Treatments, resource utilization, and outcomes of COVID-19 patients presenting to emergency departments across pandemic waves: an observational study by the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN)

The response of Canada's clinical health research ecosystem to the COVID-19 pandemic

BACKGROUND

The response of Canada's research community to the COVID-19 pandemic provides a unique opportunity to examine the country's clinical health research ecosystem. We sought to describe patterns of enrolment across Canadian Institutes of Health Research (CIHR)-funded studies on COVID-19.

METHODS

We identified COVID-19 studies funded by the CIHR and that enrolled participants from Canadian acute care hospitals between January 2020 and April 2023. We collected information on study-and site-level variables from study leads, site investigators, and public domain sources. We described and evaluated factors associated with cumulative enrolment.

RESULTS

We obtained information for 23 out of 26 (88%) eligible CIHR-funded studies (16 randomized controlled trials [RCTs] and 7 cohort studies). The 23 studies were managed by 12 Canadian and 3 international coordinating centres. Of 419 Canadian hospitals, 97 (23%) enrolled a total of 28 973 participants - 3876 in RCTs across 78 hospitals (median cumulative enrolment per hospital 30, interquartile range [IQR] 10-61), and 25 097 in cohort studies across 62 hospitals (median cumulative enrolment per hospital 158, IQR 6-348). Of 78 hospitals recruiting participants in RCTs, 13 (17%) enrolled 50% of all RCT participants, whereas 6 of 62 hospitals (9.7%) recruited 54% of participants in cohort studies.

INTERPRETATION

A minority of Canadian hospitals enrolled the majority of participants in CIHR-funded studies on COVID-19. This analysis sheds light on the Canadian health research ecosystem and provides information for multiple key partners to consider ways to realize the full research potential of Canada's health systems.

Characteristics and outcomes of patients with COVID-19 who return to the emergency department: a multicentre observational study by the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN)

OBJECTIVE

Unplanned return emergency department (ED) visits can reflect clinical deterioration or unmet need from the original visit. We determined the characteristics and outcomes of patients with COVID-19 who return to the ED for COVID-19-related revisits.

METHODS

This retrospective observational study used data for all adult patients visiting 47 Canadian EDs with COVID-19 between 1 March 2020 and 31 March 2022. Multivariable logistic regression assessed the characteristics associated with having a no return visit (SV=single visit group) versus at least one return visit (MV=return visit group) after being discharged alive at the first ED visit.

RESULTS

39 809 patients with COVID-19 had 44 862 COVID-19-related ED visits: 35 468 patients (89%) had one visit (SV group) and 4341 (11%) returned to the ED (MV group) within 30 days (mean 2.2, SD=0.5 ED visit). 40% of SV patients and 16% of MV patients were admitted at their first visit, and 41% of MV patients not admitted at their first ED visit were admitted on their second visit. In the MV group, the median time to return was 4 days, 49% returned within 72 hours. In multivariable modelling, a repeat visit was associated with a variety of factors including older age (OR=1.25 per 10 years, 95% CI (1.22 to 1.28)), pregnancy (1.86 (1.46 to 2.36)) and presence of comorbidities (eg, 1.72 (1.40 to 2.10) for cancer, 2.01 (1.52 to 2.66) for obesity, 2.18 (1.42 to 3.36) for organ transplant), current/prior substance use, higher temperature or WHO severe disease (1.41 (1.29 to 1.54)). Return was less likely for females (0.82 (0.77 to 0.88)) and those boosted or fully vaccinated (0.48 (0.34 to 0.70)).

CONCLUSIONS

Return ED visits by patients with COVID-19 within 30 days were common during the first two pandemic years and were associated with multiple factors, many of which reflect known risk for worse outcomes. Future studies should assess reasons for revisit and opportunities to improve ED care and reduce resource use.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov, NCT04702945.

Administrative data ICD-10 diagnostic codes identifies most lab-confirmed SARS-CoV-2 admissions but misses many discharged from the Emergency Department

