Sickle cell anemia: an underappreciated and unaddressed contributor to global childhood mortality

Targeted therapeutic management based on phytoconstituents for sickle cell anemia focusing on molecular mechanisms: Current trends and future perspectives

The global epidemic of Sickle cell anemia (SCA) is causing thousands of children to die. SCA, a genetic disorder affecting the hemoglobin-globin chain, affects millions globally. The primary physiological issue in these patients is the polymerization of sickle hemoglobin within their red blood cells (RBCs) during their deoxygenating state. The RBC undergoes a sickle shape due to the polymerization of mutant hemoglobin within it and membrane deformation during anoxic conditions. To prevent complications, it is essential to effectively stop the sickling of RBCs of the patients. Various medications have been studied for treating SCA patients, focusing on antisickling, γ-globulin induction, and antiplatelet action. Natural and synthetic anti-sickling agents can potentially reduce patient clinical morbidity. Numerous clinical trials focused on using natural remedies for the symptomatic therapy of SCA. Medicinal plants and phytochemical agents have antisickling properties. Recent studies on plant extracts' natural compounds have primarily focused on in vitro RBCs sickling studies, with limited data on in vivo studies. This review discussed the potential role of phytoconstituents in the management of SCA.

"Whatever is bad goes back to the woman": The gendered blame game of sickle cell disease in Malawi and Uganda

Mothers are commonly blamed for the ill-health of their children, and this is well documented in research. However, few studies have considered gendered patterns of blame for hereditary conditions caused by mutations from both parents through dual, shared genetic inheritance. This paper explores the 'gendering' of blame in the context of an inherited blood disorder known as sickle cell disease. The findings are drawn from 18 focus group discussions with 117 caregivers of children with sickle cell disease in Malawi and Uganda. Although one mutation from each parent is required for the disease to develop, low awareness about their status as healthy carriers of a sickle cell trait complicated the caregivers' recognition and acceptance of their genetic link to the child's condition. This study demonstrates how fathers and other members of the paternal side of the child's family would deflect blame from their own lineage by directing sole 'genetic responsibility' for the child's disease towards mothers. We discuss the implications of gendered blame on household dynamics and healthcare-seeking for children with sickle cell disease in this setting.

Iron restriction in sickle cell disease: When less is more

Primum non nocere! Can iron deficiency, an abnormality that causes anemia, benefit people with sickle cell disease (SCD) who already have an anemia? The published literature we review appears to answer this question in the affirmative: basic science considerations, animal model experiments, and noncontrolled clinical observations all suggest a therapeutic potential of iron restriction in SCD. This is because SCD's clinical manifestations are ultimately attributable to the polymerization of hemoglobin S (HbS), a process strongly influenced by intracellular HbS concentration. Even small decrements in HbS concentration greatly reduce polymerization, and iron deficiency lowers erythrocyte hemoglobin concentration. Thus, iron deficiency could improve SCD by changing its clinical features to those of a more benign anemia (i.e., a condition with fewer or no vaso-occlusive events). We propose that well-designed clinical studies be implemented to definitively determine whether iron restriction is a safe and effective option in SCD. These investigations are particularly timely now that pharmacologic agents are being developed, which may directly reduce red cell hemoglobin concentrations without the need for phlebotomies to deplete total body iron.

Meteorological parameters and hospitalizations of patients with sickle cell anemia: a 20-year retrospective study in Campinas, São Paulo, Brazil

To investigate the influence of climate on hospitalizations of sickle cell anemia (SCA) adults and children, we analyzed the health and meteorological parameters from a metropolis (1999-2018). 1462 hospitalizations were coded for SCA patients in crisis (M:F = 715:747) and 1354 hospitalizations for SCA patients without crisis (M:F = 698:656) [age = 22.9 vs 15.2 years and duration of hospitalization (DoH) = 5.7 vs 4.4 days, respectively,]. More hospitalizations were for adults than children in crisis, and for children than adults without crisis. More children and adults were hospitalized in winter andspring than in summer and autumn     Hospitalizations correlated positively with humidity (lag -5), maximum pressure (lag -2), mean pressure (lag -2), and thermal amplitude (lag -2), and negatively with maximum temperature (lag -3). DoH positively correlated with minimum temperature (lag -4). Understanding these complex associations would induce attitudinal/behavioral modifications among patients and their caregivers.

