Sickle cell disease among children in Africa: An integrative literature review and global recommendations

Bone Disease among Children with Sickle Cell Disease: A Scoping Review of Incidence and Interventions

Background

Children with sickle cell disease (SCD) are more likely to have deficient serum levels of vitamin D for bone metabolism. However, appropriate interventions are essential to prevent its progression and alleviate symptoms.

Purpose

The aim of this study is to determine interventions for managing bone disease in children with SCD.

Methods

This study uses a scoping review. A literature review was conducted using PubMed, CINAHL, ScienceDirect, Scopus, and Google Scholar search engines. The study was eligible for inclusion if it included articles published from 2013 to 2023, full-text, and original study design. Study quality was assessed using the Joanna Briggs Institute (JBI) appraisal tool.

Results

This review identified six studies and 114 children with SCD, including 57 boys (50%) and 57 girls (50%). The majority of SCD types experienced were HbSS (86.84%), HbS-B0 Thal (7.01%), HbSC (5.27%), and the HbSS Arab-Indian haplotype (0.88%). Bone disease problems that often arise in children with SCD include Avascular Necrosis (AVN) (78.08%), Osteonecrosis of the Femoral Head (ONFH) (18.42%), and other bone problems (3.50%). Meanwhile, four types of intervention findings were used in managing bone disease among children with SCD: 1). Surgical procedures 53 (41.09%) included total hip arthroplasty (THA), Osteotomy, and Multiple epiphyseal drilling with Autologous Bone Marrow Implantation (AMBI); 2). Invasive procedures 67 (51.93%) included intravenous bisphosphonates, hydroxyurea (HU), and core decompression (CD) with bone marrow aspirate concentrate injection: 3). Oral pharmacological or Vitamin D3 (cholecalciferol) 4 (3.10%); 4). Non-pharmacology or physical therapy 5 (3.88%).

Conclusion

Our findings highlight that surgical, invasive, pharmacological, and physical therapy interventions positively impact increasing bone mineral density (BMD) and functional improvement of bone disease among children with SCD. The interventions provided excellent functional outcomes with minimal complications and no life-threatening side effects.

Update on the practice of premarital screening for sickle cell traits in Africa: a systematic review and meta-analysis

BACKGROUND

Screening for sickle cell traits before marriage or producing children is one of the outstanding preventive measures for sickle cell disease (SCD).The disease is a collection of inherited blood disorders that impact millions globally, with a predominant 75% occurrence in the sub-Saharan region. With increasing burden of SCD on the continent amidst a cost effective prevention method, no study has systematically reviewed or presented meta-analytic uptake or practice of premarital sickle cell trait screening.

METHODS

This review systematically explored the uptake or practice of premarital genotype screening in Africa. We searched PubMed and Scopus databases for African studies on premarital screening for sickle cell traits.

RESULTS

Our results indicate that the pooled uptake of premarital sickle cell trait screening in Africa is 47.82% (95% CI: [46.53-49.11]; I2: 98.95% [98.74-99.13]). Our review observed, a significant relationship between the awareness of sickle cell disease and the uptake of genotype screening; F(1, 13) = 12.04, p = 0.004). The model explained approximately 48.08% of the variation in genotype screening (R² = 0.4808) and predicted a 0.729 increase in the likelihood of genotype screening uptake for every unit rise in sickle cell disease awareness (β = 0.729, p = 0.004). Additionally, Pearson correlation (r = 0.6934) indicated a moderately strong positive correlation between the two variables.

CONCLUSION

With over 75% of the global burden of sickle cell disease domiciled in Africa, the continent cannot overlook the cost of hemoglobinopathies. The uptake of sickle cell traits screening is suboptimal across the continent. To achieve the mandate of sustainable development goal number (3); to end preventable deaths of newborns and children under 5 years of age by 2030, there is need to intensify campaigns on premarital genetic screening through education and other health promotion tools.

Health education to promote knowledge about sickle cell disease and newborn screening in pregnant women: a community-based pilot study using the healthy beginning initiative

BACKGROUND

Pregnancy presents a critical period for any maternal and child health intervention that may impact the health of the newborn. With low antenatal care attendance by pregnant women in health facilities in Nigeria, community-based programs could enable increased reach for health education about sickle cell disease (SCD) and newborn screening (NBS) among pregnant women. This pilot study aimed to assess the effect of education on the knowledge about SCD and NBS among pregnant women using the Healthy Beginning Initiative, a community-based framework.

METHODS

A pre-post study design was used to evaluate knowledge of SCD and NBS in a convenience sample of 89 consenting pregnant women from three communities. Participants were given surveys prior to and following completion of a health education session. McNemar's test was used to compare the proportion of participants with correct responses. The level of significance was taken as p < 0.05.

RESULTS

Compared to pre-test values, post-test values showed that participants understood that SCD is hereditary (93.3% vs. 69.7%), both parents must have at least one gene for someone to have SCD (98.9% vs. 77.5) and blood test is the right way to know if one has SCD (98.8% vs. 78.7%). Also, a large proportion of participants (post-test ~ 89.9%; compared to pre-test ~ 23.6%) understood that the chance of conceiving a child with SCD was 25% for a couple with the sickle cell trait (SCT). Knowledge of the possibility of diagnosing SCD shortly after birth was highly increased in the post test phase of the study when compared to the pre-test phase (93.3% vs. 43.9%, respectively). Concerning the overall knowledge scores, those with high level of knowledge significantly increase from 12.6% pretest to 87.4% posttest (p = 0.015).

