Abstract Body: Background: Understanding the trends of stroke incidence and how those strokes are distributed across race is a critical step to implement trials and programs to decrease the burden caused by stroke nationally. In 2015, we reported that stroke incidence is decreasing in both Black and White adults. We investigated the continued trends in stroke incidence by race in 2020.
Methods: In this population-based stroke surveillance study, all cases of stroke within a 5-county population surrounding Cincinnati in adults aged ≥20 years were ascertained during a full year every 5 years from 1993 to 2020. Cases were abstracted by study nurses and adjudicated by trained study physicians. Temporal trends were evaluated by age, race (Black or White), and subtype (ischemic stroke (IS), intracranial hemorrhage (ICH), or subarachnoid hemorrhage (SAH)). Stroke incidence rates per 100,000 individuals from 1993 to 2020 were calculated using US Census data and age-, race-, and sex-standardized as appropriate. Trends were evaluated using linear regression. Disparities were evaluated using risk ratios and reported with 95% CIs.
Results: In 2020, we identified 2280 first-ever strokes. Of these, 23% (N=524) were Black adults and 52% (N=1,177) were female. The overall annual incidence of stroke in 2020 was 203/100,000. Table 1 reports the temporal trends of stroke incidence by subtype for both Black and White race from 1993 to 2020. For all races, any stroke increased between 2015 and 2020 (p=0.003, driven largely by an increase in stroke in White adults), while the overall trend since 1993 is no longer declining. Ischemic stroke also increased between 2015 and 2020 (pairwise comparison, p=0.011) in all races. Figure 1 shows the stroke incidence rate of overall stroke (any subtype) over time. The overall risk ratio of any incident stroke between Black and White adults was RR 1.84 (1.66, 2.02; p-value 0.022).
Conclusions: Compared to our analysis after our 2015 study, overall stroke incidence over time is no longer decreasing. Between 2015 and 2020, we observed an increasing rate of stroke in our population. For the first time in a 27-year period we report a significant increase in stroke incidence, mostly driven by an increase in ischemic stroke incidence in whites. ICH/SAH rates are stably higher in blacks compared to whites. More work needs to be done to investigate any possible association to COVID or other traditional risk factors to address racial disparities in stroke burden.