Current perspectives of sickle cell disease in Nigeria: changing the narratives

Treating sickle cell disease in resource-limited sub-saharan Africa: recent strategies and recommendations in addressing the gaps for the provision of evidenced based management

INTRODUCTION

The management of Sickle cell disease (SCD) in Sub-Saharan Africa (SSA) suffers from the lack of universal Infant and population screening, inadequate access to standard treatment and poor public health prioritization amidst unstable political systems.

AREAS COVERED

The state of evidence management of SCD in SSA was investigated including sustainability of international funding agencies.

EXPERT OPINION

Current efforts are fragmentary along languages lines; sometimes driven by the funder's objectives and not national agenda. The review highlighted the role of internal and external partnerships such as SPARCO, ARISE, CONSA, as well as technology-based support for the implementation of evidenced based care for SCD. We advocate for increased funding to implement SCD comprehensive care in line with the WHO SCD Framework for Primary Secondary, Tertiary and Specialist Comprehensive Care at state and national level. To achieve this objective, it is important that for SCD as a leading non-communicable disease in Africa and mandate it as a standing agenda for National Council of Ministers at African Union, WHO and regional bodies.

Awareness, attitude, and acceptance of newborn screening for sickle cell disease among health workers and caregivers at primary healthcare centers in Gwagwalada Area Council, Federal Capital Territory, Abuja, Nigeria

Introduction

Newborn Screening (NBS) is a public health program designed to identify and provide early interventions for infants with genetic disorders such as Sickle Cell Disease (SCD). Lack of awareness and unwillingness to participate in the NBS by caregivers and some healthcare workers are major contributing factors impeding NBS for SCD.

Objective

To evaluate the level of awareness and acceptance of NBS for SCD and the determinant factors influencing caregivers in Gwagwalada Area Council of the Federal Capital Territory, Abuja, Nigeria.

Methods

The study employed a descriptive, quantitative design using questionnaires administered to healthcare workers and caregivers at immunization and antenatal clinics of 10 selected Primary Healthcare Centers (PHC) in Gwagwalada Area Council of the Federal Capital Territory, Abuja, Nigeria.

Result

A total of 357 participants, comprising 301 caregivers and 56 health care workers responded to the questionnaires. Among the caregivers, 171 (57.2%) were not aware of NBS for SCD. Two hundred and ninety (97%) expressed willingness to participate in the NBS. However, 32 (10.6%) indicated reluctance to accept positive results of SCD. The majority, 175 (59.1%) of the caregivers strongly agreed that NBS for SCD helps in the early detection and management of SCD, while 7 (2.4%) disagreed. Notably 272 (90.4%) of the caregivers had secondary and tertiary education. Among the healthcare workers, 39 (73.6%) were aware of NBS for SCD and 30 (73.2%) have recommended it to caregivers.

Conclusion

This study revealed a low level of awareness of NBS for SCD among caregivers. However, there was a high level of acceptance among them. The level of awareness is high among healthcare workers. Education emerged as the major factor determining the knowledge and attitude of caregivers toward NBS for SCD.

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.

Burden and outcome of respiratory morbidities among children and adolescents with sickle cell disease-A retrospective review of emergency presentations in some Nigerian tertiary institutions

BACKGROUND

Despite the huge burden of sickle cell disease (SCD) among Nigerian children, the burden and outcome of respiratory illnesses remain undocumented. Thus, we aimed to describe the spectrum and outcome of respiratory illnesses among SCD childrenand adolescentadmissions in ten Nigerian tertiary hospitals.

METHOD

A retrospective review of the SCD admission records of children and adolescents with a confirmed diagnosis of respiratory illnesses from 2012 to 2021 in ten tertiary health facilities across five geopolitical zones in Nigeria was conducted. The data, collectedbetween March and June 2023, included the age, sex, diagnosis, complications, duration and outcome of hospitalization.

