Sickle cell disease: Reducing the global disease burden

Evaluation of anti-sickling effects of two varieties of Cajanus cajan (L.) Huth on sickle cell beta thalassemia

ETHNO-PHARMACOLOGICAL RELEVANCE

Globally, the prevalence of sickle cell disease is on the rise, with developing countries experiencing particularly alarming mortality rate compared to developed nations. The World Health Organization (WHO) and United Nations (UN) have acknowledged sickle cell disease as a significant global public health concern. Unfortunately, a cure for this condition is yet to be discovered, and existing allopathic treatments, while offering relief, come with serious side effects. In recent times, there has been a growing interest in exploring the potential of medicinal plants for treating sickle cell disease due to their content of secondary metabolites that may impact the disease's mechanisms. Cajanus cajan, a crucial grain legume in rain-fed agriculture in semi-arid tropics, has been traditionally used in folk medicine to manage various illnesses and is suggested to possess anti-sickling properties.

AIM OF THE STUDY

The present study investigated two varieties of C. cajan for their effectiveness in treating sickle cell beta thalassemia, a variant of sickle cell disease.

MATERIALS AND METHODS

The study was divided into four groups consisting of the untreated group (group 1), group treated with standard drug (group 2), group treated with white C. cajan (group 3) and group treated with brown C. cajan (group 4). The effects of the two variety of C. cajan were measured by polymerization test, reversibility test, osmotic fragility test, deoxygenation and beta globin synthesis test.

RESULT

The results revealed that both varieties of C. cajan demonstrated a reduction in polymerization rates, reversed sickled red blood cells, increased the oxygen affinity of Hb-S/β, elevated the Fe2+/Fe3+ ratio, and maintained the membrane stability of red blood cells. Notably, the white variety exhibited superior anti-sickling properties compared to the brown variety.

CONCLUSION

This suggests that this significant leguminous crop could be utilized for the treatment and management of sickling disorders, particularly in low-income countries where conventional treatments may be financially inaccessible to patients.

Reviewing the impact of hydroxyurea on DNA methylation and its potential clinical implications in sickle cell disease

Hydroxyurea (HU) is the most common drug therapy for sickle cell disease (SCD). The clinical benefits of HU derive from its upregulation of fetal hemoglobin (HbF), which reduces aggregation of the mutated sickle hemoglobin protein (HbS) and reduces SCD symptoms and complications. However, some individuals do not respond to HU, or stop responding over time. Unfortunately, current understanding of the mechanism of action of HU is limited, hindering the ability of clinicians to identify those patients who will respond to HU and to optimize treatment for those receiving HU. Given that epigenetic modifications are essential to erythropoiesis and HbF expression, we hypothesize that some effects of HU may be mediated by epigenetic modifications, specifically DNA methylation. However, few studies have investigated this possibility and the effects of HU on DNA methylation remain relatively understudied. In this review, we discuss the evidence linking HU treatment to DNA methylation changes and associated gene expression changes, with an emphasis on studies that were performed in individuals with SCD. Overall, although HU can affect DNA methylation, research on these changes and their clinical effects remains limited. Further study is likely to contribute to our understanding of hematopoiesis and benefit patients suffering from SCD.

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.

Real-world evidence of the burden of sickle cell disease: a 5-year longitudinal study at a Brazilian reference center

INTRODUCTION

Sickle cell disease (SCD) is an inherited and multisystem blood disorder characterized by hemolytic anemia, vaso-occlusive crises (VOCs), progressive multiorgan damage and increased mortality. In Brazil, it is one of the most common monogenic diseases afflicting 60,000 to 100,000 individuals, however, there are sparse epidemiological data, as well as information on the utilization of public healthcare resources.

METHOD

This was a 5-year (2016 - 2020) retrospective study conducted at one Brazilian reference center on SCD - Santa Casa de Sao Paulo, in Sao Paulo, Brazil.

RESULTS

Among a total of 100 eligible adult patients, the median age was 31.0 years old, 84% of the patients were aged between 18 and 45 years old; 59% were women and 91% presented the genotype HbSS. The number of hematologist and non-hematologist visits at the outpatient unit were 2,198 and 1,436, respectively. The number of hospital ER visits was 758, of which 51% required 864 days of hospitalization. The main cause for seeking hospital medical care was the VOCs. The numbers and ratios of VOCs were: 1 to 10 VOCs, 64%; 11 to 20, 15%, and; 21 or more, 1%. There was a statistically significant difference between the number of VOCs and hospitalizations, as well as infection.

CONCLUSION

Results indicate the burden of SCD on Brazilian patients' daily lives, the impact of VOCs on public healthcare resources, the importance of having a national surveillance program to improve resource utilization and clinical outcomes of patients with SCD and the urgent need for the revitalizing of the current national comprehensive SCD care programs.

Perceptions and preferences for genetic testing for sickle cell disease or trait: a qualitative study in Cameroon, Ghana and Tanzania

Sickle cell disease (SCD) is a single gene blood disorder characterised by frequent episodes of pain, chronic anaemic, acute chest syndrome, severe disease complications and lifelong debilitating multi-system organ damage. Genetic testing and screening programs for SCD and the sickle cell trait (SCT) are valuable for early diagnosis and management of children living with SCD, and in the identification of carriers of SCT. People with SCT are for the most part asymptomatic and mainly identified as through genetic testing or when they have a child with SCD. This qualitative study explored perceptions towards genetic testing for SCD and SCT in Cameroon, Ghana, and Tanzania. The results show a general preference for newborn screening for SCD over prenatal and premarital/preconception testing, primarily due to its simpler decision-making process and lower risk for stigmatization. Premarital testing for SCT was perceived to be of low public health value, as couples are unlikely to alter their marriage plans despite being aware of their risk of having a child with SCD. Adolescents were identified as a more suitable population for SCT testing. In the case of prenatal testing, major concerns were centred on cultural, religious, and personal values on pregnancy termination. The study revealed a gender dimension to SCD/SCT testing. Participants mentionned that women bear a heightened burden of decision making in SCD/SCT testing, face a higher risk of rejection by potential in-laws/partners if the carriers of SCT, as well as the possibility of  divorce if they have a child with SCD. The study highlights the complex cultural, ethical, religious and social dynamics surrounding genetic testing for SCD and emphasises the need for public education on SCD and the necessity of incorporating genetic and psychosocial counselling into SCD/SCT testing programs.

