Vitamin-D levels and intensive care unit outcomes of a cohort of critically ill COVID-19 patients

Objectives: The pattern of global COVID-19 has caused many to propose a possible link between susceptibility, severity and vitamin-D levels. Vitamin-D has known immune modulatory effects and deficiency has been linked to increased severity of viral infections. Methods: We evaluated patients admitted with confirmed SARS-COV-2 to our hospital between March-June 2020. Demographics and outcomes were assessed for those admitted to the intensive care unit (ICU) with normal (>50 nmol/L) and low (<50 nmol/L) vitamin-D. Results: There were 646 SARS-COV-2 PCR positive hospitalisations and 165 (25.5%) had plasma vitamin-D levels. Fifty patients were admitted to ICU. There was no difference in vitamin-D levels of those hospitalised (34, IQR 18.5-66 nmol/L) and those admitted to the ICU (31.5, IQR 21-42 nmol/L). Higher proportion of vitamin-D deficiency (<50 nmol/L) noted in the ICU group (82.0 vs. 65.2%). Among the ICU patients, low vitamin D level (<50 nmol/L) was associated with younger age (57 vs. 67 years, p=0.04) and lower cycle threshold (CT) real time polymerase chain reaction values (RT-PCR) (26.96 vs. 33.6, p=0.02) analogous to higher viral loads. However, there were no significant differences in ICU clinical outcomes (invasive and non-invasive mechanical ventilation, acute kidney injury and mechanical ventilation and hospital days) between patients with low and normal vitamin-D levels. Conclusions: Despite the association of low vitamin-D levels with low CT values, there is no difference in clinical outcomes in this small cohort of critically ill COVID-19 patients. The complex relationship between vitamin-D levels and COVID-19 infection needs further exploration with large scale randomized controlled trials.