Sickle Cell Disease in Sub-Saharan Africa

Determination of birth prevalence of sickle cell disease using point of care test HemotypeSC™ at Rundu Hospital, Namibia

BACKGROUND

Sickle cell disease (SCD), a noncommunicable disease, has the greatest burden in sub-Saharan Africa. The majority of children (50-90%) with SCD die before their 5th birthday, with approximately 150,000-300,000 annual SCD child deaths in Africa. In developed countries, newborn screening (NBS) has been shown to improve the survival of children with sickle cell disease, with under5 childhood mortality reduced tenfold due to interventions performed before the development of complications. Point -of-care tests have been developed for resource limited settings to expand NBS. The aim of this study was to determine the birth prevalence of sickle cell disease in Namibia using the HemoTypeSC™ point-of-care test.

METHODS

A cross-sectional descriptive study was carried out at Rundu Intermediate Hospital in the Kavango East Region. Two hundred and two (202) well newborns within 72 h of birth were recruited for the study from 22 February to the 23th March 2023. Descriptive statistics were used to compute the haemoglobin types of the study participants.

RESULTS

The majority of the participants (n = 105, 52%) were females, and (n = 97,48%) were males. The median age of the participants was 23 h (Q1, Q3; 11; 33),) with an age range of 2-98 h. Sickle cell trait was present in 9.4% of the screened newborns, no homozygous disease was detected, and 90.6% had Hb AA.

CONCLUSIONS

This study is the first to measure HbS gene carriage at birth using HemotypeSC point-of-care testing in Namibia. There was a moderate prevalence of sickle cell traits but no SCD. This baseline study may provide the foundation for larger epidemiological surveys to map HbS gene carriage in Namibia to provide evidence for policy makers to fashion appropriate SCD newborn screening services.

A Case of Sickle Cell Retinopathy With Retinal Artery Occlusion in African-Japanese Patients

As globalization progresses, cases of sickle cell disease (SCD) are now being seen even in Japan, where SCD did not originally exist. SCD causes not only anemia but also peripheral blood flow obstruction, which can lead to systemic complications. This report represents a case of sickle cell retinopathy (SCR) in Japan discovered with the onset of retinal artery occlusion (RAO). The patient, a 20-year-old African-Japanese male, was being monitored for SCD at the Nagoya University Hospital, Pediatrics Department, Nagoya, Japan. Following a chest pain episode, he reported a loss of vision in his right eye and was referred to the ophthalmology department. Examination showed reduced visual acuity in the right eye 20/40 compared to the left 20/20. A Goldman visual field test indicated central vision loss in the right eye, and fundoscopic examination revealed yellow-white lesions centered on the macula and peripheral salmon-patch-like lesions in the right eye, with peripheral black sunburst-like lesions in the left eye. Optical coherence tomography (OCT) of the right eye showed inner retinal edema within the macula, suggesting an SCR accompanied by branch RAO. Six months later, he complained of further vision loss in his right eye. Examination and OCT revealed sub-inner limiting membrane hemorrhage in the right eye, suggesting worsening of the SCR. SCD is exceedingly rare among native Japanese but is likely to be encountered more frequently as globalization progresses. Even in countries where SCD has traditionally been rare, attention must be paid to the occurrence of severe SCR when managing SCD.

The dawn of a cure for sickle cell disease through CRISPR-based treatment: A critical test of equity in public health genomics

Equity in access to genomic technologies, resources, and products remains a great challenge. This was evident especially during the coronavirus disease 2019 (COVID-19) pandemic when the majority of lower middle-income countries were unable to achieve at least 10% population vaccination coverage during initial COVID-19 vaccine rollouts, despite the rapid development of those vaccines. Sickle cell disease (SCD) is an inherited monogenic red blood cell disorder that affects hemoglobin, the protein that carries oxygen through the body. Globally, the African continent carries the highest burden of SCD with at least 240,000 children born each year with the disease. SCD has evolved from a treatable to a curable disease. Recently, the UK medical regulator approved its cure through clustered regularly interspaced short palindromic repeat (CRISPR)-based treatment, whereas the US Food and Drug Administration has equally approved two SCD gene therapies. This presents a remarkable opportunity to demonstrate equity in public health genomics. This CRISPR-based treatment is expensive and therefore, a need for an ambitious action to ensure that they are affordable and accessible where they are needed most and stand to save millions of lives.

Prevalence of sickle cell trait and needs assessment for uptake of sickle cell screening among secondary school students in Kampala City, Uganda

BACKGROUND

Sickle cell disease (SCD) is one of the most frequent and traumatizing genetic disease in Uganda, with the prevalence of the sickle cell trait (SCT) estimated at 13.3% leading to serious psycho-social and economic impact on the patients and their families.

AIM

This study aimed to determine the burden of SCT and factors influencing the uptake of screening services among secondary school students in Uganda.

METHODS

We used an analytical cross-sectional design with a multi-stage sampling approach. A total of 399 students from four secondary schools in Kampala City were enrolled in this study. Data were gathered using semi-structured questionnaires and blood screening. We used the sickling test to determine the presence of sickle cell alleles among the participants and hemoglobin electrophoresis as a confirmatory test. Data gathered using the questionnaire were analyzed using descriptive and inferential statistics.

RESULTS

In total, 5.8% of participants who were tested during this study had SCT. Most (80.2%) participants were not in an intimate relationship at the time of data collection. The majority (60.4%) had moderate knowledge about SCT screening and obtained information about screening from the school. Only 29 (7.3%) participants knew of a family member with sickle cell. Overall, participants had a negative attitude toward SCT screening (67%), although 41.6% believed that most people who were sickle cell carriers did not live long and were often sick. Statistically significant associations were found between testing for SCT and knowing a partner's sickle cell status (odds ratio [OR] 2.112, p = 0.043) and Anglican religion (OR 2.075, p = 0.047).

CONCLUSION

Despite the moderate level of knowledge and negative attitudes, a relatively large number of participants had SCT. This highlights the need for a comprehensive health education package targeting adolescents to promote SCD/SCT screening.

Clinically actionable secondary findings in 130 triads from sub-Saharan African families with non-syndromic orofacial clefts

INTRODUCTION

The frequency and implications of secondary findings (SFs) from genomic testing data have been extensively researched. However, little is known about the frequency or reporting of SFs in Africans, who are underrepresented in large-scale population genomic studies. The availability of data from the first whole-genome sequencing for orofacial clefts in an African population motivated this investigation.

METHODS

In total, 130 case-parent trios were analyzed for SFs within the ACMG SFv.3.0 list genes. Additionally, we filtered for four more genes (HBB, HSD32B, G6PD and ACADM).

RESULTS

We identified 246 unique variants in 55 genes; five variants in four genes were classified as pathogenic or likely pathogenic (P/LP). The P/LP variants were seen in 2.3% (9/390) of the subjects, a frequency higher than ~1% reported for diverse ethnicities. On the ACMG list, pathogenic variants were observed in PRKAG (p. Glu183Lys). Variants in the PALB2 (p. Glu159Ter), RYR1 (p. Arg2163Leu) and LDLR (p. Asn564Ser) genes were predicted to be LP.

CONCLUSION

This study provides information on the frequency and pathogenicity of SFs in an African cohort. Early risk detection will help reduce disease burden and contribute to efforts to increase knowledge of the distribution and impact of actionable genomic variants in diverse populations.

Evaluation of treatment patterns, healthcare resource utilization and cost of illness for sickle cell disease in Ghana: a private medical insurance claims database study

BACKGROUND

Sickle cell disease (SCD) is a major public health concern in sub-Saharan Africa, accounting for nearly 75% of the global disease burden. The current analysis evaluated patient characteristics, treatment patterns, healthcare resource utilization (HCRU) and associated costs in patients with SCD based on a Private Medical Insurance Database in Ghana.

METHODS

This retrospective longitudinal cohort study was conducted using an e-claims database from Ghana (01 January 2015 to 31 March 2021). Patients were stratified by age (0 month to < 2 years, ≥ 2 years to ˂6 years, ≥ 6 years to < 12 years, ≥ 12 years to < 16 years; ≥16 years), vaso-occlusive crisis (VOC) (< 1, ≥ 1 to < 3, and ≥ 3 per year), and continuous enrolment. Study outcomes related to patient characteristics, comorbidities, treatment pattern, HCRU were evaluated for pre- and post-index period (index period was between July 2015 to March 2020). Descriptive analysis was used to analyse different study variables.