Implications of climatic change on sickle cell anemia: A review

Sickle cell anemia (SCA) is a hereditary blood disorder characterized by abnormal hemoglobin, causing red blood cells to assume a sickle shape, leading to various complications. Climate change has emerged as a significant global challenge, influencing environmental conditions worldwide. This paper explores the implications of climatic variations on the prevalence, management, and outcomes of SCA. Climate change affects weather patterns, leading to altered temperatures, increased frequency of extreme weather events, and variations in humidity levels. These changes can have a profound impact on individuals living with SCA. High temperatures exacerbate the symptoms of SCA, potentially triggering painful vaso-occlusive crises due to dehydration and increased blood viscosity. Conversely, cold temperatures may induce vaso-occlusion by causing blood vessels to constrict. Changes in rainfall patterns might also affect water accessibility, which is crucial for maintaining adequate hydration, particularly in regions prone to droughts. The management of SCA is multifaceted, involving regular medical care, hydration, and avoiding triggers that could precipitate a crisis. Adverse weather events and natural disasters can disrupt healthcare infrastructure and access to essential medications and resources for SCA patients, especially in vulnerable communities. To mitigate the implications of climatic change on SCA, interdisciplinary strategies are essential. These strategies may include enhancing healthcare systems' resilience to climate-related disruptions, implementing adaptive measures to address changing environmental conditions, and promoting public awareness and education on managing SCA amidst climate variability. In conclusion, climatic variations pose significant challenges for individuals with SCA, affecting the prevalence, management, and outcomes of the disease.

Compare the Efficacy and Safety of Deferoxamine, Deferasirox, and Deferiprone in Patients With Sickle Cell Disease or Transfusion-Dependent Anemia: A Network Meta-Analysis of Randomized Control Trials

This network meta-analysis was conducted with the aim of comparing the efficacy and safety of deferiprone (DFP), deferasirox (DFX), and deferoxamine (DFO) in individuals with sickle cell disease (SCD) or transfusion-dependent anemia. This systematic review and meta-analysis adhered to the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)" guidelines. The search was conducted on electronic databases, including PubMed, CINAHIL, and EMBASE, from the inception of databases to January 10, 2024. Outcomes assessed in this study included a change in liver iron concentration (LIC) and a change in ferritin from baseline. For safety analysis, adverse events were compared among three treatment groups. A total of five studies were included in this meta-analysis. The pooled analysis showed that the change in LIC and serum ferritin from baseline was not significantly different in patients with SCD or other anemias. In terms of adverse events, deferiprone was the safest among all. In conclusion, deferiprone demonstrated noninferiority to deferoxamine and deferasirox in measures of iron load, presenting a viable treatment option. Safety outcomes revealed deferasirox carried a higher risk of adverse events compared to deferiprone, supporting its favorable safety profile.

Altered ventricular longitudinal strain in children with sickle cell disease: Role of TGF-β and IL-18

BACKGROUND

Cardiovascular involvement in sickle cell disease (SCD) has a great impact on patients' morbidity and mortality. Recently, interleukin-18 (IL-18) and transforming growth factor beta (TGF-β) were suggested as potential biomarkers for sickle cell cardiomyopathy. Global longitudinal strain (GLS) is a reliable early parameter for estimation of deformed myocardium. This study evaluated the role of TGF-β and IL-18 as risk indicators of altered strain in patients with SCD.

METHODS

Forty children with SCD (age >5 years) and 40 healthy children as controls, matched in age and sex, were enrolled in the study. All participants were subjected to clinical examination, complete blood count, serum ferritin, TGF-β, IL-18, and assessment of cardiac function by echocardiography.

RESULTS

TGF-β, IL-18, and lactic acid dehydrogenase (LDH) were significantly higher among cases (mean age: 10.6 ± 3.5 years) when compared to controls (p < .001), at cutoff values 41.7 ng/mL, 128.9 pg/mL, and 340 unit, respectively. The LS of free wall of RV (FW-RV) was significantly lower among cases when compared to controls (-23.55% ± 5.55% vs. -28.73% ± 2.43%, p < .001). Free wall longitudinal strain of the right ventricle (FWLS-RV) was significantly correlated to IL-18 and LDH (p < .001), while GLS-RV was significantly correlated to TGF-β. The GLS-LV was correlated to frequency of vaso-occlusive crises (VOCs) per year (p < .001). Diastolic function, E/A of LV, and RV were negatively correlated to the hemoglobin and serum ferritin levels.

CONCLUSIONS

The TGF-β, IL-18, and LDH along with frequent VOCs are correlated to altered LS, especially the right ventricle, and could serve as risk indicators for subclinical cardiomyopathy in children with SCD.

Genetic literacy and experiential knowledge on sickle cell disease among Canadian- and foreign-born male and female Anglophone and Francophone youth in Canada

OBJECTIVES

Growing global human mobility raises concerns about impacts on global health, particularly on the prevalence of sickle cell disease. This research unveiled the level of genetic literacy on sickle cell disease of male and female Anglophone and Francophone youth living in Canada. The research responded to questions about whether the type of information about the disease has been more prevalent among the youth's family, friends, acquaintances and school circles, and the influence of such information on shaping the current youth level of genetic literacy on the disease.

METHODS

An online survey hosted by a Canadian university (2019/2020) platform was conducted with youth (n=87, aged 16-29) recruited in their natural, social environments in seven Canadian provinces. Data analysis used descriptive statistics and manual qualitative content analysis.

RESULTS

Youth, mostly Canadian-born, 71.42 % Francophones and 67.12 % Anglophones, descend from parents who had been born in countries at risk for the disease. Results indicated that experiential knowledge is due to the familiarity with the disease occurrence among family members and acquaintances. Participants did not comment about how academic-gained knowledge could influence their own decision on becoming a parent.

CONCLUSIONS

Independently of their country of birth, Canadian youth seem to have unmet information needs: a complex challenge requiring creativity and simplicity to deliver information through attractive media.

Effects of Experienced Discrimination in Pediatric Sickle Cell Disease: Caregiver and Provider Perspectives

For Black children with sickle cell disease (SCD) and their families, high disease stigmatization and pervasive racism increase susceptibility to discrimination in healthcare settings. Childhood experiences of discrimination can result in medical nonadherence, mistrust of healthcare providers, and poorer health outcomes across the lifespan. Caregivers and medical providers are essential to childhood SCD management and are therefore well-positioned to provide insight into discrimination in the context of pediatric SCD. This mixed-methods study sought caregivers' and providers' perspectives on processes underlying discrimination and potential solutions to mitigate the negative effects of perceived discrimination among children with SCD. Caregivers (N = 27) of children with SCD (≤ 12 years old) and providers from their hematology clinics (N = 11) participated in individual semi-structured interviews exploring experiences of discrimination and daily SCD management and completed a quantitative measure of discrimination. Qualitative data were collected until themes reached saturation and subsequently transcribed verbatim, coded, and analyzed using applied thematic analysis. Quantitative and qualitative data converged to suggest the pervasiveness of discrimination in healthcare settings. Three qualitative themes emerged: (1) healthcare system factors underlie discrimination, (2) families' challenging interactions with providers lead to perceptions of discrimination, and (3) experiences of discrimination impact caregiver-provider interactions. Both caregivers and providers highlighted building trusting patient-provider relationships and encouraging patients' self-advocacy as means to reduce experiences and impacts of discrimination. These findings offer potential approaches to tangibly mitigate occurrences of discrimination in pediatric healthcare settings by trust building, accountability keeping, and fostering rapport to improve quality of care and pediatric SCD health outcomes.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Global, regional, and national prevalence and mortality burden of sickle cell disease, 2000-2021: a systematic analysis from the Global Burden of Disease Study 2021

BACKGROUND

Previous global analyses, with known underdiagnosis and single cause per death attribution systems, provide only a small insight into the suspected high population health effect of sickle cell disease. Completed as part of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021, this study delivers a comprehensive global assessment of prevalence of sickle cell disease and mortality burden by age and sex for 204 countries and territories from 2000 to 2021.

