Mortality in sickle cell disease. Life expectancy and risk factors for early death

Barriers and Facilitators to Comprehensive Pediatric Sickle Cell Care: A Qualitative Study

BACKGROUND

Children with sickle cell disease (SCD) require comprehensive care to prevent and treat serious and life-threatening complications and to access disease-specific treatment approaches that can improve outcomes. This study characterized barriers and facilitators to care for SCD in the context of the Conceptual Framework of Access to Care Model.

METHODS

This qualitative descriptive study was conducted using semi-structured interviews with 27 patient/caregivers focused on sickle cell anemia (SCA; a subtype of SCD). Data were analyzed using directed content analysis with the model above as the initial coding framework.

RESULTS

Themes were identified among healthcare system and patient/community-level factors. Healthcare system facilitators predominated themes, with a focus on the extent to which the healthcare services provided were a good match for the family and available and accommodating to patient and family needs. Additional facilitators at the patient/community level focused on whether patients and families could perceive and seek out, reach and pay for, and engage with healthcare. Barriers reflected the opposite experiences, with negative or challenging healthcare experiences and adverse social determinants of health interfering with access to care.

CONCLUSIONS

Barriers and facilitators were mapped to the Conceptual Framework of Access to Care Model, with facilitators playing a more substantial role than barriers in access to comprehensive care among children with SCA and their caregivers. A focus on optimizing facilitators at both the healthcare system and patient/family level may have a considerable impact on improving access to and engagement in care.

A replication study of novel fetal hemoglobin-associated genetic variants in sickle cell disease-only cohorts

Sickle cell disease (SCD) is the most common monogenic disease in the world and is caused by mutations in the β-globin gene (HBB). Notably, SCD is characterized by extreme clinical heterogeneity. Inter-individual variation in fetal hemoglobin (HbF) levels strongly contributes to this patient-to-patient variability, with high HbF levels associated with decreased morbidity and mortality. Genetic association studies have identified and replicated HbF levels-associated variants at three loci: BCL11A, HBS1L-MYB, and HBB. In SCD patients, genetic variation at these three loci accounts for ~ 50% of HbF heritability. Genome-wide association studies (GWAS) in non-anemic and SCD patients of multiple ancestries have identified 20 new HbF-associated variants. However, these genetic associations have yet to be replicated in independent SCD cohorts. Here, we validated the association between HbF levels and variants at five of these new loci (ASB3, BACH2, PFAS, ZBTB7A, and KLF1) in up to 3740 SCD patients. By combining CRISPR inhibition and single-cell transcriptomics, we also showed that sequences near non-coding genetic variants at BACH2 (rs4707609) and KLF1 (rs2242514, rs10404876) can control the production of the β-globin genes in erythroid HUDEP-2 cells. Finally, we analyzed whole-exome sequence data from 1354 SCD patients but could not identify rare genetic variants of large effect on HbF levels. Together, our results confirm five new HbF-associated loci that can be functionally studied to develop new strategies to induce HbF expression in SCD patients.

A retrospective research of adverse event reporting system events for voxelotor based on the FAERS database

BACKGROUND

Sickle cell disease (SCD) is a severe genetic disorder causing anemia, pain, and organ damage, affecting millions globally. Voxelotor, approved in the United States in 2019, targeted sickle cell disease pathophysiology. Despite its therapeutic benefits, concerns remain regarding its long-term safety and potential side effects, including headaches and gastrointestinal disturbances. This study used the FDA Adverse Event Reporting System (FAERS) to assess voxelotor's safety, aiming to enhance treatment strategies and clinical decision-making in SCD management.

METHODS

In this study, we utilized the FAERS to extract voxelotor-related adverse event reports from 2019 to 2024. We conducted descriptive and disproportionality analyses using four algorithms: Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), and Multi-item Gamma Poisson Shrinkage (MGPS) to identify significant adverse event signals. The reliability of voxelotor adverse drug reactions (ADRs) was further improved by comparing with hydroxyurea ADRSs. Finally, adverse reactions were divided into acute ADRS, delayed ADRs and efficacy related reports to analyze the adverse event onset time.

RESULTS

A total of 16,677,340 case reports were collected in the FAERS database, of which 20,902 reports related to voxelotor were identified. Voxelotor induced adverse events occurred in 27 system organ categories (SOC). Key system organ classes affected were the blood and gastrointestinal systems. Notably, some adverse events, such as priapism and osteonecrosis, were not listed on the drug's label. The median adverse event onset time of acute ADRs, delayed ADRs and efficacy related reports were 1, 189.5 and 271 days, respectively.

CONCLUSION

This study systematically analyzed ADRs of voxelotor, highlighting the need for ongoing monitoring and further research on voxelotor's long-term safety and efficacy in treating sickle cell disease.

The Mortality of Adults With Sickle Cell Disease at a Comprehensive Sickle Cell Center

INTRODUCTION

Sickle cell disease (SCD) is the most common hemoglobinopathy in North America. The life expectancy of SCD has extended into adulthood with screenings, preventative care, and hydroxyurea. However, comorbidities arise as adults with SCD age, leading to early mortality.

METHODS

We conducted a retrospective chart review of the Georgia Comprehensive Sickle Cell Center at Grady Health System, analyzing records of deceased SCD patients from 2013 to 2020.

RESULTS

Amongst the 72 patients analysed, majority had severe complications from SCD and at least 1 cardiovascular comorbidity. The median age of death was 44 (STD = 15.5) for all genotypes with the median age of death at 39 (STD = 14.26) for SS and Sβ0 genotypes (n = 51). There was no difference in the median age of death for patients who maintained regular clinic visits (a visit in the last 6 months prior to death) compared to those who did not. Despite hydroxyurea's known benefits in reducing SCD morbidity and mortality, less than 50% of patients had a prescription.

