Models of care for sickle cell disease in low-income and lower-middle-income countries: a scoping review

Sickle cell disease has a growing global burden falling primarily on low-income countries (LICs) and lower-middle-income countries (LMICs) where comprehensive care is often insufficient, particularly in rural areas. Integrated care models might be beneficial for improving access to care in areas with human resource and infrastructure constraints. As part of the Centre for Integration Science's ongoing efforts to define, systematise, and implement integrated care delivery models for non-communicable diseases (NCDs), this Review explores models of care for sickle cell disease in LICs and LMICs. We identified 99 models from 136 studies, primarily done in tertiary, urban facilities in LMICs. Except for two models of integrated care for concurrent treatment of other conditions, sickle cell disease care was mostly provided in specialised clinics, which are low in number and accessibility. The scarcity of published evidence of models of care for sickle cell disease and integrated care in rural settings of LICs and LMICs shows a need to implement more integrated models to improve access, particularly in rural areas. PEN-Plus, a model of decentralised, integrated care for severe chronic non-communicable diseases, provides an approach to service integration that could fill gaps in access to comprehensive sickle cell disease care in LICs and LMICs.

Impact of Sickle Cell Disease on Affected Individuals in Nigeria: A Critical Review

Sickle cell disease is an autosomal recessive disorder of the beta-globin gene, with resultant deformation of the red blood cells and variable clinical outcomes. Nigeria is recognised as the country with the highest burden of sickle cell disease globally. This study aimed at critically reviewing available literature on impact of sickle cell disease in Nigeria. A literature search was carried out on four databases, and a total of 116 articles that met the inclusion criteria were included in the critical review. It was observed that majority of the studies were carried out in South-Western part of Nigeria (47.4%), whilst the North-East had the least number of studies undertaken in this area, more than a quarter of the studies (27.6%) were related to hematologic and serologic screening. Major themes that emerged from this review were morbidity and mortality; prevalence of sickle cell disease; issues relating to blood transfusion; psychosocial impact; and anatomical dysfunction in sickle cell disease. Intervention programs from both government and non-governmental organizations aimed at reducing the burden of sickle cell disease and its socio-economic impact were identified as key to strategies aimed at overcoming challenges associated with the disease. Findings from this study also revealed that education and awareness interventions were central to reducing the prevalence of sickle cell disease in this setting.

Sickle Cell Disease in Children and Adolescents: A Review of the Historical, Clinical, and Public Health Perspective of Sub-Saharan Africa and Beyond

Sickle cell disease (SCD) is an umbrella term for a group of life-long debilitating autosomal recessive disorders that are caused by a single-point mutation (Glu→Val) that results in polymerization of hemoglobin (Hb) and reversible sickle-shape deformation of erythrocytes. This leads to increased hemolysis of erythrocytes and microvascular occlusion, ischemia-reperfusion injury, and tissue infarction, ultimately causing multisystem end-organ complications. Sickle cell anemia (HbSS) is the most common and most severe genotype of SCD, followed by HbSC, HbSβ⁰thalassemia, HbSβ+thalassemia, and rare and benign genotypes. Clinical manifestations of SCD occur early in life, are variable, and are modified by several genetic and environmental factors. Nearly 500 children with SCD continue to die prematurely every day, due to delayed diagnosis and/or lack of access to comprehensive care in sub-Saharan Africa (SSA), a trend that needs to be urgently reversed. Despite proven efficacy in developed countries, newborn screening programs are not universal in SSA. This calls for a consolidated effort to make this possible, through the use of rapid, accurate, and cheap point-of-care test kits which require minimal training. For almost two decades, hydroxyurea (hydroxycarbamide), a century-old drug, was the only disease-modifying therapy approved by the U.S. Food and Drug Administration. Recently, the list expanded to L-glutamine, crizanlizumab, and voxelotor, with several promising novel therapies in the pipeline. Despite its several limitations, hematopoietic stem cell transplant (HSCT) remains the only curative intervention for SCD. Meanwhile, recent advances in gene therapy trials offer a glimpse of hope for the near future, although its use maybe limited to developed countries for several decades.