METHODS

We estimated cause-specific sickle cell disease mortality using standardised GBD approaches, in which each death is assigned to a single underlying cause, to estimate mortality rates from the International Classification of Diseases (ICD)-coded vital registration, surveillance, and verbal autopsy data. In parallel, our goal was to estimate a more accurate account of sickle cell disease health burden using four types of epidemiological data on sickle cell disease: birth incidence, age-specific prevalence, with-condition mortality (total deaths), and excess mortality (excess deaths). Systematic reviews, supplemented with ICD-coded hospital discharge and insurance claims data, informed this modelling approach. We employed DisMod-MR 2.1 to triangulate between these measures-borrowing strength from predictive covariates and across age, time, and geography-and generated internally consistent estimates of incidence, prevalence, and mortality for three distinct genotypes of sickle cell disease: homozygous sickle cell disease and severe sickle cell β-thalassaemia, sickle-haemoglobin C disease, and mild sickle cell β-thalassaemia. Summing the three models yielded final estimates of incidence at birth, prevalence by age and sex, and total sickle cell disease mortality, the latter of which was compared directly against cause-specific mortality estimates to evaluate differences in mortality burden assessment and implications for the Sustainable Development Goals (SDGs).

FINDINGS

Between 2000 and 2021, national incidence rates of sickle cell disease were relatively stable, but total births of babies with sickle cell disease increased globally by 13·7% (95% uncertainty interval 11·1-16·5), to 515 000 (425 000-614 000), primarily due to population growth in the Caribbean and western and central sub-Saharan Africa. The number of people living with sickle cell disease globally increased by 41·4% (38·3-44·9), from 5·46 million (4·62-6·45) in 2000 to 7·74 million (6·51-9·2) in 2021. We estimated 34 400 (25 000-45 200) cause-specific all-age deaths globally in 2021, but total sickle cell disease mortality burden was nearly 11-times higher at 376 000 (303 000-467 000). In children younger than 5 years, there were 81 100 (58 800-108 000) deaths, ranking total sickle cell disease mortality as 12th (compared to 40th for cause-specific sickle cell disease mortality) across all causes estimated by the GBD in 2021.

INTERPRETATION

Our findings show a strikingly high contribution of sickle cell disease to all-cause mortality that is not apparent when each death is assigned to only a single cause. Sickle cell disease mortality burden is highest in children, especially in countries with the greatest under-5 mortality rates. Without comprehensive strategies to address morbidity and mortality associated with sickle cell disease, attainment of SDG 3.1, 3.2, and 3.4 is uncertain. Widespread data gaps and correspondingly high uncertainty in the estimates highlight the urgent need for routine and sustained surveillance efforts, further research to assess the contribution of conditions associated with sickle cell disease, and widespread deployment of evidence-based prevention and treatment for those with sickle cell disease.

FUNDING

Bill & Melinda Gates Foundation.

Expecting more: the case for incorporating fertility services into comprehensive sickle cell disease care

Assisted reproductive technologies (ART) are not yet systematically available to people with sickle cell disease or their parents. Fertility care for these groups requires addressing sickle cell disease-associated infertility risks, fertility preservation options, pregnancy possibilities and outcomes, and, when needed, infertility treatment. People with a chance of having a child with sickle cell disease can use in-vitro fertilisation with preimplantation genetic testing to conceive a child unaffected by sickle cell disease. Also, parents of children with sickle cell disease can use this technology to identify embryos to become potential future matched sibling donors for stem cell transplant. In the USA, disparities in fertility care for the sickle cell disease community are especially stark. Universal screening of newborn babies' identifies sickle cell disease and sickle cell trait, guidelines direct preconception genetic carrier screening, and standard-of-care fertility preserving options exist. However, potentially transformative treatments and cures for patients with sickle cell disease are not used due to iatrogenic infertility concerns. In diversely resourced care settings, obstacles to providing fertility care to people affected by sickle cell disease persist. In this Viewpoint, we contend that fertility care should be incorporated into the comprehensive care model for sickle cell disease, supporting alignment of treatment goals with reproductive life plans and delivering on the promise of individualised high-quality care for people with sickle cell disease and their families. We consider the obligation to provide fertility care in light of medical evidence, with acknowledgment of formidable obstacles to optimising care, and powerful historical and ethical considerations.

The Burden of Sickle Cell Disease in Saudi Arabia: A Single-Institution Large Retrospective Study

Purpose

Sickle cell disease (SCD) is a significant burden for patients and healthcare systems due to multiple factors, including high readmission rates. This study aimed to determine the general characteristics, etiology of admissions, annual admission rate, length of stay, and readmission rate of patients with SCD.

Patients and Methods

This retrospective observational study included all adult patients with SCD admitted to the General Internal Medicine (GIM) unit between 2016 and 2021.

Results

There were 160 patients (mean age, 31.08 ± 9.06 years; 51.25% female) with SCD included in this study. Most originated from southern Saudi Arabia (45.62%). The average annual number of emergency department (ED) visits was 4, and approximately 19% of patients had ≥3 annual admissions. The mean length of stay was 6 days. The readmission rates at 7, 30, 60, and 90 days were 8%, 24.5%, 13.6%, and 10.8%, respectively.

Conclusion

SCD generates a significant economic burden on the Saudi society and the effects on the healthcare system and patients' quality of life are evident in the high ED visits, readmission rates and prolonged hospitalization. Thereupon we advocate the implementation of sickle cell disease-specialized multidisciplinary clinics.

Sickle cell trait screening in students in a Ugandan university: a cross-sectional study

OBJECTIVE

To determine the uptake, knowledge level and attitude towards sickle cell trait screening in students aged 18 to 35 years in a Ugandan university.

METHODS

This was a university-based, cross-sectional study of students aged 18 to 35 years who were students at the Busitema University Faculty of Health Sciences. We used a simple random sampling technique to recruit participants. We conducted multivariable logistic regression to establish the association between factors such as age, year of study, marital status and uptake of sickle cell trait screening (SCTS) services.

RESULTS

A total of 315 students participated in the study. The uptake rate of SCTS was 24.4%. The knowledge level regarding sickle cell disease/SCTS was 93.7%, and 73.3% of respondents had a positive attitude towards SCTS, with a mean score of 23.32 ± 5.84. A multivariate analysis showed that those aged 25 to 29 years were 7.8 times more likely to have SCTS, while married respondents were 1.3 times more likely to be screened.

CONCLUSION

The uptake of SCTS services was low relative to the total number of participants recruited in this study. Therefore, the uptake of SCTS needs to be encouraged in students at universities.