CONCLUSION

As new therapies are approved, their impact on SCD-related morbidity and mortality must be evaluated. Improving access to, and education about, disease-modifying therapies like hydroxyurea for both patients and clinicians is essential to improving outcomes.

How We Approach Contraception for Adolescents and Young Adults With Sickle Cell Disease

With the increasing use of effective disease-modifying therapies, individuals with sickle cell disease (SCD) are living longer and healthier lives. This has resulted in increasing interest and discussion of sexual and reproductive health (SRH) by persons with SCD and their providers. However, SRH is often overlooked as an essential element of comprehensive SCD care. Contraception options for this population are often complex and nuanced as they relate to pain and the thrombophilia of SCD. Here we use case examples to describe how we approach contraception counseling using a multidisciplinary, holistic, and patient-centered approach.

Community-engaged research in psychological interventions for pediatric sickle cell disease: a scoping review

OBJECTIVE

The aim of this scoping review was to identify and describe the community-engaged research (CEnR) methods used in the development and evaluation of psychological interventions for pediatric sickle cell disease (SCD).

METHODS

We conducted a systematic search of three databases in April 2024 (PubMed, Scopus, and PsycINFO). The review was registered with Open Science Framework (DOI: 10.17605/OSF.IO/956AV). All titles, abstracts, and full texts for papers that appeared to meet criteria were independently reviewed by two members of the research team. Inclusion criteria were pediatric or young adult age and use of CEnR for a psychological SCD intervention. Data were extracted from articles meeting these criteria.

RESULTS

The search yielded 235 original articles, of which eight met the inclusion criteria. These articles showed that the involvement levels of community collaborators (patients, families, and community-based organizations) varied across research phases. Notable gaps in the literature were: (1) few studies reported utilizing CEnR methods, (2) variability in language/terms used to describe CEnR methods, (3) limited demographic data about community collaborators, and (4) a lack of description of CEnR frameworks guiding intervention development and evaluation.

CONCLUSIONS

This scoping review found few studies describing the use of CEnR methods in a way that would facilitate reproducibility. Recommendations include using MeSH CEnR keywords, identifying CEnR methods and frameworks, and including specific information about community when possible (e.g., demographic information, meeting frequency, etc.).

Changes in the quality of life of adults with sickle cell disease following allogeneic stem cell transplantation: A mixed-methods, prospective cohort study

Advances in conditioning regimens have made non-myeloablative allogeneic hematopoietic stem cell transplantation (HSCT) a viable curative option for adults with sickle cell disease (SCD). However, prospective studies comparing pre- and post-transplant patient-reported health outcomes are scarce. Therefore, in a prospective, mixed-methods cohort study in adults with SCD undergoing HSCT, we tested the hypothesis that physical, mental, and social health improves after HSCT relative to baseline. We compared 9 Patient-Reported Outcomes Measurement Information System (PROMIS®) measures at 6, 12, and 18 months post-transplant to baseline and general population values. Semi-structured interviews were conducted pre- and post-transplant that were thematically analyzed (MAXQDA). Seventeen patients (7 females, 10 males; median age 26 years) underwent matched sibling (9) or haploidentical donor (8) transplantation. Compared to baseline, pain interference (p = 0.008), physical function (p < 0.001), fatigue (p = 0.001), anxiety (p = 0.016), anger (p = 0.037), and the ability to (p < 0.001) and satisfaction with (p < 0.001) social roles and activities improved at 18 months. Compared to reference values, physical function, sleep disturbance, fatigue, anxiety, and the ability to and satisfaction with social roles and activities T-scores were significantly worse at baseline but comparable or better after 18 months. Thematic analysis of the interviews revealed high satisfaction with improved physical and social abilities alongside complex mental health challenges, including processing the psychological aftermath of SCD, dealing with transplant-related toxicity, adjustment challenges, and identity conflicts. In conclusion, while physical, mental, and social health improves after HSCT, the effects on mental health can be complex and warrant psychosocial support early in the process of curative therapies.

FLT1 and other candidate fetal haemoglobin modifying loci in sickle cell disease in African ancestries

Known fetal haemoglobin (HbF)-modulating loci explain 10-24% variation of HbF level in Africans with Sickle Cell Disease (SCD), compared to 50% among Europeans. Here, we report fourteen candidate loci from a genome-wide association study (GWAS) of HbF level in patients with SCD from Cameroon, Tanzania, and the United States of America. We present results of cell-based experiments for FLT1 candidate, demonstrating expression in early haematopoiesis and a possible involvement in hypoxia associated HbF induction. Our study employed genotyping arrays that capture a broad range of African and non-African genetic variation and replicated known loci (BCL11A and HBS1L-MYB). We estimated the heritability of HbF level in SCD at 94%, higher than estimated in unselected Europeans, and suggesting a robust capture of HbF-associated loci by these arrays. Our approach, which involved genotype imputation against six reference haplotype panels and association analysis with each of the panels, proved superior over selecting a best-performing panel, evidenced by a substantial proportion of panel-specific (up to 18%) and a low proportion of shared (28%) imputed variants across the panels.