CONCLUSION

The health education intervention was associated with significant improvement on almost all measures of SCD knowledge. Focused health education for pregnant women using community structures can improve knowledge of SCD and NBS.

Differential expression of adhesion molecules in sickle cell anemia and gut microbiome effect

Sickle cell anemia (SCA) causes a long-standing vascular inflammation state, leading to endothelial dysfunction and chronic overexpression of several adhesion molecules, which contributes to acute and constant vaso-occlusive (VOC) episodes. It has been demonstrated that hydroxyurea (HU) can reduce VOC events, organ damage, blood transfusions, and even the adhesion properties to endothelial cells of SCA subjects. Due to VOC episodes, these patients are also more susceptible to recurrent bacterial translocation and dysbiosis. Given this, our study aimed to uncover the interplay between adhesion molecules, gut microbiome, and hydroxyurea in a population of Angolan SCA children. Serum and fecal samples were obtained before and after HU treatment in 35 children. After HU, four of these adhesion molecules were significantly reduced: sE-selectin (p = 0.002), ADAMTS13 (p = 0.023), sICAM-1 (p = 0.003), and sVCAM-1 (p = 0.018). A positive correlation was observed between the number of neutrophils and sICAM-1, platelets, and sP-selectin, and also between leukocytes, sICAM-1, and sVCAM-1. Most taxa showing a significant correlation mainly belonged to the Clostridiales order. Specifically, from the Clostridium genera, the groups g19, g21, and g34 were all negatively correlated with HbF levels; g19, g21, and g24 positively correlated with leukocytes; g19 positively with neutrophils and sVCAM-1; and g34 positively with E- and P-selectin. Serratia, an opportunistic pathogen, was positively correlated with sE-selectin and sICAM-1 levels. Additionally, a negative correlation was observed between sP-selectin and Bifidobacterium. Research studies in this area could improve our understanding and contribute to finding new prognostic biomarkers to guarantee precise SCA patient stratification and predict severe complications.

Caught between pity, explicit bias, and discrimination: a qualitative study on the impact of stigma on the quality of life of persons living with sickle cell disease in three African countries

PURPOSE

Sickle cell disease (SCD) is an inherited blood disorder characterized by unpredictable episodes of acute pain and numerous health complications. Individuals with SCD often face stigma from the public, including perceptions that they are lazy or weak tending to exaggerate their pain crisis, which can profoundly impact their quality of life (QoL).

METHODS

In a qualitative phenomenological study conducted in Cameroon, Ghana, and Tanzania, we explored stakeholders' perceptions of SCD-related stigma using three analytical frameworks: Bronfenbrenner's Ecological Systems Theory; The Health Stigma and Discriminatory Framework; and A Public Health Framework for Reducing Stigma.

RESULTS

The study reveals that SCD-related stigma is marked by prejudice, negative labelling and social discrimination, with derogatory terms such as sickler, ogbanje (one who comes and goes), sika besa (money will finish), ene mewu (I can die today, I can die tomorrow), vampire (one who consumes human blood), and Efiewura (landlord-of the hospital), commonly used to refer to individuals living with SCD. Drivers of stigma include frequent crises and hospitalizations, distinct physical features of individuals living with SCD, cultural misconceptions about SCD and its association with early mortality. Proposed strategies for mitigating stigma include public health education campaigns about SCD, integrating SCD into school curricula, healthcare worker training and community engagement.

CONCLUSION

The results highlight the importance of challenging stigmatizing narratives on SCD and recognizing that stigmatization represents a social injustice that significantly diminishes the QoL of individuals living with SCD.

Overview of the Association Between the Pathophysiology, Types, and Management of Sickle Cell Disease and Stroke

Sickle cell disease (SCD) is a genetic blood disorder that affects hemoglobin and increases stroke risk, particularly in childhood. This review examines the pathophysiological association between SCD and stroke, the classification of stroke types, risk factors, diagnosis, management, prevention, and prognosis. A comprehensive literature search was conducted via PubMed, Scopus, and Cochrane databases. Relevant studies on SCD and stroke pathophysiology, classification, epidemiology, diagnosis, treatment, and prevention were identified. Sickle cell disease causes red blood cells to become rigid and sickle-shaped, obstructing blood vessels. Recurrent sickling alters cerebral blood flow and damages vessel walls, often leading to ischemic or hemorrhagic strokes (HS). These occur most frequently in childhood, with ischemic strokes (IS) being more common. Key risk factors include a prior transient ischemic attack (TIA), low hemoglobin, and a high leukocyte count. Neuroimaging is essential for diagnosis and determining stroke type. Primary prevention centers on blood transfusions and hydroxyurea for those at high risk. Acute treatment involves promptly restoring blood flow and managing complications. However, significant knowledge gaps remain regarding stroke mechanisms, optimizing screening protocols, and improving long-term outcomes. This review synthesizes current evidence on SCD and stroke to highlight opportunities for further research and standardizing care protocols across institutions. Ultimately, a holistic perspective is critical for mitigating the high risk of debilitating strokes in this vulnerable patient population.

