Sex-Differences in Oral Anticoagulant-Related Intracerebral Hemorrhage

Diverging Trends in Survival and Functional Outcome between Males and Females after Intracerebral Hemorrhage

BACKGROUND

Compared to ischemic stroke, sex differences in patient outcomes following intracerebral hemorrhage (ICH) are underreported. We aimed to determine sex differences in mortality and functional outcomes in a large, unselected Swedish cohort.

METHODS

In this observational study, data on 22,789 patients with spontaneous ICH registered in the Swedish Stroke Register between 2012 and 2019 were used to compare sex differences in 90-day mortality and functional outcome using multivariable Cox and logistic regression analyses, adjusting for relevant confounders. Multiple imputation was used to impute missing data.

RESULTS

The crude 90-day mortality rate was 36.7% in females (3,820/10,405) and 31.7% in males (3,929/12,384) (female hazard ratio [HR] 1.20 95% confidence interval [CI]: 1.15-1.25). In multivariable analysis, the HR for 90-day mortality following ICH in females was 0.89 (95% CI: 0.85-0.94). Age was an important driving factor for the effect of sex on mortality. After adjustment for age, vascular risk factors, and stroke severity, the 90-day functional outcome in pre-stroke independent patients was worse in females compared to males (odds ratio: 1.27 95% CI: 1.16-1.40).

CONCLUSION

In this large observational study, despite lower 90-day mortality, the female sex was independently associated with a worse functional outcome compared to males after ICH, even after adjusting for significant covariates. These diverging trends have not been previously reported for ICH. Given the observational design, our findings should be interpreted with caution, thus further external validation is warranted.

Diverging Trends in the Incidence of Spontaneous Intracerebral Hemorrhage in Sweden 2010-2019: An Observational Study from the Swedish Stroke Register (Riksstroke)

INTRODUCTION

Although ischemic stroke incidence has decreased in Sweden over the past decade, trends in spontaneous intracerebral hemorrhage (ICH) incidence are less well delineated. In this time period, there has been a dramatic increase in use of oral anticoagulants (OAC). The aim of our study was to investigate incidence trends in spontaneous first-ever ICH in Sweden between 2010 and 2019, with a focus on non-OAC-associated and OAC-associated ICH.

METHODS

We included patients (≥18 years) with first-ever ICH registered in the hospital-based Swedish Stroke Register (Riksstroke) 2010-2019. Data were stratified by non-OAC and OAC ICH and analyzed for 2010-2012, 2013-2016, and 2017-2019. Incidence rates are shown as crude and age-specific per 100,000 person-years.

RESULTS

Between 2010 and 2019, 22,289 patients with first-ever ICH were registered; 18,325 (82.2%) patients with non-OAC ICH and 3,964 (17.8%) patients with OAC ICH. Annual crude incidence (per 100,000) of all first-ever ICH decreased by 10% from 29.5 (95% CI 28.8-30.3) to 26.7 (95% CI 26.0-27.3) between 2010-2012 and 2017-2019. The crude incidence rate of non-OAC ICH decreased by 20% from 25.7 (95% CI 25.0-26.3) to 20.7 (95% CI 20.1-21.2), whereas OAC ICH increased by 56% from 3.86 (95% CI 3.61-4.12) to 6.01 (95% CI 5.70-6.32). The proportion of OAC ICH of all first-ever ICH increased between 2010-2012 and 2017-2019 from 13.1% to 22.5% (p < 0.001). Proportional changes were largest in the age group ≥85 years with a decrease in non-OAC ICH by 32% from 155 (95% CI 146-164) to 106 (95% CI 98.6-113) and an increase in OAC ICH by 155% from 25.7 (95% CI 22.1-29.4) to 65.5 (95% CI 59.9-71.2).

CONCLUSION

Incidence of first-ever ICH in Sweden decreased by 10% between 2010 and 2019. We found diverging trends with a 20% decrease in non-OAC-associated ICH and a 56% increase in OAC-associated ICH. Further research on ICH epidemiology, analyzing non-OAC and OAC-associated ICH separately, is needed to follow up these diverging trends including underlying risk factors.

Gender Differences in Intracerebral Hemorrhage

Differences exist between genders in intracerebral hemorrhage cause, epidemiology, and outcomes. These gender differences are in part attributable to physiologic differences; however, demographic, social/behavioral risk factors, along with health care system variation and potential family and/or clinician bias play a role as well. These factors vary from region to region and interact, making comprehensive and definitive conclusions regarding sex differences a challenging task. Differences between the genders in intracerebral hemorrhage epidemiology and extensive differences in underlying pathophysiology, intervention, risk factors, and outcome are all discussed.