RESULTS

The study included 2,863 patients (mean age: 20.1 years; Min age: 0; Max age: 83; females 56.1%). Overall, 52.2% (n = 1,495) of SCD patients were ≥ 16 years and 17.0% (n = 486) were in the ≥ 2 to ˂6-years age group. The majority of patients aged ≥ 16 years (62.5%) in the database did not have reported VOC episodes, 35.9% of patients had 1 to 3 VOCs per year and 1.5% had ≥ 3 VOCs per year during the follow-up period. Consultation-based prevalence of SCD was 0.5% [95% confidence interval (CI): 0-1.3%] - 1.4% [CI: 0.6-2.2%]. Malaria, upper respiratory tract infection (URTI) and sepsis were the common complications of SCD. Analgesics were the most frequently prescribed medications followed by anti-infectives, hematinics, and antimalarials. Hydroxyurea, a routine standard of care for SCD was under-utilized. SCD patients had median cost incurred for consultation/hospital services of $11.3 (Interquartile range [IQR] $6.2 - $27.2). For patients with VOC, maximum median cost was incurred for medications ($10.9 [IQR $5.0-$32.6]). Overall median healthcare cost was highest for individuals with ≥ 3 VOCs per year during the follow-up period ($166.8 [IQR $70.3-$223.5]).

CONCLUSION

In this retrospective private insurance claims database analysis, SCD imposes a significant healthcare burden, especially in patients with VOC. There is a need for reimbursed treatment options that could reduce the long-term burden associated with SCD and VOC.

Debate: Should the loss of disability adjusted life years (DALY) define the focus of Global Hematology?: The case for prioritizing capacity building in anemia management and blood transfusion

Setting priorities in healthcare is always contentious given the array of possible services at primary, secondary, and tertiary levels of care, not to mention potential public health interventions. The central goals in global policy have been reducing inequity within and between countries, protecting vulnerable groups (particularly women and children) and reducing the major communicable diseases which have historically been a major burden in lower- and middle-income countries. Here limited relative and absolute spending on healthcare have spurred a series of initiatives in Global Health over the last 50 years which have led to significant gains in measures of morbidity and mortality. Against this background there remains the continuing question of how to adapt current medical practice in higher income countries for training and planning of services in lower- and middle-income countries. Here, the historical development of Global Health is outlined, and lessons drawn from the surveys of the global burden of disease and health economic analysis to understand how we can apply these principles to define Global Hematology. It remains likely that in lower-income countries effort should be concentrated on developing laboratory services and blood transfusion, to allow safe and effective support for the assessment of treatment of anemia, sickle cell disease, maternal and child health and urgent surgery and obstetric services. However, the principles of Global Health, could also be used for hematological malignancies to develop a framework for Global Hematology for all settings.

Impact and burden of sickle cell disease in critically ill obstetric patients in a high dependency unit in Sierra Leone-a registry based evaluation

INTRODUCTION

Sickle cell disease (SCD) in pregnancy is associated with worse maternal and neonatal outcomes. There is limited available data describing the burden and outcomes of critically ill obstetric patients affected by SCD in low-income settings.

OBJECTIVES

We aimed to define SCD burden and impact on mortality in critically-ill obstetric patients admitted to an urban referral hospital in Sierra Leone. We hypothesized that SCD burden is high and independently associated with increased mortality.

METHODS

We performed a registry-based cross-sectional study from March 2020 to December 2021 in the high-dependency unit (HDU) of Princess Christian Maternity Hospital PCMH, Freetown. Primary endpoints were the proportion of patients identified in the SCD group and HDU mortality. Secondary endpoints included frequency of maternal direct obstetric complications (MDOCs) and the maternal early obstetric warning score (MEOWS).

RESULTS

Out of a total of 497 patients, 25 (5.5%) qualified to be included in the SCD group. MEOWS on admission was not different between patients with and without SCD and SCD patients had also less frequently reported MDOCs. Yet, crude HDU mortality in the SCD group was 36%, compared to 9.5% in the non SCD group (P < 0.01), with an independent association between SCD group exposure and mortality when accounting for severity on admission (hazard ratio 3.40; 95%CI 1.57-7.39; P = 0.002). Patients with SCD had a tendency to longer HDU length of stay.

CONCLUSIONS

One out of twenty patients accessing a HDU in Sierra Leone fulfilled criteria for SCD. Despite comparable severity on admission, mortality in SCD patients was four times higher than patients without SCD. Optimization of intermediate and intensive care for this group of patients should be prioritized in low-resource settings with high maternal mortality.

Hydroxyurea treatment for adult sickle cell anemia patients in Kinshasa

Background: Despite a high incidence of sickle cell anemia, hydroxyurea (HU) treatment is rarely used in the DR Congo. This study aims to assess the efficacy of HU, the incidence of side effects that may limit its use in adults and to determine the dose needed for clinical improvement in patients. Methods: In a prospective study, patients received an initial dose of 15 mg/kg/day which was increased by 5 mg/kg every 6 months, up to a maximum of 30 mg/kg/day. The response and side effects to HU were evaluated biologically and clinically every 3 months during a 2-year period. Results: Seventy adult patients with a moderate or severe clinical phenotype initiated treatment. Only minor side effects were reported. At the end of the 2-year treatment phase, 45 (64.3%) had dropped out, of whom 33 were without a clear reason. Clinical and biological improvement was more marked during the first year. There was a reduction in severe vaso-occlusive crises (p < 0.001), need for transfusion (p < 0.001), and hospitalization days (p = 0.038). Fetal hemoglobin (HbF) levels increased on average 2.9 times after 12 months (p < 0.001). The increase in mean corpuscular volume was greater in the first year (p < 0.001) than in the second year (p = 0.041). The decrease in leukocytes (p < 0.001) was significant during the first year. In 70% of patients, the 20 mg/kg/day dose was needed to reach the 20% HbF threshold. Conclusion: HU is effective and well tolerated. The magnitude of the response varies from one patient to another. Improvement of clinical manifestations is achieved in most patients with a relatively low dose. Effective implementation of HU treatment will require improved adherence to treatment.

Entire Expressed Peripheral Blood Transcriptome in Pediatric Severe Malarial Anemia

This study on severe malarial anemia (SMA: Hb < 6.0 g/dL), a leading global cause of childhood morbidity and mortality, analyzed the entire expressed transcriptome in whole blood from children with non-SMA (Hb ≥ 6.0 g/dL, n = 41) and SMA (n = 25). Analyses revealed 3,420 up-regulated and 3,442 down-regulated transcripts, signifying impairments in host inflammasome activation, cell death, innate immune responses, and cellular stress responses in SMA. Immune cell profiling showed a decreased antigenic and immune priming response in children with SMA, favoring polarization toward cellular proliferation and repair. Enrichment analysis further identified altered neutrophil and autophagy-related processes, consistent with neutrophil degranulation and altered ubiquitination and proteasome degradation. Pathway analyses highlighted SMA-related alterations in cellular homeostasis, signaling, response to environmental cues, and cellular and immune stress responses. Validation with a qRT-PCR array showed strong concordance with the sequencing data. These findings identify key molecular themes in SMA pathogenesis, providing potential targets for new malaria therapies.

[Lung manifestations of sickle-cell disease]

Sickle-cell disease is an autosomal recessive genetic disorder of hemoglobin that causes systemic damage. Hypoxia is the main actor of sickle-cell disease. It initiates acutely the pathogenic cascade leading to tissue damages that in turn induce chronic hypoxia. Lung lesions represent the major risk of morbidity and mortality. Management of sickle-cell disease requires a tight collaboration between hematologists, intensivists and chest physicians. Recurrent episodes of thrombosis and hemolysis characterize the disease. New therapeutic protocols, associating hydroxyurea, transfusion program and stem cell transplantation in severe cases allow a prolonged survival until the fifth decade. However, recurrent pain, crisis, frequent hospital admissions due to infection, anemia or acute chest syndrome and chronic complications leading to organ deficiencies degrade the patients' quality of life. In low-income countries where the majority of sickle-cell patients are living, the disease is still associated with a high mortality in childhood. This paper focuses on acute chest syndrome and chronic lung manifestations.