Impact of hemoglobin biophysical studies on molecular pathogenesis and drug therapy for sickle cell disease

Basic research on hemoglobin has been essential for understanding the origin and treatment of many hematological disorders due to abnormal hemoglobins. The most important of the hemoglobinopathies is sickle cell disease - Linus Pauling's "molecular disease" that gave birth to molecular medicine. In this review, I will describe the contributions of basic biophysical research on normal and sickle cell hemoglobin (HbS) to understanding the molecular pathogenesis of the disease and providing the conceptual basis for the various approaches to drug therapy that target HbS polymerization. Most prominent among these are the experimental results on the solubility of HbS as a function of oxygen saturation explained by the allosteric model of Monod, Wyman, and Changeux and the Gill-Wyman thermodynamic linkage relation between solubility and oxygen binding, the solubility of mixtures of HbS with normal or fetal hemoglobin explained by Minton's thermodynamic model, and the highly unusual kinetics of HbS polymerization explained by a novel double nucleation mechanism that also accounts for the aggregation kinetics of the Alzheimer's peptide. The HbS polymerization kinetics are of great importance to understanding the pathophysiology and clinical course, as well as guiding drug development for treating this common and severe disease. The article focuses primarily on experimental and theoretical results from my lab, so it is not a comprehensive review of the subject.

Clinical Features and Outcome of Sickle Cell Disease in a Tertiary Center in Northern Lebanon: A Retrospective Cohort Study in a Local, Hospital-Associated Registry

Sickle cell disease affects more than 30 million people worldwide, including 0.1% of the population in Lebanon. It is characterized by unpredictable and painful vaso-occlusive crises (VOCs) that may lead to serious complications. This study describes the clinical burden of sickle cell disease in a cohort of patients treated at a comprehensive sickle cell disease referral center in Tripoli, Northern Lebanon. Patient demographics, clinical events, treatment, and survival were evaluated from a local, hospital-based registry of 334 sickle cell disease patients treated at the Nini Hospital, Tripoli, Lebanon, between 2009 and 2019. Mean age at sickle cell disease diagnosis and at first clinic visit was 2.9 and 8.5 years, respectively. Pain was the most common clinical event observed among all patients. Over the 10-year follow-up period, 15 (4.5%) patients died. Hydroxyurea (HU) and red blood cell (RBC) transfusions were the most commonly used therapies. One hundred and thirty-one (39.0%) patients were diagnosed with sickle cell disease at the Nini Hospital; the remaining patients were referred to and subsequently followed-up at the Nini Hospital. Eighty-seven (66.0%) Nini Hospital-diagnosed patients experienced a VOC. Seventy-four (85.0%) of these patients with a VOC event required HU during follow-up. Patients with a VOC required more RBC transfusions, cholecystectomy, and splenectomy than non-VOC patients. The high disease burden observed in this population of sickle cell disease patients illustrates a continued, unmet need to both prevent and manage VOC events and other sickle cell disease-associated complications.

Mortality in sickle cell disease: A population-based study in an aboriginal community in the Gudalur Valley, Nilgiris, Tamil Nadu, India

BACKGROUND

Sickle cell disease (SCD), the most common monogenic disorder, affects more than 300 000 births annually, with 44  000 in India. Although the clinical phenotype of SCD is considered to be milder in aboriginal populations in India, there is a paucity of data on outcomes. To determine the severity of SCD in this population, we studied mortality rates and causes of mortality in a longitudinal cohort of patients with SCD in a remote aboriginal community in India receiving community-based comprehensive care.

PROCEDURES

Causes of death were analyzed in this cohort from January 2008 to December 2018. Details were collected from hospital records and in case of deaths at home by utilizing the WHO verbal autopsy questionnaire.

RESULTS

The cohort consisted of 157 patients belonging to the Paniya, Betta Kurumba, Kattunyakan, and Mullu Kurumba tribes. During the study period, there were 22 deaths, all from the Paniya tribe. Twelve deaths (54.5%) occurred in the hospital and the remaining at home (45.5%), reflecting a crude mortality rate of 140 per 1000 population. Twenty-five percent of deaths occurred in the 6-18 age group. There were no deaths in the 0-5 age group. The median age of death was 25 years, which was 30 years less than in the non-SCD aboriginal population. The leading causes of death were acute chest syndrome, anemia, and sepsis among the SCD patients and stroke and suicides in the non-SCD aboriginal population.

CONCLUSION

SCD is a severe disease among the Gudalur Valley's aboriginal population with a significant risk of premature mortality.

