Vitamin D deficiency more common among COVID-19 patients admitted to ICU
Patients with COVID-19 requiring ICU admission are more likely to have vitamin D deficiency compared with those managed on medical wards, according to a retrospective study.
“Vitamin D receptors are highly expressed in B- and T-lymphocytes, suggesting a role in modulating innate and adaptive immune responses,” Grigorios Panagiotou, MD, a clinical fellow in endocrinology and diabetes at Newcastle upon Tyne Hospitals and the NHS Foundation Trust, United Kingdom, and colleagues wrote in a letter to the editor published in Clinical Endocrinology. “[Vitamin D] levels reach their nadir at the end of winter, and low levels are associated with increased risk of acute respiratory tract infections during winter [and are] mitigated by vitamin D supplementation. Clinical trials involving vitamin D supplementation in COVID-19 are ongoing but may not report within the time frame of this pandemic.”
In a single-center, retrospective study, Panagiotou and colleagues analyzed data from 134 inpatients who tested positive for COVID-19 and had serum 25-hydroxyvitamin D levels measured on admission. Researchers assessed the prevalence of vitamin D deficiency, compliance with local treatment protocol and the relationship of baseline serum 25-(OH)D with markers of COVID-19 severity and mortality.
Within the cohort, 66.4% had vitamin D insufficiency, defined as a level between 25 nmol/L and 50 nmol/L; 37.3% had vitamin D deficiency, defined as a level less than 25 nmol/L; and 21.6% had severe vitamin D deficiency, defined as a level of 15 nmol/L or less.
Patients admitted to the ICU (n = 42) were younger than those managed on medical wards (mean, 61 years vs. 76 years; P < .001) and were more likely to have hypertension (68.6% vs. 40.5%; P < .01), a higher baseline respiratory rate (mean, 24.8 per minute vs. 21.5 per minute; P = .01) and a higher C-reactive protein level (mean, 143.4 mg/mL vs. 107.9 mg/mL; P = .045).
Mean 25-(OH)D levels were comparable between groups (mean, 33.5 nmol/L vs. 48.1 nmol/L; P = .3); however, only 19% of ICU patients had 25-(OH)D levels greater than 50 nmol/L vs. 39.1% of those managed on medical wards (P = .02). Overall, 55.8% of patients received vitamin D supplementation.
Researchers did not observe an association with vitamin D deficiency and fatality, potentially due to small sample size and prompt diagnosis and treatment of vitamin D deficiency, they wrote.
“Previous publications have highlighted potential associations between vitamin D deficiency and COVID-19 mortality,” the researchers wrote. “We found no significant association between vitamin D deficiency and mortality, which was not unexpected given our proactive treatment protocol, small sample size and observational nature of our analysis.”
The researchers wrote that vitamin D deficiency was more prevalent among patients requiring ICU admission, and that vitamin D deficiency may be an underrecognized determinant of illness-severity in COVID-19.
“These preliminary data provide impetus to the commissioning, design and interpretation of ongoing or future clinical trials to evaluate a potential therapeutic role of vitamin D in COVID-19,” the researchers wrote.