Reduction in seroprevalence of viral transfusion-transmitted infections in southwest Nigeria in children with sickle cell disease using an enhanced screening strategy

Blood transfusion is an integral component in the management of children and adults with sickle cell disease (SCD). Concerns about blood safety due to the high risk of bloodborne infections in sub-Saharan Africa limits the application of this cost-effective strategy in the management of individuals with SCD. In a single-centre, retrospective, longitudinal study in southwest Nigeria, we hypothesised that the use of stringent blood donor selection, along with very sensitive enzyme-linked immunosorbent assay (ELISA) screening methods would reduce transfusion-transmitted infections (TTIs). Among 45 002 eligible blood donors at the Lagos University Teaching Hospital in Nigeria, over a 5-year review period (2015-2019), the seroprevalence rate of viral TTIs was 9.83%. The seroprevalence rates for human immunodeficiency, hepatitis B, and hepatitis C viruses were 1.37%, 6.2%, and 2.25% respectively. Among 172 children with SCD, 71% (122/172) on regular blood transfusion and 29% (50/172) who had never been transfused or had less than two transfusions per lifetime, none acquired any TTIs using our enhanced screening approach during the study period. Thus, safe blood transfusion practices can be provided for children with SCD in sub-Saharan Africa with the use of stringent donor selection protocols and fourth-generation ELISA kits for TTI screening.

Stroke and stroke prevention in sickle cell anemia in developed and selected developing countries

This comprehensive review provides an insight into the pathophysiology, epidemiology, evaluation, and treatment of sickle cell anemia (SCA)-related stroke in developed and developing countries. Vascular injury, hypercoagulability and vaso-occlusion play a role in the pathophysiology of stroke in SCA. Transcranial Doppler ultrasound (TCD) has lowered the incidence of ischemic stroke from 11% to 1% as TCD identifies children who are at risk for stroke, providing opportunities for interventions to reduce this risk. Whereas blood exchange is indicated in acute stroke, chronic transfusions (either simple or exchange on a monthly basis) are used for primary as well as secondary stroke prevention in developed countries. Children with abnormally high TCD velocities (≥ 200 cm/s) are at high risk of stroke and might benefit from hydroxyurea or hydroxycarbamide (HU) after a period of a successful transition from chronic transfusions. Hematopoietic stem cell transplant presents a cure for SCA. Gene therapy is currently investigated and may be offered to patients with SCA who had a stroke or who are at high risk of stroke if proven efficacious and safe. However, gene therapy is not likely to be implemented in low-income countries due to cost. Alternatively, HU is utilized for primary and secondary stroke prevention in developing countries. Further expansion of TCD implementation should be a priority in those settings.

Determinants of Care-Seeking Practices for Children with Sickle Cell Disease in Ekiti, Southwest Nigeria

Background

Due to the chronic nature of sickle cell disease (SCD), affected individuals may seek help from diverse places thus raising the need to understand their health-seeking behavior (HSB) in order to design an appropriate management policy for them.

Aim

The aim of this study was to evaluate the HSB among pediatric SCD patients relative to their non-SCD counterparts attending a tertiary facility in Southwest Nigeria and identified predictors of poor HSB among SCD patients.

Methods

A total of 110 children with SCD were recruited and studied for their HSPs which were compared with 110 non-SCD patients with other chronic medical conditions. Questionnaires were used to obtain self-reported information on participants’ socio-demographic data and HSB. Logistic regression was used to determine the predictors of poor HSB among the SCD cohort.

Results

More SCD patients received treatments at private hospitals, patent medicine stores and faith-based centers compared to their non-SCD counterparts (p=0.0052; 0.006; and 0.007), respectively. No difference was observed in the patronage of traditional care centres 10 (9.1%) vs 6 (5.5%). More SCD patients 61 (55.5%) vs 35 (31.8%) exhibited poor HSB (p=0.0004). SCD patients who were not enrolled on health insurance scheme were 18 times more likely to have poor HSB (OR=18.38, 95% CI (4.41–76.57), p value= <0.0001) while absence of VOC within the preceding year reduces the risk of poor HSB by 91.5% (OR=0.085, 95% CI (0.028–0.258), p value= <0.0001).

Conclusion

SCD patients in the study locality had poor HSB. This raises the need for their education on proper HSB. More enrollment into health insurance scheme and the prevention of VOC will lessen the burden of poor HSB. The high patronage of non-hospital care facilities in this study raises the need for stakeholders to monitor activities and train the operators at these informal care centres.

