Vitamin D supplementation may be beneficial in improving the prognosis of patients with chronic obstructive pulmonary disease in the intensive care unit: a retrospective study

Abstract

Background: Vitamin D is a crucial fat-soluble vitamin that has garnered significant attention due to its potential impact on respiratory health. It is noteworthy that many patients with chronic obstructive pulmonary disease (COPD) often experience deficiencies or insufficiencies of vitamin D. To address this issue, our retrospective study aimed to explore the potential association between serum 25-hydroxyvitamin D concentration and the prognoses of COPD patients in the Intensive Care Unit (ICU).

Methods: This study utilised data from the Medical Information Marketplace in Intensive Care IV (MIMIC-IV), a database of patients admitted to the Intensive Care Unit at Beth Israel Deaconess Medical Center (BIDMC) in the United States of America, with a focus on patients with a diagnosis of COPD. These patients were categorized into two groups: those who received vitamin D supplementation during their ICU stay and those who did not. We assessed in-hospital mortality and ICU mortality outcomes. Our analysis involved various analytical tools, including Kaplan-Meier survival curves, Cox proportional risk regression models, and subgroup analyses, to investigate the relationship between vitamin D supplementation and these outcomes. Additionally, we employed propensity-score matching (PSM) to enhance the reliability of our findings.

Results: The study included a total of 3,203 COPD patients, with 587 in the vitamin D group and 2,616 in the no-vitamin D group. The Kaplan-Meier survival curve demonstrated a significant difference in survival probability between the two groups. After adjusting for potential confounders using Cox regression models, the vitamin D group exhibited a substantially lower risk of in-hospital and ICU mortalities compared to the no-vitamin D group. The hazard ratios for in-hospital and ICU mortalities in the vitamin D group were 1.7 (95% CI: 1.3, 2.3) and 1.8 (95% CI: 1.2, 2.6), respectively. Propensity-score matching (PSM) estimation yielded consistent results. Furthermore, in the subgroup analysis, female patients who received vitamin D supplementation showed a reduced risk of in-hospital mortality.

Conclusion: The study suggests that vitamin D supplementation may be linked to a reduction in in-hospital and ICU mortalities among COPD patients in the ICU. Of particular note is the potential benefit observed in terms of in-hospital mortality, especially for female patients.

Keywords: chronic obstructive pulmonary disease; exacerbations; intensive care unit; mortality; respiratory failure; vitamin D.

Figure 1

The flow chart of the included population.

Figure 2

(A) Kaplan Meier curve of in-hospital mortality risk in two groups for the original population. (B) Kaplan Meier curve of ICU mortality risk in two groups for the original population. (C) Kaplan Meier curve of in-hospital mortality risk in two groups for the PSM population. (D) Kaplan Meier curve of ICU mortality risk in two groups for the PSM population. (Yellow and blue shaded parts in the figure indicate the 95% confidence interval).

Figure 3

Kaplan Meier curve of ICU mortality risk in two groups for the original population.

Figure 4

Subgroup analysis of the associations between in-hospital mortality and vitamin D received. Confounders were consistent with the model III in Table 2.

Figure 5

Subgroup analysis of the associations between ICU mortality and vitamin D received. Confounders were consistent with the model III in Table 2.