RESULTS

Of the 72,333 paediatric admissions, 7,256 (10.0%) had SCD; the proportion of SCD from the total admission ranged from 2.1 to 16.3% in the facilities. Of the 7,256 children and adolescents with SCD, 1,213 (16.7%) had respiratory morbidities. Lower respiratory disease was the most common (70.0%) respiratory entity and the majority were pneumonia (40.1.0%), followed by acute chest syndrome (26.7%). Seventeen (1.4%) patients died; all had lower respiratory diseases [(acute chest syndrome ACS (11, 64.7%), pneumonia; 5, 29.4%, and asthma (1, 5.9%). Based on the proportion of deaths among overall SCD, the 17 death cases contributed 9.4% (95% CI 5.9 to 14.5). Factors associated with deaths included duration of hospitalization less than 72 hours and lower respiratory tract diseases.

CONCLUSION

Sickle cell disease is a major contributor to hospitalization among Nigerian children and adolescents, with high respiratory morbidity and mortality. Pneumonia and acute chest syndrome were associated with mortality, andthe highest risk of death within the first 72 hours.

Multi-criteria decision making to validate performance of RBC-based formulae to screen β -thalassemia trait in heterogeneous haemoglobinopathies

BACKGROUND

India has the most significant number of children with thalassemia major worldwide, and about 10,000-15,000 children with the disease are born yearly. Scaling up e-health initiatives in rural areas using a cost-effective digital tool to provide healthcare access for all sections of people remains a challenge for government or semi-governmental institutions and agencies.

METHODS

We compared the performance of a recently developed formula SCSB T T and its web application SUSOKA with 42 discrimination formulae presently available in the literature. 6,388 samples were collected from the Postgraduate Institute of Medical Education and Research, Chandigarh, in North-Western India. Performances of the formulae were evaluated by eight different measures: sensitivity, specificity, Youden's Index, AUC-ROC, accuracy, positive predictive value, negative predictive value, and false omission rate. Three multi-criteria decision-making (MCDM) methods, TOPSIS, COPRAS, and SECA, were implemented to rank formulae by ensuring a trade-off among the eight measures.

RESULTS

MCDM methods revealed that the Shine & Lal and SCSB T T were the best-performing formulae. Further, a modification of the SCSB T T formula was proposed, and validation was conducted with a data set containing 939 samples collected from Nil Ratan Sircar (NRS) Medical College and Hospital, Kolkata, in Eastern India. Our two-step approach emphasized the necessity of a molecular diagnosis for a lower number of the population. SCSB T T along with the condition MCV≤ 80 fl was recommended for a higher heterogeneous population set. It was found that SCSB T T can classify all BTT samples with 100% sensitivity when MCV≤ 80 fl.

CONCLUSIONS

We addressed the issue of how to integrate the higher-ranked formulae in mass screening to ensure higher performance through the MCDM approach. In real-life practice, it is sufficient for a screening algorithm to flag a particular sample as requiring or not requiring further specific confirmatory testing. Implementing discriminate functions in routine screening programs allows early identification; consequently, the cost will decrease, and the turnaround time in everyday workflows will also increase. Our proposed two-step procedure expedites such a process. It is concluded that for mass screening of BTT in a heterogeneous set of data, SCSB T T and its web application SUSOKA can provide 100% sensitivity when MCV≤ 80 fl.

Structure-based computational design of novel covalent binders for the treatment of sickle cell disease

The quest in finding an everlasting panacea to the pernicious impact of sickle cell disease (SCD) in the society hit a turn of success since the recent discovery of a small molecule reversible covalent inhibitor, Voxelotor. A drug that primarily promotes the stability of oxygenated hemoglobin and inhibit the polymerization of HbS by enhancing hemoglobin's affinity for oxygen has opened a new frontier in drug discovery and development. Despite eminent efforts made to reproduce small molecules with better therapeutic targets, none has been successful. To this end, we employed the use of structure-based computational techniques with emphasis on the electrophilic warhead group of Voxelotor to harness novel covalent binders that could elicit better therapeutic response against HbS. The PubChem database and DataWarrior software were used to design random molecules using Voxelotor's electrophilic functionality. Following the compilation of these chemical entities, a high-throughput covalent docking-based virtual screening campaign was conducted which revealed three (Compound_166, Compound_2301, and Compound_2335) putative druglike candidates with higher baseline energy value compared to the standard drug. Subsequently, in silico ADMET profiling was carried out to evaluate their pharmacokinetics and pharmacodynamics properties, and their stability was evaluated for 1 μs (1 μs) using molecular dynamics simulation. Finally, to prioritize these compounds for further development in drug discovery, MM/PBSA calculations was employed to evaluate their molecular interactions and solvation energy within the HbS protein. Despite the admirable druglike and stability properties of these compounds, further experimental validations are required to establish their preclinical relevance for drug development.