We estimated the operating characteristics of ICD-10 code U07.1, introduced by the World Health Organization in 2020, to identify lab-confirmed SARS-CoV-2. CCEDRRN is a national research registry of adults (March 2020-August 2021) with suspected/confirmed SARS-CoV-2 identified in Canadian emergency departments (EDs) using chart review (symptoms, clinical information, and lab test results including SARS-CoV-2 polymerase chain reaction, PCR results). CCEDRRN data were linked to administrative hospitalization discharge and ED ICD-10 diagnostic codes (accessed centrally via the Canadian Institute for Health Information). We identified ICD-10 diagnostic codes in CCEDRRN participants. We defined lab-confirmed SARS-CoV-2 based on at least one positive PCR in the 0-14 days before the ED presentation and/or during hospitalization (in those admitted from ED). We performed separate analyses for CCEDRRN participants discharged from ED and those hospitalized from the ED. Additional analyses were stratified by province, sex, age, and (for hospitalized patients) timing of the first PCR test. The sensitivity of ICD-10 code U07.1 for a positive SARS-CoV-2 test was 93.6% (95% CI 93.0-94.1%) in those hospitalized from ED and 83.0% (95% CI 82.1-83.9%) in those discharged from the ED. Sensitivity was similar across provinces and demographics, but in each stratified analysis, values were higher in those hospitalized versus those discharged from ED. The ICD-10 diagnostic code for U07.1 within administrative data identified most lab-confirmed SARS-CoV-2 within persons hospitalized from ED, although a significant number of cases discharged from ED were missed. This should be considered when using administrative data for research and public health planning.

Covariate adjustment in Bayesian adaptive randomized controlled trials

In conventional randomized controlled trials, adjustment for baseline values of covariates known to be at least moderately associated with the outcome increases the power of the trial. Recent work has shown a particular benefit for more flexible frequentist designs, such as information adaptive and adaptive multi-arm designs. However, covariate adjustment has not been characterized within the more flexible Bayesian adaptive designs, despite their growing popularity. We focus on a subclass of these which allow for early stopping at an interim analysis given evidence of treatment superiority. We consider both collapsible and non-collapsible estimands and show how to obtain posterior samples of marginal estimands from adjusted analyses. We describe several estimands for three common outcome types. We perform a simulation study to assess the impact of covariate adjustment using a variety of adjustment models in several different scenarios. This is followed by a real-world application of the compared approaches to a COVID-19 trial with a binary endpoint. For all scenarios, it is shown that covariate adjustment increases power and the probability of stopping the trials early, and decreases the expected sample sizes as compared to unadjusted analyses.

Heatstroke presentations to urban hospitals during BC's extreme heat event: lessons for the future

BACKGROUND

Climate change is leading to more extreme heat events in temperate climates that typically have low levels of preparedness. Our objective was to describe the characteristics, treatments, and outcomes of adults presenting to hospitals with heatstroke during BC's 2021 heat dome.

METHODS

We conducted a review of consecutive adults presenting to 7 hospitals in BC's Lower Mainland. We screened the triage records of all patients presenting between June 25th and 30th, 2021 for complaints related to heat, and reviewed the full records of those who met heatstroke criteria. Our primary outcome was in-hospital mortality. We used Mann-Whitney U tests and logistic regression to investigate associations between patient and treatment factors and mortality.

RESULTS

Among 10,247 consecutive presentations to urban hospitals during the extreme heat event, 1.3% (139; 95% confidence intervals [CI] 1.1-1.6%) met criteria for heatstroke. Of heatstroke patients, 129 (90.6%) were triaged into the two highest acuity levels. Patients with heatstroke had a median age of 84.4 years, with 122 (87.8%) living alone, and 101 (84.2%) unable to activate 911 themselves. A minority (< 5, < 3.6%) of patients presented within 48 h of the onset of extreme heat. Most patients (107, 77.0%) required admission, and 11.5% (16) died in hospital. Hypotension on presentation was associated with mortality (odds ratio [OR] 5.3).

INTERPRETATION

Heatstroke patients were unable to activate 911 themselves, and most presented with a 48-h delay. This delay may represent a critical window of opportunity for pre-hospital and hospital systems to prepare for the influx of high-acuity resource-intensive patients.

Transitions of care for older adults discharged home from the emergency department: an inductive thematic content analysis of patient comments

OBJECTIVE

Improving care transitions for older adults can reduce emergency department (ED) visits, adverse events, and empower community autonomy. We conducted an inductive qualitative content analysis to identify themes emerging from comments to better understand ED care transitions.

METHODS

The LEARNING WISDOM prospective longitudinal observational cohort includes older adults (≥ 65 years) who experienced a care transition after an ED visit from both before and during COVID-19. Their comments on this transition were collected via phone interview and transcribed. We conducted an inductive qualitative content analysis with randomly selected comments until saturation. Themes that arose from comments were coded and organized into frequencies and proportions. We followed the Standards for Reporting Qualitative Research (SRQR).

