Higher Mortality of Ischaemic Stroke Patients Hospitalized with COVID-19 Compared to Historical Controls

Abstract

Introduction: Increasing evidence suggests patients with coronavirus disease 2019 (COVID-19) may develop thrombosis and thrombosis-related complications. Some previous evidence has suggested COVID-19-associated strokes are more severe with worse outcomes for patients, but further studies are needed to confirm these findings. The aim of this study was to determine the association between COVID-19 and mortality for patients with ischaemic stroke in a large multicentre study.

Methods: A retrospective cohort study was conducted using electronic medical records of inpatients from 50 healthcare organizations, predominately from the USA. Patients with ischaemic stroke within 30 days of COVID-19 were identified. COVID-19 was determined from diagnosis codes or a positive test result identified with CO-VID-19-specific laboratory codes between January 20, 2020, and October 1, 2020. Historical controls with ischaemic stroke without COVID-19 were identified in the period January 20, 2019, to October 1, 2019. 1:1 propensity score matching was used to balance the cohorts with and without CO-VID-19 on characteristics including age, sex, race and comorbidities. Kaplan-Meier survival curves for all-cause 60-day mortality by COVID-19 status were produced.

Results: During the study period, there were 954 inpatients with ischaemic stroke and COVID-19. During the same time period in 2019, there were 48,363 inpatients with ischaemic stroke without COVID-19 (historical controls). Compared to patients with ischaemic stroke without COVID-19, patients with ischaemic stroke and COVID-19 had a lower mean age, had a lower prevalence of white patients, a higher prevalence of black or African American patients and a higher prevalence of hypertension, previous cerebrovascular disease, diabetes mellitus, ischaemic heart disease, atrial fibrillation, chronic kidney disease, chronic obstructive pulmonary disease, liver disease, neoplasms, and mental disorders due to known physiological conditions. After propensity score matching, there were 952 cases and 952 historical controls; cases and historical controls were better balanced on all included characteristics (all p > 0.05). After propensity score matching, Kaplan-Meier survival analysis showed the survival probability was significantly lower in ischaemic stroke patients with COVID-19 (78.3% vs. 91.0%, log-rank test p < 0.0001). The odds of 60-day mortality were significantly higher for patients with ischaemic stroke and COVID-19 compared to the propensity score-matched historical controls (odds ratio: 2.51 [95% confidence interval 1.88-3.34]).

Discussion/conclusions: Ischaemic stroke patients with COVID-19 had significantly higher 60-day all-cause mortality compared to propensity score-matched historical controls (ischaemic stroke patients without COVID-19).

Keywords: Cerebrovascular disease; Coronavirus; Coronavirus disease 2019; Mortality; Stroke.

Fig. 1

Kaplan-Meier survival curve of all-cause 60-day mortality for ischaemic stroke patients with and without COVID-19 after propensity score matching. Propensity score matching for age, sex, race, and history of hypertension, cerebrovascular disease, ischaemic heart disease, chronic obstructive pulmonary disease, diabetes mellitus, atrial fibrillation and flutter, liver disease, CKD, neoplasms, and mental disorders associated with physiological conditions. Purple line is patients with ischaemic stroke without COVID-19, and green line is patients with ischaemic stroke without COVID-19. COVID-19, coronavirus disease 2019.