The psychological impact on family caregivers of children and adolescents with sickle cell anemia

Abstract Sickle cell anemia represents an aversive context, placing the family in a situation of vulnerability. This study investigated the psychological impact of sickle cell anemia on family caregivers of children and adolescents with this disease. A research with a quantitative approach followed by a survey was carried out, with a non-probabilistic sample of 100 caregivers who answered the instruments for measuring family functioning, disease-related stress, coping, anxiety, and depression. Clinical and sociodemographic characteristics were obtained from medical records and specific protocols. Caregivers of children with late diagnosis presented high disengaged coping scores, and minimum depression; early diagnosis was associated with mild depression. Family functioning domain scores were lower in families with younger children. Regression analyses showed that primary control coping indicates lower depression scores, and involuntaryengagement is a predictor of depression/anxiety. This study contributes to the understanding of the relationship between psychological, clinical, and sociodemographic variables in the context of sickle cell anemia.

Changing the Clinical Paradigm of Hydroxyurea Treatment for Sickle Cell Anemia Through Precision Medicine

Sickle cell anemia (SCA) is a common and devastating inherited blood disorder, affecting millions of people across the world. Without treatment, SCA results in tremendous morbidity and early mortality. Hydroxyurea is the primary and most well-established pharmacologic therapy with proven benefits to ameliorate the clinical course of SCA, primarily due to its ability to increase the expression of fetal hemoglobin (HbF), which prevents sickling of red blood cells. The optimal induction of HbF depends upon selection and maintenance of the proper dose that maximizes benefits and minimizes toxicity. Due to the significant interpatient variability in hydroxyurea pharmacokinetics, pharmacodynamics, and dosing, most patients treated with hydroxyurea receive suboptimal doses and have only modest treatment responses. Recognizing this variability, using a precision medicine approach, we developed and prospectively evaluated an individualized dosing model for children with SCA, designed to optimize the hydroxyurea dose and clinical response. We utilize novel laboratory methods and a sparse sampling strategy requiring only 10 μL of blood collected 15 minutes, 60 minutes, and 180 minutes after a test dose. We use Bayesian adaptive control to estimate hydroxyurea exposure and to select an individual, optimal starting dose. This dosing model has resulted in HbF responses >30-40%, levels beyond what is achieved with traditional weight-based dosing and trial and error dose escalation. This hydroxyurea dosing strategy, if widely implemented, has the potential to change the treatment paradigm of hydroxyurea therapy and improve outcomes for the millions of patients with SCA across the world.

Surveillance for sickle cell disease, United Republic of Tanzania

Objective

To determine the regional- and district-level newborn prevalence of sickle cell trait and disease, and the prevalence of haemoglobin variants and genetic modifiers of sickle cell disease, in the nine regions of north-western United Republic of Tanzania.

Methods

We repurposed dried blood spot samples from children (aged 0–24 months) born to mothers living with human immunodeficiency virus (HIV), collected as part of the HIV Early Infant Diagnosis programme, for sickle cell diagnosis. We performed isoelectric focusing to determine whether samples had normal haemoglobin, sickle cell trait, sickle cell disease or a rare haemoglobin variant. We shipped samples diagnosed as disease or variant to Cincinnati Children’s Hospital in the United States of America for deoxyribonucleic-acid-based analyses to determine the prevalence of α-thalassaemia, glucose-6-phosphate dehydrogenase (G6PD) deficiency or fetal haemoglobin genetic modifiers.

Findings

We analysed a total of 17 200 specimens during February 2017–May 2018. We observed a prevalence of sickle cell trait and disease of 20.3% (3492/17 200) and 1.2% (210/17 200), respectively. District-level trait varied from 8.6% (5/58) to 28.1% (77/274). Among confirmed sickle cell disease specimens, we noted 42.7% (61/143) had 1-gene deletion and 14.7% (21/143) had 2-gene deletion α-thalassaemia trait. We documented G6PD A^– deficiency in 19.2% (14/73) of males.

Conclusion

Our calculated prevalence is twice as high as previously reported and reinforces the need for enhanced sickle cell diagnostic services. Our district-level data will inform public health policy, allowing screening and disease-modifying hydroxyurea therapy to be focused on high-prevalence areas, until universal newborn screening is available.