Deep Vein Thrombosis of the Left Lower Limb in a Sudanese Child with Sickle Cell Disease

This is a case of an eleven-year-old female Sudanese child, a known Sickle Cell Anemia (SCA) patient, who presented with fever, as well as left thigh and leg swelling that was associated with pain and warmness, which was diagnosed as Deep Vein Thrombosis (DVT) of her left lower limb. She had a previous history of admissions to the emergency room, during which she once received blood. The patient was managed by carrying out a basic routine initial laboratory investigation. A Doppler ultrasound scan showed features consistent with DVT. Based on the clinical findings and investigation results, management began by providing the patient with intravenous fluid, analgesia, packed Red Blood Cells (RBCs), intravenous antibiotics, and low-molecular-weight heparin. Further consultations showed that there was no need for vascular surgery or surgical intervention. This case highlights the need for more studies on DVT and Venous Thromboembolism (VTE) complications in children with SCA, so as to develop strategies for diagnosis and management in order to reduce the risk of life-threatening complications of VTE in patients with Sickle Cell Disease SCD.

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.

Assessment of donor cell engraftment after hematopoietic stem cell transplantation for sickle cell disease: A review of current and future methods

Hematopoietic stem cell transplantation (HSCT) is the only established curative treatment for sickle cell disease (SCD), a debilitating red blood cell (RBC) disorder with significant prevalence worldwide. Accurate assessment of RBC engraftment following HSCT is essential to evaluate the status of the graft and can enable early intervention to treat or prevent graft rejection. Currently, chimerism measurement is performed on whole blood samples, which mainly reflect white blood cell (WBC) chimerism. This approach has limitations in assessing engraftment in patients with SCD because RBCs engraft non-linearly with WBCs. Direct measures of RBC chimerism exist but are not routinely used. In this review, we critically examine the current methodologies for assessing donor engraftment; highlight the limitations of these different methods, and present emerging and novel technologies with the potential to improve clinical monitoring of RBC engraftment post-HSCT for SCD. Promising alternative methodologies include RBC-specific flow cytometry, RBC-specific RNA analysis, and quantification of plasma cell-free DNA derived specifically from nucleated RBCs.

Fluorescence Lifetime Measurement of Prefibrillar Sickle Hemoglobin Oligomers as a Platform for Drug Discovery in Sickle Cell Disease

The molecular origin of sickle cell disease (SCD) has been known since 1949, but treatments remain limited. We present the first high-throughput screening (HTS) platform for discovering small molecules that directly inhibit sickle hemoglobin (HbS) oligomerization and improve blood flow, potentially overcoming a long-standing bottleneck in SCD drug discovery. We show that at concentrations far below the threshold for nucleation and rapid polymerization, deoxygenated HbS forms small assemblies of multiple α2β2 tetramers. Our HTS platform leverages high-sensitivity fluorescence lifetime measurements that monitor these temporally stable prefibrillar HbS oligomers. We show that this approach is sensitive to compounds that inhibit HbS polymerization with or without modulating hemoglobin oxygen binding affinity. We also report the results of a pilot small-molecule screen in which we discovered and validated several novel inhibitors of HbS oligomerization.

Sickle Cell Disease in Bahia, Brazil: The Social Production of Health Policies and Institutional Neglect

A disease is considered neglected when it is not given due priority in health policies despite the social relevance of that disease, either in terms of the number of individuals affected by it or its morbidity or mortality. Although the causes are structural, neglect in health does not occur in a vacuum. In this paper, we explore how sickle cell disease (SCD) is constructed and neglected in Brazil, based on insights from our long-term participatory qualitative research in the state of Bahia. We present five overarching themes relevant to the social production of SCD, and associated health policies in Brazil: (1) The achievements and setbacks to overcome neglect in SCD, (2) Continuity of comprehensive SCD care; (3) Social movements of people with SCD; (4) Biocultural citizenship; and (5) Academic advocacy. We conclude that it is insufficient to merely recognize the health inequities that differentiate white and black populations in Brazil; racism must be understood as both a producer and a reproducer of this process of neglect. We conclude with a set of recommendations for the main SCD stakeholder groups committed to improving the lives of people living with SCD.

Clinical management of the acute complications of sickle cell anemia: 11 years of experience in a tertiary hospital

INTRODUCTION

Sickle cell disease is an emerging anemia in Europe leading to high morbidity with severe acute complications requiring hospital admission and chronic consequences. The management of these patients is complex and needs interdisciplinary care. The objective is to analyze clinical characteristics and management of patients with sickle cell disease admitted for acute complications.

METHODS

Retrospective descriptive study of admissions for acute complications of patients with sickle cell disease under 16 years of age in a tertiary hospital between 2010 and 2020. Clinical, laboratory and radiological data were reviewed.

RESULTS

We included 71 admissions corresponding to 25 patients, 40% diagnosed by neonatal screening. Admissions increased during this period. The most frequent diagnoses were vaso-occlusive crisis (35.2%), febrile syndrome (33.8%) and acute chest syndrome (32.3%). Nine patients required critical care at PICU. Positive microbiological results were confirmed in 20 cases, bacterial in 60%. Antibiotic therapy was administered in 86% of cases and the vaccination schedule of asplenia was adequately fulfilled by 89%. Opioid analgesia was required in 28%. Chronic therapy with hydroxyurea prior to admission was used in 41%.

CONCLUSIONS

Acute complications requiring hospital admission are frequent in patients with sickle cell disease, being vaso-occlusive crisis and febrile syndrome the most common. These patients need a high use of antibiotics and opioid analgesia. Prior diagnosis facilitates the recognition of life-threatening complications such as acute chest syndrome and splenic sequestration. Despite the prophylactic and therapeutic measures currently provided to these patients, many patients suffer acute complications that require hospital management.

The pharmacokinetic and safety profile of single-dose deferiprone in subjects with sickle cell disease

Patients with sickle cell disease (SCD) who undergo repeated blood transfusions often develop iron overload. Deferiprone (Ferriprox®) is an oral iron chelator indicated for the treatment of transfusional iron overload due to thalassemia syndromes and has been recently approved as a treatment for iron overload in adult and pediatric patients with SCD and other anemias. The present study aims to characterize the pharmacokinetic (PK) profile of deferiprone (DFP) in adult subjects with SCD. In this phase I, open-label study, subjects with SCD were administered a single 1500 mg dose of DFP. Blood and urine samples were collected for PK assessments of DFP and its main metabolite, deferiprone 3-O-glucuronide (DFP-G). Eight subjects were enrolled and completed the study. Following drug administration, serum levels of DFP and DFP-G rose to maximum concentrations at 1.0 and 2.8 h post-dose, respectively. The half-lives of DFP and DFP-G were 1.5 and 1.6 h, respectively. The majority of administered drug was metabolized and excreted as DFP-G, with less than 4% excreted unchanged in urine up to 10 h post-dose. Subjects received a safety assessment 7 (± 3) days post-dose. Two subjects reported mild adverse events unrelated to the study drug, and no other safety concerns were reported. The PK profile of DFP in SCD subjects is consistent with previous reports in healthy adult volunteers, suggesting no special dosing adjustments are indicated for this population. These findings provide valuable insight for treating iron overload in patients with SCD, who have limited chelation therapy treatment options (trial registration number: NCT01835496, date of registration: April 19, 2013).