Assessment of depression in children and adolescents with sickle cell anemia in a low-resource setting: a comparative study

Children with sickle cell anemia (SCA) usually face psychological complications especially depression. Assessment of depression in resource-limited settings may help identify the extent to which the children with SCA in such settings may need its introduction as part of routine care. This study aimed to assess depression in children and adolescents with SCA in a low-resource setting. This cross-sectional observational study involved 84 children and adolescents with SCA aged 7-17 years who were selected using a systematic random sampling technique. Their controls were 84 age- and sex-matched individuals with AA hemoglobin genotype. A structured questionnaire was used to collect socio-demographic data while depression was assessed with the Children's Depression Inventory. The prevalence of depression was non-significantly higher in subjects compared to the controls (8.3% vs. 2.4%) (Fisher's χ² = 1.88, p = 0.171). Though not statistically significant, the subjects had 3.7 times higher odds of having depression compared to the controls (OR = 3.7; 95% CI 0.75-18.50; p = 0.107). Of the 5 depression subscales, the subjects had a significantly higher difference in the negative mood (p = 0.042). Despite the comparable prevalence of depression with their normal controls, children and adolescents with SCA had a higher negative mood and higher odds of having depression than normal individuals. Thus, there is a need for the introduction of depression assessment as a complement to routine care of these children with SCA in resource-poor settings.

The prevalence of hemoglobin Tacoma in Finland detected by HbA1c capillary electrophoresis

Previous studies have identified occasional cases of heterozygous Hb Tacoma in areas that have attracted Finnish immigrants, especially in Sweden and North America, but large studies of this slightly unstable beta variant in vitro have not been carried out. Here we determined the prevalence of hemoglobin variants across Finland. A total of 5059 samples from 11 different hospital districts were analyzed using HbA1c capillary electrophoresis and reviewed for atypical profiles (HbA1c, Capillarys 3 Tera, Sebia). 38 heterozygous Hb Tacoma cases were found (0.75%). The prevalence was highest in South Ostrobothnia (2.0%), located in western Finland, and second highest in the neighboring provinces (1.0-1.4%), but only two districts were devoid of variants. Heterozygous Hb Tacoma was confirmed by genetic testing (NM_000518.5(HBB):c.93G > T (p.Arg31Ser)). In addition, five other variants were found, suggestive of HbE, Hb Helsinki (two cases) and an alpha variant, as interpreted from the electropherograms. The fifth variant, belonging to the South Ostrobothnian cohort, remained unknown at the time of the initial analyses, but was later interpreted as homozygous Hb Tacoma and confirmed by hemoglobin fraction analysis (Hemoglobin(E), Capillarys 3 Tera). In a subsequent retrospective study of the electropherograms of routine HbA1c diagnostics, altogether nine homozygous Hb Tacoma cases were identified in South Ostrobothnia. While heterozygous Hb Tacoma is usually an incidental finding, it interferes with several HbA1c assays. The present study is the first demonstration of homozygous Hb Tacoma. The clinical presentations of homozygous Hb Tacoma are not known and need to be addressed in future studies.

Pairing parents and offspring's HemoTypeSC Test to validate results and confirm sickle cell pedigree: a case study in Kisangani, the Democratic Republic of the Congo

OBJECTIVES

HemoTypeSC^TM is one of the immunoassay methods currently used for the early diagnosis of Sickle Cell Disease (SCD) in newborns. Earlier diagnosis remains the key strategy for early preventive care needs and parents' education about the child's future well-being throughout his life. Before considering these children as sick and aligning them for regular medical monitoring, it may be valuable to confirm the HemoTypeSC result with a secondary laboratory testing method. In resource-limited settings, where confirmatory methods are not always available, we propose testing the parents to validate the HemoTypeSC result.

METHODS

This study explored this approach in the city of Kisangani. It was a prospective diagnostic accuracy study using genotype biological parents to evaluate HemoTypeSC's performance in the newborn.

RESULTS

Fifty-eight children born to 46 known mothers, and 37 known fathers, have been tested. The phenotyping showed that 41 (70.7%) children were SS, whose 37 were born to a couple AS/AS and 4 to a couple AS/xx. Of the 41 SS children, 8 (19.5%) were newborns and 33 (80.4%) were children; 12 (20.6%) children were AS, one of whom was born to a couple SS/AA and 11 to a couple AA/SS; 5 (8.6%) children were AA. In this population, the probability of offspring born to AS/AS parents being SS rather than AS is high (odds, 1.25). No statistical difference was observed between girls and boys. The pedigree of all 58 children has been confirmed.

CONCLUSION

We demonstrated that testing biological parents with HemoTypeSC is a reliable confirmatory method for newborn screening but it presents some limitations discussed in the present article.

Sickle cell disease in Gulf Cooperation Council countries: a systematic review

INTRODUCTION

Evidence related to the national burden of Sickle Cell Disease (SCD) in Gulf Cooperation Council (GCC) largely fragmented. Thus, the aim of this study is to systemically review studies from GCC countries to assess the epidemiological profile of SCD.