Pre-transplant myeloid and immune suppression, upfront plerixafor mobilization and post-transplant cyclophosphamide: novel strategy for haploidentical transplant in sickle cell disease

Allogenic hematopoietic stem cell transplant is the only curative option for symptomatic sickle cell disease (SCD). HLA haploidentical related donor transplants are associated with high graft failure rates. We conceptualized a novel protocol (APOLLO protocol) using pre-transplant immune and myelosuppression (PTIS) using fludarabine, cyclophosphamide, and dexamethasone followed by augmented John Hopkins protocol by adding thiotepa to conditioning. Twenty-five consecutive patients suffering from symptomatic SCD were enrolled into the study. We added upfront plerixafor to granulocyte colony stimulating factor (GCSF) for mobilization of healthy donors. Graft versus host disease (GvHD) prophylaxis was done using post-transplant cyclophosphamide, sirolimus, and mycophenolate mofetil. Graft failure was not seen in any of our patients. Five patients developed acute grade II/IV GvHD (4 classical acute, 1 late onset), 3 had limited chronic GvHD. Out of 25 evaluable patients, 22 are alive and disease free, making an overall survival (OS) and disease-free survival (DFS) of 88% with a median follow up of 485 days (range 198-802). T-cell-replete haploidentical transplant with PTIS, augmented John Hopkins conditioning and plerixafor based mobilization is a safe and effective way of treating patients suffering from SCD with minimal or no risk of graft failure and acceptable GvHD rates.

Quality of life assessments in a cohort of Mozambican children with sickle cell disease

Introduction

sickle cell disease (SCD) has significant pediatric morbidity and mortality in sub-Saharan Africa, where access to therapies such as hydroxyurea and opioids is often limited. Poor disease control and Pain management adversely affects the well-being and mental health of affected children. Questionnaires have been utilized in other regions to report the quality of life (QOL) in children with SCD, but assessments from Africa are lacking.

Methods

children age 2-14 years with SCD presenting for routine outpatient consultations at Hospital Central de Maputo from June-August 2017 were offered participation. After informed consent, the Pediatric QOL Inventory (PedsQL) SCD Module was administered to all caregivers and children > 5 years. Responses were scored from 0-100, with higher scores representing better QOL.

Results

a total of 14 children were included, with six (43%), four (29%), two (14%), and two (14%) from the age groups of 2-4, 5-7, 8-12, and 13-14 years, respectively. Mean overall patient QOL was 65.3 and 56.0 in child and caregiver respondents. In patients > 5 years, the difference in mean overall QOL for those on/not on hydroxyurea was 0.6 (66.5-64.9) in child respondents and 15.8 (68.4-52.6) in caregiver respondents. Domains related to worry/emotions and communication scored lower in QOL than Pain-related domains for both patient and caregiver respondents.

Conclusion

SCD has a negative impact on QOL as reported by this cohort of Mozambican pediatric patients and caregivers, with Pain being less of a concern than emotional and interpersonal issues. A comprehensive, child-focused care approach with robust psychosocial support is needed.

Knowledge, awareness, and attitude of premarital screening with special focus on sickle cell disease: a study from Odisha

Sickle cell disease (SCD) is a genetic disorder with an estimated 5200 live births each year indicating towards a major public health issue in India. Although SCD has been described in India in numerous ethnic groups, it is most prevalent in tribal community. Prevalence of sickle cell gene is 5 to 34% in tribal communities, who have a high prevalence of socioeconomic disadvantage and are frequently medically underserved. The objective of the present study is to explore the knowledge, awareness, and attitude of premarital genetic counseling and screening for sickle cell hemoglobin among individuals of Koraput district. A cross-sectional study design was employed and a total of 152 individuals were recruited using multistage sampling technique, including 43 individuals with sickle cell hemoglobinopathy. Data was collected using a pre-tested, self-administered questionnaire and analyzed using SPSS-20. Though people are aware of SCD and SCT, majority believe that sickle cell carriers transmit the disease and they do not know that marriage between sickle cell carriers need to be avoided.

Recent Advances in the Treatment of Sickle Cell Disease

Sickle cell anemia (SCA) was first described in the Western literature more than 100 years ago. Elucidation of its molecular basis prompted numerous biochemical and genetic studies that have contributed to a better understanding of its pathophysiology. Unfortunately, the translation of such knowledge into developing treatments has been disproportionately slow and elusive. In the last 10 years, discovery of BCL11A, a major γ-globin gene repressor, has led to a better understanding of the switch from fetal to adult hemoglobin and a resurgence of efforts on exploring pharmacological and genetic/genomic approaches for reactivating fetal hemoglobin as possible therapeutic options. Alongside therapeutic reactivation of fetal hemoglobin, further understanding of stem cell transplantation and mixed chimerism as well as gene editing, and genomics have yielded very encouraging outcomes. Other advances have contributed to the FDA approval of three new medications in 2017 and 2019 for management of sickle cell disease, with several other drugs currently under development. In this review, we will focus on the most important advances in the last decade.

Mortality in children, adolescents and adults with sickle cell anemia in Rio de Janeiro, Brazil

Objective

To determine the mortality rate of children, adolescents and adults with sickle cell anemia in Rio de Janeiro, Brazil.