Myocardial Performance Index Among Patients of Sickle Cell Disorder in Rural Teaching Hospital: A Case-Control Study

OBJECTIVE

To evaluate the myocardial performance index (MPI) in sickle cell disease (SCD) patients, and to compare MPI in healthy individuals.

METHODS

In this case-controlled study, patients of SCD and age- and sex-matched controls were included. MPI was determined using echocardiographic Doppler-derived parameters. MPI according to disease type, sickle cell crisis, and in the presence of co-morbidities was compared.  Results: Between October 2018 and September 2020, we enrolled 100 SCD patients and 100 age and sex-matched controls. The MPI was significantly higher in SCD than in the control group (0.411±0.028 vs. 0.387±0.015, respectively; p<0.0001). There was no difference in MPI according to disease type as SS or AS (p=0.903). In patients with sickle cell crisis, mean MPI was significantly higher than those without sickle cell crisis (0.443±0.003 vs. 0.403±0.025, respectively; p<0.0001). In patients with comorbidities, mean MPI was significantly higher than those without any comorbidity (0.432±0.021 vs. 0.404±0.026, respectively; p<0.0001).

CONCLUSION

MPI can be a non-invasive tool for assessing subclinical cardiac dysfunction and should be considered for evaluating patients with SCD.

Deferiprone vs deferoxamine for transfusional iron overload in SCD and other anemias: a randomized, open-label, noninferiority study

The efficacy of deferiprone was noninferior to deferoxamine for treating transfusional iron overload in patients with SCD or other anemias.

The safety profile of deferiprone in patients with SCD was tolerable and similar to previous reports in patients with thalassemia syndromes.

Many people with sickle cell disease (SCD) or other anemias require chronic blood transfusions, which often causes iron overload that requires chelation therapy. The iron chelator deferiprone is frequently used in individuals with thalassemia syndromes, but data in patients with SCD are limited. This open-label study assessed the efficacy and safety of deferiprone in patients with SCD or other anemias receiving chronic transfusion therapy. A total of 228 patients (mean age: 16.9 [range, 3-59] years; 46.9% female) were randomized to receive either oral deferiprone (n = 152) or subcutaneous deferoxamine (n = 76). The primary endpoint was change from baseline at 12 months in liver iron concentration (LIC), assessed by R2* magnetic resonance imaging (MRI). The least squares mean (standard error) change in LIC was −4.04 (0.48) mg/g dry weight for deferiprone vs −4.45 (0.57) mg/g dry weight for deferoxamine, with noninferiority of deferiprone to deferoxamine demonstrated by analysis of covariance (least squares mean difference 0.40 [0.56]; 96.01% confidence interval, −0.76 to 1.57). Noninferiority of deferiprone was also shown for both cardiac T2* MRI and serum ferritin. Rates of overall adverse events (AEs), treatment-related AEs, serious AEs, and AEs leading to withdrawal did not differ significantly between the groups. AEs related to deferiprone treatment included abdominal pain (17.1% of patients), vomiting (14.5%), pyrexia (9.2%), increased alanine transferase (9.2%) and aspartate transferase levels (9.2%), neutropenia (2.6%), and agranulocytosis (0.7%). The efficacy and safety profiles of deferiprone were acceptable and consistent with those seen in patients with transfusion-dependent thalassemia. This trial study was registered at www://clinicaltrials.gov as #NCT02041299.

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

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

Point-of-care microchip electrophoresis for integrated anemia and hemoglobin variant testing

Anemia affects over 25% of the world's population with the heaviest burden borne by women and children. Genetic hemoglobin (Hb) variants, such as sickle cell disease, are among the major causes of anemia. Anemia and Hb variant are pathologically interrelated and have an overlapping geographical distribution. We present the first point-of-care (POC) platform to perform both anemia detection and Hb variant identification, using a single paper-based electrophoresis test. Feasibility of this new integrated diagnostic approach is demonstrated via testing individuals with anemia and/or sickle cell disease. Hemoglobin level determination is performed by an artificial neural network (ANN) based machine learning algorithm, which achieves a mean absolute error of 0.55 g dL^-1 and a bias of -0.10 g dL^-1 against the gold standard (95% limits of agreement: 1.5 g dL^-1) from Bland-Altman analysis on the test set. Resultant anemia detection is achieved with 100% sensitivity and 92.3% specificity. With the same tests, subjects with sickle cell disease were identified with 100% sensitivity and specificity. Overall, the presented platform enabled, for the first time, integrated anemia detection and hemoglobin variant identification using a single point-of-care test.

Towards access for all: 1st Working Group Report for the Global Gene Therapy Initiative (GGTI)

The gene and cell therapy field saw its first approved treatments in Europe in 2012 and the United States in 2017 and is projected to be at least a $10B USD industry by 2025. Despite this success, a massive gap exists between the companies, clinics, and researchers developing these therapeutic approaches, and their availability to the patients who need them. The unacceptable reality is a geographic exclusion of low-and middle-income countries (LMIC) in gene therapy development and ultimately the provision of gene therapies to patients in LMIC. This is particularly relevant for gene therapies to treat human immunodeficiency virus infection and hemoglobinopathies, global health crises impacting tens of millions of people primarily located in LMIC. Bridging this divide will require research, clinical and regulatory infrastructural development, capacity-building, training, an approval pathway and community adoption for success and sustainable affordability. In 2020, the Global Gene Therapy Initiative was formed to tackle the barriers to LMIC inclusion in gene therapy development. This working group includes diverse stakeholders from all sectors and has set a goal of introducing two gene therapy Phase I clinical trials in two LMIC, Uganda and India, by 2024. Here we report on progress to date for this initiative.

Knowledge gaps in reproductive and sexual health in girls and women with sickle cell disease

There is an immediate need to address long-standing questions about the reproductive health of girls and women with sickle cell disease (SCD). There are many SCD-related reproductive risks and uncertainties across girls' and women's reproductive life span, with particularly outstanding concerns about menstruation, contraception, fertility and pregnancy. Extant literature addressing women's reproductive health topics is mostly descriptive; there are few high-quality interventional studies. In 2020, the Centers for Disease Control and Prevention and the Foundation for Women and Girls with Blood Disorders convened an expert panel to assess the knowledge gaps in women's reproductive health in SCD. The panel identified significant limitations to clinical care due to the need for research. The panel also identified prominent barriers to research and care. In this report, we frame these issues, providing a roadmap for investigators, funding agencies, and policy makers to advance care for girls and women with SCD.

