Feasibility trial for primary stroke prevention in children with sickle cell anemia in Nigeria (SPIN trial)

Transcranial Doppler ultrasound velocities in a population of unstudied African children with sickle cell anemia

The greatest burden of sickle cell anemia (SCA) globally occurs in sub-Saharan Africa, where significant morbidity and mortality occur secondary to SCA-induced vasculopathy and stroke. Transcranial Doppler ultrasound (TCD) can grade the severity of vasculopathy, with disease modifying therapy resulting in stroke reduction in high-risk children. However, TCD utilization for vasculopathy detection in African children with SCA remains understudied. The objective was to perform a prospective, observational study of TCD findings in a cohort of children with SCA from the Democratic Republic of the Congo, Zambia, and Malawi. A total of 770 children aged 2-17 years without prior stroke underwent screening TCD. A study was scored as low risk when the time-averaged maximum of the mean (TAMMX) in the middle cerebral artery or terminal internal carotid artery was <170 cm/s but >50 cm/s, conditional risk when 170-200 cm/s, and high risk when >200 cm/s. Low-risk studies were identified in 604 children (78%), conditional risk in 129 children (17%), and high risk in three children (0.4%). Additionally, 34 (4%) were scored as having an unknown risk study (TAMMX <50 cm/s). Over the course of 15 months of follow-up, 17 children (2.2%) developed new neurologic symptoms (six with low-risk studies, seven with conditional risk, and four with unknown risk). African children with SCA in this cohort had a low rate of high-risk TCD screening results, even in those who developed new neurologic symptoms. Stroke in this population may be multifactorial with vasculopathy representing only one determinant. The development of a sensitive stroke prediction bundle incorporating relevant elements may help to guide preventative therapies in high-risk children.

Brain Magnetic Resonance Imaging and Angiography in Children with Sickle Cell Anaemia in Uganda in a Cross-Sectional Sample

OBJECTIVE

Children with sickle cell anaemia (SCA) are highly susceptible to cerebrovascular injury. We performed brain magnetic resonance imaging and angiography (MRI-MRA) in Ugandan children with SCA to identify structural cerebrovascular abnormalities and examine their relationship to standardized clinical assessments.

METHODS

A sub-sample (n=81) was selected from a cross-sectional study of children attending SCA clinic, including 52 (64.2%) with and 29 (35.8%) without clinically detected abnormalities. Clinical evaluation included assessment for prior stroke, cognitive testing and cerebral arterial transcranial doppler (TCD) flow velocity. MRI-MRA scans were interpreted by at least two neuroradiologists.

RESULTS

Mean age was 6.5±2.7 years, with 39 (48.1%) female. Mean haemoglobin was 7.3±0.9 g/dl. Overall, 13 (16.0%) were malnourished. Infarcts and/or stenoses were detected in 55 (67.9%) participants, with stenoses primarily in the anterior circulation. Infarcts were seen in those with normal 17/29 (58.6%) or abnormal 34/52 (65.4%) clinical testing (p=0.181). Neither abnormal MRI nor MRA was associated with age, sex, haemoglobin, or malnutrition. Abnormal MRA was highly associated with infarcts (p<0.0001). Participants with abnormal imaging had two-fold higher proportion of stroke on exam and/or impaired cognition. Stroke on exam was strongly associated with an imaging abnormality after adjusting for age, sex, malnutrition, and haemoglobin (OR 11.8, 95%CI 1.87-74.2).

CONCLUSION

Over half of these SCA children had cerebrovascular infarcts and/or arterial stenoses. Cerebrovascular disease was frequently undetectable by clinical assessments. While rarely available in under-resourced settings, MRI-MRA brain imaging is an important tool for defining SCA cerebrovascular disease and for assessing impact of clinical intervention trials.

The V-RAMP Program: Building Research Administration and Management Capacity in Nigeria

The increasing volume and complexity of research activities in Nigeria necessitates urgent measures to improve research infrastructure in grants administration and management. The Vanderbilt-Nigeria Research Administration and Management Training Program (V-RAMP) seeks to build infrastructure capacity in research administration and management and research ethics at a major teaching hospital in Nigeria. We will perform a mixed methods needs assessment of the administrative and management environment and develop an action plan to address infrastructure needs, prioritize processes, and guide program implementation. We will capacitate a newly established Office of Research Administration and improve the knowledge and skills of research administrators and grant managers via short term in-person trainings in Nashville, Tennessee and in Kano, Nigeria and through remote learning opportunities. We will enhance local administrative efficiency and performance of research ethics operations through training and mentoring of members and staff of the ethics review committee. Systematic processes to streamline protocols, including a REDCap protocol tracking database and standard operating procedures in the responsible conduct of research and rigor and reproducibility will also be developed. V-RAMP will enable the creation of a high-quality research administration environment that is knowledgeable, efficient, and compliant regarding the fiscal, management and ethical standards of sponsored research.