Methods

The number of deaths, the mortality rate and the causes of deaths in patients with sickle cell anemia who were treated and followed up at our institution for 15 years were determined and compared to data available for the Brazilian population.

Results

The overall number of deaths was 281 patients with a mortality rate of 16.77%. Survival probability was significantly higher in females. The number of deaths and the mortality rate were age-specific with a significant increase in the 19- to 29-year-old age group. The remaining life expectancy of the patients with sickle cell anemia was less than that of Brazilians at large. The gap between the two was about 20 years for ages between one and five years with this gap decreasing to ten years after the age of 65 years. The most common causes of death were infection, acute chest syndrome, overt stroke, organ damage and sudden death during painful crises.

Conclusion

To the best of our knowledge, this is the first Brazilian study in a single institution in Rio de Janeiro; the mortality rate was 18.87% among adult patients with sickle cell anemia. The mortality rates in children and adults are higher than those reported in developed countries of the northern hemisphere.

Simultaneous point-of-care detection of anemia and sickle cell disease in Tanzania: the RAPID study

Both anemia and sickle cell disease (SCD) are highly prevalent across sub-Saharan Africa, and limited resources exist to diagnose these conditions quickly and accurately. The development of simple, inexpensive, and accurate point-of-care (POC) assays represents an important advance for global hematology, one that could facilitate timely and life-saving medical interventions. In this prospective study, Robust Assays for Point-of-care Identification of Disease (RAPID), we simultaneously evaluated a POC immunoassay (Sickle SCAN™) to diagnose SCD and a first-generation POC color-based assay to detect anemia. Performed at Bugando Medical Center in Mwanza, Tanzania, RAPID tested 752 participants (age 1 day to 20 years) in four busy clinical locations. With minimally trained medical staff, the SCD POC assay diagnosed SCD with 98.1% sensitivity and 91.1% specificity. The hemoglobin POC assay had 83.2% sensitivity and 74.5% specificity for detection of severe anemia (Hb ≤ 7 g/dL). Interobserver agreement was excellent for both POC assays (r = 0.95-0.96). Results for the hemoglobin POC assay have informed the second-generation assay design to be more suitable for low-resource settings. RAPID provides practical feasibility data regarding two novel POC assays for the diagnosis of anemia and SCD in real-world field evaluations and documents the utility and potential impact of these POC assays for sub-Saharan Africa.

Anti-Toxoplasma gondii antibodies in patients with beta-hemoglobinopathies: the first report in the Americas

Background

In Brazil, there have been no previous studies of Toxoplasma gondii infection in sickle cell anemia patients and carriers of severe forms of beta-thalassemia. This study evaluated T. gondii infection in patients with beta-hemoglobinopathies.

Methods

A total of 158 samples, 77 (48.7%) men and 81 (51.3%) women, were evaluated. Three groups were formed: G1 (85 patients with sickle cell disease); G2 (11 patients with homozygous beta-thalassemia; G3 (62 patients with heterozygous beta-thalassemia). ELISA was employed to identify anti-T. gondii IgM and IgG antibodies, and molecular analysis was performed to determine beta-hemoglobin mutations. Fisher’s exact test was used to compare frequencies of anti-T. gondii IgM and IgG antibodies in respect to gender and age.

Results

Anti-T. gondii IgG antibodies were found in 43.5% of individuals in G1, 18.1% in G2 and 50% in G3. All samples from G1 and G2 were seronegative for anti-T. gondii IgM antibodies, but 3.2% from G3 were seropositive. Considering anti-T. gondii IgG antibodies, no statistical significant differences were found between these groups nor in seroprevalence between genders within each group. Despite this, comparisons of the mean ages between G1, G2 and G3 were statistically significant (G2 vs. G1: p value = 0.0001; G3 vs. G1: p-value <0.0001; G3 vs. G2: p-value = 0.0001).

Conclusion

A comparison by age of patients with sickle cell anemia showed a trend of lower risk of infection among younger individuals. Therefore, this study demonstrates that T. gondii infection occurs in patients with beta-thalassemia and sickle cell anemia in Brazil as seen by the presence of anti-T. gondii IgM and IgG antibodies.

Survival of children with sickle cell disease in the comprehensive newborn screening programme in Minas Gerais, Brazil

BACKGROUND

Children in developing countries with sickle cell disease SCD have high rates of mortality, especially in some parts of Africa.

AIM

To compare the 5-year estimated mortality rate in children born between 1999 and 2001 with that of children born between 2009 and 2011.

