Bad Prognosis in Critical Ill Patients with COVID-19 during Short-Term ICU Stay regarding Vitamin D Levels

Background and aims: Vitamin D inadequacy may be involved in the mechanisms of SARS-CoV-2 infection and in potential risk factors for disease propagation or control of coronavirus disease 2019 (COVID-19). This study assessed a short-term evolution of vitamin D status and its influence upon different clinical parameters in critically ill patients with COVID-19. Methods: A prospective analytical study in which 37 critically ill volunteers between 41 and 71 years of age with COVID-19 were evaluated at baseline and three days of intensive care unit (ICU) stay. 25-OH-D(3) and 25-OH-D(2) were analyzed by liquid chromatography–tandem mass spectrometry and total 25-OH-D levels were calculated as the sum of both. Results: All patients presented low 25-OH-D levels at baseline, decreasing total 25-OH-D (p = 0.011) mainly through 25-OH-D(2) (p = 0.006) levels during ICU stay. 25-OH-D(2) levels decreased a mean of 41.6% ± 89.6% versus 7.0% ± 23.4% for the 25-OH-D(3) form during the ICU stay. Patients who did not need invasive mechanical ventilation presented higher levels of 25-OH-D(2) at baseline and follow-up. Lower 25-OH-D and 25-OH-D(3) levels were associated with higher D-dimer at baseline (p = 0.003; p = 0.001) and at follow up (p = 0.029), higher procalcitonin levels (p = 0.002; p = 0.018) at follow up, and lower percentage lymphocyte counts (p = 0.044; p = 0.040) during ICU stay. Conclusions: Deficient vitamin D status in critical patients was established at the admission and further worsened after three days of stay. Lower vitamin D levels were related to key altered clinical and biochemical parameters on patients with SARS-CoV-2 infection. Given the different response of the 25-OH-D(3) and 25-OH-D(2) forms, it would be useful to monitor them on the evolution of the critically ill patient.