Cardiac Chamber Quantification by Echocardiography in Adults With Sickle Cell Disease: Need Attention to Eccentric Hypertrophy

Introduction and aim

Sickle cell anemia (SCA) is the most common hemoglobinopathy worldwide, and cardiovascular diseases are the most common causes of death. In these patients, cardiac remodeling begins from childhood and leads to sickle cell cardiomyopathy in the following years. Concentric hypertrophy and eccentric hypertrophy are known to predict early cardiac events. This study aims to reveal the relationship between cardiac remodeling types and survival in patients with SCA and investigate the factors that may affect left ventricular mass.

Materials and methods

A total of 146 patients with SCA were included in the study, and the left ventricular mass index (LVMI) and relative wall thickness (RWT) of the patients were calculated according to echocardiographic measurements, and the patients were categorized into normal, concentric remodeling (CR), concentric hypertrophy (CH), and eccentric hypertrophy (EH) groups.

Results

The median age of the patients is 32 (18-72). In logistic regression analysis, hemoglobin S (HbS) and ferritin levels were independent predictors for LVMI (p = 0.01 and p < 0.001, respectively). It was observed that 56 (38.4%) of the patients had normal left ventricles, 24 (16.4%) had CR, 21 (14.4%) had CH, and 45 (30.8%) had EH. 31 (21.2%) of the patients died. When we look at the survival curves, there was a statistically significant difference between the four groups (log-rank p < 0.001). It was observed that patients with EH were the group with the lowest probability of survival.

Conclusion

Cardiac death is one of the most common causes of death in patients with SCA. Early detection of cardiac disorders and starting treatment may be important in reducing mortality in these patients.

Compensated hypogonadism in men with sickle cell disease

OBJECTIVE

To evaluate the prevalence of hypogonadism in a population of men with SCD and characterize its aetiology. Sickle cell disease (SCD) is associated with the development of hypogonadism, but there is still controversy regarding its aetiology and clinical implications.

METHODS

We performed a cross-sectional study of 34 men with SCD aged > 18 years. Sociodemographic and clinical data, including anthropometric measurements (weight, height and BMI), were obtained. Early morning, blood samples were collected and total testosterone (TT), free testosterone (FT), luteinizing hormone (LH), follicle stimulating hormone (FSH), a complete blood count and haemoglobin electrophoresis were measured. Eugonadism was defined as T ≥300 ng/dL and LH ≤9.4 mUI/mL; primary hypogonadism as T < 300 ng/dL and LH > 9.4 mUI/mL; secondary hypogonadism as T < 300 ng/dL and LH ≤ 9.4 mUI/mL; and compensated hypogonadism as T ≥ 300 ng/dL and LH > 9.4 mUI/mL.

RESULTS

Median age was 33 (26-41) years, and SS genotype was the most frequent (73.5%). The prevalence of eugonadism, compensated hypogonadism and secondary hypogonadism was 67.5%, 26.4% and 5.88%, respectively. No men with primary hypogonadism were identified in our sample. Those with compensated hypogonadism had also higher FSH levels (>7.8 mUI/mL, P < .0001).

CONCLUSION

In our study population of men with SCD, a high prevalence of compensated hypogonadism was identified, which is a controversial and distinct clinical entity that warrants monitoring and further research.

Peripartum considerations in sickle cell disease

PURPOSE OF REVIEW

Pregnancy exacerbates sickle cell disease (SCD) and is associated with increased frequency and severity of complications resulting in high levels of maternal and fetal morbidity and mortality. We review recent recommendations for managing SCD in pregnancy.

RECENT FINDINGS

An updated pathobiological model of SCD now attributes the clinical picture to a vicious cycle of four major cellular disturbances. Management decisions should be guided by an understanding of this upgraded model. Red cell transfusions are a key therapeutic intervention used in managing several acute and chronic complications. Transfusion however has significant drawbacks. The American Society of Hematology recently published transfusion guidelines to support care providers.

SUMMARY

Patients should be managed by a multidisciplinary and experienced team. The perioperative episode is a recognized period of disease exacerbation and informed anesthetic management can contribute to improved patient outcomes.

Delta-globin gene expression improves sickle cell disease in a humanised mouse model

Sickle cell disease (SCD) is a widespread genetic disease associated with severe disability and multi-organ damage, resulting in a reduced life expectancy. None of the existing clinical treatments provide a solution for all patients. Gene therapy and fetal haemoglobin (HbF) reactivation through genetic approaches have obtained promising, but early, results in patients. Furthermore, the search for active molecules to increase HbF is still ongoing. The delta-globin gene produces the delta-globin of haemoglobin A2 (HbA2). Although expressed at a low level, HbA2 is fully functional and could be a valid anti-sickling agent in SCD. To evaluate the therapeutic potential of a strategy aimed to over-express the delta-globin gene in vivo, we crossed transgenic mice carrying a single copy of the delta-globin gene, genetically modified to be expressed at a higher level (activated), with a humanised mouse model of SCD. The activated delta-globin gene gives rise to a consistent production of HbA2, effectively improving the SCD phenotype. For the first time in vivo, these results demonstrate the therapeutic potential of delta-globin, which could lead to novel approaches to the cure of SCD.

Seizures risk factors in sickle cell disease. The cooperative study of sickle cell disease

INTRODUCTION

Although evidence suggests that neurological complications, including seizures and epilepsy, are more common among sickle cell disease (SCD) patients, few studies have assessed the risk factors of developing seizures among SCD patients METHODS: We used a nested case-control study design to compare pediatric and adult SCD patients who experienced seizures with patients who did not experience any seizure regarding clinical and laboratory parameters. We conducted a secondary analysis using the data from the Cooperative Study of Sickle Cell Disease in this study RESULTS: There were 153 out of 2804 (5.5%) pediatric patients who had seizures with a median age of 8.5 (Interquartile range [IQR] = 10.1) years at first seizure and 115 out of 1281 (9.0%) adult patients who had seizures with a median age of 28.0 (IQR = 10.6) years at first seizure. Cerebrovascular accident ([CVA], OR = 5.7, 95% CI = 2.9-11.0), meningitis (OR = 3.6, 95% CI = 1.8-7.2), and eye disease (OR = 3.4, 95% CI = 1.5-8.0) were associated with increased risk of developing seizures among pediatric patients. While CVA (OR = 7.5, 95% CI = 3.5-16.0), meningitis (OR = 5.6, 95% CI = 1.5-20.0), nephrotic syndrome (OR = 3.0, 95% CI = 1.2-7.9), spleen sequestration (OR = 2.7, 95% CI = 1.1-6.3), and pneumonia (OR = 2.1, 95% CI = 1.0-4.4) were associated with increased risk of developing seizures among adult patients CONCLUSION: These findings suggest the need for treatment optimization and regular neurological follow up for SCD patients with these identified risk factors to prevent the development of seizures.

Biophysical and rheological biomarkers of red blood cell physiology and pathophysiology

PURPOSE OF REVIEW

This review summarizes the significant biophysical and rheological aspects of red blood cell physiology and pathophysiology in relation to recent advances in microfluidic biomarker assays and emerging targeted or curative intent therapies.