HemoTypeSC point-of-care testing shows high sensitivity with alkaline cellulose acetate hemoglobin electrophoresis for screening hemoglobin SS and SC genotypes

Introduction

By providing timely actionable results for prompt management, point-of-care testing (POCT) kits have revolutionised medical care for various diseases, ranging from infectious diseases like malaria to genetic disorders, such as sickle cell disease (SCD). They are, however, underutilised in the diagnosis of SCD in developing countries, where the need is greatest.

Objective

The study was aimed at assessing the sensitivity of HemoTypeSC POCT among a cohort of children with SCD, previously diagnosed by Alkaline cellulose acetate hemoglobin electrophoresis (ACAE), with or without high-performance liquid chromatography (HPLC).

Methods

In this descriptive cross-sectional study, HemoTypeSC test was conducted on all participants and its sensitivity was determined by comparing results with those obtained using ACAE. Discordance was verified with HPLC.

Results

One hundred and forty-five children aged one to 19 years were studied. There were 84 males and 61 females (male: female ratio = 1.4: 1). The HemoTypeSC was able to correctly diagnose sickle cell anemia (SCA) and hemoglobin SC in all (100%) of the children tested.

Conclusion

The HemoTypeSC shows high sensitivity in detecting SCA and hemoglobin SC. Hence, it is useful for targeted screening of individuals suspected of having SCD, leading to rapid diagnosis of these hemoglobinopathies, even in resource-constrained settings.

Transfusion support in patients with sickle cell disease

Blood transfusions are an integral component of the management of acute and chronic complications of sickle cell disease. Red cells can be administered as a simple transfusion, part of a modified exchange procedure involving manual removal of autologous red cells and infusion of donor red cells, and part of an automated red cell exchange procedure using apheresis techniques. Individuals with sickle cell disease are at risk of multiple complications of blood transfusions, including transfusional hemosiderosis, auto- and alloimmunization to minor red cell and human leukocyte antigens, delayed hemolytic transfusion reactions, and hyper-hemolysis. In low- and middle-income countries in sub-Saharan Africa, where a directed donor system is prevalent and limited laboratory methods are in place to perform extended red cell phenotyping, leukodepletion of cellular products, and infectious disease screening, there are additional challenges to providing safe and adequate transfusion support for this patient population. We review current indications for acute and chronic transfusions in sickle cell disease that are derived primarily from randomized controlled trials and observational studies in children living in high-income countries. We will highlight populations with unique transfusion needs, such as pregnant women and children, as well as the role of the transfusion medicine consultative service for individuals with sickle cell disease planning to have curative hematopoietic stem cell transplantation or gene therapy. Finally, we will discuss risk factors for alloimmunization in individuals with sickle cell disease, emerging new strategies to prevent alloimmunization in this population, and critical gaps in the implementation of transfusion guidelines for sickle cell disease in high- and low-income countries.

Hepatitis B and C Infections Among Pediatric Patients with Sickle Cell Disease at a Tertiary Hospital in Nigeria

Background: The frequent use of blood products for patients with sickle cell disease (SCD) may put them at risk of being infected with hepatitis virus infections, especially if such blood products are not properly screened. Hepatitis B and C infections (HBV and HCV, respectively) may result in cirrhosis and liver cell cancer. Objectives: This study determined the prevalence of HBV and HCV infections among pediatric patients with sickle cell disease in comparison with matched controls at the Ekiti State University Teaching Hospitals (EKSUTH), Ado-Ekiti. Methods: This was a descriptive cross-sectional study that comprised of 116 patients with SCD and their aged and sex-matched controls who were referred to the pediatric clinics at EKSUTH. The hemoglobin (Hb) genotypes of the participants were confirmed by Hb electrophoresis and high-performance liquid chromatography (HPLC), Biorad, USA Variant II, using the Beta thalassemia short program. Moreover, HBV and HCV antigens were assessed by the Enzyme-linked Immunosorbent Assay method (Kits were manufactured by Biotech Laboratories USA). Results: The mean ages of the patients with SCD and controls were 8.35 ± 4.50 and 8.92 ± 3.25 years, respectively. The seroprevalence of HBV infection among the children with sickle cell disease and controls was 1% each (P =1.00). The seroprevalence of hepatitis C virus infection was 0% among the two groups. Most (98.3%) of the patients with SCD and controls were fully vaccinated against HBV infection. The two children (100%) that were seropositive for hepatitis B were never vaccinated against HBV infection. Conclusions: The seroprevalence of HBV infection is low among patients with SCD and controls. This may be due to the protective effect of high hepatitis B vaccination rate and high quality of care among our study population.

