The association between vitamin D intake with inflammatory and biochemical indices and mortality in critically ill patients with COVID‐19: A case‐control study

BACKGROUND: The coronavirus disease‐2019 (COVID‐19) has become a worldwide health issue with widespread hospitalization and dependence on the intensive care unit (ICU). Vitamin D has a key role in modulating immune cells and modulating the inflammatory responses. This study aimed to investigate the association of vitamin D supplementation with inflammatory, biochemical, and mortality indices in critically ill patients with COVID‐19. METHODS: This case‐control study was conducted on critically ill COVID‐19 patients hospitalized in the ICU including the survived >30 day patients as the case group and dead patients as the control group. The status of vitamin D supplementation and inflammatory and biochemical indices of the patients were retrieved from the medical records. Logistic regression method was used to assess the association between 30 days survival and vitamin D supplement intake. RESULTS: Compared to the group of COVID‐19 patients who died in <30 day, the survived patients had a lower eosinophile level (2.2 ± 0.5 vs. 6 ± 0.0, p < .001) and higher vitamin D supplementation duration (9 ± 4.4 vs. 3.3 ± 1.9 day, p = .001). Vitamin D supplementation had a positive association with survival in COVID‐19 patients (OR: 1.98, 95% CI: 1.15−3.40, p < .05). The association remained significant after adjustments fot age, sex, underlying diseases, and smoking. CONCLUSION: Vitamin D supplementation in critically ill patients with COVID‐19 has the potential to increase survivability within the first 30 days of hospitalization.