Vitamin D deficiency predicts 30-day hospital mortality of adults with COVID-19

BACKGROUND & AIMS: Several studies have shown conflicting results for the relationship between vitamin D deficiency and COVID-19 outcomes. Here, we aimed to evaluate whether plasma 25(OH)D levels predict mortality in adults admitted with COVID-19, considering potential confounders. METHODS: We conducted a retrospective cohort study that included 115 adults (age 62.1 ± 17.6 years, 65 males) admitted to a Brazilian public hospital for severely symptomatic COVID-19. Subjects were classified into two groups according to their plasma levels of 25(OH)D: sufficiency (≥50 nmol/L) and the deficiency (<50 nmol/L). The diagnosis of COVID-19 was performed using real-time polymerase chain reaction (qPCR). In addition, direct competitive chemiluminescence immunoassay assessed serum 25(OH)D levels. RESULTS: The all-cause 30-day mortality was 13.8% (95% CI: 6.5%–21%) in the group of patients with sufficient plasma 25(OH)D levels and 32.1% (95% CI: 14.8%–49.4%) among those with deficient plasma 25(OH)D levels. Cox regression showed that plasma 25(OH)D levels remained a significant predictor of mortality even after adjusting for the covariates sex, age, length of the delay between symptom onset and hospitalization, and disease severity (HR = 0.98, 95% CI: 0.96–1.00; p = 0.02). CONCLUSION: Vitamin D deficiency predicts higher mortality risk in adults with COVID-19.