Factors associated with early return visits to the emergency department in patients with vaso-occlusive crisis

BACKGROUND AND AIM

One of the most common presentations of sickle cell disease (SCD) in the emergency department (ED) is acute severe pain episodes due to a vaso-occlusive crisis (VOC). Management of these episodes is primarily through intravenous pain control, but patients often return to the ED with the same complaint a few days after discharge. While some global studies have explored the risk factors for ED revisits due to VOC, the literature is lacking in the adult population, specifically in Saudi Arabia where SCD prevalence is high. The goal of this study is to measure the incidence of ED 72-hour early revisit (ERV) among SCD patients due to a VOC episode and to identify factors that might be associated with an ERV in this population. We conducted a retrospective cohort study using the electronic medical records, retrieving all patients who presented to the ED with a VOC from the period of 2017 to 2022.

RESULTS

This study included 120 VOC visits. The percentage of 72-hour ERV to the ED among VOC patients was 39.2%, in which 91.5% received opioids, and 31.9% were admitted during the return visit. Return visitors' median age was 29, most of them were male. There was no statistically significant correlation found between the patients' 72-hour ERV to the ED and their age, gender, comorbidities, history of exchange transfusion, pain score, or dose of opiates received. Of the variables measured at the index visit only the direct bilirubin level, and time to first opioid dose was associated with 72-hour ERV with an OR of 1.08 (95%CI: 1.0 to 1.16, P = 0.022) and 0.99 (95%CI: 0.99 to 0.99, P = 0.012) respectively.

CONCLUSION

We found that 39.2% of VOC episodes discharged from the ED had an ERV. This rate is higher than what is reported internationally. Additionally, the lack of clear predictors for revisits raises doubts regarding the efficacy of the ED ''treat and release'' approach in this population.

CLINICAL TRIAL NUMBER

Not applicable.

Is allogeneic transplantation for sickle cell disease still relevant in the era of gene therapy?

ABSTRACT

Sickle cell disease (SCD) is the most common inherited blood disease. Disease-modifying therapy and supportive care have improved the survival of children with SCD in the United States and Europe. Yet, adults with SCD continue to have high risks of morbidity and early death. Recently, 2 US Food and Drug Administration-approved genetic therapies offer the potential for a short-term decrease in acute vaso-occlusive pain events if not cure. Allogeneic hematopoietic cell transplantation (allo-HCT) is also curative but, until recently, was constrained by limited donor availability and the risks of graft-versus-host disease, graft rejection, and death. Importantly, recent advances have attenuated these barriers. Here, we discuss the current state of therapies with curative intent for SCD. Both genetic therapy and allo-HCT offer the potential for cure for most with SCD. However, the cost (∼5 times higher), the current need for myeloablation, and associated late-health effects may make genetic therapies less favorable choices than allo-HCT.

Global prevalence of elevated estimated pulmonary artery systolic pressure in clinically stable children and adults with sickle cell disease: A systematic review and meta-analysis

BACKGROUND

The current study sought to determine the prevalence of elevated estimated pulmonary artery systolic pressure (ePASP) in clinically stable children and adults with sickle cell disease)SCD(worldwide.

METHODS

The studies included were identified through a search of databases such as PubMed, Scopus, Science Direct, Web of Science, and Embase, as well as Google Scholar engine, adhering to specific inclusion and exclusion criteria. Heterogeneity among the primary study results was assessed using the I-squared index, while publication bias was evaluated through funnel plots, Egger's test, and trim and fill analysis. All statistical analyses were conducted using R software, version 4.3.0.

RESULTS

79 primary studies were included, comprising 6,256 children (<18 years old) and 6,582 adults (≥18 years old) with SCD from 22 countries. The prevalence of elevated ePASP was found to be 21.8% (95% confidence interval [CI]: 18.46 to 25.07) in children and 30.6% (95% CI: 27.1 to 34.1) in adults. The prevalence of elevated ePASP among studies with severe SCD genotypes including HbSS and HbS/β0 was found to be 19.45% (95% CI: 14.95 to 23.95) in children and 29.55% (95% CI: 24.21 to 34.89) in adults. Furthermore, sex-specific prevalence among SCD patients with elevated ePASP indicated the highest prevalence in male children at 60.35% (95% CI: 54.82 to 65.88) and adult female patients at 54.41% (95% CI: 47.3 to 61.5). A comparative analysis of the mean values of clinical and laboratory results revealed significant differences in several characteristics, including age, oxygen saturation, hemoglobin levels, fetal hemoglobin, white blood cell counts, platelet counts, and reticulocyte counts between patients with elevated ePASP and those without, in both children and adult SCD populations.

CONCLUSION

Our findings regarding clinically stable SCD patients highlight a high prevalence of elevated ePASP.

Base editing HbS to HbG-Makassar improves hemoglobin function supporting its use in sickle cell disease

Adenine base editing can convert sickle hemoglobin (HbS, βΕ6V) to G-Makassar hemoglobin (HbG, βE6A), a naturally occurring variant that is clinically asymptomatic. However, the quality and functionality of purified HbG and of mature HbGG and HbGS red blood cells (RBC) has not been assessed. Here, we develop a mouse model to characterize HbG. Purified HbG appears normal and does not polymerize under hypoxia. The topology of the hemoglobin fold with the βΕ6Α mutation is similar to HbA in the oxy and deoxy states. However, RBC containing HbGS are dehydrated, showing altered function and increased sickling under hypoxia. Blood counts and mitochondrial retention measures place HbGS RBCs as intermediate in severity between HbAS and HbSS, while organ function is comparable to HbAS. HbGG resembles HbAA for most metrics. Our results highlight the importance of functionally assessing the mature red cell environment when evaluating novel gene editing strategies for hematologic disorders.

