ABSTRACT
BACKGROUND: The role of vitamin D status in COVID-19 patients is a matter of debate. OBJECTIVES: To assess serum 25-hydroxyvitamin D (25OHD) levels in hospitalized patients with COVID-19 and to analyze the possible influence of vitamin D status on disease severity. METHODS: Retrospective case-control study of 216 COVID-19 patients and 197 population-based controls. Serum 25OHD levels were measured in both groups. The association of serum 25OHD levels with COVID-19 severity (admission to the intensive care unit, requirements for mechanical ventilation, or mortality) was also evaluated. RESULTS: Of the 216 patients, 19 were on vitamin D supplements and were analyzed separately. In COVID-19 patients, meanâ ±â standard deviation 25OHD levels were 13.8â ±â 7.2 ng/mL, compared with 20.9â ±â 7.4 ng/mL in controls (Pâ <â .0001). 25OHD values were lower in men than in women. Vitamin D deficiency was found in 82.2% of COVID-19 cases and 47.2% of population-based controls (Pâ <â .0001). 25OHD inversely correlates with serum ferritin (Pâ =â .013) and D-dimer levels (Pâ =â .027). Vitamin D-deficient COVID-19 patients had a greater prevalence of hypertension and cardiovascular diseases, raised serum ferritin and troponin levels, as well as a longer length of hospital stay than those with serum 25OHD levels ≥20 ng/mL. No causal relationship was found between vitamin D deficiency and COVID-19 severity as a combined endpoint or as its separate components. CONCLUSIONS: 25OHD levels are lower in hospitalized COVID-19 patients than in population-based controls and these patients had a higher prevalence of deficiency. We did not find any relationship between vitamin D concentrations or vitamin deficiency and the severity of the disease.