Cerebral artery conditional blood velocity in sickle cell disease: a multicentre study and evidence for active treatment

OBJECTIVE

To obtain multicentre data on the prevalence of normal, high or conditional (intermediate) blood velocity in the cerebral arteries among children with sickle cell disease (SCD) in Nigeria.

DESIGN

A prospective observational study in five tertiary healthcare institutions. By transcranial Doppler (TCD) ultrasonography, cerebral artery peak systolic blood velocity (PSV) was determined in 193 children with SCD and time averaged mean of the maximum blood velocity (TAMMV) in a different cohort of 115 children. This design was to make the findings relevant to hospitals with TCD equipment that measure either PSV or TAMMV.

SETTING

Nigeria.

PARTICIPANTS

308 children (126 girls, 182 boys; age 2-16 years).

MAIN OUTCOME MEASURES

Percentage of children with SCD who have normal, high or intermediate (often termed conditional) PSV or TAMMV.

RESULTS

In the cohort of 193 children, PSV was normal in 150 (77.7%), high in 7 (3.6%) and conditional in 36 (18.7%). In the cohort of 115 children, TAMMV was normal in 96 (84%), high in 7 (6%) and conditional in 12 (10%). There were no significant differences in gender or age distribution between the PSV and TAMMV cohorts. Altogether, cerebral artery blood velocity was normal in 246/308 children (80%), high in 14 (4.5%) and conditional in 48 (15.5%).

CONCLUSION

Since conditional blood velocity in cerebral arteries can progress to high values and predispose to stroke, the proportion of children with SCD who are affected (15.5%) raises the question of whether regular monitoring and proactive intervention ought to be the standard of care.

Performance analysis of machine learning algorithms and screening formulae for β-thalassemia trait screening of Indian antenatal women

BACKGROUND

Currently, more than forty discrimination formulae based on red blood cell (RBC) parameters and some supervised machine learning algorithms (MLAs) have been recommended for β-thalassemia trait (BTT) screening. The present study was aimed to evaluate and compare the performance of 26 such formulae and 13 MLAs on antenatal woman data with a recently developed formula SCS_BTT, which is available for evaluation in over seventy countries as an Android app, called SUSOKA[16].

METHODS

A diagnostic database of 2942 antenatal females were collected from PGIMER, Chandigarh, India and was used for this analysis. The data set consists of hypochromic microcytic anemia, BTT, Hemoglobin E trait, double heterozygote for Hemoglobin S and BTT, heterozygote for Hemoglobin D Punjab and normal subjects. Performance of the formulae and the MLAs were assessed by Sensitivity, Specificity, Youden's Index, and AUC-ROC measures. A final recommendation was made from the ranking obtained through two Multiple Criteria Decision-Making (MCDM) techniques, namely, Simultaneous Evaluation of Criteria and Alternatives (SECA) and TOPSIS.

RESULTS

It was observed that Extreme Learning Machine (ELM) and Gradient Boosting Classifier (GBC) showed maximum Youden's index and AUC-ROC measures compared to all discriminating formulae. Sensitivity remains maximum for SCS_BTT. K-means clustering and the ranking from MCDM methods show that SCS_BTT, Shine & Lal and Ravanbakhsh-F4 formula ensures higher performance among all formulae. The discriminant power of some MLAs and formulae was found considerably lower than that reported in original studies.