Sickle cell disease treatment and management in India: a systematic review of interventional studies

Sickle cell disease (SCD) affects approximately 5% of the world's population, and India has been the second highest country in the numbers of predicted SCD births. Despite the high burden in India, there is no state-led public health programme, and very few interventions dealing with the treatment and management of SCD are available. This review highlights the dearth of SCD-related interventions, and demonstrates that these interventions effectively improve patients' conditions and are feasible to implement in India. We systematically searched three databases-PubMed/Medline, Google Scholar and Web of Science-for articles from India on SCD-related interventions. The PRISMA guidelines were followed during this review. We included 22 studies, of which 19 dealt with specific therapeutic interventions, and 3 with comprehensive SCD care. Hydroxyurea therapy was the main therapy in 15 studies and is efficacious. Three studies demonstrated the feasibility of comprehensive care in resource-limited settings. The low number of SCD-related intervention studies does not match the huge burden of SCD in India. Governments of endemic countries should consider the findings of available interventions and include them in their countries' programmes. Comprehensive care is feasible in India and other low-resource settings, from screening to treatment and psychosocial support.

Effective therapies for sickle cell disease: are we there yet?

Sickle cell disease (SCD) is a common genetic blood disorder associated with acute and chronic pain, progressive multiorgan damage, and early mortality. Recent advances in technologies to manipulate the human genome, a century of research and the development of techniques enabling the isolation, efficient genetic modification, and reimplantation of autologous patient hematopoietic stem cells (HSCs), mean that curing most patients with SCD could soon be a reality in wealthy countries. In parallel, ongoing research is pursuing more facile treatments, such as in-vivo-delivered genetic therapies and new drugs that can eventually be administered in low- and middle-income countries where most SCD patients reside.

Microbial gut evaluation in an angolan paediatric population with sickle cell disease

Sickle cell disease (SCD) is one of the most common genetic conditions worldwide. It can contribute up to 90% of under-5 mortality in sub-Saharan Africa. Clinical manifestations are very heterogeneous, and the intestinal microbiome appears to be crucial in the modulation of inflammation, cell adhesion and induction of aged neutrophils, the main interveners of recurrent vaso-occlusive crisis. Enterocyte injury, increased permeability, altered microbial composition and bacterial overgrowth have all been documented as microbial and pathophysiologic changes in the gut microbiome of SCD patients in recent studies. Our aim was to sequence the bacterial 16S rRNA gene in order to characterize the gut microbiome of Angolan children with SCA and healthy siblings as a control. A total of 72 stool samples were obtained from children between 3 and 14 years old. Our data showed that the two groups exhibit some notable differences in microbiota relative abundance at different classification levels. Children with SCA have a higher number of the phylum Actinobacteria. As for the genus level, Clostridium cluster XI bacteria was more prevalent in the SCA children, whereas the siblings had a higher abundance of Blautia, Aestuariispira, Campylobacter, Helicobacter, Polaribacter and Anaerorhabdus. In this study, we have presented the first microbiota analysis in an Angolan paediatric population with SCD and provided a detailed view of the microbial differences between patients and healthy controls. There is still much to learn before fully relying on the therapeutic approaches for gut modulation, which is why more research in this field is crucial to making this a reality.

Genetic modulation of anemia severity, hemolysis level, and hospitalization rate in Angolan children with Sickle Cell Anemia

BACKGROUND

Sickle Cell Anemia (SCA) is a genetic disease caused by the c.20 A > T mutation in HBB gene, generally characterized by sickle erythrocytes, chronic hemolytic anemia, and vaso-occlusive events. This study aimed to investigate genetic modulators of anemia severity, chronic hemolytic rate, and clinical manifestations in pediatric SCA patients from Angola, where the disease is a severe public health problem.

METHODS AND RESULTS

The study was conducted on 200 SCA children living in Luanda or Caxito province. Their clinical phenotype was collected from patients' hospital records. Hematological and biochemical phenotypes were characterized in steady state condition. Twelve polymorphic regions in VCAM1, CD36 and NOS3 genes were genotyped using PCR, RFLP, and Sanger sequencing. CD36 gene promoter variants showed a significant impact on anemia severity. Particularly, the rs1413661_C allele was associated with lower hemoglobin levels, and increased number of hospitalizations and transfusions. This is the first report associating this SNP with SCA phenotypic heterogeneity. Moreover, the rs1041163_C allele in VCAM1 was associated with lower LDH levels; inversely the rs2070744_C allele in NOS3 was related with higher LDH levels and number of hospitalizations, being a risk factor for increased hemolytic rate.

CONCLUSION

This study highlights, for the first time in the Angolan population, the importance of the genetic modifiers of vascular cell adhesion and nitric oxide metabolism in SCA pediatric phenotypic variability.

Hematological and molecular analyses of the HbS allele among the Sudanese population

Objective

The purpose of this study was to perform hematological and molecular analyses of the HbS allele of the hemoglobin subunit beta gene in the Sudanese population.

Methods

This was a descriptive cross-sectional study. Hematological parameters and fetal hemoglobin (HbF) levels were assessed in all participants. Data were gathered through the use of questionnaires and laboratory investigations. The β^S-globin haplotypes, S allele distributions, and hematological parameters with HbF levels were investigated using PCR-restriction fragment length polymorphism, gel electrophoresis, and a Sysmex hematology analyzer, respectively.

Results

According to our findings, the Bantu (BA) haplotype was found in 10.8% of participants with homozygous uncontested haplotypes, followed by Benin (BA) and Sudan (SU), each in 9.8% of participants. This Sudanese group from Northern Kordofan lacked the Arab-Indian haplotype. Two heterozygous versions of undisputed haplotypes were found in 17.3% of participants: SU/BA in 10.8% and CA/BE in 6.5%.

Conclusion

As a result of sickle cell anemia, this investigation found changes in hematological parameters. In the Sudanese population, a new haplotype of the S gene was discovered.

Sickle cell anaemia and severe Plasmodium falciparum malaria: a secondary analysis of the Transfusion and Treatment of African Children Trial (TRACT)

BACKGROUND

Sickle cell anaemia (SCA) has historically been associated with high levels of childhood mortality in Africa. Although malaria has a major contribution to this mortality, to date, the clinical pathology of malaria among children with SCA has been poorly described. We aimed to explore the relationship between SCA and Plasmodium falciparum malaria in further detail by investigating the burden and severity of malaria infections among children recruited with severe anaemia to the TRACT trial of blood transfusion in Africa.

METHODS

This study is a post-hoc secondary analysis of the TRACT trial data, conducted after trial completion. TRACT was an open-label, multicentre, factorial, randomised controlled trial enrolling children aged 2 months to 12 years who presented with severe anaemia (haemoglobin <6·0 g/dL) to four hospitals in Africa. This secondary analysis is restricted to Uganda, where the birth prevalence of SCA is approximately 1% and malaria transmission is high. Children were classified as normal (HbAA), heterozygous (HbAS), or homozygous (HbSS; SCA) for the rs334 A→T sickle mutation in HBB following batch-genotyping by PCR at the end of the trial. To avoid confounding from SCA-specific medical interventions, we considered children with an existing diagnosis of SCA (known SCA) separately from those diagnosed at the end of the trial (unknown SCA). The outcomes considered in this secondary analysis were measures of P falciparum parasite burden, features of severe malaria, and mortality at day 28 in malaria-positive children.

FINDINGS

Between Sept 17, 2014, and May 15, 2017, 3944 children with severe anaemia were enrolled into the TRACT trial. 3483 children from Uganda were considered in this secondary analysis. Overall, 1038 (30%) of 3483 Ugandan children had SCA. 1815 (78%) of 2321 children without SCA (HbAA) tested positive for P falciparum malaria, whereas the prevalence was significantly lower in children with SCA (347 [33%] of 1038; p<0·0001). Concentrations of plasma P falciparum histidine-rich protein 2 (PfHRP2), a marker of the total burden of malaria parasites within an individual, were significantly lower in children with either known SCA (median 8 ng/mL; IQR 0-57) or unknown SCA (7 ng/mL; 0-50) than in HbAA children (346 ng/mL; 21-2121; p<0·0001). In contrast to HbAA children, few HbSS children presented with classic features of severe and complicated malaria, but both the frequency and severity of anaemia were higher in HbSS children. We found no evidence for increased mortality at day 28 in those with SCA compared with those without SCA overall (hazard ratios 1·07 [95% CI 0·31-3·76] for known SCA and 0·67 [0·15-2·90] for unknown SCA).