RESULTS

Comments from 690 patients (339 pre-COVID, 351 during COVID) composed of 351 women (50.9%) and 339 men (49.1%) were analyzed. Patients were satisfied with acute emergency care, and the proportion of patients with positive acute care experiences increased with the COVID-19 pandemic. Negative patient comments were most often related to communication between health providers across the care continuum and the professionalism of personnel in the ED. Comments concerning home care became more neutral with the COVID-19 pandemic.

CONCLUSION

Patients were satisfied overall with acute care but reported gaps in professionalism and follow-up communication between providers. Comments may have changed in tone from positive to neutral regarding home care over the COVID-19 pandemic due to service slowdowns. Addressing these concerns may improve the quality of care transitions and provide future pandemic mitigation strategies.

Hospitalization and hospital mortality rates during the first and second waves of the COVID-19 pandemic in Quebec: interrupted time series and decomposition analysis

OBJECTIVES

We investigated hospitalization and hospital mortality rates by cause during the first year of the COVID-19 pandemic in Quebec, Canada.

STUDY DESIGN

Interrupted time series and decomposition analysis.

METHODS

We analyzed hospital mortality during the first (February 25-August 22, 2020) and second waves (August 23, 2020-March 31, 2021), compared with 2019. We identified the cause of death and examined trends using: 1) interrupted time series analysis; 2) log-binomial regression; and 3) decomposition of cause-specific mortality.

RESULTS

Hospitalization rates decreased; however, the proportion of deaths increased from 27.0 per 1000 in 2019 to 35.0 per 1000 in the first wave, for an excess of 8.0 deaths per 1000 admissions. COVID-19 was the cause of a third of excess deaths (2.6 per 1000). Other drivers of excess deaths included respiratory conditions (1.6 deaths per 1000), circulatory disorders (0.6 deaths per 1000), and cancer (0.9 deaths per 1000). COVID-19 was the cause of 58% of excess deaths in the second wave. Interrupted time series regression indicated that the proportion of deaths increased at the outset of the first wave but returned to prepandemic levels before increasing again in the second wave. Compared with 2019, the first wave was associated with 1.31 times (95% confidence interval [CI] 1.28-1.33) and the second wave with 1.17 times (95% CI 1.15-1.19) the risk of death during hospitalization.

CONCLUSIONS

The pandemic was associated with a greater risk of hospital mortality. Excess deaths were driven by COVID-19 but also other causes, including respiratory conditions, circulatory disorders, and cancer.

Understanding the impacts of the COVID-19 pandemic on the care experiences of people with mental-physical multimorbidity: protocol for a mixed methods study

BACKGROUND

Primary care and other health services have been disrupted during the COVID-19 pandemic, yet the consequences of these service disruptions on patients' care experiences remain largely unstudied. People with mental-physical multimorbidity are vulnerable to the effects of the pandemic, and to sudden service disruptions. It is thus essential to better understand how their care experiences have been impacted by the current pandemic. This study aims to improve understanding of the care experiences of people with mental-physical multimorbidity during the pandemic and identify strategies to enhance these experiences.

METHODS

We will conduct a mixed-methods study with multi-phase approach involving four distinct phases. Phase 1 will be a qualitative descriptive study in which we interview individuals with mental-physical multimorbidity and health professionals in order to explore the impacts of the pandemic on care experiences, as well as their perspectives on how care can be improved. The results of this phase will inform the design of study phases 2 and 3. Phase 2 will involve journey mapping exercises with a sub-group of participants with mental-physical multimorbidity to visually map out their care interactions and experiences over time and the critical moments that shaped their experiences. Phase 3 will involve an online, cross-sectional survey of care experiences administered to a larger group of people with mental disorders and/or chronic physical conditions. In phase 4, deliberative dialogues will be held with key partners to discuss and plan strategies for improving the delivery of care to people with mental-physical multimorbidity. Pre-dialogue workshops will enable us to synthesize an prepare the results from the previous three study phases.

DISCUSSION

Our study results will generate much needed evidence of the positive and negative impacts of the COVID-19 pandemic on the care experiences of people with mental-physical multimorbidity and shed light on strategies that could improve care quality and experiences.

Causes of Death Among Medical ICU Patients With Pneumonia Due to COVID-19 in a Safety-Net Hospital

We sought to identify the primary causes of death of adult patients admitted to the medical ICU with symptomatic COVID-19 who ultimately suffered in-hospital mortality over the span of three major waves of COVID-19: Wild-type, alpha/epsilon, and delta.

DESIGN

Retrospective single-center cohort study from March 2020 to December 2021.