The V-BRCH Project: building clinical trial research capacity for HIV and noncommunicable diseases in Nigeria

Antiretroviral therapy has turned HIV into a chronic condition, with morbidity from HIV-associated noncommunicable diseases (NCDs) becoming more common as HIV-infected individuals live longer. In Nigeria, the additional challenge of an under-capacitated health system highlights the need for skilled clinical investigators who can generate evidence to tackle the double burden of HIV and NCDs. The Vanderbilt-Nigeria Building Research Capacity in HIV and Non-communicable Diseases (V-BRCH) programme is a training platform to create a cohort of skilled Nigerian investigators with the capacity to lead independent clinical trial research focused on the intersection of HIV and NCDs. V-BRCH will solidify an atmosphere of continuous mentoring and skills acquisition for physician faculty at the Aminu Kano Teaching Hospital via short- and medium-term learning opportunities, paired mentoring arrangements, and mentored research projects. Trainees will attend an annual faculty enrichment programme in Nashville, in addition to on-site workshops in Nigeria on HIV-associated NCD epidemiology, clinical trials methodology, evidence synthesis, qualitative research methods, stakeholder engagement, knowledge translation, and grant writing. Research-oriented junior faculty will undergo focused training in clinical trials administration and regulatory oversight. Scholars will share best practices through mentoring panels, regular ‘Works in Progress’ meetings, and monthly career development seminars. Competitive seed grants will be provided to mentor–mentee teams to promote targeted in-country pilot studies focused on HIV-associated NCDs. For long-term training, physician scientists will be supported to undergo enhanced Master of Public Health (MPH) training at Bayero University in Nigeria and Master of Science in Clinical Investigation (MSCI) training at Vanderbilt. Short-term regional courses, staff development workshops, and MPH curriculum refinement will help to strengthen institutional capacity in HIV-associated NCD clinical trial research. V-BRCH will create a cohort of skilled Nigerian scientists who will be able to compete for independent funding and design and implement high quality research that will generate evidence to inform policy and practice and lead to improved outcomes for Nigerians impacted by HIV-associated NCDs.

Primary prevention of stroke in children with sickle cell anemia in sub-Saharan Africa: rationale and design of phase III randomized clinical trial

Strokes in children with sickle cell anemia (SCA) are associated with significant morbidity and premature death. Primary stroke prevention in children with SCA involves screening for abnormal transcranial Doppler (TCD) velocity coupled with regular blood transfusion therapy for children with abnormal velocities, for at least one year. However, in Africa, where the majority of children with SCA live, regular blood transfusions are not feasible due to inadequate supply of safe blood, cost, and the reluctance of caregivers to accept transfusion therapy for their children. We describe the Primary Prevention of Stroke in Children with Sickle Cell Disease in Nigeria Trial [StrokePreventioninNigeria (SPRING) trial, NCT02560935], a three-center double-blinded randomized controlled Phase III clinical trial to 1) determine the efficacy of moderate fixed-dose (20 mg/kg/day) versus low fixed-dose (10 mg/kg/day) hydroxyurea therapy for primary stroke prevention; 2) determine the efficacy of moderate fixed-dose hydroxyurea for decreasing the incidence of all cause-hospitalization (pain, acute chest syndrome, infection, other) compared to low fixed-dose hydroxyurea. We will test the primary hypothesis that there will be a 66% relative risk reduction of strokes in children with SCA and abnormal TCD measurements, randomly allocated, for a minimum of three years to receive moderate fixed-dose versus low fixed-dose hydroxyurea (total n = 220). The results of this trial will advance the care of children with SCA in sub-Saharan Africa, while improving research capacity for future studies to prevent strokes in children with SCA.

Blood transfusion for preventing primary and secondary stroke in people with sickle cell disease

BACKGROUND

Sickle cell disease is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta globin) genes. Sickle cell disease can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Stroke affects around 10% of children with sickle cell anaemia (HbSS). Chronic blood transfusions may reduce the risk of vaso-occlusion and stroke by diluting the proportion of sickled cells in the circulation. This is an update of a Cochrane Review first published in 2002, and last updated in 2017.