Improving blood transfusion safety in resource-poor countries: a case study of using leucocyte reduced blood in Uganda

Background:

The majority of blood transfusion safety strategies recommended by the WHO for resource-poor countries focus mainly on reducing the risk of transfusion-transmitted infections (TTIs). Other technologies such as leucocyte reduction may represent complementary strategies for improving transfusion safety.

Objective:

To evaluate the role of using leucocyte reduced blood in a resource-poor country.

Methods:

Pre-storage leucocyte reduced (LR) red blood cells (RBCs) were specially prepared for the Tissue Oxygenation by Transfusion in severe Anaemia and Lactic acidosis (TOTAL) study, at the Uganda Blood Transfusion Services from February 2013 through May 2015. Quality control tests were performed to evaluate the procedure, and the incremental cost of an LR-RBC unit was estimated.

Results:

A total of 608 RBCs units were leucocyte reduced. Quality control tests were performed on 55 random RBCs units. The median (IQR) residual leucocyte count was 4 (0·5–10) WBC/uL, equivalent to 1·8x106 WBC per unit. The estimated incremental unit cost of leucocyte reduction was $37 USD per LR RBC unit.

Conclusion:

Leucocyte reduction of blood in a resource-poor country is doable although relatively costly. As such, its value in resource-poor countries should be weighed against other transfusion safety propositions.

Perceptions and Practice of Early Diagnosis of Sickle Cell Disease by Parents and Physicians in a Southwestern State of Nigeria

Background

Early sickle cell disease (SCD) diagnosis has shown promise in combating SCD in many countries. The aim of this study was to assess the practice and perception of early SCD diagnosis among a group of parents and physicians in Nigeria. Patients and Methods. This was a cross-sectional descriptive study conducted to assess the opinions and practice of early diagnosis of SCD among 135 physicians caring for SCD patients and 164 mothers of children with SCD in a southwestern state of Nigeria.

Results

Most physicians 132 (97.8%) were aware of prenatal SCD diagnosis, but only 51 (37.8%) would recommend it. Most physicians 129 (95.6%) routinely recommend premarital SCD genetic counseling and testing, and 89 (65.1%) were aware of the national government newborn screening program but lesser proportion 75 (55.6%) were willing to recommend it. Amongst the mothers, 154 (94%) and 158 (96%) had encountered genetic counseling for SCD and were willing to offer newborn screening to their children, respectively. On the contrary, fewer mothers 42 (25%) were aware of prenatal SCD diagnosis, 28 (17%) were willing to partake in it, and 44 (26%) were undecided. There were discrepancies in the willingness by physicians to practice early SCD diagnosis and its uptake by mothers (p < 0.0001). The commonest reason given by both the physicians and mothers for not practicing SCD prenatal diagnosis was the high cost of the procedure.

Conclusion

The perceptions and practice of early SCD diagnosis was suboptimal in the study locality. Scaling up awareness and universal coverage are required.

Uridine diphosphate glucuronosyl transferase 1A (UGT1A1) promoter polymorphism in young patients with sickle cell anaemia: report of the first cohort study from Nigeria

Background

(TA) n repeat sequence (rs8175347) of UGT1A1 gene promoter polymorphism is associated with serum bilirubin levels and gallstones among different sickle cell anaemia (SCA) populations. There are no data on UGT1A1 polymorphisms and their impact on Nigerian SCA patients. In this study, we determined the distribution of the UGT1A1 (TA) n genotypes among a group of young Nigerian SCA patients and healthy controls. In addition, the influence of UGT1A1 (TA) n genotypes on the laboratory and clinical events among the patients was determined.

Methods

The distribution of the UGT1A1 (TA) n genotypes among 101 young Nigerian SCA patients and 64 normal appropriate controls were determined and studied. The UGT1A1 (TA) n genotypes were further classified into subgroups and used to differentiate the clinical events and laboratory parameters of the patients.