SETTING

One medical ICU in a 600-bed Tertiary Care Hospital in Los Angeles, CA.

PATIENTS

Adult (n = 306) ICU patients admitted with symptomatic COVID-19 who suffered in-hospital mortality.

INTERVENTIONS

None.

MAIN RESULTS

Of the 306 patients with COVID-19 who died in the hospital, 86.3% were Hispanic/Latino. The leading cause of death was respiratory failure, occurring in 57.8% of patients. There was no significant change in the rate of pulmonary deaths across the three waves of COVID-19 in our study period. The mean time from symptom onset to admission was 6.5 days, with an average hospital length of stay of 18 days. This did not differ between pulmonary and other causes of death. Sepsis was the second most common cause of death at 23.9% with a significant decrease from the wild-type wave to the delta wave. Among patients with sepsis as the cause of death, 22% (n = 16) were associated with fungemia. There was no significant association between steroid administration and cause of death. Lastly, the alpha/epsilon wave from December 2020 to May 2021 had the highest mortality rate when compared with wild-type or delta waves.

CONCLUSIONS

We found the primary cause of death in ICU patients with COVID-19 was acute respiratory failure, without significant changes over the span of three waves of COVID-19. This finding contrasts with reported causes of death for patients with non-COVID-19 acute respiratory distress syndrome, in which respiratory failure is an uncommon cause of death. In addition, we identified a subset of patients (5%) who died primarily due to fungemia, providing an area for further investigation.

Research recruitment and consent methods in a pandemic: a qualitative study of COVID-19 patients' perspectives

BACKGROUND

Virtual data collection methods and consent procedures adopted in response to the COVID-19 pandemic enabled continued research activities, but also introduced concerns about equity, inclusivity, representation, and privacy. Recent studies have explored these issues from institutional and researcher perspectives, but there is a need to explore patient perspectives and preferences. This study aims to explore COVID-19 patients' perspectives about research recruitment and consent for research studies about COVID-19.

METHODS

We conducted an exploratory qualitative focus group and interview study among British Columbian adults who self-identified as having had COVID-19. We recruited participants through personal contacts, social media, and REACH BC, an online platform that connects researchers and patients in British Columbia. We analyzed transcripts inductively and developed thematic summaries of each coding element.

RESULTS

Of the 22 individuals recruited, 16 attended a focus group or interview. We found that autonomy and the feasibility of participation, attitudes toward research about COVID-19, and privacy concerns are key factors that influence participants' willingness to participate in research. We also found that participants preferred remote and virtual approaches for contact, consent, and delivery of research on COVID-19.

CONCLUSIONS

Individuals who had COVID-19 are motivated to participate in research studies and value autonomy in their decision to participate, but researchers must be sensitive and considerate toward patient preferences and concerns, particularly as researchers adopt virtual recruitment and data collection methods. Such awareness may increase research participation and engagement.

Intubation practices and outcomes for patients with suspected or confirmed COVID-19: a national observational study by the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN)

OBJECTIVE

Intubation practices changed during the COVID-19 pandemic to protect healthcare workers from transmission of disease. Our objectives were to describe intubation characteristics and outcomes for patients tested for SARS CoV-2 infection. We compared outcomes between patients testing SARS COV-2 positive with those testing negative.

METHODS

We conducted a health records review using the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN) registry. We included consecutive eligible patients who presented to one of 47 EDs across Canada between March 1, 2020 and June 20, 2021, were tested for SARS-CoV-2 and intubated in the ED. The primary outcome was the proportion of patients experiencing a post-intubation adverse event during the ED stay. Secondary outcomes included first-pass success, intubation practices, and hospital mortality. We used descriptive statistics to summarize variables with subgroup differences examined using t tests, z tests, or chi-squared tests where appropriate with 95% CIs.

RESULTS

Of 1720 patients with suspected COVID-19 who were intubated in the ED during the study period, 337 (19.6%) tested SARS-CoV-2 positive and 1383 (80.4%) SARS-CoV-2 negative. SARS-CoV-2 positive patients presented to hospital with lower oxygen levels than SARS-CoV-2 negative patients (mean pulse oximeter SaO2 86 vs 94%, p < 0.001). In total, 8.5% of patients experienced an adverse event post-intubation. More patients in the SARS-CoV-2 positive subgroup experienced post-intubation hypoxemia (4.5 vs 2.2%, p = 0.019). In-hospital mortality was greater for patients who experienced intubation-related adverse events (43.2 vs 33.2%, p = 0.018). There was no significant difference in adverse event-associated mortality by SARS-CoV-2 status. First-pass success was achieved in 92.4% of all intubations, with no difference by SARS-CoV-2 status.