INTERPRETATION

The current study suggests that children with SCA are innately protected against classic severe malaria. However, it also shows that even low-level infections can precipitate severe anaemic crises that would likely prove fatal without rapid access to blood transfusion services.

FUNDING

UK Medical Research Council, Wellcome, and UK National Institute for Health and Care Research.

Sickle Cell Disease and Its Respiratory Complications

Sickle cell disease (SCD) is a hematological disorder that is inherited in an autosomal recessive (AR) fashion. It is caused by mutations in the genes encoding for the globin apoprotein of hemoglobin (Hb), leading to diminished oxygen-carrying ability. Its pathophysiologic mechanism affects multiple organ systems, making it crucial to understand the complications of SCD and find the best ways to prevent and treat them. Some important ways that SCD manifests in the respiratory system are acute chest syndrome (ACS), pulmonary hypertension (PH), asthma, and venous thromboembolism (VTE). This article summarizes their salient features, including pathogenesis related to the adverse outcomes, screening practices, and management guidelines, with the intent to provide greater insight into forming better practices that increase the quality of life in SCD patients.

Economic burden of sickle cell disease in Brazil

Background

Sickle cell disease (SCD) may cause several impacts to patients and the whole society. About 4% of the population has the sickle cell trait in Brazil, and 60,000 to 100,000 have SCD. However, despite recognizing the significant burden of disease, little is known about SCD costs.

Objective

To estimate SCD societal costs based on disease burden modelling, under Brazilian societal perspective.

Methods

A disease burden model was built considering the societal perspective and a one-year time horizon, including direct medical and indirect costs (morbidity and mortality). The sum of life lost and disability years was considered to estimate disability-adjusted life years (DALYs). Data from a public database (DATASUS) and the prevalence obtained from literature or medical experts were used to define complications prevalence and duration. Costs were defined using data from the Brazilian public healthcare system table of procedures and medications (SIGTAP) and the human capital method.

Results

Annual SCD cost was 413,639,180 USD. Indirect cost accounted for the majority of burden (70.1% of the total; 290,158,365 USD vs 123,480,816 USD). Standard of care and chronic complications were the main source of direct costs among adults, while acute conditions were the main source among children. Vaso-occlusive crisis represented the complication with the highest total cost per year in both populations, 11,400,410 USD among adults and 11,510,960 USD among children.

Conclusions

SCD management may impose an important economic burden on Brazilian society that may reach more than 400 million USD per year.

Skills Capacity Building For Health Care Services and Research Through the Sickle Pan African Research Consortium

Skills development, the building of human capacity, is key to any sustainable capacity building effort, however, such undertakings require adaptable and tailored strategies. The Sickle Pan-African Research Consortium (SPARCo) is building capacity in sickle cell disease (SCD) management and research in sub-Saharan Africa, including a multi-national SCD patient registry, this is underpinned by skills development activities in data, research, and SCD management.

Method: The SPARCo Skills Working Group was set up with the mandate of coordinating skills development activities across the three SPARCo sites in Ghana, Nigeria and Tanzania. To tailor activities to the requirements of the consortium, a needs assessment was conducted at the start of the project which identified skills required for SCD management and research and catalogued existing external and internal training programmes. The needs assessment highlighted differences in skill levels between the sites and different organisational structures which required tailored skills development activities at individual, site and consortium levels.

Strategy: Based on the needs and the resources available, different types of training activities were implemented: these included online, blended and face to face activities. In order to create a sustainable skills development programme, existing short, medium, long-term, on-job training activities were used wherever possible. World Sickle Cell Day (19th June) was leveraged for training and health education activities.

Results: SPARCo has recorded 1,726 participants in skills development activities across the three sites. Skills have been enhanced in data management, SCD and research to underpin the core deliverables of SPARCo.

Conclusion and Lessons Learned: The baseline needs assessments and continual review and adjustment were critical for development of an effective skill development strategy for the consortium. This adaptability was particularly valuable during the COVID-19 pandemic. The sustainability plan leveraged existing programmes and activities and has created a pool of people with required skills for health care and research in SCD. To be effective, skills development programmes need to take into account existing capacity, training opportunities and local conditions. The model was applied to SCD and is adaptable to other skills development in healthcare and research in low and middle- income countries.

Addressing Severe Chronic NCDs Across Africa: Measuring Demand for the Package of Essential Noncommunicable Disease Interventions-Plus (PEN-Plus)

Severe chronic non-communicable diseases (NCDs) pose important challenges for health systems across Africa. This study explores the current availability of and demand for decentralization of services for four high-priority conditions: insulin-dependent diabetes, heart failure, sickle cell disease, and chronic pain. Ministry of Health NCD Programme Managers from across Africa (N = 47) were invited to participate in an online survey. Respondents were asked to report the status of clinical care across the health system. A care package including diagnostics and treatment was described for each condition. Respondents were asked whether the described services are currently available at primary, secondary and tertiary levels, and whether making the service generally available at that level is expected to be a priority in the coming 5 years. Thirty-seven (79%) countries responded. Countries reported widespread gaps in service availability at all levels. We found that just under half (49%) of respondents report that services for insulin-dependent diabetes are generally available at the secondary level (district hospital); 32% report the same for heart failure, 27% for chronic pain and 14% for sickle cell disease. Reported gaps are smaller at tertiary level (referral hospital) and larger at primary care level (health centres). Respondents report ambitious plans to introduce and decentralize these services in the coming 5 years. Respondents from 32 countries (86%) hope to make all services available at tertiary hospitals, and 21 countries (57%) expect to make all services available at secondary facilities. These priorities align with the Package of Essential NCD Interventions-Plus. Efforts will require strengthened infrastructure and supply chains, capacity building for staff and new monitoring and evaluation systems for efficient implementation. Many countries will need targeted financial assistance in order to realize these goals. Nearly all (36/37) respondents request technical assistance to organize services for severe chronic NCDs.

Evaluation of Microchip-Based Point-Of-Care Device "Gazelle" for Diagnosis of Sickle Cell Disease in India

Sickle cell disease is a major public health problem in India. Lack of rapid and reliable diagnostic methods result in many avoidable deaths in affected population. Current diagnostic tools are laboratory based, expensive and need trained manpower. Here, we evaluated the performance of a microchip-based cellulose acetate electrophoresis test, “Gazelle” in the tribal-dominated Indian states of Chhattisgarh and Madhya Pradesh. A total of 1,050 patients were screened by sickle cell solubility, hemoglobin (cellulose acetate) electrophoresis, high-performance liquid chromatography (HPLC) and Gazelle. Of the total 1,027 test results obtained, 960 tests were “Valid” (93.5%) and included in the analysis. Gazelle identified all patients with disease (HbSS and Thalassemia Major) with 100% accuracy. Gazelle demonstrated 100% sensitivity when comparing sickle cell disease (SCD) vs. sickle cell trait and SCD vs. normal. Specificity was 98.9% and 99.5% when comparing SCD vs. trait and trait vs. normal, respectively. Specificity was 99.8% when comparing SCD vs. normal and sensitivity was 99.3% when comparing trait vs. normal. Overall, Gazelle yielded a high accuracy (99.0%) compared to reference standard tests (hemoglobin electrophoresis and HPLC). Gazelle is a low-cost, rapid diagnostic test with high accuracy for detecting SCD both quantitatively and qualitatively. Gazelle can be a potential screening tool for the rapid diagnosis in resource limited settings and developing countries with high burden of hemoglobin disorders.

Prevalence and changes of anemia among young children and women in 47 low- and middle-income countries, 2000-2018

BACKGROUND

Anemia remains a major public health issue, particularly for children and women in low- and middle-income countries (LMICs). However, the current prevalence and recent changes of anemia among young children and women of reproductive age, particularly for pregnant women in different trimesters are unclear. We examined the current prevalence of anemia among children aged less than 5 years by age (6-35 months vs. 36-59 months) and women of reproductive age by pregnant status (pregnant vs. non-pregnant) and trimesters (the third vs. the second vs. the first trimester) between 2010 and 2018 and further examined changes in the prevalence from 2000-2009 to 2010-2018.

