Rates of Strokes in Californians with Sickle Cell Disease in the Post-STOP Era

• Following a transient decrease after the STOP trial, rates of ischemic stroke are increasing in children with SCD in California.

• Stroke in adults with SCD linked to modifiable risk factors like hypertension and hyperlipidemia warrants additional prevention strategies.

Neurovascular complications, including strokes and transient ischemic attacks (TIAs), are common and cause significant morbidity in individuals with sickle cell disease (SCD). The STOP trial (1998) established chronic transfusions as the standard of care for children with SCD at high risk for stroke. Using statewide emergency department and hospitalization data from the California Department of Health Care Access and Innovation (1991-2019), we determined the cumulative incidence and rates for primary and recurrent strokes and TIAs in people with SCD pre- and post-STOP. For the 7,636 patients included in our SCD cohort, cumulative incidence for first ischemic stroke was 2.1% (95% CI: 1.8%, 2.4%) by age 20 years and 13.5% (95% CI: 12.3%, 14.7%) by age 60 years. Cumulative incidence for first intracranial hemorrhage (ICH) was 0.5% (95% CI: 0.4%, 0.7%) by age 20 years and 6.8% (95%CI: 5.9%, 7.7%) by age 60 years. Ischemic stroke rates increased in children (age <18 years, 234.9 vs 165.1 per 100,000PY, P=0.012) and adults (ages 31-50 years, 431.1 vs 303.2 per 100,000PY, P=0.031) in 2010-2019, compared to the preceding decade. There was an increase in rates of ICH in ages 18-30 and TIA in children <18 years from 2010-2019 when compared to the prior decade. Risk factors for stroke and TIA included increasing age, hypertension, and hyperlipidemia. These findings underscore the need for prevention of strokes in adults with SCD and suggest an emphasis on the management of modifiable cerebrovascular risk factors that have been demonstrated to be effective in the general population.