Maternal and Infant Outcomes in a Subset of Patients with Sickle Cell Disease in South Carolina

OBJECTIVES

Sickle cell disease (SCD), which disproportionately affects minorities, increases complications during pregnancy. Severe maternal mortality is increased in women with SCD, including morbidity related to the disease and other nondisease-related complications. It also can have devastating complications for fetuses, with increases in premature birth and low birth weight. This study aimed to describe the characteristics of women with SCD in South Carolina, with a specific focus on fetal and maternal outcomes and complications. The secondary aim of this study was to identify the effect of maternal characteristics on birth outcomes, including social determinants of health.

METHODS

A secondary analysis of women from a single institution, the Medical University of South Carolina, which was part of the registry from the multi-institutional Sickle Cell Disease Implementation Consortium, was conducted. Patient demographics, self-reported pregnancy history, hydroxyurea use, and maternal and fetal outcomes were collected from patient-reported survey data. In addition, the number of vaso-occlusive episodes surrounding their pregnancies was collected for analysis.

RESULTS

Fifty-nine percent (116/195) of the female participants reported ever being pregnant. Seventy-two percent had live births, 15.8% had miscarriages, 1.8% had stillbirths, and 6.1% had an abortion. The mean age was 22.3 ± 4 years, with no difference in markers of severity between the groups. Most women were HbSS genotype with high rates of pain in the last year. No difference was found in age, education, employment, or income between these groups of women. Women in the nonlive birth cohort had higher body weights (78.7 versus 72.1 kg, P = 0.045). The Distressed Community Index was used as a marker for social determinants of health and was similar between the two groups, with a majority of both cohorts (61.7% and 52%) living in "at risk" and "distressed" communities. Complications related to SCD were high, including 43% of women experiencing pain during pregnancy, 5.2% developing acute chest syndrome, and 22.4% requiring transfusion. An additional 11% experienced preeclampsia. Unfavorable infant outcomes included 49% of the infants being premature and 40% having babies weighing less than 5.5 lb at birth.

CONCLUSIONS

High rates of complications to both mother and infant were found in the women with SCD. Although few statistically significant predictors were found, by identifying and addressing specific needs of pregnant women with SCD, we can work toward reducing fetal and maternal mortality in an already vulnerable population.

Biomarkers to Differentiate Acute Chest Syndrome From Vaso-Occlusive Crisis in Children With Sickle Cell Disease

BACKGROUND

Acute Chest Syndrome (ACS) is the leading cause of death in children with sickle cell disease (SCD) in the US-about half of the children who develop ACS present initially with pain.

METHODS

Here, we studied biomarkers to differentiate ACS from vaso-occlusive crises (VOC) in children with SCD who presented with pain to the emergency department (ED). We conducted a prospective cohort study of consecutive patients who presented to the ED with pain and were discharged with ACS or VOC between March, 2017 and February, 2020.

RESULTS

We identified 7 patients with ACS and 19 patients with VOC. The two groups were comparable in age and sex. All patients with ACS had asthma versus 42% of the VOC group. The ACS group had lower weight and BMI z-scores. Patients with ACS compared to VOC had significantly higher respiratory rates, lower O2 saturation, and longer hospital stays. They also had higher white blood cell count, glucose level (> 99 mg/dL), anion gap (> 9 mEq/L), sPLA2 (> 7 pg/mL), IFN-γ (> 17.8 pg/mL), IL-10 (1.54 pg/mL), and IL-12 (> 0.5 pg/mL) levels.

CONCLUSIONS

We identified biomarkers associated with ACS development in children with SCD presenting with pain that allow for earlier ACS interventions to reduce mortality and morbidity.

Variants in the β-globin locus are associated with pneumonia in African American children

In African American adults, the strongest genetic predictor of pneumonia appears to be the A allele of rs334, a variant in the β-globin gene, which in homozygous form causes sickle cell disease (SCD). No comparable studies have been done in African American children. We performed genome-wide association analyses of 482 African American children with documented pneumonia and 2,048 African American control individuals using genotypes imputed from two reference panels: 1000 Genomes (1KG) (which contains rs334) and TOPMed (does not contain rs334). Using 1KG imputed genotypes, the most significant variant was rs334 (A allele; odds ratio [OR] = 2.76; 95% CI, 2.21-3.74; p = 5.9 × 10-19); using TOPMed imputed genotypes the most significant variant was rs2226952, found in the β-globin locus control region (G allele; OR = 2.14; 95% CI, 1.78-2.57; p = 5.1 × 10-16). After conditioning on rs334, the most strongly associated variant in the β-globin locus, rs33930165 (T allele, 1KG: OR = 4.09; 95% CI, 2.29-7.29; p = 1.7 × 10-6; TOPMed: OR = 3.58; 95% CI, 2.18-5.90; p = 4.7 × 10-7), which as a compound heterozygote with rs334 A allele, can cause SCD. To compare the power of different sample sets we developed a way to estimate the power of sample sets with different sample sizes, genotype arrays, and imputation platforms. Our results suggest that, in African American children, the strongest genetic determinants of pneumonia are those that increase the risk of SCD.

Long-Term Survival Rates of a Sickle Cell Disease Cohort in Saudi Arabia: A 2009-2023 Observational Study

BACKGROUND

Sickle cell disease (SCD) is prevalent in Saudi Arabia. This study evaluates the long-term survival rates of a cohort of SCD patients.

METHODS

This observational cohort study was conducted at King Saud University Medical City from January 2009 to September 2023. We enrolled 223 SCD patients between 2009 and 2014, collecting comprehensive data at baseline and during follow-up. The primary endpoint was overall survival.

