Timing of Methicillin-resistant Staphylococcus aureus (MRSA) Bloodstream Infections among Hospitalized Patients and Its Association with Patient and Prior Healthcare Exposures Open Access

Gouin, Katryna (Spring 2019)

Permanent URL: https://etd.library.emory.edu/concern/etds/nv935409w?locale=en
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Abstract

Background: There have been no significant reductions in hospital-onset MRSA bloodstream infections (BSIs) in recent years. Therefore, we sought to identify patient and healthcare exposures that differ by timing of MRSA BSI among hospitalized patients.

Methods: We estimated the timing of MRSA BSI in adults hospitalized from 2013-2016 in New York using surveillance data from the National Healthcare Safety Network. MRSA events were linked to administrative data to capture patient and healthcare variables. Daily risk was calculated using the number of MRSA events per day and the number of patients remaining in the hospital each day. Among those with MRSA, events were divided into three groups: community-onset (diagnosed on days 1-3), early hospital-onset (days 4-7), late hospital-onset (days 8-30). Univariate and multinomial modeling were performed to identify risk factors for the timing of onset.

Results: The median time to hospital-onset MRSA BSI was 11 days. Of 10,081 (80%) linked events, 19.2% were hospital-onset and 80.8% were community-onset. The daily risk of hospital-onset MRSA BSI was highest for patients with longer length of stay (18.8 events per 100,000 patients on day 28). Patients that were admitted from a skilled nursing facility, had surgery in the previous year, or were on dialysis during hospitalization were more likely to have community-onset vs. early hospital-onset MRSA BSI (aOR=1.74, 95% CI:1.32,2.30, aOR=1.26, 95% CI: 1.02, 1.57, and aOR=1.33, 95% CI: 1.10, 1.61, respectively). Patients with prior inpatient hospitalization or dialysis during hospitalization were less likely to have late hospital-onset vs. early hospital-onset MRSA BSI (aOR=0.79, 95% CI: 0.66, 0.96 and aOR=0.63, 95% CI: 0.49, 0.81).

Conclusion: Using large-scale linkage of surveillance and administrative data, we showed that half of hospital-onset MRSA BSI occurs on or after day 11 of hospitalization. The risk of hospital-onset MRSA BSI is highest with longer length of stay and different healthcare exposures are associated with both community-onset and late hospital-onset MRSA BSI compared to early hospital-onset MRSA BSI. This suggests that length of stay and prior healthcare exposures could be targeted in hospital-based infection prevention. 

Table of Contents

Introduction…………………………………………………………………………......1

Methods……………………………………………………………………………….…11

Study Design, Population and Data Sources………………...………………...11

Outcome Variable…………………………………………………………….…......12

Potential Factors Associated with Time to MRSA Event…………...……....13

Analytic Approach…………………………………………………………….........15

Ethics Approval……………………...………………………………………….......17

Results……………………………………………………………………………………18

Distribution of Time to MRSA Event……………………………...…………....18

Hospital Characteristics……………………..………………………………….....18

Data Linkage……………………………………………………………………........19

Daily Risk………………………………...……………………………………..........20

Patient Characteristics……………………………………………………………...21

Healthcare Exposures……………………………………………………………....22

Discussion……………………………………………………………………………...26

Timing of MRSA BSI…………………………...……………………………….....26

Daily Risk of Hospital-onset MRSA BSI………………………......…………..28

Early vs. Late HO MRSA…………………………...…………………………......30

Patient Characteristics Associated with MRSA Events………………........31

Healthcare Exposures……………………………………………………………...32

Limitations………………………………………………………………………......35

Strengths………………………………………………………………….......……..38

Future Directions…………………………………………...………………....…..39

Conclusion……………………………………………………………………………..40

References……………………………………………………………………………...41

Tables and Figures……………………...………………………………………..….51

Appendix……………………………………………………………………………….62

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