METHODS

During the period 1998-2012, sickle cell disease was diagnosed in 2591 of 3,617,919 newborns screened in Minas Gerais, Brazil (1 : 1,400). The estimated probability of death [1 - Survival] was calculated by the Kaplan-Meier method. The logrank test was used to compare groups of survival data.

RESULTS

Of the 2576 children (15 were excluded), 193 died (7.4%): 153 (79.3%) had SS/Sβ(0)-thalassaemia, 34 had SC (17.6%), and six (3.1%) had Sβ(+) thalassaemia. The 5-year estimated mortality was lower for children born between 2009 and 2011 (n=509) than for those born between 1999 and 2001 (n=624), although not significantly [mean (SD) 5.8% (1.1) vs 6.2% (1.0)], respectively).

CONCLUSION

Despite an effective ongoing comprehensive screening programme, mortality from SCD in Minas Gerais is still high. To decrease mortality rates, socio-economic development and SCD education programmes for health professionals and families are required.

Characteristics of a rapid, point-of-care lateral flow immunoassay for the diagnosis of sickle cell disease

Sickle cell disease (SCD) is a common and life-threatening hematological disorder, affecting approximately 400,000 newborns annually worldwide. Most SCD births occur in low-resource countries, particularly in sub-Saharan Africa, where limited access to accurate diagnostics results in early mortality. We evaluated a prototype immunoassay as a novel, rapid, and low-cost point-of-care (POC) diagnostic device (Sickle SCAN) designed to identify HbA, HbS, and HbC. A total of 139 blood samples were scored by three masked observers and compared to results using capillary zone electrophoresis. The sensitivity (98.3-100%) and specificity (92.5-100%) to detect the presence of HbA, HbS, and HbS were excellent. The test demonstrated 98.4% sensitivity and 98.6% specificity for the diagnosis of HbSS disease and 100% sensitivity and specificity for the diagnosis of HbSC disease. Most variant hemoglobins, including samples with high concentrations of HbF, did not interfere with the ability to detect HbS or HbC. Additionally, HbS and HbC were accurately detected at concentrations as low as 1-2%. Dried blood spot samples yielded clear positive bands, without loss of sensitivity or specificity, and devices stored at 37°C gave reliable results. These analyses indicate that the Sickle SCAN POC device is simple, rapid, and robust with high sensitivity and specificity for the detection of HbA, HbS, and HbC. The ability to obtain rapid and accurate results with both liquid blood and dried blood spots, including those with newborn high-HbF phenotypes, suggests that this POC device is suitable for large-scale screening and potentially for accurate diagnosis of SCD in limited resource settings.

Hydroxyurea Therapy for Children With Sickle Cell Anemia in Sub-Saharan Africa: Rationale and Design of the REACH Trial

BACKGROUND

Sickle cell anemia (SCA) is an inherited hematological disorder that causes a large but neglected global health burden, particularly in Africa. Hydroxyurea represents the only available disease-modifying therapy for SCA, and has proven safety and efficacy in high-resource countries. In sub-Saharan Africa, there is minimal use of hydroxyurea, due to lack of data, absence of evidence-based guidelines, and inexperience among healthcare providers.

PROCEDURE

A partnership was established between investigators in North America and sub-Saharan Africa, to develop a prospective multicenter research protocol designed to provide data on the safety, feasibility, and benefits of hydroxyurea for children with SCA.

RESULTS

The Realizing Effectiveness Across Continents with Hydroxyurea (REACH, ClinicalTrials.gov NCT01966731) trial is a prospective, phase I/II open-label dose escalation study of hydroxyurea that will treat a total of 600 children age 1-10 years with SCA: 150 at each of four different clinical sites within sub-Saharan Africa (Angola, Democratic Republic of Congo, Kenya, and Uganda). The primary study endpoint will be severe hematological toxicities that occur during the fixed-dose treatment phase. REACH has an adaptive statistical design that allows for careful assessment of toxicities to accurately identify a safe hydroxyurea dose.

CONCLUSIONS

REACH will provide data that address critical gaps in knowledge for the treatment of SCA in sub-Saharan Africa. By developing local expertise with the use of hydroxyurea and helping to establish treatment guidelines, the REACH trial results will have the potential to transform care for children with SCA in Africa.

Hydroxyurea therapy for sickle cell anemia

INTRODUCTION

Sickle cell anemia (SCA) is a severe, inherited hemoglobin disorder affecting 100,000 persons in the US and millions worldwide. Hydroxyurea, a once daily oral medication, has emerged as the primary disease-modifying therapy for SCA. The accumulated body of evidence over 30 years demonstrates that hydroxyurea is a safe and effective therapy for SCA, but hydroxyurea remains underutilized for a variety of reasons.