Results

Four (TA) n alleles:(TA)5, 6, 7, and 8 were found. These were associated with 10 genotypes: TA5/5, 5/6, 5/7, 5/8, 6/6, 6/7, 6/8, 7/7, 7/8, 8/8. The normal (wild-type)-(TA) 6/6), low- (TA) 7/7, 7/8, 8/8), intermediate- (TA) 5/7, 5/8, 6/7, 6/8), and high-activity (TA) 5/5, 5/6,) genotypes were found in 24.8, 24.8, 41.5, and 8.9% patients and 20.3, 15.6, 61, and 3.1% controls respectively. The general genotype distribution of the patients and control group were not significantly different. There were significant differences in serum bilirubin and lactate dehydrogenase (LDH) of the patients when differentiated by the UGT1A1 (TA) n genotypes (p<0.05). Asymptomatic gallstones were found in 5.9% of patients and were significantly of the low-activity genotypes sub-group 5 (20%) vs 1(1.3%) p = 0.0033. Although, bilirubin and fetal hemoglobin (HbF) of patients with gallstones were significantly different from those without gallstone, only the serum bilirubin was associated with UGT1A1 (TA) n genotypes on multivariate analysis (p < 0.0001).

Conclusion

This study highlights the contribution of UGT1A1 polymorphisms, a non-globin genetic factor, to the laboratory and clinical manifestations of young Nigerian SCA patients for the first time. It also shows that children with co-inheritance of low UGT1A1 (TA) n affinity genotypes may be at risk of gallstone, hence the need to follow them up.

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

Introduction: Sickle cell disease (SCD) is an inherited blood disorder characterized by clinical heterogeneity that may be influenced by environmental factors, ethnicity, race, social and economic factors as well as genetic and epigenetic factors. Areas covered: The present review was carried out to provide a comprehensive assessment of the current burden of SCD and treatments available for persons with SCD in Nigeria with the aim of identifying surveillance and treatment gaps, informing to guide the planning and implementation of better crisis prevention measures for SCD patients and set an agenda for new areas of SCD research in the country. This review assessed medical, biomedical and genetic studies on SCD patients in Nigeria and other endemic countries of the world. Expert opinion: Integration of hydroxyurea therapy into the management of SCD and surveillance via new-born screening (NBS) for early detection and management will improve the survival of persons with SCD in Nigeria. However, it will be important to carry out pilot studies, initiate strategic advocacy initiatives to educate the people about NBS benefits, develop collaborations between potential stakeholders and design sustainable financing scheme.

Influence of alpha thalassemia on clinical and laboratory parameters among nigerian children with sickle cell anemia

BACKGROUND

There is paucity of data on the influence of alpha thalassemia on the clinical and laboratory parameters among Nigerian sickle cell anemia (SCA) patients. This study aimed to determine the prevalence of alpha thalassemia and the influence of alpha thalassemia on laboratory parameters and clinical manifestations in a group of young Nigerian SCA patients.

METHODS

This was a cross-sectional retrospective study conducted on 100 patients with SCA and 63 controls. The diagnosis of SCA was confirmed by DNA studies. Alpha thalassemia genotyping was performed by multiplex gap-PCR method. Laboratory parameters including complete blood count, hemoglobin quantitation, serum lactate dehydrogenase (LDH), and bilirubin were determined with standard techniques.

RESULTS

Alpha thalassemia was found in 41 (41.0%) patients compared to 24 (38.1%) controls (P = 0.744), and all were due to the 3.7 κb α-globin gene deletions. Alpha thalassemia was associated with more frequent bone pain crisis, higher hemoglobin concentration, red blood cell count, and HbA₂ level among the patients. On the contrary, patients with alpha thalassemia had lower mean corpuscular volume, mean corpuscular hemoglobin, and white blood cell count (WBC) (P ˂ 0.05). There were 6 (6.0%) patients with leg ulcers, and none of them had alpha thalassemia, P = 0.04.

CONCLUSION

This study confirms that coexistence of alpha thalassemia with SCA significantly influences both the clinical and laboratory manifestations of young Nigerian SCA patients. The coexistence of this genetic modifier is associated with increased bone pain crisis and protects against sickle leg ulcers among the patients.