Primary prevention of stroke in children with sickle cell anemia in Nigeria: Protocol for a mixed methods implementation study in a community hospital

BACKGROUND: In Nigeria, approximately 150,000 children with sickle cell anemia (SCA) are born annually, accounting for more than half of all SCA births worldwide. Without intervention, about 11% of children with SCA will develop a stroke before their 20th birthday. Evidence-based practices for primary stroke prevention include screening for abnormal transcranial Doppler (TCD) measurements coupled with regular blood transfusion therapy for at least one year, followed by hydroxyurea (HU) therapy indefinitely. In high-resource countries, this strategy contributes to a 92% decrease in stroke incidence rates. In 2016, as part of a capacity building objective of the Stroke Prevention Trial in Nigeria (1R01NS094041: SPRING), TCD screening was adopted as standard care at Barau Dikko Teaching Hospital in Kaduna. However, with just 70 radiologists and only 3 certified in TCD screening in the state, just 5.49% (1101/20,040) of eligible children with SCA were screened. Thus, there is a need to explore alternate implementation strategies to ensure children with SCA receive standard care TCD screening to decrease stroke incidence. OBJECTIVE: This protocol describes a study to create a stroke prevention program in a community hospital in Kaduna through task shifting TCD screening to nurses and training medical officers to initiate and monitor HU utilization for stroke prevention. METHODS: This study will be conducted at 2 sites (teaching hospital and community hospital) over a period of 3 years (November 2020 to November 2023), in 3 phases using both quasi-experimental and effectiveness-implementation study designs. In the needs assessment phase, focus groups and structured interviews will be conducted with health care providers and hospital administrators to identify barriers and facilitators to evidence-based stroke prevention practices. Results from the needs assessment will inform intervention strategies and a process plan to fit the needs of the community hospital. In the capacity building phase, nurses and medical officers at the community hospital will be trained on TCD screening and HU initiation and monitoring. In the implementation phase, children with SCA aged 2-16 years will be recruited into a nonrandomized single-arm prospective trial to determine the feasibility of initiating a task-shifted stroke prevention program by recording recruitment, retention, and adherence rates. The Reach and Effectiveness components of the RE-AIM (Reach, Effectiveness, Adoption, Implementation and Maintenance) framework will be used to evaluate implementation outcomes between the community and teaching hospitals. RESULTS: The needs assessment phase of the study was completed in February 2021. Manuscript on findings is currently in preparation. Capacity building is ongoing with TCD training and sickle cell disease and stroke education sessions for nurses and doctors in the community hospital. Recruitment for the implementation trial is expected to commence in July 2022. CONCLUSIONS: This study proposes a structured, theory-driven approach to create a stroke prevention program in a community hospital in Kaduna, Nigeria, to decrease stroke incidence among children with SCA. Results will provide preliminary data for a definitive randomized clinical trial in implementation science. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/37927

Randomized controlled trial of fixed low-vs moderate-dose hydroxyurea for primary stroke prevention in Sub-Saharan Africa: Final results of the Spring Trial

Introduction: In children with sickle cell anemia (SCA) without transcranial Doppler (TCD) screening, the incidence rates of ischemic strokes is approximately the same among children living in low- and high- low-resource settings (Pediatr Neurol. 2019;95:73-78.) with a prevalence of ~ 11%. However, in high-income settings, the standard use of TCD ultrasonography, coupled initially with monthly blood transfusion therapy has dropped the stroke prevalence to < 1%. In a low-income setting, such as Nigeria, where 50% of children in the world with SCA are born (150,000 per year), initial monthly blood transfusion therapy is not practical for most children.In the Stroke Prevention in Nigeria (SPIN) Feasibility Trial (NCT01801423), fixed moderate-dose hydroxyurea was associated with a decreased rate of strokes in children with SCA and abnormal time-averaged mean of the maximum velocity (TAMMV) TCD measurements (≥200cm/sec) when compared to no treatment in the STOP Trial, 0.76 and 10.7 strokes per 100 person-years, repsectively (Am J Hematol. 2020). Based on the success of the SPIN trial, plus the challenges of real-world implementation of a government-supported primary stroke prevention programs for estimated 40,0000 children with SCA in three states in Nigeria, we tested the hypothesis that fixed-moderate dose (~20 mg/kg/day) hydroxyurea therapy for primary stroke prevention results in a 66% relative risk reduction (9 to 3 events per 100 person-years) when compared to fixed low-dose hydroxyurea (~10 mg/kg/day) therapy in a randomized controlled trial (The SPRING Trial; NCT02560935).Methods: In this partial-blind controlled phase III trial, we randomly assigned children between 5 and 12 years of age with SCA and a TCD time-averaged mean of the maximum velocity (TAMMV) ≥ 200 cm/sec measured independently twice or TAMMV ≥220 cm/sec once at study screening to receive fixed low-dose or fixed moderate-dose hydroxyurea. The primary endpoint was a clinical stroke or a transient ischemic attack (TIA). Myelosuppression was assessed with monthly complete blood counts (CBCs). Adherence to hydroxyurea was primarily based on an increase in MCV from baseline and monthly pill count return as a percent of dispensed pills. Hemoglobin F levels were measured at baseline, annually and upon trial exit. To evaluate the safety of hydroxyurea in the trial, children attending the same SCA clinics with TCD (TAMMV) <200 cm/sec at study screening were prospectively followed with biweekly phone calls and annual research visits.Results: A total of 220 children (mean age: 7.5 years, 51.8% female) were randomly assigned to fixed low- (10 mg/kg/day) or moderate- (20 mg/kg/day) dose hydroxyurea, and were followed for a median of 2.4 years (IQR 2.0-2.8). NINDS Clinical Trials leaders stopped the trial early because of futility for the primary outcome. In the fixed low- and moderate-dose hydroxyurea groups, the incidence rates of strokes per 100 person-years were 1.19 and 1.92 respectively, with an incidence rate ratio of 1.60 (95% CI: 0.31-10.34), p = 0.768. The incidence rate ratio of mortality when comparing the children treated with low- and moderate- fixed-dose hydroxyurea to the non-elevated TCD group (no hydroxyurea therapy, n= 211) was 1.97 (95% CI: 0.64-6.02) and 0.47 (95% CI: 0.05-2.38), p = 0.265 and 0.545, respectively. Returned pills during the trial was 5.4% and 4.8% in the fixed low- and moderate-dose groups, respectively, p= 0.144. MCV from baseline to endpoint increased 1.5fl and 7.2 fl in the fixed low- and moderate-dose groups, respectively, p<0.001. Upon exit from the trial 29.4% and 66.7% of the fixed- low and moderate -dose groups, respectively, had either hemoglobin level ≥ 9.0 g/dl, or a fetal hemoglobin level ≥ 20%.Conclusions: For primary stroke prevention in children with SCA, fixed low-dose, when compared to fixed moderate-dose hydroxyurea therapy, demonstrated no difference in the incidence rate of strokes. Both fixed low- and moderate -dose hydroxyurea doses are superior to no treatment for primary stroke prevention with abnormal TCD values. In partnership with Katsina, Kano, and Kaduna health department's leaders in Nigeria, 9 distinct SCA and primary stroke prevention clinics have been established, with the provision of free fixed low-dose hydroxyurea therapy (Bond Chemical, Nigeria; $0.15 per 500 mg) for abnormal TCD values, and biannual CBCs as standard care ,for over 40,000 children with SCA