AREAS COVERED

We searched combinations of key terms in MEDLINE/PubMed, CINAHL, and EMBASE. We selected relevant observational studies reporting the frequency, incidence, prevalence, risk factors, mortality rate, and complications of SCD among the GCC population. Studies restricted to laboratory diagnostic tests, experimental and animal studies, review articles, case reports and series, and conference proceedings and editorials were excluded. A total of 1,347 articles were retrieved, out of which 98 articles were found to be eligible and included in the study. The total number of participants from all the included studies was 3496447. The prevalence of SCD ranged from 0.24%-5.8% across the GCC and from 1.02%-45.8% for the sickle cell trait. Consanguineous marriage was a risk factor for likely giving children affected with hemoglobinopathies.

EXPERT OPINION

The prevalence of SCD and its complications vary among GCC. Because of the high prevalence of SCD and its complications, health authorities should focus on more rigorous prevention and treatment strategies.

How Hydroxyurea Alters the Gut Microbiome: A Longitudinal Study Involving Angolan Children with Sickle Cell Anemia

Sickle cell anemia (SCA) is an inherited hematological disorder and a serious global health problem, especially in Sub-Saharan Africa. Although hydroxyurea (HU) is the leading treatment for patients with SCA, its effects on the gut microbiome have not yet been explored. In this context, the aim of this study was to investigate this association by characterizing the gut microbiome of an Angolan SCA pediatric population before and after 6 months of HU treatment. A total of 66 stool samples were obtained and sequenced for the 16S rRNA gene (V3-V4 regions). Significant associations were observed in alpha and beta-diversity, with higher values of species richness for the children naïve for HU. We also noticed that children after HU had higher proportions of several beneficial bacteria, mostly short-chain fatty acids (SCFAs) producing species, such as Blautia luti, Roseburia inulinivorans, Eubacterium halli, Faecalibacterium, Ruminococcus, Lactobacillus rogosae, among others. In addition, before HU there was a higher abundance of Clostridium_g24, which includes C. bolteae and C. clostridioforme, both considered pathogenic. This study provides the first evidence of the HU effect on the gut microbiome and unravels several microorganisms that could be considered candidate biomarkers for disease severity and HU efficacy.

Research knowledge transfer to improve the care and support of adolescents with sickle cell disease in Ghana

INTRODUCTION

Effective transfer of research findings to key knowledge users, particularly in low- and middle-income countries, is not always achieved, despite being a shared priority among researchers, funders, healthcare and community stakeholders and decision-makers. A constructivist grounded theory study conducted in 2015-2019 in Ghana that explored sickle cell-related fatigue in adolescence resulted in numerous implications for practice and policy. Peer-reviewed funding was obtained to support disseminating these findings to relevant stakeholders.

METHODS

Key steps in implementing this study dissemination project included: (1) identifying and attracting target stakeholders from healthcare and community organizations; (2) tailoring tools for communication of research findings for the stakeholder groups and (3) designing interactive workshops to facilitate knowledge sharing and uptake.

FINDING

Despite the COVID-19 pandemic, 50 healthcare and community stakeholders participated in the dissemination workshops. The dissemination activities contributed new layers of understanding to the original research findings through discussions. Through the workshops, participants identified culturally valuable and actionable recommendations that they could take forward to improve care and support for young people with sickle cell disease in Ghana. A follow-up 6 months post the workshops indicated some positive knowledge usage and benefits.

CONCLUSION

This dissemination project provided a unique opportunity for researchers and stakeholders to share in the interpretation of research findings and to strategically plan recommendations to improve SCD-focused care and support for young people in Ghana. Further research dissemination should continue to be grounded in locally generated knowledge, include systematic, long-term evaluation of dissemination outcomes and be adequately financed.

PATIENT AND PUBLIC CONTRIBUTION

Public involvement in this study was critical to the research dissemination project. The Sickle Cell Association of Ghana (Kumasi chapter) actively supported the project's development, organization and facilitation. Parent members of the Association, the Association's executive members and volunteers, and the health professionals involved in sickle cell care at the Komfo Anokye Teaching Hospital participated in the project workshops. They contributed to the knowledge transfer and uptake.

Sickle cell disease as an accelerated aging syndrome

Sickle cell disease (SCD) is characterized by vaso-occlusion, hemolysis, and systemic manifestations that form the hallmark of the disease. Apart from morbidity, SCD is also associated with increased mortality and decreased quality of life. Aging is a natural phenomenon that is associated with changes at cellular, tissue, and organ levels, in addition to the loss of physical fitness, increased susceptibility to diseases, and a higher likelihood of mortality. Some of the cellular mechanisms involved in normal (or physiological) aging include abnormalities of sphingolipids (ceramides) and reduced length of the telomere. These changes have also been documented in SCD. Cellular, organs, and physical manifestations of SCD resemble an accelerated aging syndrome. Sickle erythrocytes also acquire morphological features similar to that of aged normal erythrocytes and are thus picked up early by the macrophages for destruction. Brain, kidney, heart, innate and adaptive immune system, and musculoskeletal system of patients with SCD exhibit morphological and functional changes that are ordinarily seen in the elderly in the general population. Stroke, silent cerebral infarcts, cardiomegaly, heart failure, pulmonary hypertension, nephropathy with proteinuria, osteopenia, osteoporosis, osteonecrosis, gout, and infections are exceedingly common in SCD. In this review, we have attempted to draw parallels between SCD and accelerated aging syndromes.