OBJECTIVES

To assess risks and benefits of chronic blood transfusion regimens in people with sickle cell disease for primary and secondary stroke prevention (excluding silent cerebral infarcts).

SEARCH METHODS

We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 8 October 2019. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register: 19 September 2019.

SELECTION CRITERIA

Randomised controlled trials comparing red blood cell transfusions as prophylaxis for stroke in people with sickle cell disease to alternative or standard treatment. There were no restrictions by outcomes examined, language or publication status.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility and the risk of bias and extracted data.

MAIN RESULTS

We included five trials (660 participants) published between 1998 and 2016. Four of these trials were terminated early. The vast majority of participants had the haemoglobin (Hb)SS form of sickle cell disease. Three trials compared regular red cell transfusions to standard care in primary prevention of stroke: two in children with no previous long-term transfusions; and one in children and adolescents on long-term transfusion. Two trials compared the drug hydroxyurea (hydroxycarbamide) and phlebotomy to long-term transfusions and iron chelation therapy: one in primary prevention (children); and one in secondary prevention (children and adolescents). The quality of the evidence was very low to moderate across different outcomes according to GRADE methodology. This was due to the trials being at a high risk of bias due to lack of blinding, indirectness and imprecise outcome estimates. Red cell transfusions versus standard care Children with no previous long-term transfusions Long-term transfusions probably reduce the incidence of clinical stroke in children with a higher risk of stroke (abnormal transcranial doppler velocities or previous history of silent cerebral infarct), risk ratio 0.12 (95% confidence interval 0.03 to 0.49) (two trials, 326 participants), moderate quality evidence. Long-term transfusions may: reduce the incidence of other sickle cell disease-related complications (acute chest syndrome, risk ratio 0.24 (95% confidence interval 0.12 to 0.48)) (two trials, 326 participants); increase quality of life (difference estimate -0.54, 95% confidence interval -0.92 to -0.17) (one trial, 166 participants); but make little or no difference to IQ scores (least square mean: 1.7, standard error 95% confidence interval -1.1 to 4.4) (one trial, 166 participants), low quality evidence. We are very uncertain whether long-term transfusions: reduce the risk of transient ischaemic attacks, Peto odds ratio 0.13 (95% confidence interval 0.01 to 2.11) (two trials, 323 participants); have any effect on all-cause mortality, no deaths reported (two trials, 326 participants); or increase the risk of alloimmunisation, risk ratio 3.16 (95% confidence interval 0.18 to 57.17) (one trial, 121 participants), very low quality evidence. Children and adolescents with previous long-term transfusions (one trial, 79 participants) We are very uncertain whether continuing long-term transfusions reduces the incidence of: stroke, risk ratio 0.22 (95% confidence interval 0.01 to 4.35); or all-cause mortality, Peto odds ratio 8.00 (95% confidence interval 0.16 to 404.12), very low quality evidence. Several review outcomes were only reported in one trial arm (sickle cell disease-related complications, alloimmunisation, transient ischaemic attacks). The trial did not report neurological impairment, or quality of life. Hydroxyurea and phlebotomy versus red cell transfusions and chelation Neither trial reported on neurological impairment, alloimmunisation, or quality of life. Primary prevention, children (one trial, 121 participants) Switching to hydroxyurea and phlebotomy may have little or no effect on liver iron concentrations, mean difference -1.80 mg Fe/g dry-weight liver (95% confidence interval -5.16 to 1.56), low quality evidence. We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: risk of stroke (no strokes); all-cause mortality (no deaths); transient ischaemic attacks, risk ratio 1.02 (95% confidence interval 0.21 to 4.84); or other sickle cell disease-related complications (acute chest syndrome, risk ratio 2.03 (95% confidence interval 0.39 to 10.69)), very low quality evidence. Secondary prevention, children and adolescents (one trial, 133 participants) Switching to hydroxyurea and phlebotomy may: increase the risk of sickle cell disease-related serious adverse events, risk ratio 3.10 (95% confidence interval 1.42 to 6.75); but have little or no effect on median liver iron concentrations (hydroxyurea, 17.3 mg Fe/g dry-weight liver (interquartile range 10.0 to 30.6)); transfusion 17.3 mg Fe/g dry-weight liver (interquartile range 8.8 to 30.7), low quality evidence. We are very uncertain whether switching to hydroxyurea and phlebotomy: increases the risk of stroke, risk ratio 14.78 (95% confidence interval 0.86 to 253.66); or has any effect on all-cause mortality, Peto odds ratio 0.98 (95% confidence interval 0.06 to 15.92); or transient ischaemic attacks, risk ratio 0.66 (95% confidence interval 0.25 to 1.74), very low quality evidence.

