Possible association of vitamin D status with lung involvement and outcome in patients with COVID-19: a retrospective study

Abstract

Purpose: Vitamin D deficiency has been reported as a key factor in the development of infectious diseases such as respiratory tract infections and inflammatory processes like acute respiratory distress syndrome. However, the impact of vitamin D on the severity and outcome of COVID-19 is still not fully known. Herein, we aimed to evaluate the prognostic role of serum vitamin D concentration on the extent of lung involvement and final outcome in patients with COVID-19.

Methods: Seventy-three subjects with confirmed diagnosis of COVID-19 were investigated in this study. The patients had been admitted to our academic hospital from February 28, 2020 to April 19, 2020. Demographic and clinical data, serum 25(OH)D levels, and findings of initial chest computed tomography were recorded. Linear and binary logistic regression, cox regression and ROC curve tests were used for statistical analysis.

Results: The mean age of patients was 55.18 ± 14.98 years old; 46.4% were male. Mean serum 25(OH)D concentration was significantly lower in the deceased (13.83 ± 12.53 ng/ mL compared with discharged patients (38.41 ± 18.51 ng/mL) (P < 0.001). Higher levels of 25(OH)D were associated with significantly less extent of total lung involvement (β = - 0.10, P = 0.004). In addition, vitamin D deficiency [25(OH) D < 25 ng/mL] was associated with a significant increase in the risk of mortality (hazard ratio = 4.15, P = 0.04).

Conclusion: This study suggests that serum vitamin D status might provide useful information regarding the clinical course, extent of lung involvement and outcome of patients with COVID-19. However, further studies with larger sample size are needed to confirm these findings.

Keywords: COVID-19; Computed tomography; Outcome; Vitamin D.

Fig. 1

Log minus log of hazard function. The evaluation of the assumption of proportionality of hazards in cox survival models. The parallel log minus log functions in 25(OH)D deficiency groups and Schoenfeld residues analysis (chi-square = 8.02, DF = 4, P = 0.10) indicates that comparing hazard of death in two groups does not depend on time and the proportionality assumption is hold in cox regression

Fig. 2

a–c A 55-year-old man presented with 5-day history of fever and dry cough without any comorbidity [25(OH)D level was 40 ng/mL] with initial lung computed tomography (CT) involvement score of eight/24. On admission, CT images showed subtle patchy ground-glass opacities (GGO) (long arrows) predominantly in upper zones and reticular pattern (wide arrows) in lower zones. The patient discharged after 6 days. d–f A 54-year-old man presented with 4-day history of fever, dry cough and dyspnea and no other comorbidity [25(OH)D level was 7 ng/mL]. Lung CT score involvement score of ninety/24. On admission, CT images showed diffuse GGO (long arrows) with slight consolidation change (thick head arrow) in right mid zone. The patient died after 19 days

Fig. 3

ROC curve analysis results to achieve predictive values of 25(OH)D in classifying patients into dead or discharge

Fig. 4

Cumulative hazard function of death in patients with and without 25(OH)D deficiency. The “death” status considered as the event and hospitalization days considered as the event time in cox regression