The Impact of Sickle Cell Disease on Academic Performance among Affected Students

Background: Sickle cell disease (SCD) is a genetic disease that is highly prevalent in Jazan Province, Saudi Arabia, and is mostly characterized by many complications such as vaso-occlusive crises (VOC), acute chest syndrome (ACS) and well-documented neurological complications. These complications may affect patients’ academic performance. Methods: An observational, cross-sectional, retrospective study was conducted in Jazan Province. General and demographic data were collected and questions about academic performance of students with SCD were answered. Both t-tests and chi-square tests, along with multiple logistic regression, were used for analysis. Results: 982 participants were selected for this study with a mean age of 23 years (SD: 7). Most of the participants were female (64%). The number of participants with SCD was 339 (36%), of whom 42% were male. Students with SCD recorded lower grade point averages (GPA) and more absences compared to healthy participants. Further, about 60% of students with SCD thought they performed better than 40% of the participants without SCD during the COVID-19 pandemic when most of the educational activities were online. Conclusion: As has been previously reported, this study suggested that the academic performance of students with SCD is negatively affected compared to healthy individuals, and this is mostly due to complications associated with the disease. Further, students with SCD acknowledged better performance with online education, an option that should be considered to improve their academic performance. National studies on a larger population are required by health and education officials, and supportive online educational programs are warranted to enhance the academic performance of this population.

Ovarian reserve in nigerian women with sickle cell anaemia: a cross- sectional study

INTRODUCTION

Sickle cell disease is the most common monogenetic disorder worldwide. There have been reports of endocrine dysfunction and gonadal failure among affected individuals, especially in males. The findings on ovarian reserve and failure in women with sickle anaemia have been inconsistent.

AIM AND OBJECTIVE

The aim of this study was to determine and compare the ovarian reserve of Nigerian women with and without sickle cell anaemia attending a University Teaching Hospital.

STUDY DESIGN

This cross-sectional study was carried out at the Adult Sickle Cell Clinic and the Community Health Clinic of the Lagos University Teaching Hospital.

METHODOLOGY

A total of 166 participants who met the selection criteria, were recruited for the study. The study population consisted of two groups of women matched for age: 83 women with HbSS and 83 women with HbAA. The haemoglobin phenotype of each participant was determined on alkaline electrophoresis (pH 8.4) before analysis. Serum Anti-Mullerian Hormone (AMH) was determined using Enzyme-linked immunosorbent assay (ELISA) method (Calbiotech Inc. USA, Catalog no AM448T).

RESULTS

The mean ± SD of serum AMH level in women with HbSS was 3.64 ± 0.65 ng/mL and was lower than that of women with HbAA 7.35 ±1.19 ng/mL (p < 0.001). Serum AMH negatively correlated with age in both study groups (HbAA and HbSS). Also, a significant negative correlation was found between serum AMH and BMI in women with HbAA.

CONCLUSION

The study showed diminished ovarian reserve in women with HbSS when compared to age-matched women with HbAA.

A systematic review of cases of West African crystalline maculopathy

AIM

West African crystalline maculopathy (WACM) is, reportedly, a rare condition whose aetiology remains unclear. This study aims to describe the epidemiology, summarizing the identified risk factors and clinical characteristics of cases of WACM, with the goal of highlighting presentation patterns and the clinical course of the condition.

METHODS

A comprehensive PubMed, Medline, EMBASE, Web of Science, OMIM and Google scholar search of all articles written in English, and non-English language articles with abstract translated to English on WACM was carried out. Only full case reports and series were included. Data reviewed included epidemiology, risk factors, clinical presentations, imaging characteristics, management and prognosis of WACM. Information on the location of the study was also extracted.

RESULTS

Ten studies - seven case reports and three case series - comprising of 30 patients were included. The patients were from West, Central and North-east Africa, with all the studies carried out in North America and Europe. The majority of the patients (76.7%) had diabetes mellitus, 80% had a vascular retinopathy (diabetic retinopathy, sickle cell retinopathy, familial exudative vitreoretinopathy and branch retinal vein occlusion) and 50% had macular oedema. There was no report of associated visual impairment or retinal degeneration. Clinical improvement in the number of crystals was documented in two cases with retinal laser photocoagulation for associated vascular retinopathies. Clinical observation was employed by most clinicians.

CONCLUSION

West African crystalline retinopathy is a seemingly innocuous condition affecting black or African people, who were also born in Africa. The majority of the patients have a vascular retinopathy. Longitudinal studies, particularly in Africa, may be required to elucidate the aetiology, as well as the long-term prognosis, of the crystals.

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.

Management of sickle cell disease: current practices and challenges in a northeastern region of the Democratic Republic of the Congo

BACKGROUND

The Democratic Republic of the Congo (DRC) is the third most affected country worldwide by sickle cell disease (SCD). However, this disease is still orphaned in the country; large-scale control actions are rare, and little is known about its management.

OBJECTIVE

To assess current practices in the management of SCD in Kisangani, DRC.

METHODS

This cross-sectional study was conducted in six health facilities in Kisangani. It involved 198 presumed sickle cell patients attending the above health facilities. The study focused on the sociodemographic and clinical data of the participants, obtained through a clinical examination and their medical records. Diagnostic confirmation of SCD was made by high-performance liquid chromatography coupled to mass spectrometry. Data were analyzed using SPSS 20.0.