AUTHORS' CONCLUSIONS

There is no evidence for managing adults, or children who do not have HbSS sickle cell disease. In children who are at higher risk of stroke and have not had previous long-term transfusions, there is moderate quality evidence that long-term red cell transfusions reduce the risk of stroke, and low quality evidence they also reduce the risk of other sickle cell disease-related complications. In primary and secondary prevention of stroke there is low quality evidence that switching to hydroxyurea with phlebotomy has little or no effect on the liver iron concentration. In secondary prevention of stroke there is low-quality evidence that switching to hydroxyurea with phlebotomy increases the risk of sickle cell disease-related events. All other evidence in this review is of very low quality.

Initiating adjunct low-dose hydroxyurea therapy for stroke prevention in children with SCA during the COVID-19 pandemic

In anticipation of possible blood shortages during the current COVID-19 pandemic, DeBaun proposes rapid initiation of administration of low, fixed doses of hydroxyurea for children with sickle cell anemia (SCA) who receive regular prophylactic transfusions for stroke prevention.

Effectiveness and Safety of Hydroxyurea in the Treatment of Sickle Cell Anaemia Children in Jos, North Central Nigeria

BACKGROUND

Hydroxyurea has been shown to positively modify sickle cell disease pathogenesis, but its use is low among Nigerian sickle cell anaemia (SCA) patients because of effectiveness and safety concerns.

METHODS

We conducted a quasi-experimental study to evaluate the effectiveness and safety of hydroxyurea in 54 SCA children aged 4-17 years. Clinical and haematological parameters were compared at baseline and 12 months after hydroxyurea therapy. The participants were monitored for adverse events. The parameters were compared using relative risk and Wilcoxon Signed-Rank Test.

RESULTS

The number of subjects who had more than two episodes of painful crises reduced from 27 (50%) to 2 (2.7%) (p < 0.001), while those who had acute chest syndrome reduced from 6 (11.1%) to 0 (0.0%; p < 0.001). The risk of being transfused more than once was 0.11 times the risk in the 12 months period preceding therapy (95% CI = 0.02-0.85; p = 0.016). Similarly, the risk of hospital stay >7 days was 0.08 times the risk at the baseline (95% CI = 0.02-0.24; p < 0.0001). The median haematocrit and percentage foetal haemoglobin increased from 26 to 28% and 7.8 to 14%, respectively (p < 0.0001). A dose-dependent but reversible leucopenia was observed among six children (11.1%), otherwise, hydroxyurea was safe in the study population.

CONCLUSION

Hydroxyurea is effective and safe in SCA children in Jos, Nigeria. The findings could strengthen educational programme aimed at improving the utilization of hydroxyurea among SCA children.

Transcranial Doppler Ultrasound in Peninsular Arab Patients With Sickle Cell Disease

OBJECTIVES

Transcranial Doppler ultrasound is used to identify patients with sickle cell disease (SCD) at risk for stroke. We performed transcranial Doppler studies in patients from 4 countries in the Arabian Peninsula (Kuwait, Oman, Iraq, and United Arab Emirates) to document the prevalence of abnormal transcranial Doppler findings.

METHODS

The patients were recruited from outpatient clinics and studied in a steady state. Transcranial Doppler examinations were performed with standard equipment by experienced operators. The time-averaged maximum mean velocity (TAMMV) was documented in the arteries of the circle of Willis. The hemoglobin (Hb) genotype was confirmed, and the fetal Hb level and complete blood counts were determined.

RESULTS

There were 415 patients in the study, aged 2 to 18 years (mean ± SD, 8.6 ± 3.5 years). None of the patients had an abnormal TAMMV (ie, > 200 cm/s), whereas only 13 (3.1%), all from Iraq, had conditional values (170-200 cm/s) in the right middle cerebral artery and 7 (1.7%) in the left middle cerebral artery. There were no consistent TAMMV differences among male and female patients or in patients with different Hb genotypes (sickle cell anemia, sickle cell β^0- thalassemia, and sickle D). The use of hydroxyurea was associated with a lower TAMMV, whereas a blood transfusion history had no influence. Total hemoglobin, reticulocyte count, serum bilirubin, and fetal Hb values showed varying degrees of association with the TAMMV in the different vessels.

CONCLUSIONS

This study has demonstrated the rarity of abnormal transcranial Doppler findings among Peninsular Arab patients with SCD. The guidelines for transcranial Doppler screening in this population need further studies and recommendations.