RT Journal Article
SR Electronic
T1 Organ dysfunction and death in patients admitted to hospital with COVID-19 in pandemic waves 1 to 3 in British Columbia, Ontario and Quebec, Canada: a cohort study
JF CMAJ Open
JO CMAJ
FD Canadian Medical Association
SP E379
OP E389
DO 10.9778/cmajo.20210216
VO 10
IS 2
A1 Lee, Terry
A1 Cheng, Matthew P.
A1 Vinh, Donald C.
A1 Lee, Todd C.
A1 Tran, Karen C.
A1 Winston, Brent W.
A1 Sweet, David
A1 Boyd, John H.
A1 Walley, Keith R.
A1 Haljan, Greg
A1 McGeer, Allison
A1 Lamontagne, François
A1 Fowler, Robert
A1 Maslove, David
A1 Singer, Joel
A1 Patrick, David M.
A1 Marshall, John C.
A1 Burns, Kevin D.
A1 Murthy, Srinivas
A1 Mann, Puneet K.
A1 Hernandez, Geraldine
A1 Donohoe, Kathryn
A1 Rocheleau, Genevieve
A1 Russell, James A.
A1 
YR 2022
UL http://www.cmajopen.ca/content/10/2/E379.abstract
AB Background: There have been multiple waves in the COVID-19 pandemic in many countries. We sought to compare mortality and respiratory, cardiovascular and renal dysfunction between waves in 3 Canadian provinces.Methods: We conducted a substudy of the ARBs CORONA I study, a multicentre Canadian pragmatic observational cohort study that examined the association of pre-existing use of angiotensin receptor blockers with outcomes in adults admitted to hospital with acute COVID-19 up to April 2021 from 9 community and teaching hospitals in 3 Canadian provinces (British Columbia, Ontario and Quebec). We excluded emergency department admissions without hospital admission, readmissions and admissions for another reason. We used logistic and 0–1-inflated β regression models to compare 28-day and in-hospital mortality, and the use of invasive mechanical ventilation, vasopressors and renal replacement therapy (RRT) between the first 3 waves of the COVID-19 pandemic in these provinces.Results: A total of 520, 572 and 245 patients in waves 1, 2 and 3, respectively, were included. Patients in wave 3 were on average younger and had fewer comorbidities than those in waves 1 and 2. The unadjusted 28-day mortality rate was significantly lower in wave 3 (7.8%) than in wave 1 (18.3%) (odds ratio [OR] 0.43, 95% confidence interval [CI] 0.24–0.78) and wave 2 (16.3%) (OR 0.46, 95% CI 0.27–0.79). After adjustment for differences in baseline characteristics, the difference in 28-day mortality remained significant (adjusted OR wave 3 v. wave 1: 0.46, 95% CI 0.26–0.81; wave 3 v. wave 2: 0.52, 95% CI 0.29–0.91). In-hospital mortality findings were similar. Use of invasive mechanical ventilation or vasopressors was less common in waves 2 and 3 than in wave 1, and use of RRT was less common in wave 3 than in wave 1.Interpretation: Severity of illness decreased (lower mortality and less use of organ support) across waves among patients admitted to hospital with acute COVID-19, possibly owing to changes in patient demographic characteristics and management, such as increased use of dexamethasone. Continued application of proven therapies may further improve outcomes.Study registration: ClinicalTrials.gov, no. NCT04510623