RECENT FINDINGS

Alterations in red cell biophysical properties and blood rheology have been associated with numerous hematologic and circulatory disorders. Recent advances in biomarker assays enable effective assessment of these biophysical and rheological properties in normoxia or physiological hypoxia in a clinically meaningful way. There are emerging targeted or curative therapies that aim to improve red cell pathophysiology, especially in the context of inherited hemoglobin disorders, such as sickle cell disease.

SUMMARY

Red cell pathophysiology can be therapeutically targeted and the improvements in membrane and cellular biophysics and blood rheology can now be feasibly assessed via new microfluidic biomarker assays. Recent advances provide a new hope and novel treatment options for major red cell ailments, including inherited hemoglobin disorders, membrane disorders, and other pathologies of the red cell, such as malaria.

Improvement of SCD morbimortality in children: experience in a remote area of an African country

BACKGROUND

Sickle cell disease (SCD) is a public health problem in the Democratic Republic of Congo. While reference sickle cell centers have been implemented in capital cities of African countries and have proven to be beneficial for SCD patients. In the Democratic Republic of Congo, they have never been set up in remote areas for families with low or very low sources of income.

METHOD

A cohort of 143 children with SCD aged 10 years old (IQR (interquartile range): 6-15 years) (sex ratio male/female = 1.3) were clinically followed for 12 months without any specific intervention aside from the management of acute events, and then for 12 months with a monthly medical visit, biological follow-up, and chemoprophylaxis (folic acid/penicillin), adequate fluids and malaria prevention.

RESULTS

The median age of patients at the diagnosis of SCD was 2 years (IQR: 1-5). The implementation of standardized and regular follow-ups in a new sickle cell reference center in a remote city showed an increase in the annual mean hemoglobin level from 50 to 70 g/L (p = 0.001), and a decrease in the lymphocyte count and spleen size (p < 0.001). A significant decrease (p < 0.001) in the average annual number of hospitalizations and episodes of vaso-occlusive crises, blood transfusions, infections, and acute chest syndromes were also observed.

CONCLUSIONS

The creation of a sickle cell reference center and the regular follow-up of children with sickle cell disease are possible and applicable in the context of a remote city of an African country and represent simple and accessible measures that can reduce the morbimortality of children with sickle cell disease.

Allele-Specific Recombinase Polymerase Amplification to Detect Sickle Cell Disease in Low-Resource Settings

Sickle cell disease (SCD) is a group of common, life-threatening disorders caused by a point mutation in the β globin gene. Early diagnosis through newborn and early childhood screening, parental education, and preventive treatments are known to reduce mortality. However, the cost and complexity of conventional diagnostic methods limit the feasibility of early diagnosis for SCD in resource-limited areas worldwide. Although several point-of-care tests are commercially available, most are antibody-based tests, which cannot be used in patients who have recently received a blood transfusion. Here, we describe the development of a rapid, low-cost nucleic acid test that uses real-time fluorescence to detect the point mutation encoding hemoglobin S (HbS) in one round of isothermal recombinase polymerase amplification (RPA). When tested with a set of clinical samples from SCD patients and healthy volunteers, our assay demonstrated 100% sensitivity for both the β^A globin and β^S globin alleles and 94.7 and 97.1% specificities for the β^A globin allele and β^S globin allele, respectively (n = 91). Finally, we demonstrate proof-of-concept sample-to-answer genotyping of genomic DNA from capillary blood using an alkaline lysis procedure and direct input of diluted lysate into RPA. The workflow is performed in <30 min at a cost of <$5 USD on a commercially available benchtop fluorimeter and an open-source miniature fluorimeter. This study demonstrates the potential utility of a rapid, sample-to-answer nucleic acid test for SCD that may be implemented near the point of care and could be adapted to other disease-causing point mutations in genomic DNA.

Evidence-based interventions implemented in low-and middle-income countries for sickle cell disease management: A systematic review of randomized controlled trials

BACKGROUND

Despite ~90% of sickle cell disease (SCD) occurring in low-and middle-income countries (LMICs), the vast majority of people are not receiving evidence-based interventions (EBIs) to reduce SCD-related adverse outcomes and mortality, and data on implementation research outcomes (IROs) and SCD is limited. This study aims to synthesize available data on EBIs for SCD and assess IROs.

METHODS

We conducted a systematic review of RCTs reporting on EBIs for SCD management implemented in LMICs. We identified articles from PubMed/Medline, Global Health, PubMed Central, Embase, Web of Science medical subject heading (MeSH and Emtree) and keywords, published from inception through February 23, 2020, and conducted an updated search through December 24, 2020. We provide intervention characteristics for each study, EBI impact on SCD, and evidence of reporting on IROs.

MAIN RESULTS

29 RCTs were analyzed. EBIs identified included disease modifying agents, supportive care agents/analgesics, anti-malarials, systemic treatments, patient/ provider education, and nutritional supplements. Studies using disease modifying agents, nutritional supplements, and anti-malarials reported improvements in pain crisis, hospitalization, children's growth and reduction in severity and prevalence of malaria. Two studies reported on the sustainability of supplementary arginine, citrulline, and daily chloroquine and hydroxyurea for SCD patients. Only 13 studies (44.8%) provided descriptions that captured at least three of the eight IROs. There was limited reporting of acceptability, feasibility, fidelity, cost and sustainability.

CONCLUSION

EBIs are effective for SCD management in LMICs; however, measurement of IROs is scarce. Future research should focus on penetration of EBIs to inform evidence-based practice and sustainability in the context of LMICs.

CLINICAL TRIAL REGISTRATION

This review is registered in PROSPERO #CRD42020167289.

Xanthine Oxidase Drives Hemolysis and Vascular Malfunction in Sickle Cell Disease

OBJECTIVE

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

CONCLUSIONS

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

Paediatric sickle cell disease at a tertiary hospital in Malawi: a retrospective cross-sectional study

INTRODUCTION

Sickle cell disease (SCD) remains a major cause of childhood mortality and morbidity in Malawi. However, literature to comprehensively describe the disease in the paediatric population is lacking.

METHODS

A retrospective review of clinical files of children with SCD was conducted. Descriptive statistics were performed to summarise the data. χ² or Fisher's exact test was used to look for significant associations between predictor variables and outcome variables (case fatality and length of hospital stay). Predictor variables that were significantly associated with outcome variables (p≤0.05) in a χ² or Fisher's exact test were carried forward for analysis in a binary logistic regression. A multivariable binary logistic regression was used to identify covariates that independently predicted length of hospital stay.

