Stroke Prevention in Young Adults With Sickle Cell Anemia

The Investigator's global hypothesis, to be tested eventually in an NIH-funded phase III controlled trial, is that hydroxyurea at a fixed moderate dose of 20 mg/kg is safe and effective for primary and secondary stroke prevention in young adults with SCA. Prior to testing this global hypothesis, the Investigators must develop a multi-disciplinary team that provides medical care for young adults with SCD and establish the clinical epidemiology of neurological morbidity in this distinct age group. Building upon the existing research platforms of ongoing NINDS-funded primary stroke prevention trials in Nigeria, the Investigators are uniquely positioned to extend their stroke assessment and treatment to the next sequential age group, young adults with SCA. The immediate goals of this project are 1) to estimate the prevalence of neurological morbidity in young adults with SCA (R21 application to NIH); 2) to establish a prospective cohort of young adults to determine the incidence of neurological morbidity, and 3) to determine the safety and feasibility of fixed moderate dose of hydroxyurea therapy for prevention of further neurological disease in young adults with SCA in Nigeria. The leadership of the current pediatric primary and secondary stroke prevention trials (NCT01801423, NCT02560935, NCT02675790) in Nigeria will apply a similar effective strategy used in the Investigator's previous pediatric NINDS-R21 and current pediatric NINDS-R01 to estimate the prevalence and incidence of neurological morbidity in young adults with SCA. Young adults with SCA have different stroke risk factors than children less than 16 years of age with SCA, including risk factors for stroke seen in the general population resulting in the need for age and disease-specific evidence-based management for primary and secondary stroke prevention strategies. the Investigators propose to enroll 250 participants with SCA between 16-25 years of age. The Investigators believe this sample size is sufficient to estimate the prevalence of stroke and SCI. This cohort will be followed for 12-18 months to determine the short-term incidence of strokes and SCI. The Investigators do not intend to calculate a precise incidence of these neurological injuries due to the short duration of the follow-up. For young adults with SCIs, strokes, and elevated TCD measurements (based on the pediatric threshold of abnormal ≥180 cm/s in the middle cerebral artery or terminal portion of the internal carotid) the Investigators will initially offer regular blood transfusion therapy as standard care. If they refuse, the Investigators will offer a dose of 20 mg/kg/day of hydroxyurea for at least one year of therapy. The hydroxyurea will be supplied free of charge with monthly follow-up.