key: cord-0929672-jzdy1aq2
authors: Kilaru, Austin S.; Lee, Kathleen; Snider, Christopher K.; Meisel, Zachary F.; Asch, David A.; Mitra, Nandita; Delgado, M. Kit
title: Return Hospital Admissions Among 1419 Covid‐19 Patients Discharged from Five US Emergency Departments
date: 2020-08-27
journal: Acad Emerg Med
DOI: 10.1111/acem.14117
sha: af191f8e32b0e3c0b8b404792c6dd8b83d8a19cd
doc_id: 929672
cord_uid: jzdy1aq2

Although many ED patients with known or suspected Covid‐19 require hospital admission, the majority are discharged home. Concern for surges in hospital occupancy compel emergency providers to preserve inpatient resources and discern which patients benefit most from admission. Even in the absence of surge conditions, patients may prefer to recover at home if safe to do so. However, some patients with Covid‐19 experience delayed decompensation.

Although many ED patients with known or suspected Covid-19 require hospital 8 admission, the majority are discharged home. 1 Concern for surges in hospital 9 occupancy compel emergency providers to preserve inpatient resources and 10 discern which patients benefit most from admission. 2 Even in the absence of surge 11 conditions, patients may prefer to recover at home if safe to do so. 3 However, 12 some patients with Covid-19 experience delayed decompensation. 4 Patients may 13 develop serious illness several days after initial symptoms and require respiratory 14 support. 5 Additional complications, including venous thromboembolism, 15 myocarditis, and acute kidney injury, may also require advanced therapies. 6 It is 16 not known how often and which patients with Covid-19 return to the hospital 17 following initial evaluation in the ED. To date, prediction models have focused on 18 the risk of critical illness among hospitalized patients. 1, 5 In this study, we describe 19 the incidence of return hospital admission within 72 hours for patients with 20

Covid-19 who were discharged from the ED upon initial presentation. We also 21 evaluate patient characteristics associated with return hospital admission. 22

We conducted a retrospective cohort study of adult patients with Covid-19 24 discharged from five distinct hospital EDs within a multi-hospital health system 25 spanning Pennsylvania and New Jersey. Using electronic health record data, we 26 identified all ED encounters from March 1 to May 28, 2020 for patients whose 27

Covid-19 infection was confirmed by diagnostic testing. Patients were included in 28

the study cohort if they tested positive for Covid-19 within 7 days before or after 29 the ED encounter, an extension of the case definition employed by the Centers for 30 Disease Control and Prevention. 7 Testing was performed either internally within 31

This article is protected by copyright. All rights reserved the health system or externally with documentation of the test date. Patients were 1 excluded if no vital signs were recorded during the ED encounter or if they were 2 younger than age 18. The initial ED encounter is defined as the index ED 3 encounter. For patients with multiple qualifying encounters during the study 4 period, only the first was included. 5 6 The binary primary outcome was inpatient admission or observation within 72 7 hours of the index ED encounter, defined as return hospital admission. Prior 8 studies and quality metrics use this time period to examine return visits. Although 9 ED encounters were limited to hospitals within the health system, data available 10 through a regional health information exchange (HIE) allowed us to identify 11 return admissions at unaffiliated hospitals in the region. We determined outcomes 12 using electronic health record data or from the HIE. In addition to the primary 13 outcome, we assessed whether patients had return hospital admissions at 7 days 14 following discharge. 15 16 Selection of covariates occurred prior to analysis and was based on previous 17 literature on risk factors for severe Covid-19 illness. While many patient 18 characteristics, co-morbidities, and diagnostic tests have been evaluated as risk 19 factors for severe Covid-19 infection, we sought to include risk factors relevant to 20 patients being considered for ED discharge and ensure the robustness of the 21 model by limiting the number of covariates. We chose not to include high-risk 22 conditions or lab tests because they may only apply to admitted patients. 1,4 23

Covariates included patient age, sex, and race/ethnicity, as well as the presence or 24 absence of hypertension, diabetes, and obesity (body mass index ≥ 30 kg/m 2 ). 5,6 25

We also included chest radiograph findings, based on the attending radiologist 26 interpretation, in two categories: 1) normal or not performed, and 2) indeterminate 27 or abnormal. Finally, we created binary covariates for the presence or absence of 28 three abnormal vital signs upon presentation: fever (temperature > 38C), hypoxia 29 (pulse oximetry less than 95% on room air), and tachycardia (pulse rate > 100 30 beats per minute). 31

1 Descriptive statistics were used to summarize covariates and unadjusted 2 outcomes. We performed diagnostic checks to examine influential data points; no 3 outliers were excluded. For the adjusted analysis, we used a generalized 4 estimating equations (GEE) approach to compare characteristics of patients with 5 return hospital admissions and those without. 8 The GEE clustered patients by 6 hospital site, using an independent working correlation structure, logit link 7 function, and robust standard errors. We report adjusted odds ratios (AOR) and 8 adjusted marginal probabilities, along with corresponding 95% confidence 9 intervals (CI). Measures of the discriminative ability of the model and goodness-10 of-fit are presented in the Supplement. For all analyses, we consider P < .05 (2-11 sided test) to be statistically significant. Analyses were conducted using Stata, 12 version 15.1 (StataCorp LLC). The ___ institutional review board approved this 13 study. 14 15