METHODS

Data were from the cross-sectional Demographic and Health Surveys performed between 2000 and 2018. A total of 47 countries were included to examine the current prevalence of anemia (weighted prevalence and 95% confidence interval [CI]) among young children aged less than 5 years (N = 459,785) and 46 countries among women of reproductive age (N = 1,079,805) between 2010 and 2018. To examine changes in the prevalence of anemia, a total of 29 countries with at least two Demographic and Health Surveys performed between 2000 and 2009 (children: N = 130,772; women: N = 371,845) and 2010-2018 (children: N = 386,202; women: N = 928,889) were included. Modified Poisson regression analyses with robust error variance were used to examine changes in anemia between 2000-2009 and 2010-2018 in participants by child age (6-5 months vs. 36-59 months), women pregnant status (pregnant vs. non-pregnant), trimesters (the second or third trimester vs. the first trimester) with the adjustment for potential covariates.

FINDINGS

In 47 LMICs for children aged less than 5 years between 2010 and 2018, the total prevalence of anemia was 56.5% (95% CI 56.2, 56.8). Younger children aged 6-35 months were more likely to have anemia than older children aged 36-59 months (adjusted odds ratio [OR] 1.38, 95% CI 1.36-1.39, P < 0.001). In 46 LMICs for women of reproductive age, the total prevalence was 40.4% (95% CI 40.1, 40.7). Pregnant women were more likely to have anemia than non-pregnant women (adjusted OR 1.14, 1.12-1.16, P < 0.001). Moreover, pregnant women in the third trimester (adjusted OR 1.55, 1.48-1.62, P < 0.001) and the second trimester (adjusted OR 1.51, 1.45-1.58, P < 0.001) were more likely to have anemia than those in the first trimester. Among 29 included countries, although there was a decreasing change (absolute change, relative change, and average annual rate of reduction) in young children and women between 2000-2009 and 2010-2018 in a majority of countries, the current prevalence of anemia remained at a high level.

INTERPRETATION

The prevalence of anemia among children aged less than 5 years and women of reproductive age was still high in LMICs, particularly for younger children and pregnant women. The relative change among women of reproductive age was far away from the WHO goal of reduction of anemia by 50% by 2025 (i.e., prevalence reduction to about 15.2% by 2025 from 30.3% at 2012 baseline). Continued and effective efforts, particularly for high-risk populations, are needed to improve the general health of the population.

FUNDING

Innovation Team of "Climbing" Program of Shandong University, and the Youth Team of Humanistic and Social Science of Shandong University (20820IFYT1902).

A retrospective case study of successful translational research: Gazelle Hb variant point-of-care diagnostic device for sickle cell disease

Evaluation researchers at Clinical and Translational Science Award (CTSA) hubs are conducting retrospective case studies to evaluate the translational research process. The objective of this study was to deepen knowledge of the translational process and identify contributors to successful translation. We investigated the successful translation of the HemeChip, a low-cost point-of-care diagnostic device for sickle cell disease, using a protocol for retrospective translational science case studies of health interventions developed by evaluators at the National Health Institutes (NIH) and CTSA hubs. Development of the HemeChip began in 2013 and evidence of device use and impact on public health is growing. Data collection methods included five interviews and a review of press, publications, patents, and grants. Barriers to translation included proving novelty, manufacturing costs, fundraising, and academic-industry relations. Facilitators to translation were CTSA pilot program funding, university resources, entrepreneurship training, due diligence, and collaborations. The barriers to translation, how they were overcome, and the key facilitators identified in this case study pinpoint areas for consideration in future funding mechanisms and the infrastructure required to enable successful translation.

Systemic T Cell Subsets and Cytokines in Patients With Homozygous Sickle Cell Disease and Asymptomatic Urinary Tract Infections in Togo

Background: In sickle cell disease (SCD), cytokine expression influences the pivotal pathways that contribute to disease pathogenesis. Additional infection could affect the immune profile of patients with SCD and increase disease mortality. The aim of this study was to investigate the cytokines and T helper cells profile in patients with asymptomatic urinary tract infection and homozygous SCD (HbSS).

Methods: From July to September 2018, 22 HbSS subjects were recruited at Centre Hospitalier Universitaire Campus in Lomé, Togo, 12 of whom had urinary tract bacterial infections and 10 of whom were uninfected. Cytokines from plasma were measured by the enzyme-linked immunosorbent assay (ELISA) sandwich method, and immune cell profiles were performed by flow cytometry. The immunogenicity of bacteria-derived antigens isolated from the urine of HbSS subjects with asymptomatic urinary tract infections was studied in a cell culture system, and the induction of the cytokines was measured.

Results: The mean age of HbSS subjects with urinary tract infections was 20.33 ± 3.58 years, and the male/female ratio was 0.09 (1:11). HbSS subjects with asymptomatic urinary tract infections had elevated plasma levels of interferon gamma (IFN-γ) and interleukin (IL)-10. CD4⁺Tbet⁺IFN-γ⁺ and CD4⁺FoxP3⁺IL-10⁺ T cell populations were decreased in HbSS subjects with asymptomatic urinary tract infections. Bacterial antigens from HbSS subjects induced the production of IL-10 but not IFN-γ in uninfected volunteer donors (HbAA).

Conclusion: Our study demonstrated that patients with SCD and asymptomatic urinary tract infections had elevated IFN-γ and IL-10 levels. This chronic inflammatory condition could be a risk for this group of patients in terms of vaso-occlusive crisis. Systematic cytobacteriologic examination of the urine of HbSS subjects would be of interest.

Sickle Cell Disease and the Respiratory System: A Tangential Perspective to the Hematopulmonological Dilemma

Sickle cell disease (SCD) is a genetically inherited hematological condition that predominantly affects the African-American subset of the population. It leads to the precipitation of multi-systematic manifestations throughout the course of the life of the patient leading to an increased rate of inpatient admissions and decreased quality of life. This article has reviewed some of the most common pulmonary complications of SCD with a brief overview of the clinical features and their management and has also highlighted the fatality of the complications placing a strong focus on screening, monitoring, and the treatment of the disease. The article has also discussed the management of SCD from a pulmonological perspective rather than hematological alone.

Genotypic Diversity among Angolan Children with Sickle Cell Anemia

Background. Sickle cell anemia (SCA) is an inherited blood disorder that affects over 300,000 newborns worldwide every year, being particularly prevalent in Sub-Saharan Africa. Despite being a monogenic disease, SCA shows a remarkably high clinical heterogeneity. Several studies have already demonstrated the existence of some polymorphisms that can provide major clinical benefits, producing a mild phenotype. Moreover, the existence of distinct haplotypes can also influence the phenotype patterns of certain populations, leading to different clinical manifestations. Our aim was to assess the association between polymorphisms in genes previously related to SCA disease severity in an Angolan pediatric population. Methods. This study analyzed clinical and biological data collected from 192 Angolan children. Using NGS data, we classified the HBB haplotypes based on four previously described SNPs (rs3834466, rs28440105, rs10128556, and rs968857) and the genotype for the SNPs in HBG2 (rs7482144), BCL11A (rs4671393, rs11886868, rs1427407, rs7557939), HBS1L-MYB (rs66650371) and BGLT3 (rs7924684) genes. Results. The CAR haplotype was undoubtedly the most common HBB haplotype in our population. The HbF values and the ratio of gamma chains were statistically significant for almost all of the variants studied. We reported for the first time an association between rs7924684 in the BGLT3 gene and gamma chains ratio. Conclusions. The current findings emphasize the importance personalized medicine would have if applied to SCA patient care, since some of the variants studied might predict the phenotype and the overall response to treatment.

COVID-19 and Vulnerable Populations in Sub-Saharan Africa

The novel corona virus 2019 (COVID-19) outbreak which started in Hubei province in China has now spread to every corner of the earth. While the pandemic started later in Africa, it is now found in all African countries to varying degrees. It is thought that the prevalence and severity of disease is influenced by a number of non-communicable diseases (NCDs) which are all becoming increasingly prevalent in sub-Saharan Africa (SSA). In addition, SSA bears the major burden of human immunodeficiency virus (HIV) and tuberculosis (TB) infections. While data from Europe and the United States show that children are spared severe disease, it is uncertain if the same holds true in SSA where children suffer from sickle cell disease and malnutrition in addition to other infectious diseases. There is limited data from Africa on the effects of these conditions on COVID-19. In this review, we discuss the epidemiology of some of these conditions in Africa and the possible pathogenesis for the interactions of these with COVID-19.