RESULTS

The diagnosis of SCD was confirmed in 194 (98.0%; 95% CI: 94.9-99.2) participants, while it was not confirmed in 4 (2.0%; 95% CI: 0.8-5.1) participants. The diagnosis was mainly made by the Emmel test (42.9%). 45.8% of participants had previously been transfused with the blood of their parents. Folic acid was taken by 48.5% of participants and the previous intake of hydroxyurea was reported in 5.1% of participants. The participants vaccinated against Pneumococcus were 13.6% and against Haemophilus influenzae type b 28.3%. Penicillin prophylaxis was received by only 1.5% and malaria prophylaxis by 11.6% of participants.

CONCLUSION

Standard-care practices for SCD patients in Kisangani are insufficient. The Congolese government should regard this disease as a health priority and consider actions to improve its management.

Techniques for the Detection of Sickle Cell Disease: A Review

Sickle cell disease (SCD) is a widespread disease caused by a mutation in the beta-globin gene that leads to the production of abnormal hemoglobin called hemoglobin S. The inheritance of the mutation could be homozygous or heterozygous combined with another hemoglobin mutation. SCD can be characterized by the presence of dense, sickled cells that causes hemolysis of blood cells, anemia, painful episodes, organ damage, and in some cases death. Early detection of SCD can help to reduce the mortality and manage the disease effectively. Therefore, different techniques have been developed to detect the sickle cell disease and the carrier states with high sensitivity and specificity. These techniques can be screening tests such as complete blood count, peripheral blood smears, and sickling test; confirmatory tests such as hemoglobin separation techniques; and genetic tests, which are more expensive and need to be done in centralized labs by highly skilled personnel. However, advanced portable point of care techniques have been developed to provide a low-cost, simple, and user-friendly device for detecting SCD, for instance coupling solubility tests with portable devices, using smartphone microscopic classifications, image processing techniques, rapid immunoassays, and sensor-based platforms. This review provides an overview of the current and emerging techniques for sickle cell disease detection and highlights the different potential methods that could be applied to help the early diagnosis of SCD.

Patterns and patient factors associated with loss to follow-up in the Muhimbili sickle cell cohort, Tanzania

BACKGROUND

Monitoring patient's clinical attendance is a crucial means of improving retention in care and treatment programmes. Sickle cell patients' outcomes are improved by participation in comprehensive care programmes, but these benefits cannot be achieved when patients are lost from clinical care. In this study, patients are defined as loss to follow-up when they did not attend clinic for more than 9 months. Precise information on the retention rate and characteristics of those who are not following their clinic appointments is needed to enable the implementation of interventions that will be effective in increasing the retention to care.

METHOD

This was a retrospective study involving sickle cell patients registered in the Muhimbili Sickle Cohort in Tanzania. Descriptive and survival analysis techniques both non-parametric methods (Kaplan-Meier estimator and Log-rank test) and semi-parametric method (Cox's proportional hazard model), were used. A p-value of 0.05 was considered significant to make an inference from the analysis.

RESULTS

A total of 5476 patients were registered in the cohort from 2004 to 2016. Of these, 3350 (58.13%) were actively participating in clinics, while 2126 (41.87%) were inactive, of which 1927 (35.19%) were loss to follow-up. We used data from 2004 to 2014 because between 2015 and 2016, patients were referred to other government hospitals. From the survival analysis results, pediatric (HR: 14.29,95% CI: 11.0071-18.5768, p <  0.001) and children between 5 and 17 years [HR:2.61,95% CI:2.2324-3.0705, p <  0.001] patients were more likely to be loss to follow-up than the adult (18 and above years) patients. It was found that patients with above averages for hematocrit (HR: 2.38, 95% CI: 1.0076-1.0404, p = 0.0039) or mean cell volume (HR: 4.28, (95% CI: 1.0260-1.0598, p < 0.001) were more likely to be loss to follow-up than their counterparts.

CONCLUSION

Loss to follow-up is evident in the cohort of patients in long term comprehensive care. It is, therefore, necessary to design interventions that improve patients' retention. Suggested solutions include refresher training for health care workers and those responsible for patient follow-up on techniques for retaining patients and comprehensive transition programs to prepare patients who are moving from pediatric to adult clinics.

Genetic counselling in sickle cell disease: views of single young adults in Ghana

Sickle cell disease is a chronic inherited blood disorder affecting many people globally as well as in Sub-Saharan Africa. In Ghana, the disease has a prevalence of 2% with carrier rate of 20-25% among the populace. Genetic counselling is a cost-effective strategy in reducing the burden of this disorder. However, little is known about the relevance of this intervention particularly among young adults in their reproductive age. The purpose of this is to explore the views of single young adults about genetic counselling in the Accra metropolis, Ghana. An exploratory descriptive qualitative designed was used. Thirty-two (32) young adults between the ages of 18 and 28 years were purposively selected from a private university in Ghana. Four focus group discussions and twelve in-depth interviews were conducted. Data was analysed using content analysis technique. The results of the study revealed that young adults had knowledge about SCD and due to that showed positive perceptions towards genetic counselling in SCD. However, they were unaware of genetic counselling facilities in the country. They expressed willingness to accept genetic counselling related to SCD whether for a fee or for free. It was concluded that establishment of a number of genetic counselling centres is very crucial in the metropolis.

