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.

Due to the COVID-19 pandemic, many research groups started conducting research activities virtually. In this study, we invited individuals who had COVID-19 to share their views about how researchers recruit patients and get their consent to participate in studies about COVID-19. Through interviews and focus groups, we found that British Columbians who had COVID-19 are motivated to participate in COVID-related studies, as long as researchers maintain usual precautions around data privacy and accommodate preferences for participation. Future studies may use these patient perspectives to make informed decisions that will increase and support patient recruitment, consent and retention in research studies.

The burden of incidental SARS-CoV-2 infections in hospitalized patients across pandemic waves in Canada.

Many health authorities differentiate hospitalizations in patients infected with SARS-CoV-2 as being "for COVID-19" (due to direct manifestations of SARS-CoV-2 infection) versus being an "incidental" finding in someone admitted for an unrelated condition. We conducted a retrospective cohort study of all SARS-CoV-2 infected patients hospitalized via 47 Canadian emergency departments, March 2020-July 2022 to determine whether hospitalizations with "incidental" SARS-CoV-2 infection are less of a burden to patients and the healthcare system. Using a priori standardized definitions applied to hospital discharge diagnoses in 14,290 patients, we characterized COVID-19 as (i) the "Direct" cause for the hospitalization (70%), (ii) a potential "Contributing" factor for the hospitalization (4%), or (iii) an "Incidental" finding that did not influence the need for admission (26%). The proportion of incidental SARS-CoV-2 infections rose from 10% in Wave 1 to 41% during the Omicron wave. Patients with COVID-19 as the direct cause of hospitalization exhibited significantly longer LOS (mean 13.8 versus 12.1 days), were more likely to require critical care (22% versus 11%), receive COVID-19-specific therapies (55% versus 19%), and die (17% versus 9%) compared to patients with Incidental SARS-CoV-2 infections. However, patients hospitalized with incidental SARS-CoV-2 infection still exhibited substantial morbidity/mortality and hospital resource use.

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.

RéSUMé: OBJECTIF: Les pratiques d'intubation ont changé au cours de la pandémie de COVID-19 afin de protéger le personnel de santé contre la transmission de la maladie. Nos objectifs étaient de décrire les caractéristiques de l'intubation et les résultats pour les patients testés pour l'infection par le CoV-2 du SRAS. Nous avons comparé les résultats entre les patients testés positifs au SARS COV-2 et ceux testés négatifs. MéTHODES: Nous avons effectué un examen des dossiers de santé à l'aide du registre du Réseau canadien d'intervention rapide dans les services d'urgence pour la COVID-19 (RCIRSUC). Nous avons inclus les patients éligibles consécutifs qui se sont présentés à l'un des 47 services d'urgence du Canada entre le 1er mars 2020 et le 20 juin 2021, qui ont été testés pour le SRAS-CoV-2 et qui ont été intubés dans le service d'urgence. Le résultat principal était la proportion de patients ayant subi un événement indésirable après l'intubation pendant leur séjour aux urgences. Les critères de jugement secondaires comprenaient le succès du premier passage, les pratiques d'intubation et la mortalité hospitalière. Nous avons utilisé des statistiques descriptives pour résumer les variables avec des différences de sous-groupes examinées à l'aide de tests t, de tests z ou de tests du chi carré, le cas échéant, avec des IC à 95%. RéSULTATS: Sur les 1720 patients suspects de COVID-19 qui ont été intubés aux urgences pendant la période de l'étude, 337 (19,6%) ont été testés positifs au SARS-CoV-2 et 1383 (80,4%) négatifs au SARS-CoV-2. Les patients positifs au SRAS-CoV-2 se sont présentés à l'hôpital avec des niveaux d'oxygène inférieurs à ceux des patients négatifs pour le SRAS-CoV-2 (oxymètre de pouls moyen SaO2 86% contre 94%, p < 0,001). Au total, 8,5% des patients ont présenté un événement indésirable après l'intubation. Un plus grand nombre de patients du sous-groupe positif au SRAS-CoV-2 ont présenté une hypoxémie post-intubation (4,5% vs 2,2%, p = 0,019). La mortalité hospitalière était plus élevée chez les patients ayant subi des événements indésirables liés à l'intubation (43,2% vs 33,2%, p = 0,018). Il n'y avait pas de différence significative dans la mortalité associée aux événements indésirables selon le statut du SRAS-CoV-2. Le succès du premier passage a été obtenu dans 92,4% de toutes les intubations, sans différence selon le statut SARS-CoV-2 CONCLUSIONS: Pendant la pandémie de COVID-19, nous avons observé un faible risque d'événements indésirables associés à l'intubation, même si l'hypoxémie était fréquente chez les patients atteints de SRAS-CoV-2 confirmé. Nous avons observé des taux élevés de réussite du premier passage et des taux faibles d'incapacité à intuber. Le nombre limité d'événements indésirables a empêché les ajustements multivariés. Les résultats de l'étude devraient rassurer les praticiens de la médecine d'urgence que les modifications apportées aux processus d'intubation en réponse à la pandémie de COVID-19 ne semblent pas être associées à des résultats plus défavorables que les pratiques antérieures à la pandémie de COVID-19.