AREAS COVERED

In this review, we summarize the available evidence regarding the pharmacology, clinical, and laboratory benefits, and safety of hydroxyurea therapy for the treatment of SCA. The purpose of this review is to provide the reader a comprehensive understanding of hydroxyurea and to reinforce the fact that hydroxyurea is a safe and effective medication for the treatment of SCA.

EXPERT OPINION

In our opinion, hydroxyurea therapy should be considered standard-of-care for SCA, representing an essential component of patient management. Early initiation and broader use of hydroxyurea will alter the natural history of SCA, so affected children can live longer and healthier lives. In addition, hydroxyurea use should be extended to low-resource settings such as sub-Saharan Africa, where the burden of SCA and the need for hydroxyurea is arguably the greatest.

The Daily Experiences of Adolescents in Lebanon With Sickle Cell Disease

OBJECTIVES

Despite the psychosocial and physical consequences associated with sickle cell disease (SCD), the daily lived experience of adolescents diagnosed with this disease is a phenomenon rarely described. The objective of this study was to explore the daily lived experience of adolescents with SCD living in Lebanon.

METHOD

Twelve adolescents with SCD between the ages of 12 and 17 years were interviewed with use of a semi-structured interview during a routine follow-up visit after they were assessed as being pain free. Interviews were transcribed verbatim, and thematic analysis was conducted.

RESULTS

Adolescents with SCD experience a layered burden consisting of physical, emotional, and sympathetic pain that affects much of their daily personal and social lives. Nevertheless, they seem to claim normalcy and to downplay their pain and suffering in order to limit their caregivers' distress.

CONCLUSION

These findings can be used to assist health care providers in designing culturally sensitive interventions specifically designed for adolescents with SCD and their families to enable them to better cope with their illness.

Environmental determinants of severity in sickle cell disease

Sickle cell disease causes acute and chronic illness, and median life expectancy is reduced by at least 30 years in all countries, with greater reductions in low-income countries. There is a wide spectrum of severity, with some patients having no symptoms and others suffering frequent, life-changing complications. Much of this variability is unexplained, despite increasingly sophisticated genetic studies. Environmental factors, including climate, air quality, socio-economics, exercise and infection, are likely to be important, as demonstrated by the stark differences in outcomes between patients in Africa and USA/Europe. The effects of weather vary with geography, although most studies show that exposure to cold or wind increases hospital attendance with acute pain. Most of the different air pollutants are closely intercorrelated, and increasing overall levels seem to correlate with increased hospital attendance, although higher concentrations of atmospheric carbon monoxide may offer some benefit for patients with sickle cell disease. Exercise causes some adverse physiological changes, although this may be off-set by improvements in cardiovascular health. Most sickle cell disease patients live in low-income countries and socioeconomic factors are undoubtedly important, but little studied beyond documenting that sickle cell disease is associated with decreases in some measures of social status. Infections cause many of the differences in outcomes seen across the world, but again these effects are relatively poorly understood. All the above factors are likely to account for much of the pathology and variability of sickle cell disease, and large prospective studies are needed to understand these effects better.

Impact of a Comprehensive Sickle Cell Center on Early Childhood Mortality in a Developing Country: The Jamaican Experience

OBJECTIVE

To compare mortality in children <5 years of age with sickle cell disease (SCD) in Jamaica, a resource-limited country, diagnosed by newborn screening and managed in a comprehensive care facility, to that of the general population.

STUDY DESIGN

The study was carried out at the Sickle Cell Unit in Kingston, Jamaica. We determined the status (dead/alive) at age 5 years in a cohort of 548 children with SCD diagnosed by newborn screening and managed at the Sickle Cell Unit during the period November 1995 to December 2009. The standardized mortality ratio was calculated using World Health Organization life tables for reference mortality.

RESULTS

Eight deaths (1.5%) occurred in children <5 years of age during the study period. The mean age at death was 2.0 ± 1.5 years. The overall mortality incidence in children <5 years of age was 3.1 (95% CI 1.6, 6.2) per 1000 person-years with a standardized mortality ratio of 0.52 (95% CI 0.3, 1.0).

CONCLUSIONS

Mortality in children <5 years of age with SCD diagnosed at birth and managed at a comprehensive care clinic in Jamaica is equivalent to that of the general population. Children with SCD, a highly vulnerable population, can be effectively managed, even in resource-limited environments.