Xanthine Oxidase Drives Hemolysis and Vascular Malfunction in Sickle Cell Disease

OBJECTIVE

Chronic hemolysis is a hallmark of sickle cell disease (SCD) and a driver of vasculopathy; however, the mechanisms contributing to hemolysis remain incompletely understood. Although XO (xanthine oxidase) activity has been shown to be elevated in SCD, its role remains unknown. XO binds endothelium and generates oxidants as a byproduct of hypoxanthine and xanthine catabolism. We hypothesized that XO inhibition decreases oxidant production leading to less hemolysis. Approach and Results: Wild-type mice were bone marrow transplanted with control (AA) or sickle (SS) Townes bone marrow. After 12 weeks, mice were treated with 10 mg/kg per day of febuxostat (Uloric), Food and Drug Administration-approved XO inhibitor, for 10 weeks. Hematologic analysis demonstrated increased hematocrit, cellular hemoglobin, and red blood cells, with no change in reticulocyte percentage. Significant decreases in cell-free hemoglobin and increases in haptoglobin suggest XO inhibition decreased hemolysis. Myographic studies demonstrated improved pulmonary vascular dilation and blunted constriction, indicating improved pulmonary vasoreactivity, whereas pulmonary pressure and cardiac function were unaffected. The role of hepatic XO in SCD was evaluated by bone marrow transplanting hepatocyte-specific XO knockout mice with SS Townes bone marrow. However, hepatocyte-specific XO knockout, which results in >50% diminution in circulating XO, did not affect hemolysis levels or vascular function, suggesting hepatocyte-derived elevation of circulating XO is not the driver of hemolysis in SCD.

CONCLUSIONS

Ten weeks of febuxostat treatment significantly decreased hemolysis and improved pulmonary vasoreactivity in a mouse model of SCD. Although hepatic XO accounts for >50% of circulating XO, it is not the source of XO driving hemolysis in SCD.

Predictors of outcome in childhood Plasmodium falciparum malaria

Plasmodium falciparum malaria is classified as either uncomplicated or severe, determining clinical management and providing a framework for understanding pathogenesis. Severe malaria in children is defined by the presence of one or more features associated with adverse outcome, but there is wide variation in the predictive value of these features. Here we review the evidence for the usefulness of these features, alone and in combination, to predict death and other adverse outcomes, and we consider the role that molecular biomarkers may play in augmenting this prediction. We also examine whether a more personalized approach to predicting outcome for specific presenting syndromes of severe malaria, particularly cerebral malaria, has the potential to be more accurate. We note a general need for better external validation in studies of outcome predictors and for the demonstration that predictors can be used to guide clinical management in a way that improves survival and long-term health.

What is the future of patient-reported outcomes in sickle-cell disease?

INTRODUCTION

Sickle cell disease (SCD) is a complex, chronic disease caused by abnormal polymerization of hemoglobin, which leads to severe pain episodes, fatigue, and end-organ damage. Patient reported outcomes (PROs) have emerged as a critical tool for measuring SCD disease severity and response to treatment.

AREAS COVERED

Authors review the key issues involved when deciding to use a PRO in a clinical trial. We describe the most highly recommended generic and disease-specific PRO tools in SCD and discuss the challenges of incorporating them in clinical practice.

EXPERT OPINION

PRO measures are essential to incorporate into SCD clinical trials either as primary or secondary outcomes. The use of PRO measures in SCD facilitates a patient-centered approach, which is likely to lead to improved outcomes. Significant challenges remain in adapting PRO tools to routine clinical use and in developing countries.

Parental Notification Via Text Messaging for Infant Sickle Screening Programs: Exploration of Feasibility and Acceptability in Uganda

Sickle cell disease (SCD) in Africa has high prevalence, morbidity, and early mortality. Difficulties in reaching parents following infant SCD screening dampen program effectiveness. Text messaging may support initial postscreening parental notification. We explored SCD awareness, and feasibility and acceptability of text messaging about screening follow-up among convenience samples of caretakers with children under 5 years (n=115) at 3 sites: a SCD family conference or 2 general pediatric clinics in urban or rural Uganda. Two thirds of the conference-based participants and 8% at clinic sites had affected children. At the clinics, 64% of caretakers were aware of SCD. In all, 87% claimed current possession of mobile phones; 89% previously had received messages. A sample text on the availability of screening results and need to bring their child to SCD clinic was at least partially understood by 82%. Overall, 52% preferred communication for initial follow-up by telephone over text message. Concerns about texting included phone access, privacy or cost, and readability of messages. Caretakers identified concerns about distance, cost, or preference for another clinic as additional barriers to SCD follow-up. Findings suggest that text messaging to caretakers may be feasible, but less acceptable compared with a telephone call about initial follow-up from newborn SCD screening.

End points for sickle cell disease clinical trials: renal and cardiopulmonary, cure, and low-resource settings

To address the global burden of sickle cell disease and the need for novel therapies, the American Society of Hematology partnered with the US Food and Drug Administration to engage the work of 7 panels of clinicians, investigators, and patients to develop consensus recommendations for clinical trial end points. The panels conducted their work through literature reviews, assessment of available evidence, and expert judgment focusing on end points related to patient-reported outcome, pain (non-patient-reported outcomes), the brain, end-organ considerations, biomarkers, measurement of cure, and low-resource settings. This article presents the findings and recommendations of the end-organ considerations, measurement of cure, and low-resource settings panels as well as relevant findings and recommendations from the biomarkers panel.

Co-Inheritance of alpha-thalassemia and sickle cell disease in a cohort of Angolan pediatric patients

The aim of this study was to explore the association between alpha-thalassemia, fetal hemoglobin, hematological indices, and clinical adverse events in Angolan sickle cell disease pediatric patients. A total of 200 sickle cell disease (SCD) children were sampled in Luanda and Caxito. A venous blood sample was collected and used for hematological analyses, fetal hemoglobin quantification, and genotyping of 3.7 kb alpha-thalassemia deletion by GAP-PCR. The frequency of the 3.7 kb alpha-thalassemia deletion in homozygosity was 12.5% and in heterozygosity was 55.0%. An increase in alpha-thalassemia frequency was observed in children older than 5 years old (11.7% vs. 13.00%). Furthermore, 3.7 kb alpha-thalassemia deletion homozygotes had a significantly higher age of the first manifestation, lower number of blood transfusions by year, higher hemoglobin, lower mean corpuscular volume, mean corpuscular hemoglobin, and lower hemolytic rate observed by a lower number of reticulocytes count. There were no differences in fetal hemoglobin between the three genotypes. Moreover, the number of stroke events, osteomyelitis, splenomegaly, splenectomy, and hepatomegaly were lower when alpha-thalassemia was co-inherited. For the first time in Angolan population, the effect of alpha-thalassemia deletion in sickle cell disease was analyzed and results reinforce that this trait influences the hematological and clinical aspects and produces a milder phenotype.

Emerging therapies in sickle cell disease

Despite sickle cell disease (SCD) being the most common and severe inherited condition worldwide, therapeutic options are limited. To date, hydroxyurea remains the main treatment option in SCD. However, in the last decade the numbers of interventional clinical trials focussing on therapies for SCD have increased significantly. Many new drugs with various pharmacological targets have emerged and, although the majority have failed to show benefit in clinical trials, some have produced encouraging results. It seems probable that more drugs will soon become available for the treatment of SCD. Furthermore, promising clinical trials with improved outcomes have recently changed the perspective of curative therapies in SCD. Nevertheless, the application of novel therapeutic agents and potential curative treatments will most likely be limited to high-income countries and, thus, will remain unavailable for the majority of people with SCD in the foreseeable future.

