Characterization of the long-term health effects of Legionnaires’ Disease among U.S. Veterans Open Access

Ross, Natasha (Spring 2018)

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Background: Legionnaires’ Disease (LD) is responsible for 2-9% of community-acquired pneumonias in the U.S. (7).  Previous research suggests there may be long-term health complications, but data is limited and no research extends beyond 2 years after post-LD infection. Our study characterizes the health effects of LD up to 5 years post-LD diagnosis and investigates whether an association exists between ICU admission during acute LD infection and negative health outcomes in 5-year follow-up. Methods: In this retrospective cohort study of 292 Veterans’ Health Administration patients hospitalized between 2005 and 2010 with laboratory-confirmed LD, we collected data from electronic medical records on health history, LD severity (including ICU admission during LD hospitalization) and ICD-9 discharge diagnoses codes for 5 years post-LD or until death.  Ordinal logistic regression was used to explore associations between ICU admission and risk of hospitalization after the incident LD admission. Results:  Among the 161 veterans with at least one hospitalization within 5 years of their LD admission, among the most frequently observed discharge diagnoses for acute conditions were acute renal failure (n=49, 2.8%) and unspecified pneumonia (n=47, 2.7%). Patients admitted to the ICU during their qualifying LD visit were more likely to have a greater number of hospitalizations within 5 years compared to non-ICU patients (ORHosp 1.92 CI95% 1.25, 2.95). Conclusions: In addition to chronic conditions prevalent in this population, we found acute diagnoses that may warrant further research regarding their associations with LD. Findings also indicate that LD requiring ICU admission may be associated with more subsequent hospitalizations.Further research is needed regarding the prevalence of pre-existing conditions and their effects on hospital course for LD and other pneumonias, differences in health outcomes after pneumonias of different etiologies, and associations between the severity of incident pneumonias and adverse health outcomes.

Table of Contents

1  Introduction

2  Methods

5  Results

8 Discussion

13 References

14 Figure 1

15 Table 1

16 Table 2

17 Table 3 

18 Table 4 

19 Table 5

20 Table 6

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