Prognostic association between d-dimer thresholds and 30-day pulmonary embolism diagnosis among emergency department patients with suspected SARS-CoV-2 infection: a Canadian COVID-19 Emergency Department Rapid Response Network study.

OBJECTIVE: The primary objective was to quantify the prognostic association between various D-dimer thresholds and 30-day PE diagnosis among emergency department (ED) patients with suspected SARS-CoV-2 infection. METHODS: This was a retrospective study of patients enrolled in the Canadian COVID-19 ED Rapid Response Network (CCEDRRN) registry from March 1, 2020 to July 2, 2021. We included consecutive adults (≥ 18 years) presenting to 49 EDs with chest pain, shortness of breath, hypoxia, syncope, presyncope, or hemoptysis who were tested for both SARS-CoV-2 and D-dimer at index ED visit. The primary outcome measure was the sensitivity, specificity, and negative predictive value of D-dimer test thresholds for the outcome of 30-day PE diagnosis. RESULTS: Among 10,837 patients included in our study, 404 (3.7%) were diagnosed with PE at 30-days. A standard D-Dimer threshold of 500 ng/mL had a sensitivity of 97.8% (95% confidence interval [CI] 95.8-99.0%), specificity of 40.9% (95% CI 39.9-41.8%), and negative predictive value of 99.8% (95% CI 99.6-99.9%). An age-adjusted D-dimer threshold had a sensitivity of 96.0% (95% CI 93.6-97.7%), specificity of 48.5% (95% CI 47.5-49.4%), and negative predictive value of 99.7% (95% CI 99.5-99.8%). D-dimer testing had slightly lower prognostic performance among SARS-CoV-2 positive compared to SARS-CoV-2 negative patients in predicting 30-day PE diagnosis. CONCLUSIONS: Among ED patients with suspected SARS-CoV-2, the standard 500 ng/mL and age-adjusted D-dimer thresholds were comparable for the prediction of PE at 30-days. The prognostic performance of D-dimer was lower among SARS-CoV-2 positive patients. TRIAL REGISTRATION: Clinicaltrials.gov, NCT04702945.

RéSUMé: OBJECTIF: L'objectif principal était de quantifier l'association pronostique entre différents seuils de D-dimères et le diagnostic d'EP à 30 jours chez les patients des services d'urgence suspectés d'être infectés par le SRAS-CoV-2. MéTHODES: Il s'agissait d'une étude rétrospective des patients inscrits au registre du réseau canadien de réponse rapide aux urgences COVID-19 (CCEDRRN) du 1er mars 2020 au 2 juillet 2021. Nous avons inclus des adultes consécutifs (>18 ans) se présentant dans 49 services d'urgence pour une douleur thoracique, un essoufflement, une hypoxie, une syncope, une présyncope ou une hémoptysie et qui ont été testés à la fois pour le SRAS-CoV-2 et les D-dimères lors de la visite de référence aux urgences. Le principal critère d'évaluation était la sensibilité, la spécificité et la valeur prédictive négative des seuils du test des D-dimères pour le diagnostic de l'EP à 30 jours. RéSULTATS: Parmi les 10 837 patients inclus dans notre étude, 404 (3,7 %) ont reçu un diagnostic d'EP à 30 jours. Un seuil standard de D-Dimer de 500 ng/mL avait une sensibilité de 97,8 % (intervalle de confiance [IC] à 95 % 95,8-99,0 %), une spécificité de 40,9 % (IC à 95 % 39,9-41,8 %) et une valeur prédictive négative de 99,8 % (IC à 95 % 99,6-99,9 %). Un seuil de D-dimères ajusté à l'âge avait une sensibilité de 96,0% (IC à 95 % 93,6-97,7 %), une spécificité de 48,5% (IC à 95 % 47,5-49,4 %) et une valeur prédictive négative de 99,7 % (IC à 95 % 99,5-99,8 %). Le test des D-dimères avait une performance pronostique légèrement inférieure chez les patients positifs pour le SRAS-CoV-2 par rapport aux patients négatifs pour le SRAS-CoV-2 en ce qui concerne la prédiction du diagnostic d'EP à 30 jours. CONCLUSIONS: Chez les patients des urgences suspectés d'être atteints du SRAS-CoV-2, les seuils standard de 500 ng/ml et les seuils de D-dimères ajustés à l'âge étaient comparables pour la prédiction de l'EP à 30 jours. La performance pronostique des D-dimères était plus faible chez les patients positifs pour le SRAS-CoV-2. ENREGISTREMENT DE L'ESSAI: Clinicaltrials.gov, NCT04702945.

