Stroke severity ‘milder’ in past 2 decades regardless of sex, stroke types

Men and women with ischemic stroke had improved functional outcomes in the past 2 decades, likely due in part to the development of acute reperfusion therapy, according to results of a prospective, registry cohort study.

“In Japan, both the age-adjusted incidence and mortality of stroke decreased drastically during the past half century, but these trends slowed in recent decades,” Kazunori Toyoda, MD, PhD, of the department of cerebrovascular medicine at the National Cerebral and Cardiovascular Center in Japan, and colleagues wrote in JAMA Neurology. “In addition, notable technologies were introduced domestically every 5 years, with official approval for intravenous thrombolysis in 2005, official approval for the first device for mechanical thrombectomy in 2010, and far-reaching spread of stent retrievers for thrombectomy in 2015.

“However, whether the changes in demographic characteristics and therapeutic technologies altered stroke severity and functional outcomes from a long-range perspective remains unknown,” they added.

To help fill this research gap, investigators conducted a nationwide, hospital-based, multicenter, prospective, registry cohort study to examine the secular changes in initial neurological severity and short-term functional outcomes among patients with acute stroke based on sex. They obtained data from the Japan Stroke Data Bank of 183,080 patients with acute stroke development between January 2000 and December 2019. Included patients had stroke, including ischemic and hemorrhagic strokes, and registered within 1 week of symptom onset. Toyoda and colleagues examined all patients’ modified Rankin Scale scores at hospital discharge. They used the NIH Stroke Scale for ischemic stroke and intracerebral hemorrhage and the World Federation of Neurological Surgeons grading for subarachnoid hemorrhage to assess initial severity. Favorable outcomes included those with modified Rankin Scale score of between zero and two, and unfavorable were scores between five and six.

Results showed 135,266 patients (39.8% were women; median age, 74 years) developed ischemic stroke, 36,014 (42.7% were women; median age, 70 years) developed intracerebral hemorrhage and 11,800 (67.2% were women; median age, 64 years) developed subarachnoid hemorrhage. Toyoda and colleagues noted an increase in median ages at onset for all three stroke types and a decrease in the NIH Stroke Scale and World Federation of Neurological Surgeons scores across the 2 decades, according to results of multivariable analysis. Further, they reported an increase in the proportion of favorable outcomes over time following adjustment for age ([OR = 1.02; 95% CI, 1.015-1.024 for women]; [OR = 1.105; 95% CI, 1.011-1.018 for men]) among those with ischemic stroke, followed by stagnation, or even a decrease among men, according to multivariate adjustment that included reperfusion therapy ([OR = 0.997; 95% CI, 0.991-1.003 for women]; [OR = 0.99; 95% CI, 0.985-0.994 for men]). Both sexes exhibited decreases in unfavorable outcomes and in-hospital deaths. Favorable outcomes decreased among those with intracerebral hemorrhage for both sexes, with a decrease in unfavorable outcomes only among women. For those with subarachnoid hemorrhage, the proportion of favorable outcomes did not change, although the proportion of unfavorable outcomes and deaths decreased among both sexes.

“Stroke became milder in severity during the past 20 years regardless of sex or stroke types although age at stroke onset became older in the nationwide stroke registry in

Japan,” Toyoda and colleagues wrote. “Short-term functional outcomes at hospital discharge improved gradually in patients with [ischemic stroke], presumably partly owing to development of acute reperfusion therapy. In contrast, outcomes of patients with hemorrhagic stroke did not clearly improve during the same period.

“Such differences among stroke types might reflect the existence of decisively effective acute therapeutic strategies for [ischemic stroke] and not for [intracerebral hemorrhage] and [subarachnoid hemorrhage],” they added.