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Background incidence rates of hospitalisations and emergency department visits for thromboembolic and coagulation disorders in Ontario, Canada for COVID-19 vaccine safety assessment: a population-based retrospective observational study.
Nasreen, Sharifa; Calzavara, Andrew J; Sundaram, Maria E; MacDonald, Shannon E; Righolt, Christiaan H; Pai, Menaka; Field, Thalia S; Zhou, Lily W; Wilson, Sarah E; Kwong, Jeffrey C.
  • Nasreen S; Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
  • Calzavara AJ; ICES, Toronto, Ontario, Canada.
  • Sundaram ME; ICES, Toronto, Ontario, Canada.
  • MacDonald SE; Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
  • Righolt CH; ICES, Toronto, Ontario, Canada.
  • Pai M; Faculty of Nursing, University of Alberta, Edmonton, Alberta, Canada.
  • Field TS; School of Public Health, University of Alberta, Edmonton, Alberta, Canada.
  • Zhou LW; Vaccine and Drug Evaluation Centre, Department of Community Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.
  • Wilson SE; Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
  • Kwong JC; Division of Neurology, The University of British Columbia, Vancouver, Columbia, Canada.
BMJ Open ; 11(12): e052019, 2021 12 17.
Article in English | MEDLINE | ID: covidwho-1583101
ABSTRACT

OBJECTIVE:

The objective of this study was to estimate background rates of selected thromboembolic and coagulation disorders in Ontario, Canada.

DESIGN:

Population-based retrospective observational study using linked health administrative databases. Records of hospitalisations and emergency department visits were searched to identify cases using International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Canada diagnostic codes.

PARTICIPANTS:

All Ontario residents. PRIMARY OUTCOME

MEASURES:

Incidence rates of ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, deep vein thrombosis, pulmonary embolism, idiopathic thrombocytopaenia, disseminated intravascular coagulation and cerebral venous thrombosis during five prepandemic years (2015-2019) and 2020.

RESULTS:

The average annual population was 14 million with 51% female. The mean annual rates per 100 000 population during 2015-2019 were 127.1 (95% CI 126.2 to 127.9) for ischaemic stroke, 22.0 (95% CI 21.6 to 22.3) for intracerebral haemorrhage, 9.4 (95% CI 9.2 to 9.7) for subarachnoid haemorrhage, 86.8 (95% CI 86.1 to 87.5) for deep vein thrombosis, 63.7 (95% CI 63.1 to 64.3) for pulmonary embolism, 6.1 (95% CI 5.9 to 6.3) for idiopathic thrombocytopaenia, 1.6 (95% CI 1.5 to 1.7) for disseminated intravascular coagulation, and 1.5 (95% CI 1.4 to 1.6) for cerebral venous thrombosis. Rates were lower in 2020 than during the prepandemic years for ischaemic stroke, deep vein thrombosis and idiopathic thrombocytopaenia. Rates were generally consistent over time, except for pulmonary embolism, which increased from 57.1 to 68.5 per 100 000 between 2015 and 2019. Rates were higher for females than males for subarachnoid haemorrhage, pulmonary embolism and cerebral venous thrombosis, and vice versa for ischaemic stroke and intracerebral haemorrhage. Rates increased with age for most of these conditions, but idiopathic thrombocytopaenia demonstrated a bimodal distribution with incidence peaks at 0-19 years and ≥60 years.

CONCLUSIONS:

Our estimated background rates help contextualise observed events of these potential adverse events of special interest and to detect potential safety signals related to COVID-19 vaccines.
Subject(s)
Keywords

Full text: Available Collection: International databases Database: MEDLINE Main subject: Pulmonary Embolism / Brain Ischemia / Stroke / Disseminated Intravascular Coagulation / COVID-19 Type of study: Incidence study / Observational study / Prognostic study / Risk factors Topics: Vaccines Limits: Adolescent / Adult / Child / Child, preschool / Female / Humans / Infant / Male / Infant, Newborn / Young adult Country/Region as subject: North America Language: English Journal: BMJ Open Year: 2021 Document Type: Article Affiliation country: Bmjopen-2021-052019

Full text: Available Collection: International databases Database: MEDLINE Main subject: Pulmonary Embolism / Brain Ischemia / Stroke / Disseminated Intravascular Coagulation / COVID-19 Type of study: Incidence study / Observational study / Prognostic study / Risk factors Topics: Vaccines Limits: Adolescent / Adult / Child / Child, preschool / Female / Humans / Infant / Male / Infant, Newborn / Young adult Country/Region as subject: North America Language: English Journal: BMJ Open Year: 2021 Document Type: Article Affiliation country: Bmjopen-2021-052019