Long-Term Trends in Incidence and Risk Factors for Hemorrhagic Stroke Subtypes Over 24 Years: The South London Stroke Register.

BACKGROUND

Hemorrhagic stroke (HS), including intracerebral and subarachnoid hemorrhage (ICH and SAH), has high mortality and morbidity. We assessed the 24-year trends in incidence, prestroke risk factors, medications, and demographic patterns in a multiracial and multiethnic population.

METHODS

We used 1995 to 2018 data from the South London Stroke Register. The annual incidence rates of HS, ICH, and SAH were standardized to the 2011 England and Wales population and stratified by age, sex, and race or ethnicity. Incidence trends were assessed using Cochran-Armitage tests and Poisson regression. Multiple logistic regressions (with imputed data) assessed shifts in prestroke variables across demographics.

RESULTS

Among 811 patients with ICH and 308 patients with SAH, HS incidence declined by 52% (ICH), 58% (SAH), and 53% overall all demographic groups between 1995 to 2000 and 2013 to 2018 but plateaued or slightly increased from 2007 to 2018. HS incidence per 100 000/year was 19.26 (ICH, 15.35 [95% CI, 13.66-17.19]; SAH, 3.91 [95% CI, 3.07-4.88)] in 2007-2012, and 19.38 (ICH, 15.04 [95% CI, 13.36-16.86]; SAH, 4.34 [95% CI, 3.45-5.35]) in 2013 to 2018. Antiplatelet use declined (OR, 0.10 [95% CI, 0.02-0.44]), and cholesterol-lowering drugs (OR, 7.8 [95% CI, 3.41-17.81]) and anticoagulants (OR, 5.54 [95% CI, 2.77-11.07]) increased. Diabetes (OR, 1.92 [95% CI, 1.11-3.32]), hypercholesterolemia (OR, 7.8 [95% CI, 3.41-17.81]), and atrial fibrillation (OR, [95% CI, 2.87 1.55-5.3]) increased, and hypertension remained static (OR, 0.89 [95% CI, 0.6-1.32]). Smoking and alcohol use substantially decreased (OR, 0.37 [95% CI, 0.24-0.57]; OR, 0.28 [95% CI, 0.17-0.48], respectively).

CONCLUSIONS

HS (ICH and SAH) incidence declined over 50% in 25 years, mainly in the first 12 years. Medication and prestroke comorbidities only partly explain this reduction. Improved prevention and reduced smoking and drinking may have contributed further.