COVID-19 mortality is associated with low vitamin D levels in patients with risk factors and/or advanced age

Background & aims: Although conclusive evidence is yet lacking, it has been suggested that vitamin D deficiency (VD) may be associated with a more severe course of SARS-CoV-2 Infection (COVID-19). In this retrospective study we assessed the association of VD deficiency with mortality in a group of COVID-19 patients treated in a tertiary referral center.

Methods: Data of 257 Covid-19 patients hospitalized between 30th September 2020 and 2nd March 2021 have been collected retrospectively. The following parameters were collected: age, gender, serum level of 25-OH-Vitamin D₃, outcome (survival/death), comorbidities (cancer, diabetes mellitus and chronic obstructive pulmonary disease). Serum VD measurement was done within 3 days of admission.

Results: VD levels were significantly lower in patients who did not survive, however, in this patients' group the average age was significantly higher than among those, who survived. After age-matching, in a subgroup of patients with risk factors and/or 60 years of age or older who survived had significantly higher VD level in their serum than those who deceased. Serum C-reactive protein, lactate-dehydrogenase and creatinin-kinase were significantly higher in the group in which the patients died, however these laboratory parameters did not correlate with the VD levels.

Conclusion: We found that in COVID-19 infection, when old age as risk factor (60 years of age or older) was pooled with risk factors (cancer, diabetes and/or COPD), the VD levels were significantly lower in the patient group, in which the patients did not survive. We suggest further, prospective studies in similar subgroups to explore a possible causal relationship.