) D on admission and taking vitamin D supplements according to the prophylactic or treatment protocols is recommended for all COVID-19 patients.