Allogeneic donor availability for hematopoietic stem cell transplantation in children with sickle cell disease

Hematopoietic stem cell transplant is curative of sickle cell disease (SCD) but limited by donor availability. Searches for 85 patients with SCD without matched sibling donors from 2009-2013 using modern techniques (allele-level HLA matching for unrelated donors and higher total nucleated cell doses for umbilical cord blood (UCB)) showed potential match probabilities of 20% for 8/8 HLA-matched unrelated donors, 84% for 7/8 donors, and 97% for two 4-6/6 UCBs suitable for ex-vivo expanded/double cord transplant. Searches performed by age 43 months would have a 90% chance of finding a suitable 5-6/6 UCB.

Caries prevalence and impact on oral health-related quality of life in children with sickle cell disease: cross-sectional study

BACKGROUND

Children with sickle cell disease (SCD) may present oral conditions that can compromise children's health even more. However, there is still no consensus on the association between SCD and dental caries. The aim of this study was to assess caries prevalence in children with sickle cell disease (SCD), and the association of dental caries with socioeconomic factors, disease severity, and oral-health related to quality of life (OHRQoL).

METHODS

The sample was comprised of 106 children with SCD aged 8 to 14 years who were attending the Center for Hematology (Hemominas) in Belo Horizonte, Brazil. They were matched to 385 healthy peers. Data collection included interviews with guardians concerning SCD characteristics, and previous social and oral examinations to determine the caries prevalence. Caries prevalence as measured through the Decayed, Missing and Filled (dmft and DMFT) indices. OHRQoL was evaluated through the Brazilian versions of the Child Perceptions Questionnaires (CPQ8-10, and CPQ11-14 short-form version). Statistical analyses were performed using the chi-square test or Fisher`s exact test and the Mann Whitney test, as well as linear regression.

RESULTS

The DMFT index was 1.3 (SD: 2.1) in younger children with SCD and 1.5 (SD: 1.9) in SCD teens. Younger children with SCD had lower caries experience compared to healthy peers (p = .03). The experience of dental caries among teens with SCD was similar to healthy peers (p > 0.05). In addition, we did not see a significant difference on the mean overall scores of CPQ8-10 between SCD younger children and controls. There was no statistically significant difference in the mean overall scores of teens CPQ11-14 between SCD and the control group. Socioeconomic variables were not associated with dental caries in the participants with SCD. However, SCD severity was associated with higher DMFT indexes (p < 0.05).

CONCLUSIONS

Younger children with SCD had a low experience of dental caries. The dental caries experience in teenagers with SCD was similar to their healthy peers. OHRQoL was similar between SCD participants and controls.

Characterization of mortality in children with sickle cell disease diagnosed through the Newborn Screening Program

OBJECTIVE

To characterize the deaths of 193 children with sickle cell disease screened by a neonatal program from 1998 to 2012 and contrast the initial years with the final years.

METHODS

Deaths were identified by active surveillance of children absent to scheduled appointments in Blood Bank Clinical Centers (Hemominas). Clinical and epidemiological data came from death certificates, neonatal screening database, medical records, and family interviews.

RESULTS

Between 1998 and 2012, 3,617,919 children were screened and 2,591 had sickle cell disease (1:1,400). There were 193 deaths (7.4%): 153 with SS/Sβ(0)-thalassemia, 34 SC and 6 Sβ(+)thalassemia; 76.7% were younger than five years; 78% died in the hospital and 21% at home or in transit. The main causes of death were infection (45%), indeterminate (28%), and acute splenic sequestration (14%). In 46% of death certificates, the term "sickle cell" was not recorded. Seven-year death rate for children born between 1998 and 2005 was 5.43% versus 5.12% for those born between 2005 and 2012 (p = 0.72). Medical care was provided to 75% of children; 24% were unassisted. Medical care was provided within 6 hours of symptom onset in only half of the interviewed cases. In 40.5% of cases, death occurred within the first 24 hours. Low family income was recorded in 90% of cases, and illiteracy in 5%.

CONCLUSIONS

Although comprehensive and effective, neonatal screening for sickle cell disease was not sufficient to significantly reduce mortality in a newborn screening program. Economic and social development and increase of the knowledge on sickle cell disease among health professionals and family are needed to overcome excessive mortality.

Prevalence of Hb S (HHB: c.20A > T) in a Honduran population of African descent

Sickle cell disease is the most common hemoglobinopathy worldwide, particularly in Africa and among people of African descent. Serious clinical consequences characterize the homozygous condition. To determine the prevalence of Hb S (HBB: c.20A > T) and anemia in a community of people of African descent from Honduras, 202 individuals were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The high prevalence found indicates that it is necessary to implement a program to prevent the consequences of this disease in vulnerable populations of Honduras.