RESULTS

The cohort had a median follow-up of 11.5 years, totaling 2,118 patient-years. The recent median age was 28.9 years (12.2-63.8). The survival rates at ages 20, 30, 40, and 50 years were 100%, 98.4%, 95.1%, and 89.0%, respectively, with no mortality observed before the age of 20 years. The incidence of mortality was 0.28 deaths per 100 patient-years. Among the six deaths (2.7%), causes included non-Hodgkin lymphoma, acute chest syndrome, and a sepsis-like condition, with three unknown causes. The median age of death was 36.3 years. The increased use of hydroxyurea, from 47% to 80%, was associated with reduced pain crises and acute chest syndrome, and improved hemoglobin and HbF levels. Of the patients, 43 (19.2%) were lost to follow-up, 16 (7.2%) were referred for stem cell transplant, and 16 (7.2%) were followed at other institutions.

CONCLUSIONS

This study highlights excellent survival rates for SCD patients in our cohort. Nonetheless, the considerable loss to follow-up highlights the need for strategies to address this issue and larger multicenter studies to confirm our results.

Prevent Acute Chest Syndrome checklist (PACScheck): A quality improvement initiative to reduce acute chest syndrome

BACKGROUND

Acute chest syndrome (ACS) is a life-threatening complication of sickle cell disease (SCD). The Prevent Acute Chest Syndrome checklist (PACScheck) was created to drive appropriate ordering of opioids, incentive spirometry (IS), intravenous fluids (IVF), evaluation of oxygen desaturation, and bronchodilator use.

OBJECTIVES

Decrease the development of ACS by 5% in a hospitalized pediatric SCD population.

METHODS

A multidisciplinary team conducted a quality improvement (QI) project between April 2020 and August 2021 on an inpatient pediatric hematology unit. At-risk hospitalizations were patients with SCD who did not have ACS upon hospital admission. PACScheck was implemented and weekly run charts assessed documentation. Process control (p) charts, geometric control (g) charts, and chi-square tests assessed checklist process measures pre- and post-PACScheck. G chart assessed the number of encounters between ACS events.

RESULTS

A total of 483 at-risk hospitalizations were identified in the 12 months prior and 363 during the study period. A g chart demonstrated that fewer encounters developed ACS during PACScheck. A p chart demonstrated that IS documentation increased during PACScheck. A run chart of PACScheck documentation demonstrated a median of 100% documentation at least once per hospitalization during the last six months of the intervention.

CONCLUSION

Development of ACS can be reduced by implementing a best-practices checklist (PACScheck) on an inpatient pediatric hematology unit with a multidisciplinary team.

TR4 and BCL11A repress γ-globin transcription via independent mechanisms

ABSTRACT

Nuclear receptor TR4 (NR2C2) was previously shown to bind to the -117 position of the γ-globin gene promoters in vitro, which overlaps the more recently described BCL11 transcription factor A (BCL11A) binding site. The role of TR4 in human γ-globin gene repression has not been extensively characterized in vivo, whereas any relationship between TR4 and BCL11A regulation through the γ-globin promoters is unclear at present. We show here that TR4 and BCL11A competitively bind in vitro to distinct, overlapping sequences, including positions overlapping -117 of the γ-globin promoter. We found that TR4 represses γ-globin transcription and fetal hemoglobin accumulation in vivo in a BCL11A-independent manner. Finally, examination of the chromatin occupancy of TR4 within the β-globin locus, compared with BCL11A, shows that both bind avidly to the locus control region and other sites, but only BCL11A binds to the γ-globin promoters at statistically significant frequency. These data resolve an important discrepancy in the literature and, thus, clarify possible approaches to the treatment of sickle cell disease and β-thalassaemia.

Living with sickle cell in Uganda: A comprehensive perspective on challenges, coping strategies, and health interventions

Sickle cell anemia (SCA) is a hereditary blood disorder with profound implications for affected individuals, particularly in resource-limited settings such as Uganda. This review explores the multifaceted aspects of SCA in Uganda, focusing on epidemiology, challenges faced by individuals, coping strategies, healthcare disparities, and community support. The study incorporates a thorough examination of the genetic landscape, prevalence, and the impact of SCA on the quality of life in Uganda. Coping strategies and resilience play a pivotal role in mitigating the impact of SCA on affected individuals. This review critically evaluates the various coping mechanisms employed by individuals in Uganda and the resilience demonstrated in the face of chronic illness. It explores the psychological, social, and cultural dimensions of coping and resilience, shedding light on adaptive strategies that contribute to improved quality of life. This article aims to contribute valuable insights into the specific challenges faced by individuals with SCA in Uganda, offering a foundation for targeted interventions, improved healthcare policies, and increased awareness within both the medical community and the broader society.

Circulating biomarkers associated with pediatric sickle cell disease

Introduction

Sickle cell disease (SCD) is a genetic blood disorder caused by a mutation in the HBB gene, which encodes the beta-globin subunit of hemoglobin. This mutation leads to the production of abnormal hemoglobin S (HbS), causing red blood cells to deform into a sickle shape. These deformed cells can block blood flow, leading to complications like chronic hemolysis, anemia, severe pain episodes, and organ damage. SCD genotypes include HbSS, HbSC (HbC is an abnormal variant of hemoglobin), and HbS/β-thalassemia. Sickle cell trait (SCT), HbAS, represents the carrier state, while other hemoglobin variants include HbCC, HbAC, and the normal HbAA. Over 7.5 million people worldwide live with SCD, with a high mortality rate in sub-Saharan Africa, including Ghana. Despite its prevalence, SCD is underdiagnosed and poorly managed, especially in children. Characterized by intravascular hemolysis, SCD leads to oxidative stress, endothelial activation, and systemic inflammation. Identifying circulating blood biomarkers indicative of organ damage and systemic processes is vital for understanding SCD and improving patient management. However, research on biomarkers in pediatric SCD is limited and few have been identified and validated. This study explores specific circulating biomarkers in pediatric SCD in Ghana (West Africa), hypothesizing that inflammatory and neuronal injury markers in children with SCD could predict disease outcomes.