RESULTS

There were 16 333 paediatric hospitalisations during the study period. Of these, 512 were patients with SCD representing 3.1% (95% CI: 2.9%- 3.4%). Sixty-eight of the 512 children (13.3%; 95% CI: 10.5% - 16.5%) were newly diagnosed cases. Of these, only 13.2% (95% CI: 6.2% - 23.6%) were diagnosed in infancy. Anaemia (94.1%), sepsis (79.5%) and painful crisis (54.3%) were the most recorded clinical features. The mean values of haematological parameters were as follows: haemoglobin (g/dL) 6.4 (SD=1.9), platelets (×10⁹/L) 358.8 (SD=200.9) while median value for white cell count (×10⁹/L) was 23.5 (IQR: 18.0-31.2). Case fatality was 1.4% (95% CI: 0.6% - 2.8%)and 15.2% (95% CI: 12.2% -18.6%) of the children had a prolonged hospital stay (>5 days). Patients with painful crisis were 1.7 (95% CI: 1.02 - 2.86) times more likely to have prolonged hospital stay than those without the complication.

CONCLUSION

Anaemia, sepsis and painful crisis were the most common clinical features paediatric patients with SCD presented with. Patients with painful crisis were more likely to have prolonged hospital stay. Delayed diagnosis of SCD is a problem that needs immediate attention in this setting. Although somewhat encouraging, the relatively low in-hospital mortality among SCD children may under-report the true mortality from the disease considering community deaths and deaths occurring before SCD diagnosis is made.

Improving the Capacity of Health System and Community for Sickle Cell Disease Screening and Management Among Tribal Population in India: Protocol of an Intervention Study

Sickle cell disease (SCD) is one of the major public health problems in the world. In India, the burden of SCD is comparatively high in socio-economically disadvantaged tribal communities. Though efficacious interventions are available to manage SCD, they are not reaching to these communities and no comprehensive programme is in place in the health care system. Therefore, the Indian Council of Medical Research has initiated a nation-wide study to develop an effective intervention model for SCD patients in tribal areas through the government health care system. This intervention includes increasing awareness and preparing the communities for accessing the government health care system for SCD care, and improving the capacity of the primary health care systems including the training of the health care providers on prevention and management of SCD. The study adopted a quasi-experimental design with pre-vs. post-intervention comparisons of outcome variables within the interventional groups and with the control group. The study will be implemented in 6 districts which are endemic for SCD, spread across different geographical zones of India. In each district, four primary health centre (PHC) areas which are predominantly inhabited by tribal population will be selected. Of these four PHC areas, two will be selected randomly for implementing the intervention and the remaining two will be the control area. Information necessary for development and implementation of the intervention will be gathered during formative research, by using both quantitative and qualitative research methods. Intervention with an inclusive partnership and community mobilization will be implemented. The major steps in the implementation of intervention are partnership building with various health and non-health partners including the community. Capacity building and strengthening is another important component to enable the primary health facilities to screen and manage SCD patients. Primarily, sub-health centres and primary healthcare centres will be equipped with appropriate SCD screening techniques. All doctors in the system will be trained in advanced treatment and management issues. To improve the community's awareness and readiness, community mobilization activities will be conducted. An impact evaluation will be carried out at the end of the intervention by comparing the improvement of SCD management in intervention PHCs to that of the control PHCs. However, the process evaluation and necessary mid-term corrections will be made throughout the intervention period. Thus, an intervention model in terms of its suitability, replicability and sustainability for the tribal population will be developed and tested. The findings of this study are more suitable to use during advocacy and to replicate the model by the state health departments. This study develops and places an appropriate referral system for SCD patients at the PHC level. Improving the community's access to health care, improving the quality of care in government health centres and raising awareness among tribal communities are crucial to achieving through innovation. Taken together, these innovations would significantly contribute to better access to health care and management of the SCD patients of underserved tribal population.

Family management ofchildren who experience sickle cell disease: a qualitative study

OBJECTIVE

to know the family management experience of children with sickle cell disease in the light of the Family Management Style Framework.

METHODS

a qualitative case study carried out between September/2015 and July/2016 with 12 members of eight families registered in a blood center in Minas Gerais. The semi-structured interviews were recorded, and the data were analyzed and interpreted by the hybrid model thematic analysis.

RESULTS

three management styles were identified: five families in the accommodating style; two families in the struggling style; and only one family in the enduring style.It was noted that empowerment was paramount in the acquisition of skills and abilities to care for these children.

FINAL CONSIDERATIONS

family management knowledge of children with sickle cell disease provided a reflection on nurses' role in supporting, orienting and encouraging the empowerment of these families aiming at the search for comprehensive care.

Mortality of children aged 5-15 years in a tertiary care center in Yaoundé, Cameroon

INTRODUCTION

Although sub-Saharan Africa accounts for only 21% of the global population of children and adolescents aged 5-15 years, 55% of deaths among children in this age group occur in this region. This seems to be related to infectious diseases. We hypothesized that besides infectious diseases, in our context, a chronic underlying condition increases mortality. Our goal was to describe the leading causes of mortality among this age group.

PATIENTS AND METHODS

We conducted a retrospective study in a tertiary care center in Yaoundé. We included the medical files of children who died between January 2013 and December 2017.

RESULTS

The in-hospital mortality rate was 10.3 per 1000. Coma and/or convulsion was the main cause of death (70.6%), followed by severe anemia (64.7%) and respiratory distress (56.8%). We identified a chronic illness in 62.2% of cases: HIV infection (39.2%) and sickle cell disease (24.5%) were the most prevalent. The main diagnoses were severe malaria, severe sepsis, and meningitis (Cryptococcus sp. included) in 25 (n=35), 16.4 (n=27), and 10.3% (n=17) of cases, respectively.

CONCLUSION

HIV infection and sickle cell disease are the most prevalent chronic diseases related to the patients' death in the age group studied. Specific interventions focusing on this age group are recommended including intensification of impregnated bednet usage as well as HIV and sickle cell disease management.

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

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

Updated Worldwide Epidemiology of Inherited Erythrocyte Disorders

INTRODUCTION

Timely diagnosis and effective treatment, based on epidemiologic data, consistently reduce the clinical, social and economic burden of inherited erythrocyte disorders.

OBJECTIVE

This article provides an overview on current worldwide epidemiology of the most frequent inherited erythrocyte disorders.

METHODS

Information was obtained from Global Health Data Exchange (GHDx) database.

RESULTS

Glucose-6-phosphate dehydrogenase (G6PD) deficiency has the largest worldwide incidence and prevalence. Sickle cell disorders (SCD) cause the highest cause-specific disability-adjusted life years (DALYs). Incidence and prevalence of SCD have recently increased, whilst DALYs and mortality remained stable. All epidemiologic measures of thalassemias have recently declined, whilst those of G6PD deficiency remained stable or increased. Africa has the highest incidence of G6PD deficiency and SCD, whilst thalassemias are more frequent in Western Pacific. The incidence of all inherited erythrocyte disorders is increasing in Africa and Eastern Mediterranean, whilst is decreasing in South-East Asia, Western Pacific and Europe. Thalassemias and SCD display a peak of prevalence and mortality between 0 and 15 years, whilst mortality for G6PD deficiencies and other hemoglobinopathies peaks between 45 and 75 years and >80 years, respectively. Men have higher burden of G6PD deficiencies, whilst sex distribution of SCD and thalassemias is similar.

CONCLUSIONS

The worldwide epidemiologic burden of inherited erythrocyte disorders remains particularly high.