Investigators partly attribute different trends in ischemic vs hemorrhagic strokes to differences in the development of acute therapeutic strategies over the 20-year study period.
Data from a recent study suggest that functional outcomes improved in mean and women with ischemic stroke during a 20-year period. Comparably, during the same period, outcomes for patients with hemorrhagic stroke did not clearly improve, a difference that may be attributed to the development of acute reperfusion therapy for ischemic stroke.
The hospital-based, multicenter, prospective registry included a total of 183,080 patients diagnosed with acute stroke between January 2000 and December 2019 from the Japan Stroke Data Bank (JSDB). Investigators, led by Kazunori Toyoda, MD, PhD, deputy director general, department of cerebrovascular medicine, National Cerebral and Cardiovascular Center, in Suita, Japan, included patients with ischemic and hemorrhagic strokes registering within 7 days of symptom onset.
Within the larger cohort, 135,266 individuals developed ischemic stroke, including 53,800 women (39.8%), with a median age for both sexes of 74 years (interquartile range [IQR], 66.82). A total of 36,014 patients developed intracerebral hemorrhage, including 15,365 women (42.7%), with a median age for both sexes of 70 years (IQR, 59-79). A total of 11,800 patients developed subarachnoid hemorrhage, including 7924 women (67.2%), with a median age for both sexes of 64 years (IQR, 53-75). In a multivariable analysis, median age at onset for all 3 stroke subtypes increased over the 20-year period, and the National Institutes of Health Stroke Scale (NIHSS) and World Federation of Neurological Surgeons scores decreased.
After age adjustment in ischemic stroke, the proportion of favorable outcomes had an increase over time for women (odds ratio [OR], 1.020; 95% CI, 1.015-1.024) and men (OR, 1.015; 95% CI, 1.011-1.018), but did not continue to increase after additional adjustment by NIHSS scores and stroke history. This outcome then decreased after another adjustment by reperfusion therapy in both sexes, with a significant decrease in men (OR, 0.990; 95%CI, 0.985-0.994) when compared with women (OR, 0.997; 95% CI, 0.991-1.003). For both sexes, unfavorable outcomes and in-hospital deaths decreased.
When looking at intracerebral hemorrhage, favorable outcomes decreased for both men and women, but unfavorable outcomes and deaths only decreased in women. The proportion of favorable outcomes was unchanged in subarachnoid hemorrhage, but unfavorable outcomes and deaths decreased in both men and women.
“In the present cohort, NIHSS scores decreased over time in both sexes in all 3 IS subtypes and ICH, regardless of adjustment for age and stroke history. The trends were similar to the above results from the Austrian and Israeli registries,” Toyoda et al wrote. “The decrease could be explained by the 2 reasons proposed previously: improvement in preventive therapy and changes in case mix.”
The JSDB study was limited due to ongoing operation and “secular changes” in participating sites, as well as registration of approximately 3%, more recently 6%, of total patients in Japan estimated to have stroke. In addition, high-volume stroke centers were more likely to join the study, eliminating the possibility to generalize results to low-volume hospitals in Japan. Due to unavailable data on stroke types or demography, 6388 patients (3.2%) were excluded, who also had lower median NIHSS scores and a lower percentage of favorable outcomes and in-hospital mortality than those included in the study. Further, collected data varied according to changes made over the 20-year period, functional outcomes were assessed at the time of discharge because longer-term outcomes were not collected for all patients, and data from 2020 was not collected, meaning the effect of the COVID-19 pandemic was not evaluated.
According to investigators, improved short-term functional outcomes for patients with ischemic stroke are presumably due to the development of acute reperfusion therapy. This is further emphasized by the lack of improvement in outcomes for patients with hemorrhagic stroke, for which there are no “decisively effective acute therapeutic strategies.”