Trends of Sex Differences and Associated Factors in Stroke Outcomes Among Patients With Acute Ischemic Stroke 2007 to 2018

Background and ObjectivesFemale patients have been shown to experience worse clinical outcomes after acute ischemic stroke (AIS) compared with male patients. We aimed to estimate the temporal trends in the sex differences in stroke outcomes and identify risk factors contributing to the sex differences spanning 10 years in China.MethodsThis cohort study was conducted based on data from the China National Stroke Registries (CNSRs, comprising 3 phases, I-III, from 2007 to 2018). Patients with ischemic stroke within 7 days of symptom onset were included. The primary outcome was a 12-month poor functional outcome. Other outcomes included mortality and disability-adjusted life-year (DALY) lost. The sex differences in outcomes and associated factors were estimated using multivariable logistic regression. The sex differences between CNSRs were tested by the interaction of sex and time.ResultsAmong 42,564 patients included, 35.4% were female. The age-adjusted event rate of 12-month poor functional outcome and mortality decreased both in male and female patients after stroke onset (CNSRs I, II, and III, all p varies over time <0.001). There was a decrease in DALY lost for both sexes over the decade (male patients: from 10.1 to 9.3 DALYs; female patients: from 10.9 to 9.6 DALYs). Female patients showed worse 12-month poor functional outcome in CNSRs I and II (odds ratio [OR] with 95% CI: 1.24 [1.10-1.39] and 1.12 [1.01-1.25], respectively) compared with male patients, but the sex difference attenuated in CNSR III (OR with 95% CI: 1.02 [0.89-1.16]), with the temporal trend (p varies over time = 0.004). The sex difference and the temporal trend of the sex difference in mortality from 2007 to 2018 were not found (p varies over time = 0.45). The most important factors attenuating the sex difference in poor functional outcome in CNSRs I and III were education level, socioeconomic deprivation, baseline stroke severity, and current smoking.DiscussionThis study demonstrated that the sex disparity in poor functional outcome at 12 months was substantially narrowed covering 10 years and completely attenuated in 2015-2018. The findings suggested that female patients have experienced larger improvements in stroke outcomes than male patients over the past decade.