The Consortium on Newborn Screening in Africa for sickle cell disease: study rationale and methodology

Current Status of Newborn Bloodspot Screening Worldwide 2024: A Comprehensive Review of Recent Activities (2020-2023)

Newborn bloodspot screening (NBS) began in the early 1960s based on the work of Dr. Robert "Bob" Guthrie in Buffalo, NY, USA. His development of a screening test for phenylketonuria on blood absorbed onto a special filter paper and transported to a remote testing laboratory began it all. Expansion of NBS to large numbers of asymptomatic congenital conditions flourishes in many settings while it has not yet been realized in others. The need for NBS as an efficient and effective public health prevention strategy that contributes to lowered morbidity and mortality wherever it is sustained is well known in the medical field but not necessarily by political policy makers. Acknowledging the value of national NBS reports published in 2007, the authors collaborated to create a worldwide NBS update in 2015. In a continuing attempt to review the progress of NBS globally, and to move towards a more harmonized and equitable screening system, we have updated our 2015 report with information available at the beginning of 2024. Reports on sub-Saharan Africa and the Caribbean, missing in 2015, have been included. Tables popular in the previous report have been updated with an eye towards harmonized comparisons. To emphasize areas needing attention globally, we have used regional tables containing similar listings of conditions screened, numbers of screening laboratories, and time at which specimen collection is recommended. Discussions are limited to bloodspot screening.

Incidence Trends of Inherited Anemias at the Global, Regional, and National Levels Over Three Decades

Inherited anemia continues to pose a significant public health concern on a global scale, owing to its extensive geographical prevalence, substantial patient population, and profound ramifications. Here, we investigated detailed information on inherited anemias (including thalassemias, thalassemias trait, sickle cell disease, sickle cell trait, G6PD deficiency, and G6PD trait) for the period 1990-2019 from the Global Burden of Disease study. Over the course of three decades, there has been a persistent rise in the incidence of inherited anemias worldwide, culminating in a total of 44,896,026 incident cases in 2019. However, the prevalence of inherited anemias has exhibited a consistent downward trend over successive years. Significantly, these inherited anemias primarily impact females, exhibiting a male-to-female ratio of 1:1.88. Among males, the most prevalent inherited anemia is G6PD deficiency, whereas G6PD trait prevails among females. The incidence rates of inherited anemias and their temporal trend exhibited significant variations across different regions, with Central Sub-Saharan Africa displaying the highest incidence rates and Central Latin America experiencing the most substantial decline. The findings of this study suggest a significant correlation between the Socio-Demographic index (SDI) and incidence rates of inherited anemias, particularly in regions with lower SDI levels such as Africa and South Asia. These results contribute valuable insights for the analysis of global trends in the burden of inherited anemias.

Perceptions and preferences for genetic testing for sickle cell disease or trait: a qualitative study in Cameroon, Ghana and Tanzania

Sickle cell disease (SCD) is a single gene blood disorder characterised by frequent episodes of pain, chronic anaemic, acute chest syndrome, severe disease complications and lifelong debilitating multi-system organ damage. Genetic testing and screening programs for SCD and the sickle cell trait (SCT) are valuable for early diagnosis and management of children living with SCD, and in the identification of carriers of SCT. People with SCT are for the most part asymptomatic and mainly identified as through genetic testing or when they have a child with SCD. This qualitative study explored perceptions towards genetic testing for SCD and SCT in Cameroon, Ghana, and Tanzania. The results show a general preference for newborn screening for SCD over prenatal and premarital/preconception testing, primarily due to its simpler decision-making process and lower risk for stigmatization. Premarital testing for SCT was perceived to be of low public health value, as couples are unlikely to alter their marriage plans despite being aware of their risk of having a child with SCD. Adolescents were identified as a more suitable population for SCT testing. In the case of prenatal testing, major concerns were centred on cultural, religious, and personal values on pregnancy termination. The study revealed a gender dimension to SCD/SCT testing. Participants mentionned that women bear a heightened burden of decision making in SCD/SCT testing, face a higher risk of rejection by potential in-laws/partners if the carriers of SCT, as well as the possibility of  divorce if they have a child with SCD. The study highlights the complex cultural, ethical, religious and social dynamics surrounding genetic testing for SCD and emphasises the need for public education on SCD and the necessity of incorporating genetic and psychosocial counselling into SCD/SCT testing programs.

Hydroxyurea Therapy for Neurological and Cognitive Protection in Pediatric Sickle Cell Anemia in Uganda (BRAIN SAFE II): Protocol for a single-arm open label trial

Background

Children with sickle cell anemia (SCA) in Sub-Saharan Africa are at high risk of sickle cerebrovascular injury (SCVI). Hydroxyurea, a commonly used disease-modifying therapy, may prevent or decrease SCVI for reduced incident stroke, stroke risk and potentially cognitive dysfunction. We aim to test the impact of daily hydroxyurea therapy on these outcomes in Ugandan children with SCA. We hypothesize that hydroxyurea therapy over 36 months will prevent, stabilize or improve these complications of SCA.