CONCLUSIONS

During the COVID-19 pandemic, we observed a low risk of adverse events associated with intubation, even though hypoxemia was common in patients with confirmed SARS-CoV-2. We observed high rates of first-pass success and low rates of inability to intubate. The limited number of adverse events precluded multivariate adjustments. Study findings should reassure emergency medicine practitioners that system modifications made to intubation processes in response to the COVID-19 pandemic do not appear to be associated with worse outcomes compared to pre-COVID-19 practices.

Decisions and Decisional Needs of Canadians From all Provinces and Territories During the COVID-19 Pandemic: Population-Based Cross-sectional Surveys

BACKGROUND

Never before COVID-19 had Canadians faced making health-related decisions in a context of significant uncertainty. However, little is known about which type of decisions and the types of difficulties that they faced.

OBJECTIVE

We sought to identify the health-related decisions and decisional needs of Canadians.

METHODS

Our study was codesigned by researchers and knowledge users (eg, patients, clinicians). Informed by the CHERRIES (the Checklist for Reporting Results of Internet E-Surveys) reporting guideline, we conducted 2 online surveys of random samples drawn from the Leger consumer panel of 400,000 Canadians. Eligible participants were adults (≥18 years) who received or were receiving any health services in the past 12 months for themselves (adults) or for their child (parent) or senior with cognitive impairment (caregiver). We assessed decisions and decisional needs using questions informed by the Ottawa Decision Support Framework, including decisional conflict and decision regret using the Decision Conflict Scale (DCS) and the Decision Regret Scale (DRS), respectively. Descriptive statistics were conducted for adults who had decided for themselves or on behalf of someone else. Significant decisional conflict (SDC) was defined as a total DCS score of >37.5 out of 100, and significant decision regret was defined as a total DRS score of >25 out of 100.

RESULTS

From May 18 to June 4, 2021, 14,459 adults and 6542 parents/caregivers were invited to participate. The invitation view rate was 15.5% (2236/14,459) and 28.3% (1850/6542); participation rate, 69.3% (1549/2236) and 28.7% (531/1850); and completion rate, 97.3% (1507/1549) and 95.1% (505/531), respectively. The survey was completed by 1454 (97.3%) adults and 438 (95.1%) parents/caregivers in English (1598/1892, 84.5%) or French (294/1892, 15.5%). Respondents from all 10 Canadian provinces and the northern territories represented a range of ages, education levels, civil statuses, ethnicities, and annual household income. Of 1892 respondents, 541 (28.6%) self-identified as members of marginalized groups. The most frequent decisions were (adults vs parents/caregivers) as follows: COVID-19 vaccination (490/1454, 33.7%, vs 87/438, 19.9%), managing a health condition (253/1454, 17.4%, vs 47/438, 10.7%), other COVID-19 decisions (158/1454, 10.9%, vs 85/438, 19.4%), mental health care (128/1454, 8.8%, vs 27/438, 6.2%), and medication treatments (115/1454, 7.9%, vs 23/438, 5.3%). Caregivers also reported decisions about moving family members to/from nursing or retirement homes (48/438, 11.0%). Adults (323/1454, 22.2%) and parents/caregivers (95/438, 21.7%) had SDC. Factors making decisions difficult were worrying about choosing the wrong option (557/1454, 38.3%, vs 184/438, 42.0%), worrying about getting COVID-19 (506/1454, 34.8%, vs 173/438, 39.5%), public health restrictions (427/1454, 29.4%, vs 158/438, 36.1%), information overload (300/1454, 20.6%, vs 77/438, 17.6%), difficulty separating misinformation from scientific evidence (297/1454, 20.4%, vs 77/438, 17.6%), and difficulty discussing decisions with clinicians (224/1454, 15.4%, vs 51/438, 11.6%). For 1318 (90.6%) adults and 366 (83.6%) parents/caregivers who had decided, 353 (26.8%) and 125 (34.2%) had significant decision regret, respectively. In addition, 1028 (50%) respondents made their decision alone without considering the opinions of clinicians.

CONCLUSIONS

During COVID-19, Canadians who responded to the survey faced several new health-related decisions. Many reported unmet decision-making needs, resulting in SDC and decision regret. Interventions can be designed to address their decisional needs and support patients facing new health-related decisions.

