Vitamin D deficiency on hospital admission associated with COVID-19 disease stage and mortality

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Vitamin D deficiency on admission was associated with coronavirus disease 2019 (COVID-19) disease stage and mortality, according to a study published in the American Journal of Clinical Pathology.

Dieter De Smet, MD, AZ Delta Medical Laboratories, Roeselare, Belgium, and colleagues conducted a retrospective observational trial in 186 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected individuals hospitalized at AZ Delta General Hospital, Roeselare, from March 1 to April 7, 2020, of whom 109 were males (median age, 68 years) and 77 were females (median age, 71 years). On admission, serum 25-hydroxyvitamin D (25[OH]D) level and the radiologic stage of COVID-19 pneumonia was determined by chest CT. These stages, said the authors, are considered a proxy for the immunologic phase of COVID-19, with an early phase of active viral replication in lower airways (stage 1) and progressive recruitment of proinflammatory cells to the lung interstitial space (stage 2), ending in consolidation with diffuse alveolar damage and fibrosis (stage 3).

Most patients (45.7%) presented in late stage 3, while 24.7% and 29.6% were in stages 1 and 2, respectively, with similar distribution in men and women. Meanwhile, prevalence of chronic lung disease, coronary artery disease, and diabetes in all patients with COVID-19 was 15%, 59%, and 14%, respectively, with no differences across COVID-19 disease stages.

Overall, 59% of the patients were vitamin D deficient (25(OH)D <20 ng/mL) on admission, whereby the deficiency was more prevalent among male patients compared with female patients (67% vs 47%). Further, male patients showed progressively lower median 25(OH)D level with advancing radiologic stage, resulting in vitamin D deficiency rates increasing from 55% in stage 1, 67% in stage 2, to 74% in stage 3 (P = .0010). However, no such stage-dependent 25(OH)D variations were observed in female patients. On the other hand, there was no statistically significant difference in prevalence of chronic lung disease, coronary artery disease, and diabetes between patients who were vitamin D sufficient and vitamin D deficient. Bivariable logistic regression analysis showed that vitamin D deficiency on admission was independently predicted only by male sex (odds ratio [OR], 2.43; 95% confidence interval [CI], 1.32-4.50; P = .0046) but not by age or any of the listed possible confounding comorbidities.

Of the patients, 27 (15%) died. The researchers found that vitamin D deficiency was associated with mortality (OR, 3.87; 95% CI, 1.30-11.55), independent of age (OR, 1.09; 95% CI, 1.03-1.14), chronic lung disease (OR, 3.61; 95% CI, 1.18-11.09), and extent of lung damage expressed by chest CT severity score (OR, 1.12; 95% CI, 1.01-1.25).

“A strength of our study is the simultaneous assessment of 25(OH)D status and the extent of pulmonary involvement and radiologic stage of viral pneumonia as measured by structured chest CT,” the authors wrote. “The latter indicated a clear correlation between 25(OH)D level and temporal stages of viral pneumonia, particularly in male patients, with lower 25(OH)D levels on admission associated with a more advanced stage. It also allowed a correction for possible confounding comorbidities.”

In addition, the authors noted that 25(OH)D levels analyzed in the study were single time points, measured on admission, and were thus not biased by secondary decreases during hospitalization due to inflammatory consumption of 25(OH)D or dilutions resulted from therapeutic interventions such as fluid resuscitation, extracorporeal oxygenation, or dialysis.

Further, the study, according to the authors, highlights the need for randomized controlled trials targeting vitamin D-deficient patients at intake and suggests preventing vitamin D deficiency as a safe and inexpensive possible mitigation of the COVID-19 pandemic.