Methods

The BRAIN SAFE II study is an open-label, single-arm trial of daily hydroxyurea for 270 children with SCA (HbSS) in Uganda, ages 3-9 years. Following baseline assessments, participants began hydroxyurea therapy and clinically followed per local guidelines. Standard hydroxyurea dose is escalated to maximum tolerated dose (MTD). SCVI is assessed by cerebral arterial velocity using Doppler ultrasound, with cognitive function determined by formal neurocognitive testing (primary outcomes). Structural SCVI is assessed by magnetic resonance imaging (MRI) and angiography (MRA) in a sub-sample of 90 participants ages ≥5 years, along with biomarkers of anemia, inflammation and malnutrition (secondary outcomes). At trial midpoint (18 months) and completion (36 months), primary outcomes will be compared to participants' baseline to determine hydroxyurea impact and relationships to secondary outcomes.

Conclusion

This open-label, single-arm trial will examine the impact of hydroxyurea on preventing or ameliorating SCA SCVI in children, assessed by reducing incident stroke, stroke risk and neurocognitive dysfunction. Trial results will provide important insight into the role of hydroxyurea therapy on critical manifestations of SCVI in children with SCA.

Bridging the gaps in newborn screening programmes: Challenges and opportunities to detect haemoglobinopathies in Africa

Background

Haemoglobinopathies, including sickle cell disease and β-thalassaemia, are monogenic disorders with a relatively higher prevalence among malaria-endemic areas in Africa. Despite this prevalence, most African countries lack the necessary resources for diagnosing and managing these debilitating conditions.

Aim

This study provides a critical review of newborn screening for detecting haemoglobinopathies in Africa, highlighting challenges and proposing strategies for improved diagnosis and management.

Methods

A literature search on haemoglobinopathies in Africa was conducted in PubMed, Google Scholar and ScienceDirect, using specific keywords and Boolean operators, including articles published from January 1981 to December 2022.

Results

The data show that sickle cell disease is prevalent among populations in Central and West Africa; however, β-thalassaemia is prevalent among people in the northern parts of Africa. Newborn screening pilot initiatives for haemoglobinopathies were being implemented in Angola, Nigeria, Ghana, the Democratic Republic of Congo and the Republic of Benin. The cost of testing, lack of sufficient and accessible medical records, and inadequacy in healthcare infrastructure pose significant challenges in bridging the gaps in newborn screening. Furthermore, the stigmatisation and lack of awareness of haemoglobinopathies and access to newborn screening programmes pose additional challenges.

Conclusion

This review highlights the challenges associated with haemoglobinopathy testing, effective strategies for mitigating these challenges, and future perspectives for expanding efforts toward detecting and managing these disorders across Africa. Providing affordable diagnostic tools, mobile clinics, government subsidies, education campaigns, and the implementation of electronic medical records systems could help bridge the gaps in newborn screening in Africa.

What this study adds

The study presents a comprehensive view of newborn screening of haemoglobinopathies in Africa, provides a detailed outline of the challenges faced by newborn screening for haemoglobinopathies in Africa, and offers strategies for better diagnosis and care.

Evidence-based interventions for reducing sickle cell disease-associated morbidity and mortality in sub-Saharan Africa: A scoping review

Objective

Sickle cell disease is a lifelong illness affecting millions of people globally, but predominantly burdensome in sub-Saharan Africa, where most affected children do not live to adulthood, despite available evidence-based interventions that reduce the disease burden in high-income countries.

Method

We reviewed studies evaluating evidence-based interventions that decrease sickle cell disease-related morbidity and mortality among children living in sub-Saharan Africa. We used the Joanna Briggs scoping review methodological framework and grouped identified evidence-based interventions into preventative pharmacotherapeutic agents, newborn screening and comprehensive healthcare, disease-modifying agents, nutritional supplementation, systemic treatment, supportive agents and patient/carer/population education.

Results

We included 36 studies: 18 randomized controlled trials, 11 observational studies, 5 before-and-after studies and 2 economic evaluation studies, with most of the studies performed in West African countries. Included studies suggest evidence-based interventions effectively to reduce the common morbidities associated with sickle cell disease such as stroke, vaso-occlusive crisis, acute chest syndrome, severe anaemia and malaria infection. Evidence-based interventions also improve survival among study participants. Specifically, our review shows hydroxyurea increases haemoglobin and foetal haemoglobin levels, a finding with practical implications given the challenges with blood transfusion in this setting. The feasibility of implementing individual interventions is hampered by challenges such as affordability, accessibility and the availability of financial and human resources.

Conclusion

Our review suggests that regular use of low-dose hydroxyurea therapy, sulphadoxine-pyrimethamine chemoprophylaxis, L-arginine and Omega-3 fatty acid supplementation and establishment of specialist stand-alone sickle cell clinics could reduce the sickle cell disease-associated morbidity and mortality in sub-Saharan Africa countries.