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.

Diagnostic yield of screening for SARS-CoV-2 among patients admitted to hospital for alternate diagnoses: an observational cohort study.

OBJECTIVES: To determine the diagnostic yield of screening patients for SARS-CoV-2 who were admitted with a diagnosis unrelated to COVID-19 and to identify risk factors for positive tests. DESIGN: Cohort from the Canadian COVID-19 Emergency Department Rapid Response Network registry. SETTING: 30 acute care hospitals across Canada. PARTICIPANTS: Patients hospitalised for non-COVID-19-related diagnoses who were tested for SARS-CoV-2 between 1 March and 29 December 2020. MAIN OUTCOME: Positive nucleic acid amplification test for SARS-CoV-2. OUTCOME MEASURE: Diagnostic yield. RESULTS: We enrolled 15 690 consecutive eligible adults who were admitted to hospital without clinically suspected COVID-19. Among these patients, 122 tested positive for COVID-19, resulting in a diagnostic yield of 0.8% (95% CI 0.64% to 0.92%). Factors associated with a positive test included presence of fever, being a healthcare worker, having a positive household contact or institutional exposure, and living in an area with higher 7-day average incident COVID-19 cases. CONCLUSIONS: Universal screening of hospitalised patients for COVID-19 across two pandemic waves had a low diagnostic yield and should be informed by individual-level risk assessment in addition to regional COVID-19 prevalence. TRIAL REGISTRATION NUMBER: NCT04702945.

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).

BACKGROUND: Treatment for coronavirus disease 2019 (COVID-19) evolved between pandemic waves. Our objective was to compare treatments, acute care utilization, and outcomes of COVID-19 patients presenting to emergency departments (ED) across pandemic waves. METHODS: This observational study enrolled consecutive eligible COVID-19 patients presenting to 46 EDs participating in the Canadian COVID-19 ED Rapid Response Network (CCEDRRN) between March 1 and December 31, 2020. We collected data by retrospective chart review. Our primary outcome was in-hospital mortality. Secondary outcomes included treatments, hospital and ICU admissions, ED revisits and readmissions. Logistic regression modeling assessed the impact of pandemic wave on outcomes. RESULTS: We enrolled 9,967 patients in 8 provinces, 3,336 from the first and 6,631 from the second wave. Patients in the second wave were younger, fewer met criteria for severe COVID-19, and more were discharged from the ED. Adjusted for patient characteristics and disease severity, steroid use increased (odds ratio [OR] 7.4; 95% confidence interval [CI] 6.2-8.9), and invasive mechanical ventilation decreased (OR 0.5; 95% CI 0.4-0.7) in the second wave compared to the first. After adjusting for differences in patient characteristics and disease severity, the odds of hospitalization (OR 0.7; 95% CI 0.6-0.8) and critical care admission (OR 0.7; 95% CI 0.6-0.9) decreased, while mortality remained unchanged (OR 0.7; 95% CI 0.5-1.1). INTERPRETATION: In patients presenting to cute care facilities, we observed rapid uptake of evidence-based therapies and less use of experimental therapies in the second wave. We observed increased rates of ED discharges and lower hospital and critical care resource use over time. Substantial reductions in mechanical ventilation were not associated with increasing mortality. Advances in treatment strategies created health system efficiencies without compromising patient outcomes. TRIAL REGISTRATION: Clinicaltrials.gov, NCT04702945.