Methods

Clinical data were collected from 377 children aged 3-8 years with various Hb genotypes, including SCD and SCT, at Korle-Bu Teaching Hospital in Accra, Ghana (2021-2022). A total of 80 age- and sex-matched subjects were identified. A cross-sectional study utilized a multiplexed immunoassay procedure to evaluate serum biomarkers, including cytokines, chemokines, vascular injury markers, systemic inflammation markers, cell-free heme scavengers, brain-derived neurotrophic factor (BDNF), and angiogenic factors.

Results

Elevated levels of BDNF, Ang-2, CXCL10, CCL11, TNF-α, IL-6, IL-10, IL12p40, ICAM-1, VCAM-1, Tie-2, and VEGFA were observed in HbSS subjects, correlating with hemoglobin level, leukocyte, and erythrocyte counts. Heme scavengers like HO-1, hemopexin, and haptoglobin also correlated with these parameters. ROC and AUC analyses demonstrated the potential of these biomarkers in predicting SCD outcomes.

Conclusion

These findings suggest that there are significant differences between biomarker expression among the different genotypes examined. We conclude that a predictive algorithm based on these biomarkers could be developed and validated through longitudinal assessment of within-genotype differences and correlation of the data with disease severity or outcomes. With such a tool one can enhance SCD management and improve patient outcomes. This approach may pave the way for personalized interventions and better clinical care for pediatric SCD patients.

Hotspots and status of Fetal Alpha-Thalassemia from 2009 to 2023: a bibliometric analysis

Objective

to evaluate the research status and development hotspots of fetal α-thalassemia by quantitatively analyzing the diagnostic status, key areas, related management measures and prospects of the disease by bibliometrics.

Methods

The global literature on fetal α-thalassemia and severe α-thalassemia from 2009-2023 in the Web of Science Core Collection (WOSCC) was visually analyzed by VOSviewer and CiteSpace.

Results

(1) The examination of the quantity of publications concerning fetal α-thalassemia indicates a rising tendency prior to 2018, followed by a decrease after 2018. (2)The United States, China, Italy, Thailand have published more papers, and the United States has more collaborating countries such as Italy and China. (3) Chiang Mai University and Harvard University are the top two institutions with the highest contribution. However, Chiang Mai University's H index (12) and citation frequency per article (8.05) are relatively low and the NC (6,342), H index (33) and citations per article (75.42) of Harvard University are higher than those of the other institutions. (4) Tongsong T, Gambari R and Fucharoen S are the top three prolific authors. Fucharoen S emerges as the most frequently cited author with 738 citations, excluding self-citations. (5) HEMOGLOBIN leading with 87 published papers (NC:601,IF: 0.82, H-index: 13), followed by BLOOD(58 papers, Nc: 3755, IF: 25.48, H-index: 40) and BLOOD CELLS MOLECULES AND DISEASES(39 papers, Nc: 729, IF: 2.37, H-index: 16). (6) The most cited article was published in science and the second and third cited articles were featured in the Proceedings of the National Academy of Sciences; the top 3 clusters of co-cited literature are "gene editing", "polymorphisms", "hydroxyurea". (7) Keywords analysis showe that the top two categories of keyword cluster focus on the prenatal diagnosis and the current treatment strategy of the disease, which remain the research hotspots.

Conclusions

Recent research on this topic has primarily focused on prenatal diagnosis and treatment strategies. A particular area of interest is the ongoing research on gene therapy.The advances in non-invasive diagnosis and therapeutic methods will change the current management approaches for fetal severe α-thalassemia in the future.

Incremental eligibility criteria for the BMT CTN 1507 haploidentical trial for children with sickle cell disease

ABSTRACT

The Blood and Marrow Transplant Clinical Trials Network (BMT CTN) 1507 leadership and the data safety monitoring board (DSMB) established incremental entry criteria for children aged 5 to 14.99 years with sickle cell disease (SCD) enrolling in a phase 2 trial of HLA-haploidentical hematopoietic stem cell transplantation. First, the enrollment was limited to overt stroke in the first 10 participants (stage 4). Subsequently, the DSMB reviewed the interim results and expanded the eligibility to include children with silent cerebral infarcts or abnormal transcranial Doppler velocities with magnetic resonance angiography-defined cerebral vasculopathy (stage 3). A third cohort was enrolled after the DSMB reviewed the clinical outcomes in these cumulative initial enrollments (n = 18) and additions were made to the entry criteria that included nonneurologic morbidities (stage 2). Added eligibility criteria included the following: (1) life-threatening acute chest syndrome requiring exchange transfusion; (2) right heart catheterization confirmed pulmonary hypertension; (3) persistent systemic hypertension despite maximum medical therapy; (4) acute pain despite maximum medical therapy in the absence of psychosocial factors and unmanaged asthma after adjudication; and (5) 2 major priapism episodes in 12 months or 3 in 24 months. Children with SCD who did not meet the criteria for stages 4, 3, and 2 were not eligible. To our knowledge, for the first time, we introduce a staged strategy for eligibility in a curative therapy trial for children with SCD concordant with 45 Code of Federal Regulations § 46.405(b). The research governance-mandated eligibility strategy used within the BMT CTN 1507 phase 2 study may apply to future pediatric SCD curative therapy trials. This trial was registered at www.ClinicalTrials.gov as #NCT032635590.