Knowledge and awareness of individual sickle cell genotype among adolescents in a unity school in Southeast, Nigeria: a cross-sectional study

Objective Our study sought to assesses the knowledge and awareness of individual sickle cell genotype among adolescents. Methods Participants were recruited from a large school in Southeast Nigeria where adult prevalence of sickle cell trait is 25%. Data was collected through a 50-item survey with previously pretested questions that assessed awareness of individual genotype, general knowledge of sickle cell disease, perception of sickle cell trait and sickle cell anaemia (SCA). Additionally, self-reported genotype was compared to the school's admission records to determine accuracy of self-reported genotype. The knowledge scores were summed on a binary basis with one point assigned for a correct answer while zero was given for an incorrect response. Results Four hundred and nine (409) students were approached and enrolled in the study. A vast majority (94%) of the respondents reported being aware of their genotype and two-thirds had the awareness during school admission. However, in specific knowledge of sickle cell, majority (89.7%) of the participants miscalculated the probability of having a child with SCA in married carrier couple and 71.9% misidentified the proportion of Nigerians with sickle cell trait. Assessing level of knowledge of sickle cell, only very few of the adolescents (7.3%) were found with the expected high knowledge scores of 7-8. Conclusion Although a significant proportion of respondents were aware of their genotype, most were unaware of the implications of sickle cell trait and thought that people with sickle cell trait also have symptoms of sickle cell disease. Also, only a few of the respondents have the expected level of sickle cell knowledge. A focused educational intervention among this age group is crucial as they embark on making reproductive health decisions.

Twelve tips for teaching a comprehensive disease-focused course with a global perspective: A sickle cell disease example

A disease-focused course entitled "Understanding Sickle Cell Disease: A Biopsychosocial Approach" addressed the complex nature of SCD using patient-centered, global and interdisciplinary approaches. Sickle cell disease (SCD) is a rare inherited blood disorder that requires multidisciplinary care. Worldwide 20-25 million individuals have SCD, which is associated with a shortened lifespan due to many medical complications and social and behavioral health challenges. Health care professionals often have limited knowledge of SCD as they typically learn about it within the context of their own disciplines. This article provides twelve tips for educators that can be used to develop a similar course on any disease, with considerations for both low- and high-resource countries. The tips were devised from personal experience and available literature. Through these twelve tips, we provide a practical framework for increasing knowledge of complex diseases like SCD using a comprehensive elective course.

Population Screening for Hemoglobinopathies

Hemoglobinopathies are the most common single-gene disorders in the world. Their prevalence is predicted to increase in the future, and low-income hemoglobinopathy-endemic regions need to manage most of the world's affected persons. International organizations, governments, and other stakeholders have initiated national or regional prevention programs in both endemic and nonendemic countries by performing population screening for α- and β-thalassemia, HbE disease, and sickle cell disease in neonates, adolescents, reproductive-age adults (preconceptionally or in the early antenatal period), and family members of diagnosed cases. The main aim of screening is to reduce the number of affected births and, in the case of sickle cell disease, reduce childhood morbidity and mortality. Screening strategies vary depending on the population group, but a few common screening test methods are universally used. We discuss the salient features of population-screening programs around the globe as well as current and proposed screening test methodologies.

Evaluation of Umbilical Artery Doppler Indices in Pregnant Women With Sickle Cell Anemia Disease at a Nigerian Tertiary Hospital

Pregnant patients with sickle cell anemia (HbSS) are at risk of adverse outcomes to the mother and the fetus due to unique pathophysiologic changes. The purpose of this study was to determine the umbilical artery (UA) Doppler indices at 26 weeks gestational age (GA) in HbSS women with uncomplicated pregnancies and compare with the obstetric outcome. In this cohort study, 60 HbSS and 60 normal hemoglobin (HbAA) women with uncomplicated pregnancies were recruited from the antenatal clinic and prospectively followed to delivery. UA velocimetry, fetal biometry, maternal hematocrit, and parity were assessed at 26 weeks. Fetomaternal outcomes were also documented. UA Doppler indices and estimated fetal weights were comparable to those of HbAA control subjects at 26 weeks GA. There was a statistically significant increase in adverse obstetric outcomes in HbSS patients. There was no correlation between maternal hematocrit and artery indices. Further research is required to determine cutoff values and optimal timing for sonography in HbSS patients.

Prevalence and incidence of congenital anomalies amongst babies born to women with sickle cell disease and exposed to hydroxyurea during pregnancy: a systematic review protocol

REVIEW QUESTION/OBJECTIVE

What is the prevalence and incidence of congenital anomalies among babies born to women with sickle cell disease (SCD) and who have been exposed to hydroxyurea (HU) therapy at any time in their pregnancy?The objective of this review is to identify the proportion of babies born with congenital anomalies among babies born to mothers with SCD who have been exposed to HU therapy at any point during pregnancy and to describe the specific types of congenital anomalies encountered.