RéSUMé: CONTEXTE: Le traitement de la maladie à coronavirus 2019 (COVID-19) a évolué entre les vagues pandémiques. Notre objectif était de comparer les traitements, l'utilisation des soins aigus et les résultats des patients atteints de la maladie COVID-19 se présentant aux urgences à travers les vagues de pandémie. MéTHODES: Cette étude observationnelle a recruté des patients COVID-19 éligibles consécutifs se présentant à 46 services d'urgence participant au Réseau canadien de réponse rapide aux services d'urgence COVID-19 (CCEDRRN) entre le 1er mars et le 31 décembre 2020. Nous avons recueilli des données au moyen d'un examen rétrospectif des dossiers. Notre principal résultat a été la mortalité à l'hôpital. Les résultats secondaires incluaient les traitements, les admissions à l'hôpital et aux soins intensifs, les revisites aux urgences et les réadmissions. La modélisation par régression logistique a évalué l'impact de la vague de pandémie sur les résultats. RéSULTATS: Nous avons recruté 9 967 patients dans 8 provinces, 3 336 de la première vague et 6 631 de la deuxième vague. Les patients de la deuxième vague étaient plus jeunes, moins nombreux à répondre aux critères de gravité de la COVID-19 et plus nombreux à quitter les urgences. Après ajustement en fonction des caractéristiques des patients et de la gravité de la maladie, le recours aux stéroïdes a augmenté (rapport de cotes [RC] 7.4 ; intervalle de confiance à 95 % [IC] 6.2­8.9) et la ventilation mécanique invasive a diminué (RC 0.5 ; IC à 95 % 0.4­0.7) lors de la deuxième vague par rapport à la première. Après ajustement pour tenir compte des différences dans les caractéristiques des patients et la gravité de la maladie, les probabilités d'hospitalisation (RC 0.7 ; IC à 95 % 0.6­0.8) et d'admission en soins intensifs (RC 0.7 ; IC à 95 % 0.6­0.9) ont diminué, tandis que la mortalité est restée inchangée (RC 0.7 ; IC à 95 % 0.5­1.1). INTERPRéTATION: Chez les patients se présentant dans les établissements de soins de santé, nous avons observé une adoption rapide des thérapies fondées sur des données probantes et un moindre recours aux thérapies expérimentales lors de la deuxième vague. Nous avons observé une augmentation des taux de sortie des services d'urgence et une diminution de l'utilisation des ressources hospitalières et des soins intensifs au fil du temps. Les réductions substantielles de la ventilation mécanique n'étaient pas associées à une augmentation de la mortalité. Les progrès réalisés dans les stratégies de traitement ont permis d'améliorer l'efficacité des systèmes de santé sans compromettre les résultats pour les patients.

The CCEDRRN COVID-19 Mortality Score to predict death among nonpalliative patients with COVID-19 presenting to emergency departments: a derivation and validation study.

BACKGROUND: Predicting mortality from COVID-19 using information available when patients present to the emergency department can inform goals-of-care decisions and assist with ethical allocation of critical care resources. The study objective was to develop and validate a clinical score to predict emergency department and in-hospital mortality among consecutive nonpalliative patients with COVID-19; in this study, we define palliative patients as those who do not want resuscitative measures, such as intubation, intensive care unit care or cardiopulmonary resuscitation. METHODS: This derivation and validation study used observational cohort data recruited from 46 hospitals in 8 Canadian provinces participating in the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN). We included adult (age ≥ 18 yr) nonpalliative patients with confirmed COVID-19 who presented to the emergency department of a participating site between Mar. 1, 2020, and Jan. 31, 2021. We randomly assigned hospitals to derivation or validation, and prespecified clinical variables as candidate predictors. We used logistic regression to develop the score in a derivation cohort and examined its performance in predicting emergency department and in-hospital mortality in a validation cohort. RESULTS: Of 8761 eligible patients, 618 (7.0%) died. The CCEDRRN COVID-19 Mortality Score included age, sex, type of residence, arrival mode, chest pain, severe liver disease, respiratory rate and level of respiratory support. The area under the curve was 0.92 (95% confidence interval [CI] 0.90-0.93) in derivation and 0.92 (95% CI 0.90-0.93) in validation. The score had excellent calibration. These results suggest that scores of 6 or less would categorize patients as being at low risk for in-hospital death, with a negative predictive value of 99.9%. Patients in the low-risk group had an in-hospital mortality rate of 0.1%. Patients with a score of 15 or higher had an observed mortality rate of 81.0%. INTERPRETATION: The CCEDRRN COVID-19 Mortality Score is a simple score that can be used for level-of-care discussions with patients and in situations of critical care resource constraints to accurately predict death using variables available on emergency department arrival. The score was derived and validated mostly in unvaccinated patients, and before variants of concern were circulating widely and newer treatment regimens implemented in Canada. STUDY REGISTRATION: ClinicalTrials.gov, no. NCT04702945.