Paper-based microchip electrophoresis for point-of-care hemoglobin testing

Nearly 7% of the world's population live with a hemoglobin variant. Hemoglobins S, C, and E are the most common and significant hemoglobin variants worldwide. Sickle cell disease, caused by hemoglobin S, is highly prevalent in sub-Saharan Africa and in tribal populations of Central India. Hemoglobin C is common in West Africa, and hemoglobin E is common in Southeast Asia. Screening for significant hemoglobin disorders is not currently feasible in many low-income countries with the high disease burden. Lack of early diagnosis leads to preventable high morbidity and mortality in children born with hemoglobin variants in low-resource settings. Here, we describe HemeChip, the first miniaturized, paper-based, microchip electrophoresis platform for identifying the most common hemoglobin variants easily and affordably at the point-of-care in low-resource settings. HemeChip test works with a drop of blood. HemeChip system guides the user step-by-step through the test procedure with animated on-screen instructions. Hemoglobin identification and quantification is automatically performed, and hemoglobin types and percentages are displayed in an easily understandable, objective way. We show the feasibility and high accuracy of HemeChip via testing 768 subjects by clinical sites in the United States, Central India, sub-Saharan Africa, and Southeast Asia. Validation studies include hemoglobin E testing in Bangkok, Thailand, and hemoglobin S testing in Chhattisgarh, India, and in Kano, Nigeria, where the sickle cell disease burden is the highest in the world. Tests were performed by local users, including healthcare workers and clinical laboratory personnel. Study design, methods, and results are presented according to the Standards for Reporting Diagnostic Accuracy (STARD). HemeChip correctly identified all subjects with hemoglobin S, C, and E variants with 100% sensitivity, and displayed an overall diagnostic accuracy of 98.4% in comparison to reference standard methods. HemeChip is a versatile, mass-producible microchip electrophoresis platform that addresses a major unmet need of decentralized hemoglobin analysis in resource-limited settings.

Rational Drug Design of Peptide-Based Therapies for Sickle Cell Disease

Sickle cell disease (SCD) is a group of inherited disorders affecting red blood cells, which is caused by a single mutation that results in substitution of the amino acid valine for glutamic acid in the sixth position of the β-globin chain of hemoglobin. These mutant hemoglobin molecules, called hemoglobin S, can polymerize upon deoxygenation, causing erythrocytes to adopt a sickled form and to suffer hemolysis and vaso-occlusion. Until recently, only two drug therapies for SCD, which do not even fully address the manifestations of SCD, were approved by the United States (US) Food and Drug Administration. A third treatment was newly approved, while a monoclonal antibody preventing vaso-occlusive crises is also now available. The complex nature of SCD manifestations provides multiple critical points where drug discovery efforts can be and have been directed. These notwithstanding, the need for new therapeutic approaches remains high and one of the recent efforts includes developments aimed at inhibiting the polymerization of hemoglobin S. This review focuses on anti-sickling approaches using peptide-based inhibitors, ranging from individual amino acid dipeptides investigated 30–40 years ago up to more promising 12- and 15-mers under consideration in recent years.

Nursing students and nurses' knowledge and attitudes regarding children's pain: A comparative cross-sectional study

INTRODUCTION

Nurses encounter children who report of pain of diverse and unknown causes in their professional work. The current study therefore assessed and compared nursing students and nurses' knowledge and attitudes pertaining to children's pain in the Ghanaian context. The goal of this was to have a baseline information to guide the development and implementation of the content for a sustainable educational programme (short-course) for nursing students and nurses in Ghana.

METHODS

Between October and December 2018, a cross-sectional study was carried out among 554 final year nursing students and 65 nurses in Ghana. The Pediatric Nurses Knowledge and Attitudes Survey Regarding Pain (PNKAS) was used to collect data from participants who were affiliated to four educational institutions and eight hospitals. Data were descriptively and inferentially analyzed using chi-square test of independence, independent samples t-test and one-way analysis of variance (ANOVA).

RESULTS

Our findings revealed that nursing students and nurses generally had unsatisfactory knowledge and attitudes towards pain management in children. Nursing students however, had significantly higher scores than nurses in the total PNKAS score and in 10 out of the 13 identified item-areas. Greater scores were obtained by nursing students in areas which were related to pain physiology, pharmacokinetics, pharmacology of analgesics and pain perceptions (p < .05). All the participating nurses could not accurately determine: the onset of action of orally administered analgesics, equianalgesia of orally administered morphine, and the right dosage of prescribed morphine for a child who consistently reported of moderate to severe pain.

CONCLUSION

Final year nursing students and nurses have unsatisfactory knowledge and attitudes regarding children's pain; which reiterates the need for urgent and effective educational efforts in this area. Regular in-service training should be offered to post-registration nurses to enhance their pediatric pain knowledge and attitudes for improved pain care in children.

The epidemiology of sickle cell disease in children recruited in infancy in Kilifi, Kenya: a prospective cohort study

BACKGROUND

Sickle cell disease is the most common severe monogenic disorder in humans. In Africa, 50-90% of children born with sickle cell disease die before they reach their fifth birthday. In this study, we aimed to describe the comparative incidence of specific clinical outcomes among children aged between birth and 5 years with and without sickle cell disease, who were resident within the Kilifi area of Kenya.

METHODS

This prospective cohort study was done on members of the Kilifi Genetic Birth Cohort Study (KGBCS) on the Indian Ocean coast of Kenya. Recruitment to the study was facilitated through the Kilifi Health and Demographic Surveillance System (KHDSS), which covers a resident population of 260 000 people, and was undertaken between Jan 1, 2006, and April 30, 2011. All children who were born within the KHDSS area and who were aged 3-12 months during the recruitment period were eligible for inclusion. Participants were tested for sickle cell disease and followed up for survival status and disease-specific admission to Kilifi County Hospital by passive surveillance until their fifth birthday. Children with sickle cell disease were offered confirmatory testing and care at a dedicated outpatient clinic.

FINDINGS

15 737 infants were recruited successfully to the KGBCS, and 128 (0·8%) of these infants had sickle cell disease, of whom 70 (54·7%) enrolled at the outpatient clinic within 12 months of recruitment. Mortality was higher in children with sickle cell disease (58 per 1000 person-years of observation, 95% CI 40-86) than in those without sickle cell disease (2·4 per 1000 person-years of observation, 2·0-2·8; adjusted incidence rate ratio [IRR] 23·1, 95% CI 15·1-35·3). Among children with sickle cell disease, mortality was lower in those who enrolled at the clinic (adjusted IRR 0·26, 95% CI 0·11-0·62) and in those with higher levels of haemoglobin F (HbF; adjusted IRR 0·40, 0·17-0·94). The incidence of admission to hospital was also higher in children with sickle cell disease than in children without sickle cell disease (210 per 1000 person-years of observation, 95% CI 174-253, vs 43 per 1000 person-years of observation, 42-45; adjusted IRR 4·80, 95% CI 3·84-6·15). The most common reason for admission to hospital among those with sickle cell disease was severe anaemia (incidence 48 per 1000 person-years of observation, 95% CI 32-71). Admission to hospital was lower in those with a recruitment HbF level above the median (IRR 0·43, 95% CI 0·24-0·78; p=0·005) and those who were homozygous for α-thalassaemia (0·07, 0·01-0·83; p=0·035).

INTERPRETATION

Although morbidity and mortality were high in young children with sickle cell disease in this Kenyan cohort, both were reduced by early diagnosis and supportive care. The emphasis must now move towards early detection and prevention of long-term complications of sickle cell disease.

FUNDING

Wellcome Trust.

The clinical characteristics of Congolese children and adolescents suffering from sickle-cell anemia are marked by the high frequencies of epistaxis compared to Western series

Background: Sickle cell anaemia (SCA) is the most common genetic diseases in the Democratic Republic of Congo (DRC). It is estimated 30,000 to 40,000 neonates with SCA are born annually. Despite this high incidence rate, and the severity of the Bantu haplotype found in Congolese patients, major clinical characteristics remain poorly defined. The objective of this study was to assess the clinical and haematological profile of the SCA in patients less than 24 years of age. Methods: A cross-sectional study was conducted in Kinshasa, the large city of the DRC. Patients were consecutively selected in three health institutions. Results: The study includes 256 sickle cell patients. The mean age of 8.4 (SD = 4.9) years. The Hand-foot syndrome was most common (52.7%) first presentation revealing the disease in our series. The most prevalent crises found in our series were vaso-occlusive crises (VOC) in 170 cases (66.4%) and severe hemolysis in 136 cases (53.1%). Splenic sequestration was noted in 19 cases (7.4%). The age at the first pain crisis was 18.2±15.2 months-of-age and the age at the first transfusions was 29.2±27.6 months-of -age. The most common signs associated with sickle cell disease in our series were hepatomegaly (53.9%), splenomegaly (41.7%), and adenotonsillar hypertrophy (34.8%). Epistaxis was reported in 9.4%. Conclusion: The clinical course of patients in DRC was comparable to reports from Western countries, with the notable exception of epistaxis which was significantly higher in patients in the DRC.

