Vitamin D and the Risk of Hospital-Acquired Infections in Adults Admitted to the Intensive Care Unit Open Access

Kempker, Jordan (2013)

Permanent URL: https://etd.library.emory.edu/concern/etds/bg257f46q?locale=en
Published

Abstract

Introduction: There is evidence that vitamin D is integral to the function of the innate immune response and that low serum 25-hydroxyvitamin D (25(OH)D) concentrations may be a risk factor for infection. There have been no prospective studies examining the relationship between serum 25(OH)D levels and the risk for hospital-acquired infections (HAI) in patients admitted to the intensive care unit (ICU).

Methods: This is a prospective observational cohort of adult patients admitted to the Emory University medical ICU at Grady Memorial Hospital, Atlanta, Georgia from November 1, 2011 through October 31, 2012. Patients were included in the study if they were anticipated to have an ICU stay ≥ 1 day and did not refuse enrollment, and excluded if they were not able to undergo study phlebotomy within 5 days of ICU admission.

Results: The cohort consisted of 314 subjects, with 136 (43%) of subjects deficient in vitamin D, as evidenced by serum 25(OH)D concentrations < 15 ng/mL. The patient characteristics significantly associated with low 25(OH)D levels included admission during winter months (28% vs. 18%, p = 0.04), higher PaO2/FiO2 (275 ± 142 vs. 226 ± 243 torr, p = 0.03) and longer time from ICU admission to study phlebotomy (1.8 vs. 1.5 days, p = 0.02). A total of 36 (11%) patients developed an HAI prior to discharge, death or within 30 days from ICU admission. In multivariate analysis adjusting for gender, APACHE II score, time to study phlebotomy, ICU length of stay and net volume status, serum 25(OH)D levels < 15 ng/mL were not associated with risk for HAIs (HR 0.94, 95% CI 0.44 - 2.00).

Conclusions: In this prospective, observational cohort of adults admitted to a single-center medical ICU, there was no significant association between 25(OH)D deficiency and the risk for HAI.

Table of Contents

Introduction

1

Background

2

Methods

8

Results

13

Discussion

16

References

20

List of Tables

Table 1. Summary of Demographic Characteristics and Severity of Illness in Patients Admitted to the Medical Intensive Care Unit at Grady Memorial Hospital, Atlanta, GA November 1, 2011 - October 31, 2012

25

Table 2. Summary of Hospital-Acquired Infections at 30 days from Admission to the Intensive Care Unit by Infective Site and Organism in Patients Admitted to the Medical Intensive Care Unit at Grady Memorial Hospital, Atlanta, GA November 1, 2011 - October 31, 2012

26

Table 3. Patient Characteristics and Hospital Outcomes by Vitamin D Status in Patients Admitted to the Medical Intensive Care Unit at Grady Memorial Hospital, Atlanta, GA November 1, 2011 - October 31, 2012

27

Table 4. Results from An Adjusted Cox-Proportional Hazards Model For the Risk of Hospital-Acquired Infection in Patients Admitted to the Medical Intensive Care Unit at Grady Memorial Hospital, Atlanta, GA November 1, 2011 - October 31, 2012

29

List of Figures

Figure 1. Flowchart of Study Enrollment Process and Results

30

Figure 2. Distribution of Vitamin D Concentrations in Patients Admitted to the Medical Intensive Care Unit at Grady Memorial Hospital, Atlanta, GA November 1, 2011 - October 31, 2012

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Figure 3. Mean Vitamin D by Month in Patients Admitted to the Medical Intensive Care Unit at Grady Memorial Hospital, Atlanta, GA November 1, 2011 - October 31, 2012

32

Figure 4. Adjusted Cox Proportional Hazards Curves for Hospital-Acquired Infection in Patients Admitted to the Medical Intensive Care Unit at Grady Memorial Hospital, Atlanta, GA November 1, 2011 - October 31, 2012

33

Figure 5. Kaplan-Meier Survival Curves by Vitamin D Status Infection in Patients Admitted to the Medical Intensive Care Unit at Grady Memorial Hospital, Atlanta, GA November 1, 2011 - October 31, 2012

34

Figure 6. Cumulative Incidence Functions For Hospital-Acquired Infection by Vitamin D Status in Patients Admitted to the Medical Intensive Care Unit at Grady Memorial Hospital, Atlanta, GA November 1, 2011 - October 31, 2012.

35

Appendices

Appendix A. Effects of Imputation of Missing Values

36


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