Association of co-morbidity with acute stroke mortality by age and time since stroke: A population-based study

Raed A Joundi; James A King; Jillian Stang; Dana Nicol; Michael D Hill; Hude Quan; Peter Faris; Amy Y X Yu; Moira K Kapral; Eric E Smith

doi:10.1016/j.jstrokecerebrovasdis.2023.107236

Association of co-morbidity with acute stroke mortality by age and time since stroke: A population-based study

J Stroke Cerebrovasc Dis. 2023 Aug;32(8):107236. doi: 10.1016/j.jstrokecerebrovasdis.2023.107236. Epub 2023 Jul 8.

Authors

Raed A Joundi¹, James A King², Jillian Stang³, Dana Nicol³, Michael D Hill², Hude Quan⁴, Peter Faris⁵, Amy Y X Yu⁶, Moira K Kapral⁷, Eric E Smith⁸

Affiliations

¹ Division of Neurology, Hamilton Health Sciences, McMaster University & Population Health Research Institute, Hamilton, ON, Canada; Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Canada. Electronic address: raed.joundi@phri.ca.
² Alberta Strategy for Patient Oriented Research Support Unit Data Platform; Provincial Research Data Services, Alberta Health Services.
³ Data and Analytics (DnA), Alberta Health Services, Alberta, Canada.
⁴ Department of Community Health Sciences, University of Calgary, Alberta Canada; Centre for Health Informatics, Calgary, Alberta Canada.
⁵ The O'Brien Institute for Public Health, University of Calgary, Health Services Statistical and Analytic Methods, Data and Analytics (DnA), Alberta Health Services, Foothills Medical Centre, Calgary, AB Canada.
⁶ ICES, Department of Medicine (Neurology), University of Toronto, Sunnybrook Health Sciences Centre, ON, Canada.
⁷ Department of Medicine (General Internal Medicine), University of Toronto-University Health Network, ON, Canada.
⁸ Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Canada; Department of Community Health Sciences, University of Calgary, Alberta Canada; Centre for Health Informatics, Calgary, Alberta Canada.

PMID: 37429113
DOI: 10.1016/j.jstrokecerebrovasdis.2023.107236

Abstract

Objective: To examine whether the association of co-morbidity with mortality after acute stroke is influenced by stroke type, age, sex, or time since stroke.

Materials and methods: We conducted a province-wide population-based study using linked administrative databases to identify all admissions for acute stroke between 2007-2018 in Alberta, Canada. We used Cox proportional hazard models to determine the association of severe co-morbidity based on the Charlson Co-morbidity Index with 1-year mortality after stroke, assessing for effect modification by stroke type, age, and sex, and with adjustment for estimated stroke severity, comprehensive stroke centre care, hypertension, atrial fibrillation, and year of study. We used a piecewise model to analyze the impact of co-morbidity across four time periods.

Results: We had 28,672 patients in our final cohort (87.8% ischemic stroke). The hazard of mortality with severe co-morbidity was higher for individuals with ischemic stroke (adjusted hazard ratio [aHR] 2.20, 95% CI 2.07-2.32) compared to those with intracerebral hemorrhage (aHR 1.70, 95% CI 1.51-1.92; p_int<0.001), and higher in individuals under age 75 (aHR 3.20, 95% CI 2.90-3.53) compared to age ≥75 (aHR 1.93, 95% CI 1.82-2.05, p_int<0.001). There was no interaction by sex. The hazard ratio increased in a graded fashion at younger ages and was higher after the first 30 days of acute stroke.

Conclusion: There was a stronger association between co-morbidity and mortality at younger age and in the subacute phase of stroke. Further research is needed to determine the reason for these findings and identify ways to improve outcomes among those with stroke and co-morbid conditions at young age.

Keywords: Acute stroke; Age; Co-morbidity; Mortality; Population-based.