Challenges and opportunities for conceiving genetically diverse sickle cell mice

A milestone in sickle cell disease (SCD) therapeutics was achieved in December 2023 with the FDA-approved gene therapy for patients aged 12 years and older. However, these therapies may only suit a fraction of patients because of cost or health risks. A better understanding of SCD outcome heterogeneity is needed to propose patient-specific pharmacological interventions. To achieve this, humanized and genetically diverse mouse models are essential for associating candidate genotypes with specific hematological traits, organ function, and disease resilience. Here, we discuss the challenges and opportunities in developing genetically diverse sickle cell mice (GDS mice). These models are expected to complement current approaches in SCD research and enhance our understanding of SCD heterogeneity and anemia.

Structural insights into the DNA-binding mechanism of BCL11A: The integral role of ZnF6

The transcription factor BCL11A is a critical regulator of the switch from fetal hemoglobin (HbF: α2γ2) to adult hemoglobin (HbA: α2β2) during development. BCL11A binds at a cognate recognition site (TGACCA) in the γ-globin gene promoter and represses its expression. DNA-binding is mediated by a triple zinc finger domain, designated ZnF456. Here, we report comprehensive investigation of ZnF456, leveraging X-ray crystallography and NMR to determine the structures in both the presence and absence of DNA. We delve into the dynamics and mode of interaction with DNA. Moreover, we discovered that the last zinc finger of BCL11A (ZnF6) plays a different role compared to ZnF4 and 5, providing a positive entropic contribution to DNA binding and γ-globin gene repression. Comprehending the DNA binding mechanism of BCL11A opens avenues for the strategic, structure-based design of novel therapeutics targeting sickle cell disease and β-thalassemia.

Leukocytosis as a Risk Factor for Coronary Artery Disease: Pathophysiology and Epidemiology

Coronary artery disease (CAD) is a significant health concern characterized by reduced blood flow to the heart muscle, primarily due to the buildup of atherosclerotic plaques in the coronary arteries. This process begins with endothelial injury, leading to a cascade of biological responses contributing to plaque formation. Endothelial injury attracts the migration of monocytes which differentiate into macrophages upon uptake of oxidized low-density lipoproteins, changing into lipid-laden macrophage or “foam cells.” The process of plaque formation is influenced by many factors which have been studied extensively in literature such as smoking, hypertension, and diabetes mellitus. Chronic inflammatory illnesses are often associated with a high prevalence of coronary artery syndromes, prompting the evaluation of markers of inflammation such as white blood cell count and inflammatory markers as independent risk factors for CAD. White blood cells play a remarkable role in the pathophysiology of disease formation and progression. The article below aims to discuss the pathophysiology and epidemiology of leukocytosis as a risk factor for CAD.

Trends in Sickle Cell Disease Mortality: 1979-2020

BACKGROUND AND OBJECTIVES

Although sickle cell disease (SCD)-related childhood mortality in the United States significantly improved in the 1990s, unclear is the trend in SCD-related mortality more recently given the continued disparities faced by this minoritized population. In this analysis, we aimed to (1) compare the overall and age-specific mortality rates from 1999 to 2009 vs 2010 to 2020 with a particular focus on the age of transition and (2) determine the most common causes of death for the US SCD population for 2010 to 2020.

METHODS

We analyzed publicly available data from the Centers for Disease Control and Prevention WONDER database, a compilation of national-level mortality statistics from 1979 to 2020 derived from death certificates compiled by the National Center for Health Statistics. We searched by all individuals of all ethnicities, sexes, and ages using the underlying cause of death.

RESULTS

The crude mortality rate for individuals with SCD for 2010 to 2020 was 1.6 per 1 000 000 individuals, which was significantly lower than the period 1999 to 2009 (crude rate 1.7 per 1 000 000, P < .0001). In addition, the mean age at mortality of those with SCD was older in 2010 to 2020 (43 years) versus 1999 to 2009 (39 years). However, there remains a significant increase in mortality rate in the 20 to 24 year age group versus 15 to 19 years (1.7 per 1 000 000 versus 0.7 per 1 000 000, P < .0001), corresponding with the age of transition from pediatric to adult centers. In addition, 39% of underlying causes of death were not caused by SCD, but rather primarily chronic conditions, including cardiovascular, cerebrovascular, malignancy, and renal disease. The study has several limitations mostly because of the imperfections of administrative data sources, including inaccuracies in diagnoses codes, risking over or undercounting.

CONCLUSIONS

Although the US SCD-related mortality rate continues to decrease, the age of transition to adult care is a particularly vulnerable time in the lives of this marginalized group. Innovative and expanded approaches to care are greatly needed.

Post-exchange neutrophil count, but not post-hematocrit, predicts endogenous erythropoiesis in patients with sickle cell disease undergoing chronic red cell exchange

BACKGROUND

With chronic transfusion in sickle cell disease (SCD), equipoise exists regarding whether increasing the post-procedure hematocrit (Hct) suppresses endogenous erythropoiesis. Reticulocytosis predicts SCD morbidity and mortality, so this study's objective was to clarify the role of the post-procedure Hct in suppressing reticulocytosis and to identify other potential red cell exchange (RCE) parameters predictive of reticulocytosis.

STUDY DESIGN AND METHODS

This retrospective analysis of 17 patients who underwent chronic RCE at a single institution between 2014 and 2022 examined both standard red cell exchanges (SRCE) and exchanges preceded by isovolemic hemodilution (IVH-RCE). Post-procedure parameters with biologic plausibility to influence the subsequent procedure's absolute reticulocyte count (sPre-ARC) were examined using regression modeling.

