@article {HohlE261, author = {Corinne M. Hohl and Rhonda J. Rosychuk and Andrew D. McRae and Steven C. Brooks and Patrick Archambault and Patrick T. Fok and Philip Davis and Tomislav Jelic and Joel P. Turner and Brian H. Rowe and {\'E}ric Mercier and Ivy Cheng and John Taylor and Raoul Daoust and Robert Ohle and Gary Andolfatto and Clare Atzema and Jake Hayward and Jaspreet K. Khangura and Megan Landes and Eddy Lang and Ian Martin and Rohit Mohindra and Daniel K. Ting and Samuel Vaillancourt and Michelle Welsford and Baljeet Brar and Tara Dahn and Hana Wiemer and Krishan Yadav and Justin W. Yan and Maja Stachura and Colleen McGavin and Jeffrey J. Perry and Laurie J. Morrison}, editor = {,}, title = {Development of the Canadian COVID-19 Emergency Department Rapid Response Network population-based registry: a methodology study}, volume = {9}, number = {1}, pages = {E261--E270}, year = {2021}, doi = {10.9778/cmajo.20200290}, publisher = {Canadian Medical Association Open Access Journal}, abstract = {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}, URL = {https://www.cmajopen.ca/content/9/1/E261}, eprint = {https://www.cmajopen.ca/content/9/1/E261.full.pdf}, journal = {Canadian Medical Association Open Access Journal} }