CONCLUSION

Comparative information on MLAs can aid researchers in developing new discriminating formulae that simultaneously ensure higher sensitivity and specificity. More multi-centric verification of the formulae on heterogeneous data is indispensable. SCS_BTT and Shine & Lal formula, and ELM and GBC are recommended for screening BTT based on MCDM. SCS_BTT can be used with certainty as a tangible cost-saving screening tool for mass screening for antenatal women in India and other countries.

Co-existing sickle cell anaemia and inflammatory bowel disease: case report and review of the literature

Sickle cell anaemia (SCA) is a chronic haemolytic anaemia associated with vaso-occlusive painful crises which may affect several systems including the gastro-intestinal system, resulting in abdominal pain. The concurrence of inflammatory bowel disease and haemoglobinopathy is rare. No previously reported concurrent cases of both SCA and ulcerative colitis (UC) in sub-Saharan Africa were found in the literature. A 16-year-old girl with concurrent SCA and UC is presented. She was admitted to University College Hospital, Ibadan with a 1-year history of recurrent peri-umbilical pain and bloody stools. These symptoms were mainly attributed to SCA at the referring hospital, and she was managed for chronic tropical diarrhoea without a remarkable clinical response. This case illustrates the concurrent presentation of SCA and ulcerative colitis which led to the missed and delayed diagnosis of ulcerative colitis.

Barriers and Facilitators of Use of Hydroxyurea among Children with Sickle Cell Disease: Experiences of Stakeholders in Tanzania

Factors contributing to low use of HU among SCD patients exist in high-income countries. The latter leaves a drift of literature on factors for low utilization of HU in developing countries. This study aimed to explore the factors influencing the use of HU in the management of SCD in Tanzania. A qualitative study was employed to interview purposively selected participants for this study. The in-depth interviews were conducted with 11 parents of children with SCD, four medical doctors working at sickle cell clinics, and two representatives of the national health insurance fund (NHIF). Interviews were audio-recorded, transcribed, and thematically analysed. Barriers identified were misconception of parents on SCD, financial constraints, regulatory restrictions, worries and fears of medical doctors on the acceptability of HU, shortages of laboratory equipment and consumables, and limited availability of HU. Adequate knowledge of the parents and medical doctors on SCD and HU and opportunities for HU accessibility were the facilitators identified. The utilization of HU by the individual with SCD is affected by several factors, from individual to policy level. Nevertheless, parents of children with SCD and medical doctors working in sickle cell clinics demonstrated good knowledge of the diseases and HU.

Sickle cell disease in sub-Saharan Africa: transferable strategies for prevention and care

Sickle cell disease can be life-threatening or chronically debilitating for both children and adults. Worldwide, more than 300 000 children are born with sickle cell disease every year, over 75% of whom in sub-Saharan Africa. Increased awareness and early interventions, such as neonate screening and comprehensive care, have led to considerable reductions in mortality in children younger than 5 years in high-income countries. However, sickle cell disease prevention and care have largely been neglected in Africa. Without intervention, 50-90% of affected children in many sub-Saharan African countries die before their fifth birthday. Fortunately, increasing initiatives in sub-Saharan Africa are piloting interventions such as neonate screening and comprehensive care, and as mortality declines, quality of life and increased life expectancy become major targets for interventions. Hydroxyurea (hydroxycarbamide) and haematopoietic stem-cell transplantation have already been shown to be effective therapies in high-income countries, but are either not widely accessible or too expensive for most African populations. These challenges are being alleviated by numerous networks evolving through international collaborations that are positively changing the outlook of sickle cell disease management in sub-Saharan Africa. In this Series paper, we describe the epidemiology, pathophysiology, clinicobiological profile, and psychosocial effects of sickle cell disease in sub-Saharan Africa. We highlight transferable strategies already used for the successful management of the condition and key strategies and recommendations for affordable and comprehensive care on the continent. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.

Hydroxyurea in children with sickle cell disease in a resource-poor setting: Monitoring and effects of therapy. A practical perspective

BACKGROUND

Although effectiveness of hydroxyurea (HU) in sickle cell disease is well established, unanswered questions persist about its use in African children. We determined real-life issues of acceptability, availability, and monitoring of HU use in Nigeria.