Clinical Characteristics and Outcomes of Patients with Acute Respiratory Failure Due to SARS-CoV-2 Interstitial Pneumonia Treated with CPAP in a Medical Intermediate Care Setting: A Retrospective Observational Study on Comparison of Four Waves

BACKGROUND

In COVID-19 patients non-invasive-positive-pressure-ventilation (NIPPV) has held a challenging role to reduce mortality and the need for invasive mechanical ventilation (IMV). The aim of this study was to compare the characteristics of patients admitted to a Medical Intermediate Care Unit for acute respiratory failure due to SARS-CoV-2 pneumonia throughout four pandemic waves.

METHODS

The clinical data of 300 COVID-19 patients treated with continuous positive airway pressure (CPAP) were retrospectively analysed, from March-2020 to April-2022.

RESULTS

Non-survivors were older and more comorbid, whereas patients transferred to ICU were younger and had fewer pathologies. Patients were older (from 65 (29-91) years in I wave to 77 (32-94) in IV, p < 0.001) and with more comorbidities (from Charlson's Comorbidity Index = 3 (0-12) in I to 6 (1-12) in IV, p < 0.001). No statistical difference was found for in-hospital mortality (33.0%, 35.8%, 29.6% and 45.9% in I, II, III and IV, p = 0.216), although ICU-transfers rate decreased from 22.0% to 1.4%.

CONCLUSIONS

COVID-19 patients have become progressively older and with more comorbidities even in critical care area; from risk class analyses by age and comorbidity burden, in-hospital mortality rates remain high and are thus consistent over four waves while ICU-transfers have significantly reduced. Epidemiological changes need to be considered to improve the appropriateness of care.

Sensitivity and Diagnostic Yield of the First SARS-CoV-2 Nucleic Acid Amplification Test Performed for Patients Presenting to the Hospital

IMPORTANCE

Early and accurate diagnostic testing for SARS-CoV-2 is essential to initiate appropriate treatment and infection control and prevention measures among patients presenting to the hospital.

OBJECTIVE

To evaluate the diagnostic sensitivity of the SARS-CoV-2 nucleic acid amplification test (NAAT) performed within 24 hours of arrival to the emergency department among a nationally representative sample of patients.

DESIGN, SETTING, AND PARTICIPANTS

This diagnostic study was conducted at 47 hospitals across 7 provinces in Canada participating in the Canadian COVID-19 Rapid Response Emergency Department Network among consecutive eligible patients presenting to a participating emergency department who were tested for SARS-CoV-2 from March 1, 2020, to December 31, 2021. Patients not tested within 24 hours of arrival and those presenting with a positive result from a test performed in the community were excluded.

MAIN OUTCOMES AND MEASURES

The primary outcome was a positive result from the SARS-CoV-2 NAAT. Outcome measures were the diagnostic sensitivity and yield of the SARS-CoV-2 NAAT.

RESULTS

Of 132 760 eligible patients (66 433 women [50.0%]; median age, 57 years [IQR, 37-74 years]), 17 174 (12.9%) tested positive for SARS-CoV-2 within 14 days of their first NAAT. The diagnostic sensitivity of the SARS-CoV-2 NAAT was 96.2% (17 070 of 17 740 [95% CI, 95.9%-96.4%]) among all of the tests performed. Estimates ranged from a high of 97.7% (1710 of 1751 [95% CI, 96.8%-98.3%]) on day 2 of symptoms to a low of 90.4% (170 of 188 [95% CI, 85.3%-94.2%]) on day 11 of symptoms among patients presenting with COVID-19 symptoms. Among patients reporting COVID-19 symptoms, the sensitivity of the SARS-CoV-2 NAAT was 97.1% (11 870 of 12 225 [95% CI, 96.7%-97.3%]) compared with 87.6% (812 of 927 [95% CI, 85.2%-89.6%]) among patients without COVID-19 symptoms. The diagnostic yield of the SARS-CoV-2 NAAT was 12.0% (18 985 of 158 004 [95% CI, 11.8%-12.2%]) and varied from a high of 20.0% (445 of 2229 [95% CI, 18.3%-21.6%]) among patients tested on day 10 after symptom onset to a low of 8.1% (1686 of 20 719 [95% CI, 7.7%-8.5%]) among patients presenting within the first 24 hours of symptom onset.

CONCLUSIONS AND RELEVANCE

This study suggests that the diagnostic sensitivity was high for the first SARS-CoV-2 NAAT performed in the hospital and did not vary significantly by symptom duration. Repeated testing of patients with negative test results should be avoided unless their pretest probability of disease is high.