CCEDRRN COVID-19 Infection Score (CCIS): development and validation in a Canadian cohort of a clinical risk score to predict SARS-CoV-2 infection in patients presenting to the emergency department with suspected COVID-19.

OBJECTIVES: To develop and validate a clinical risk score that can accurately quantify the probability of SARS-CoV-2 infection in patients presenting to an emergency department without the need for laboratory testing. DESIGN: Cohort study of participants in the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN) registry. Regression models were fitted to predict a positive SARS-CoV-2 test result using clinical and demographic predictors, as well as an indicator of local SARS-CoV-2 incidence. SETTING: 32 emergency departments in eight Canadian provinces. PARTICIPANTS: 27 665 consecutively enrolled patients who were tested for SARS-CoV-2 in participating emergency departments between 1 March and 30 October 2020. MAIN OUTCOME MEASURES: Positive SARS-CoV-2 nucleic acid test result within 14 days of an index emergency department encounter for suspected COVID-19 disease. RESULTS: We derived a 10-item CCEDRRN COVID-19 Infection Score using data from 21 743 patients. This score included variables from history and physical examination and an indicator of local disease incidence. The score had a c-statistic of 0.838 with excellent calibration. We externally validated the rule in 5295 patients. The score maintained excellent discrimination and calibration and had superior performance compared with another previously published risk score. Score cut-offs were identified that can rule-in or rule-out SARS-CoV-2 infection without the need for nucleic acid testing with 97.4% sensitivity (95% CI 96.4 to 98.3) and 95.9% specificity (95% CI 95.5 to 96.0). CONCLUSIONS: The CCEDRRN COVID-19 Infection Score uses clinical characteristics and publicly available indicators of disease incidence to quantify a patient's probability of SARS-CoV-2 infection. The score can identify patients at sufficiently high risk of SARS-CoV-2 infection to warrant isolation and empirical therapy prior to test confirmation while also identifying patients at sufficiently low risk of infection that they may not need testing. TRIAL REGISTRATION NUMBER: NCT04702945.

Development of the Canadian COVID-19 Emergency Department Rapid Response Network population-based registry: a methodology study.

BACKGROUND: Emergency physicians lack high-quality evidence for many diagnostic and treatment decisions made for patients with suspected or confirmed coronavirus disease 2019 (COVID-19). Our objective is to describe the methods used to collect and ensure the data quality of a multicentre registry of patients presenting to the emergency department with suspected or confirmed COVID-19. METHODS: This methodology study describes a population-based registry that has been enrolling consecutive patients presenting to the emergency department with suspected or confirmed COVID-19 since Mar. 1, 2020. Most data are collected from retrospective chart review. Phone follow-up with patients at 30 days captures the World Health Organization clinical improvement scale and contextual, social and cultural variables. Phone follow-up also captures patient-reported quality of life using the Veterans Rand 12-Item Health Survey at 30 days, 60 days, 6 months and 12 months. Fifty participating emergency departments from 8 provinces in Canada currently enrol patients into the registry. INTERPRETATION: Data from the registry of the Canadian COVID-19 Emergency Department Rapid Response Network will be used to derive and validate clinical decision rules to inform clinical decision-making, describe the natural history of the disease, evaluate COVID-19 diagnostic tests and establish the real-world effectiveness of treatments and vaccines, including in populations that are excluded or underrepresented in clinical trials. This registry has the potential to generate scientific evidence to inform our pandemic response, and to serve as a model for the rapid implementation of population-based data collection protocols for future public health emergencies. TRIAL REGISTRATION: Clinicaltrials.gov, no. NCT04702945.