key: cord-0821215-x71iy2by authors: Lipes, Jed; Yang, Stephen Su title: Re: ‘clinical course and outcomes of critically ill patients with COVID-19 infection: a systematic review' by Serafim et al date: 2021-01-21 journal: Clin Microbiol Infect DOI: 10.1016/j.cmi.2021.01.010 sha: 92686c838ed3c01a81b80edf89cb0c5f969594cf doc_id: 821215 cord_uid: x71iy2by nan Re: 'Clinical course and outcomes of critically ill patients with COVID-19 infection: a systematic review' by Serafim et al. I have read with interest the above article, and notice there does not appear to be any associated reference for the Canadian data eluded to in Figure 2 . We have briefly reviewed the literature with similar keywords and provide a brief table describing the Canadian data for COVID-19 patients requiring ICU admission. We hope this information complements the message of the authors and completes the missing data. All the best, It was with great interest we read the recent systematic review by Serafim and colleagues (Clinical course and outcomes of critically ill patients with COVID-19 infection: a systematic review) (1), whereby they describe overall patient outcomes with severe coronavirus disease of 2019 (COVID-19) pneumonia, across many countries, whom required intensive care unit (ICU) admission. Importantly, they also describe various therapies utilized in treating COVID-19 patients in the ICU, and some of the associated outcomes. Their important work adds to the growing knowledge of COVID-19 and we congratulate them on this publication. In Figure 2 of the article, an illustration of more than 30 countries which were included in the systematic review are depicted (1) . Included in this figure is Canada, with 200-700 patients apparently represented. However, there does not appear to be any reference for the Canadian data. We performed a MEDLINE search from inception to January 3 rd 2021 using the following keywords: "COVID-19", "Intensive Care" and "Canada", and found three observational studies describing COVID-19 ICU outcomes in Canada (2) (3) (4) . The studies were published between May and November 2020, describe patients in Canada during the first wave of the Canadian COVID-19 pandemic, and satisfy all of the authors inclusion criteria. Only the study by Mitra et al (117 patients) , was available at the time of the authors search, and ideally should have been included in the primary analysis (2). In the three Canadian studies, a total of 298 ICU patients were described. The ICU mortality in this Canadian cohort ranged from 15-23% with similar ICU lengths of stays, use of invasive mechanical ventilation and renal replacement therapy (Table 1) . Mortality in patients undergoing invasive mechanical ventilation was approximately 20% in all three studies, which is considerably lower than reported in other jurisdictions (1). The observed ICU mortality across several hospital settings in Canada describe a lower mortality compared to the observed outcomes internationally described by Serafim and colleagues. More research will be required to better understand why different outcomes have been observed across international borders. Clinical course and outcomes of critically ill patients with COVID-19 infection: a systematic review Baseline characteristics and outcomes of patients with COVID-19 admitted to intensive care units in Vancouver, Canada: a case series Early experience with critically ill patients with COVID-19 in Montreal Outcomes and clinical practice in patients with COVID-19 admitted to the intensive care unit in Montréal, Canada: a descriptive analysis