Current challenges and new approaches to implementing optimal management of sickle cell disease in sub-Saharan Africa

Sickle cell disease (SCD) is the most common life-threatening monogenic disorder in the world. The disease is highly prevalent in malaria endemic areas with over 75% of patients residing in Sub-Saharan Africa (SSA). It is estimated that, without proper care, up to 90% of children with SCD will not celebrate their fifth birthday. Early identification and enrolment into comprehensive care has been shown to reduce the morbidity and mortality related with SCD complications. However, due to resource constraints, the SSA is yet to implement universal newborn screening programs for SCD. Furthermore, care for patients with SCD in the region is hampered by the shortage of qualified healthcare workers, lack of guidelines for the clinical management of SCD, limited infrastructure for inpatient and outpatient care, and limited access to blood and disease modifying drugs such as Hydroxyurea which contribute to poor clinical outcomes. Curative options such as bone marrow transplant and gene therapy are expensive and not available in many SSA countries. In addressing these challenges, various initiatives are ongoing in SSA which aim to enhance awareness on SCD, improve patient identification and retention to care, harmonize the standards of care for SCD, improve the skills of healthcare workers and conduct research on pertinent areas in SCD in the SSA context. Fortifying these measures is paramount to improving the outcomes of SCD in SSA.

Hydroxyurea treatment is associated with lower malaria incidence in children with sickle cell anemia in sub-Saharan Africa

Realizing Effectiveness Across Continents with Hydroxyurea (REACH, NCT01966731) provides hydroxyurea at maximum tolerated dose (MTD) for children with sickle cell anemia (SCA) in sub-Saharan Africa. Beyond reducing SCA-related clinical events, documented treatment benefits include ∼50% reduction in malaria incidence. To identify associations and propose mechanisms by which hydroxyurea could be associated with lower malaria rates, infections were recorded across all clinical sites (Angola, Democratic Republic of Congo, Kenya, and Uganda). Hazard ratios (HR) with 95% confidence intervals (CIs) for baseline demographics, and time-varying laboratory and clinical parameters were estimated in a modified Cox gap-time model for repeated events. Over 3387 patient-years of hydroxyurea treatment, 717 clinical malaria episodes occurred in 336 of 606 study participants; over half were confirmed by blood smear and/or rapid diagnostic testing with 97.8% Plasmodium falciparum. In univariate analysis limited to 4 confirmed infections per child, malaria risk was significantly associated with absolute neutrophil count (ANC), splenomegaly, hemoglobin, and achieving MTD; age, malaria season, MTD dose, fetal hemoglobin, α-thalassemia, and glucose-6-phosphate dehydrogenase deficiency had no effect. In multivariable regression of confirmed infections, ANC was significant (HR, 1.37 per doubled value; 95% CI, 1.10-1.70; P = .0052), and ANC values <3.0 × 109/L were associated with lower malaria incidence. Compared with nonpalpable spleen, 1- to 4-cm splenomegaly also was associated with higher malaria risk (HR, 2.01; 95% CI, 1.41-2.85; P = .0001). Hydroxyurea at MTD is associated with lower malaria incidence in SCA through incompletely defined mechanisms, but treatment-associated mild myelosuppression with ANC <3.0 × 109/L is salutary. Splenomegaly is an unexplained risk factor for malaria infections among children with SCA in Africa.

Determinants of retention in care of newborns diagnosed with sickle cell disease in Liberia: Results from a mixed-methods study of caregivers

High-income nations have established that early diagnosis and preventive treatment reduces early deaths in sickle cell disease (SCD). However, in low-/middle-income countries where SCD is common, attrition from clinical care is common. Reasons for poor retention in care are multi-factorial and poorly understood. The objective of this study was to identify factors that influence caregiver decision-making around chronic health care needs of a child with SCD. We conducted an exploratory sequential mixed methods study of caregivers of children diagnosed with SCD during a newborn screening program in Liberia. Caregivers completed questionnaires and semi-structured interviews designed to identify drivers of health decision-making. Interviews were digitally recorded, transcribed, coded, and analyzed using semi-structured thematic analysis to identify themes. Data integration occurred by using quantitative results to expand and clarify the qualitative themes. Twenty-six caregivers participated in the study. The mean age of the child at the interview was 43.7 months. Five themes influencing health decisions were identified: grief, the importance of support networks, stigma, perceived benefits, and the burden of chronic disease. The five themes crossed multiple domains of a socioecological model and identified complex interactions between family, community, social and cultural norms, and organizational structures. This study highlights the importance of community awareness of SCD and appropriate health communication by healthcare workers. Healthcare decision-making is multifactorial and complex. These results provide a framework for improving retention in care. In a low-resource country such as Liberia, much can be done by leveraging existing resources and cultural practices.