Collider bias and the apparent protective effect of glucose-6-phosphate dehydrogenase deficiency on cerebral malaria

Case fatality rates in severe falciparum malaria depend on the pattern and degree of vital organ dysfunction. Recent large-scale case-control analyses of pooled severe malaria data reported that glucose-6-phosphate dehydrogenase deficiency (G6PDd) was protective against cerebral malaria but increased the risk of severe malarial anaemia. A novel formulation of the balancing selection hypothesis was proposed as an explanation for these findings, whereby the selective advantage is driven by the competing risks of death from cerebral malaria and death from severe malarial anaemia. We re-analysed these claims using causal diagrams and showed that they are subject to collider bias. A simulation based sensitivity analysis, varying the strength of the known effect of G6PDd on anaemia, showed that this bias is sufficient to explain all of the observed association. Future genetic epidemiology studies in severe malaria would benefit from the use of causal reasoning.

Utilising the 'Getting to Outcomes®' Framework in Community Engagement for Development and Implementation of Sickle Cell Disease Newborn Screening in Kaduna State, Nigeria

BACKGROUND

Sickle Cell Disease (SCD) has been designated by WHO as a public health problem in sub-Saharan Africa, and the development of newborn screening (NBS) is crucial to the reduction of high SCD morbidity and mortality. Strategies from the field of implementation science can be useful for supporting the translation of NBS evidence from high income countries to the unique cultural context of sub-Saharan Africa. One such strategy is community engagement at all levels of the healthcare system, and a widely-used implementation science framework, "Getting to Outcomes^®" (GTO), which incorporates continuous multilevel evaluation by stakeholders about the quality of the implementation.

OBJECTIVES

(1) to obtain critical information on potential barriers to NBS in the disparate ethnic groups and settings (rural and urban) in the healthcare system of Kaduna State in Nigeria; and, (2) to assist in the readiness assessment of Kaduna in the implementation of a sustainable NBS programme for SCD.

METHODS

Needs assessment was conducted with stakeholder focus groups for two days in Kaduna state, Nigeria, in November 2017.

RESULTS

The two-day focus group workshop had a total of 52 participants. Asking and answering the 10 GTO accountability questions provided a structured format to understand strengths and weaknesses in implementation. For example, we found a major communication gap between policy-makers and user groups.

CONCLUSION

In a two-day community engagement workshop, stakeholders worked successfully together to address SCD issues, to engage with each other, to share knowledge, and to prepare to build NBS for SCD in the existing healthcare system.

Anaemia and malaria

Malaria is a major cause of anaemia in tropical areas. Malaria infection causes haemolysis of infected and uninfected erythrocytes and bone marrow dyserythropoiesis which compromises rapid recovery from anaemia. In areas of high malaria transmission malaria nearly all infants and young children, and many older children and adults have a reduced haemoglobin concentration as a result. In these areas severe life-threatening malarial anaemia requiring blood transfusion in young children is a major cause of hospital admission, particularly during the rainy season months when malaria transmission is highest. In severe malaria, the mortality rises steeply below an admission haemoglobin of 3 g/dL, but it also increases with higher haemoglobin concentrations approaching the normal range. In the management of severe malaria transfusion thresholds remain uncertain. Prevention of malaria by vector control, deployment of insecticide-treated bed nets, prompt and accurate diagnosis of illness and appropriate use of effective anti-malarial drugs substantially reduces the burden of anaemia in tropical countries.

The clinical epidemiology of sickle cell anemia In Africa

Sickle cell anemia (SCA) is the commonest severe monogenic disorders of humans. The disease has been highly characterized in high‐income countries but not in sub‐Saharan Africa where SCA is most prevalent. We conducted a retrospective cohort study of all children 0–13 years admitted from within a defined study area to Kilifi County Hospital in Kenya over a five‐year period. Children were genotyped for SCA retrospectively and incidence rates calculated with reference to population data. Overall, 576 of 18,873 (3.1%) admissions had SCA of whom the majority (399; 69.3%) were previously undiagnosed. The incidence of all‐cause hospital admission was 57.2/100 person years of observation (PYO; 95%CI 52.6–62.1) in children with SCA and 3.7/100 PYO (95%CI 3.7–3.8) in those without SCA (IRR 15.3; 95%CI 14.1–16.6). Rates were higher for the majority of syndromic diagnoses at all ages beyond the neonatal period, being especially high for severe anemia (hemoglobin <50 g/L; IRR 58.8; 95%CI 50.3–68.7), stroke (IRR 486; 95%CI 68.4–3,450), bacteremia (IRR 23.4; 95%CI 17.4–31.4), and for bone (IRR 607; 95%CI 284–1,300), and joint (IRR 80.9; 95%CI 18.1–362) infections. The use of an algorithm based on just five clinical features would have identified approximately half of all SCA cases among hospital‐admitted children with a number needed to test to identify each affected patient of only fourteen. Our study illustrates the clinical epidemiology of SCA in a malaria‐endemic environment without specific interventions. The targeted testing of hospital‐admitted children using the Kilifi Algorithm provides a pragmatic approach to early diagnosis in high‐prevalence countries where newborn screening is unavailable.

The frequency and severity of epistaxis in children with sickle cell anaemia in eastern Uganda: a case-control study

Background

There are a paucity of data on epistaxis as it pertains to sickle cell anaemia. Some case studies suggest epistaxis to be a significant complication in patients with sickle cell anaemia in sub-Saharan Africa; however, no robust studies have sought to establish the epidemiology or pathophysiology of this phenomenon.

Methods

We conducted a case-control study with the aim of investigating the importance of epistaxis among children presenting with sickle cell anaemia at the Mbale Regional Referral Hospital in eastern Uganda. Cases were children aged 2–15 years with an existing diagnosis of laboratory confirmed sickle cell anaemia, while controls were children without sickle cell anaemia who were frequency matched to cases on the basis of age group and gender. The frequency and severity of epistaxis was assessed using a structured questionnaire developed specifically for this study. Odds ratios controlled for age group and gender were calculated using unconditional logistic regression.

Results

A total of 150 children were included, 73 children with sickle cell anaemia and 77 children without sickle cell anaemia. The overall prevalence of epistaxis among children with sickle cell anaemia and children without sickle cell anaemia was 32.9 and 23.4% respectively. The case-control odds ratios for epistaxis, recurrent epistaxis and severe epistaxis were, 1.6 (95%CI 0.8–3.4; p = 0.2), 7.4 (1.6–34.5; 0.01), and 8.3 (1.0–69.8; 0.05) respectively.

Conclusions

Our results suggest that in eastern Uganda, children with sickle cell anaemia experience epistaxis more frequently and with greater severity than children without sickle cell anaemia. Further studies are indicated to confirm this conclusion and investigate aetiology.

Efficacy and Safety of Manual Partial Red Cell Exchange in the Management of Severe Complications of Sickle Cell Disease in a Developing Country

Introduction

The realization of red cell exchange (RCE) in Africa faces the lack of blood, transfusion safety, and equipment. We evaluated its efficacy and safety in severe complications of sickle cell disease.

Patients and Method

Manual partial RCE was performed among sickle cell patients who had severe complications. Efficacy was evaluated by clinical evolution, blood count, and electrophoresis of hemoglobin. Safety was evaluated on adverse effects, infections, and alloimmunization.

Results

We performed 166 partial RCE among 44 patients including 41 homozygous (SS) and 2 heterozygous composites SC and 1 S/β0-thalassemia. The mean age was 27.9 years. The sex ratio was 1.58. The regression of symptoms was complete in 100% of persistent vasoocclusive crisis and acute chest syndrome, 56.7% of intermittent priapism, and 30% of stroke. It was partial in 100% of leg ulcers and null in acute priapism. The mean variations of hemoglobin and hematocrit rate after one procedure were, respectively, +1.4 g/dL and +4.4%. That of hemoglobin S after 2 consecutive RCE was −60%. Neither alloimmunization nor viral seroconversion was observed.

Conclusion

This work shows the feasibility of manual partial RCE in a low-resource setting and its efficacy and safety during complications of SCD outside of acute priapism.