Beta-globin gene haplotypes and selected Malaria-associated variants among black Southern African populations

Partial carrier-resistance to Plasmodium falciparum malaria conferred by the sickle cell (HbS) mutation has resulted in the local amplification and positive selection of sickle cell disease (SCD) in malaria-endemic regions and particularly in sub-Saharan Africa (SSA). The present study investigated the β-globin gene haplotypes, and selected malaria-associated variants among three cohorts of Bantu-speaking individuals from Malawi, Zimbabwe and South Africa compared with reports with data from others SSA populations. The data suggest a south-ward frequency decrease of malaria-associated variants in SSA linked to the evolutionary dynamics of various African populations’ genomes through selective pressure of malaria. These selected genomics differences, positive selection of SCD in malaria-endemic regions among ‘Bantus’ from various part of Africa emphasise the evidence of the dissociation between genetics, anthropology and culture. The present study also showed a relatively prevalent Benin haplotype, which is mostly found in West Africa, among Southern African Blacks and very low Bantu haplotype, which could suggest a major migration route, of Southern Africa Bantu, along the African west coast, post-occurrence of the Sickle cell mutation, which date remain to be fully elucidated.

Monodora myristica (African nutmeg) modulates redox homeostasis and alters functional chemistry in sickled erythrocytes

The antioxidative effect of Monodora myristica seed acetone extract and its effect on chemical functional groups were investigated in sickled erythrocytes as well as molecular modeling of the antisickling potentials of its secondary metabolites. The extract was subjected to gas chromatography–mass spectrometry to identify the compounds present, which were then docked into the allosteric-binding site of deoxy-hemoglobin. The extract was incubated with sickled erythrocytes at 37°C for 6, 12, and 24 h and were subjected to antioxidative analysis for reduced glutathione (GSH), superoxide dismutase (SOD), catalase, and lipid peroxidation (LPO). Chemical functional group of the treated cells was analyzed via Fourier transform infrared spectroscopy (FTIR). The predominant compounds identified were 17-octadecynoic acid; oleic acid, androstan-3-one, 17-hydroxy-2-methyl- (2.beta.,5.beta.,17.beta.)-; estran-3-one, 17-(acetyloxy)-2-methyl-, (2.alpha., 5.alpha., 17.beta.), and (+)-3-carene, 10-(acetylmethyl)-. They all fitted well within the active site of Hb with good binding affinity, as evidenced by the negative CDocker interaction energies of their complexes ranging between −54.4 and −26.7 kcal/mol. Treatment with the extract exacerbated SOD and catalase activities as well as GSH level, while LPO was suppressed. This antioxidative activity was time and/or dose dependent, with 6 and 12 h incubation showing the optimum activity. FTIR analysis of the treated cells showed the presence of hydrophobic functional groups. The synergetic molecular interaction of the major compounds of the extract with the α-dimer of Hb depicts an antisickling effect of M. myristica acetone extract. This is accompanied by exacerbation of endogenous antioxidant enzymes activity and modification of the functional chemistry of the cells.

Emerging point-of-care technologies for sickle cell disease screening and monitoring

INTRODUCTION

Sickle Cell Disease (SCD) affects 100,000 Americans and more than 14 million people globally, mostly in economically disadvantaged populations, and requires early diagnosis after birth and constant monitoring throughout the life-span of the patient. Areas covered: Early diagnosis of SCD still remains a challenge in preventing childhood mortality in the developing world due to requirements of skilled personnel and high-cost of currently available modalities. On the other hand, SCD monitoring presents insurmountable challenges due to heterogeneities among patient populations, as well as in the same individual longitudinally. Here, we describe emerging point-of-care micro/nano platform technologies for SCD screening and monitoring, and critically discuss current state of the art, potential challenges associated with these technologies, and future directions. Expert commentary: Recently developed microtechnologies offer simple, rapid, and affordable screening of SCD and have the potential to facilitate universal screening in resource-limited settings and developing countries. On the other hand, monitoring of SCD is more complicated compared to diagnosis and requires comprehensive validation of efficacy. Early use of novel microdevices for patient monitoring might come in especially handy in new clinical trial designs of emerging therapies.

A rapid, inexpensive and disposable point-of-care blood test for sickle cell disease using novel, highly specific monoclonal antibodies

Sickle cell disease (SCD) is a significant healthcare burden worldwide, but most affected individuals reside in low-resource areas where access to diagnostic testing may be limited. We developed and validated a rapid, inexpensive, disposable diagnostic test, the HemoTypeSC™ , based on novel monoclonal antibodies (MAbs) that differentiate normal adult haemoglobin (Hb A), sickle haemoglobin (Hb S) and haemoglobin C (Hb C). In competitive enzyme-linked immunosorbent assays, each MAb bound only its target with <0·1% cross-reactivity. With the HemoTypeSC™ test procedure, the sensitivity for each variant was <5·0 g/l. The accuracy of HemoTypeSC™ was evaluated on 100 whole blood samples from individuals with common relevant haemoglobin phenotypes, including normal (Hb AA, N = 20), carrier or trait (Hb AS, N = 22; Hb AC, N = 20), SCD (Hb SS, N = 22; Hb SC, N = 13), and Hb C disease (Hb CC, N = 3). The correct haemoglobin phenotype was identified in 100% of these samples. The accuracy of the test was not affected by Hb F (0-94·8% of total Hb) or Hb A2 (0-5·6% of total Hb). HemoTypeSC™ requires <1 μl of whole blood and no instruments or power sources. The total time-to-result is <20 min. HemoTypeSC™ may be a practical solution for point-of-care testing for SCD and carrier status in low-resource settings.