METHODS

A retrospective longitudinal review of laboratory data of patients on HU was done from case files, followed by a cross-sectional survey that captured families' perception of medication and clinic adherence, laboratory tests, benefits, side effects, and acceptability.

RESULTS

One hundred sixteen patients (1.2-17 years) received HU (mean ± SD = 18.5 ± 4.3 mg/kg/day) in 33 months. Eighty-nine had laboratory analysis. Dose escalation was the initial goal, but only 80% of patients had some form of it. Parents reported improvement in general well-being and reduction in bone pain episodes, hospital admissions, and blood transfusion. While most parents (89.5%) reported satisfaction with HU, 61% reported dissatisfaction with daily drug use, and the frequency and cost of monitoring. Sixteen percent voluntarily stopped therapy. Adherence to daily HU was 88.8%, doctor's appointments 24.5%, hematology tests 18.9%, and organ function tests 37.4%. There were no significant toxicities. Significant increases in hemoglobin, hemoglobin F and mean corpuscular volume, and reduction in absolute neutrophil count occurred despite inconsistent dose escalation.

CONCLUSION

HU (10-15 mg/kg/day starting dose) is safe and seems effective and acceptable to parents. Parental commitment to therapy, pre-HU education (that continues during therapy), provision of affordable HU, and subsidized laboratory tests are important considerations for initiating therapy. Special HU clinics may facilitate dose escalation and reduce frequency of monitoring. Studies are needed on feasibility of maximum tolerable dose HU protocols in sub-Saharan Africa without compromising safety.

Feasibility and acceptability of early infant screening for sickle cell disease in Lagos, Nigeria-A pilot study

In Nigeria, about 150000 babies are born annually with sickle cell disease (SCD), and this figure has been estimated to increase by 100% by the year 2050 without effective and sustainable control strategies. Despite the high prevalence, newborn screening for SCD which allows for early prophylactic treatment, education of parents/guardians and comprehensive management is not yet available. This study explored a strategy for screening in early infancy during the first and second immunization visits, determined the prevalence, feasibility and acceptability of early infant screening for SCD and the evaluation of the HemoTypeSC diagnostic test as compared to the high-performance liquid chromatography (HPLC) gold standard. A cross-sectional study was conducted in two selected primary health care centres in Somolu local government area (LGA) in Lagos, Nigeria. Two hundred and ninety-one mother-infant pairs who presented for the first or second immunization visit were consecutively enrolled in the study following written informed consent. The haemoglobin genotype of mother-infant pairs was determined using the HemoTypeSC rapid test kit. Confirmation of the infants’ Hb genotype was done with HPLC. Data were analysed with SPSS version 22. Validity and Predictive value of HemotypeSC rapid screening test were also calculated. Infant screening for SCD was acceptable to 86% of mothers presenting to the immunization clinics. The prevalence of SCD among the infant cohort was 0.8%. The infants diagnosed with SCD were immediately enrolled in the paediatric SCD clinic for disease-specific care. The HemoTypeSC test had 100% sensitivity and specificity for sickle cell disease in early infancy compared to HPLC. This study affirms that it is feasible and acceptable for mothers to implement a SCD screening intervention program in early infancy in Lagos State. The study also demonstrates the utility of the HemotypeSC rapid testing for ease and reduced cost of screening infants for SCD.

Empowering newborn screening programs in African countries through establishment of an international collaborative effort

In an effort to explore new knowledge and to develop meaningful collaborations for improving child health, the First Pan African Workshop on Newborn Screening was convened in June 2019 in Rabat, Morocco. Participants included an informal network of newborn screening stakeholders from across Africa and global experts in newborn screening and sickle cell disease. Over 150 attendees, representing 20 countries, were present including 11 African countries. The agenda focused on newborn screening rationale, techniques, system development, implementation barriers, ongoing research, and collaborations both globally and across Africa. We provide an overview of the workshop and a description of the newborn screening activities in the 11 African countries represented at the workshop, with a focus on sickle cell disease.