The cohort included 1419 patients with an index ED encounter that resulted in 16 discharge. A total of 66 patients (4.7%; 95%CI 3.6 to 5.7) had a return hospital 17 admission within 72 hours (Table) . An additional 56 (3.9%) patients returned to 18 an ED within 72 hours but were again discharged. 19 20 In the adjusted model, compared to patients aged 18-39, patients aged >60 (AOR 21 4.6; 95%CI 2.2 to 9.5) had significantly increased odds of return admission 22 (Table) . The adjusted probability of return admission for patients aged > 60 years 23 was 9.0% (95%CI 5.5 -12.5) as compared to 2.6% (95%CI 1.2 -4.0) for patients 24 aged 18-39 years. 25

Odds of return admission were significantly higher for patients presenting with 27 hypoxia (AOR 2.9; 95%CI 1.2 to 7.2) compared to those with normal 28 oxygenation. Patients presenting with fever also had higher odds of return 29 admission (AOR 2.4; 95%CI 1.3 to 4.5) compared to those who were afebrile. 30

Finally, patients with abnormal chest radiograph (AOR 2.4; 95%CI 1.5 to 3.7) had 31

This article is protected by copyright. All rights reserved higher odds of return admission compared to the group with chest radiographs 1 that were normal or not performed. 2 3 A total of 117 (8.2%; 95%CI 6.8 to 9.6) returned to a hospital for admission 4 within 7 days (Supplement). All statistically significant risk factors identified for 5 the primary outcome remained significant. Three additional risk factors were 6 associated with increased odds of return hospital admission within 7 days of the 7 index ED encounter: hypertension (AOR 1.5; 95%CI 1.1 to 2.0), obesity (AOR 8 1.5; 95%CI 1.1 to 2.0), and age between 41-59 years (AOR 2.1; 95%CI 1.6 to 9 2.8). 10 11 To our knowledge, no prior study has evaluated the outcome of return hospital 12 admission in patients with Covid-19 following ED discharge. This overall rate of 13 return hospital admission is twice that reported for the general ED population 14 prior to the pandemic, and elderly patients returned at a markedly higher rate. 9 15 Furthermore, some risk factors, including age > 60 years, fever on presentation, 16 and hypoxia on presentation, were associated with more than twice the probability 17 of subsequent return hospital admission. 18 19 While emergency clinicians are well-suited to manage patients who present to the 20 hospital with severe illness, patients who appear relatively well represent a 21 different challenge. Early reports indicated that patients with mild symptoms of 22

Covid-19 might worsen days after the onset of symptoms, defying expectations 23 for their prognosis. 4,10 The uncertain natural history of this illness may make it 24 difficult for emergency providers to predict which patients will worsen among 25 those who initially appear well. 26

Even with better evidence to guide disposition, it may not be feasibleor 28 effectiveto admit all patients with higher risk upon first presentation. 29

Importantly, return hospital admission does not equate to failure in patient care. 30

Rather, this outcome represents the need for a higher level of care than can be 31

This article is protected by copyright. All rights reserved provided at home. Patients may prefer to be discharged from their initial ED visit, 1 despite the risks, with a plan for hospitalization if the need develops. Both 2 physicians and patients can benefit from information on the risk for return 3 hospitalization and receive anticipatory guidance for symptoms that should 4 prompt return. Risk stratification may further improve the efficiency and 5 effectiveness of home monitoring and telemedicine services by focusing attention 6 on patients at higher risk for deterioration. 11 7 8 This study has several limitations. First, the cohort included only patients 9 presenting to the EDs within a single health system. Second, patients might travel 10 for return hospital admissions outside the geographic range of the health 11 information exchange. Third, we intentionally did not examine specific diagnoses 12 for the index ED encounter or return hospital admission; some ED visits and 13 return hospital admissions were unrelated to Covid-19 but rather occurred 14 incidentally in patients infected with the novel coronavirus. Fourth, providers 15 treating patients in this study were not necessarily aware of the Covid-19 status of 16 patients. Fifth, we do not account for patients who may have died at home. Sixth, 17 we did not include the full range of potential risk factors as covariates in the 18 model that may be associated with return hospital admission. Finally, this study 19

does not include patients with Covid-19 with false-negative tests. 20

In this study, we found that approximately 5 percent of patients with Covid-19 22 discharged from the ED returned for an unscheduled hospital admission within 72 23 hours. Age, abnormal chest x-ray findings, and fever or hypoxia on presentation 24 were independently associated with increased rate of return admission. The 25

Covid-19 pandemic has challenged emergency providers to deliver time-sensitive 26 interventions under difficult circumstances. An additional challenge is posed by 27 patients that appear well enough to be discharged upon initial presentation but 28 may require subsequent admission. As the pandemic evolves, further investigation 29 may be needed to develop risk stratification tools that guide disposition for 30 patients with Covid-19 in the ED. 31

This article is protected by copyright. All rights reserved 

This article is protected by copyright. All rights reserved 

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