RESULTS

Neither post-hematocrit, nor post-hemoglobin (Hb), nor ΔHb/day was associated with sPre-ARC or the change in HbS% per day (ΔHbS%/day). Concurrent Hb was predictive for SRCE but not IVH-RCE, where ARC trended lower than with SRCE. Male gender and post-procedure neutrophil and white cell counts were predictors of sPre-ARC, consistent with their associations with SCD morbidity and mortality. IVH-RCE had a stronger correlation than standard RCE between pre-Hct and neutrophil or white cell depletion.

DISCUSSION

Although targeting a post-procedure Hct maintains a higher subsequent pre-procedure Hb and a lower sPre-HbS%, it does not lead to sustained suppression of reticulocytosis as measured by the sPre-ARC or the ΔHbS%/day. IVH-RCE or the addition of hydroxyurea could be considered in those patients with high reticulocyte, white blood cell, or neutrophil counts.

Baseline characteristics of Ghanaian children and adults enrolled in PIVOT, a randomised clinical trial of hydroxyurea in HbSC disease in sub-Saharan Africa

HbSC disease is a common form of sickle cell disease with significant morbidity and early mortality. Whether hydroxyurea is beneficial for HbSC disease is unknown. Prospective Identification of Variables as Outcomes for Treatment (PIVOT, Trial ID PACTR202108893981080) is a double-blind, randomised, placebo-controlled phase II trial of hydroxyurea for people with HbSC, age 5-50 years, in Ghana. After screening, participants were randomised to placebo (standard of care) or hydroxyurea. The primary outcome is the cumulative incidence of haematological toxicities during 12 months of blinded treatment; secondary outcomes include multiple laboratory and clinical assessments. Between April 2022 and June 2023, 112 children and 102 adults were randomised, including 44% females and average age 21.6 ± 14.5 years. Participants had substantial morbidity including previous hospitalisations (93%), vaso-occlusive events (86%), malaria (79%), often received transfusions (20%), with baseline haemoglobin 11.0 ± 1.2 g/dL and foetal haemoglobin 1.8% ± 1.5%. The spleen was palpable in six children and one adult, and ultrasonographic volumes were collected. Proliferative sickle retinopathy was common (30% children, 75% adults), but proteinuria was less common (3% children, 8% adults). Whole blood viscosity, ektacytometry, point-of-sickling, transcranial Doppler, near-infrared spectrometry (NIRS), 6-minute walk, and quality of life were also measured. Now fully enrolled, PIVOT will document the safety and potential benefits of hydroxyurea on clinical and laboratory outcomes in HbSC disease.

Total Hip Arthroplasty Complications in Patients With Sickle Cell Disease: A Comparison Study

Background

Total hip arthroplasty (THA) is one of the most common orthopaedic procedures performed in the United States, but there are rare complications which can be devastating. Sickle cell disease (SCD) can lead to avascular necrosis of the femoral head, often necessitating THA. This article seeks to better characterize the complication risks in patients undergoing THA with SCD when compared to osteoarthritis (OA) using a large database from the National Inpatient Sample.

Methods

National Inpatient Sample data from 2006 through the third quarter of 2015 were analyzed using International Classification of Diseases, Ninth Revision codes. A weighted frequency of 4,350,961 THAs were recorded for OA and 4279 for SCD. These were compared using a Rao-Scott chi-squared test, and the prespecified complications were given sampling weights to approximate national estimates.

Results

The following complications were found to occur at a significantly increased frequency in patients with OA with SCD vs OA only: wound infection (0.69% vs 0.36%), dislocation (1.68% vs 0.80%), and urinary complications (3.61% vs 2.35%). SCD, when evaluated independent of avascular necrosis, was reported with higher frequency wound infection (0.86% vs 0.36%), and overall complications (7.25% vs 5.06%). Additionally, multiple comorbidities were significantly more prevalent in the SCD population compared to OA patients.

Conclusions

This study illustrates that patients with SCD have increased complication rates when compared to OA patients. This information benefits orthopaedic surgeons in preoperative and postoperative planning and counseling patients for realistic expectations. Furthermore, this study provides data that could benefit decision-making on bundled reimbursement for this specific patient population.

A Meta-analysis of the Utility of Red Cell Distribution Width as a Biomarker to Predict Outcomes in Pediatric Illness (PROSPERO CRD42020208777)

Red cell distribution width (RDW) is an average of the variation in red blood cell (RBC) sizes reported on a complete blood count. An elevated RDW indicates a pathological process that is affecting erythropoiesis. Studies showed that as the severity of disease process increases, the RDW often increases as well. Particularly in resource-limited countries, RDW has been studied as an outcome predictor for conditions in a variety of disciplines and is offered as an adjunct monitoring tool that is cost effective, readily available, and indicative of pathological processes amenable to intervention. Particularly in pediatric critical care settings, RDW has been shown to be a reliable tool for surveillance of disease states such as sepsis. Despite the increased attention of RDW as a marker for disease outcome, collective evaluation on the utility of RDW as a marker for outcome in pediatric critical care settings is lacking. We offer a systematic review and meta-analysis of published studies to assess the ability of RDW to predict illness severity and mortality among pediatric critical care patients. Among eight studies of over 4,800 patients, we found over a two-fold increase in odds for mortality in critically ill children whose RDW was above 15.7%. This is the first systematic review of RDW being used to predict mortality in critically ill children and findings of this study may prompt early intervention in the pediatric critical care setting.

Inflammatory pathways and anti-inflammatory therapies in sickle cell disease

Sickle cell disease (SCD) is a monogenic disease, resulting from a single-point mutation, that presents a complex pathophysiology and high clinical heterogeneity. Inflammation stands as a prominent characteristic of SCD. Over the past few decades, the role of different cells and molecules in the regulation of the inflammatory process has been elucidated. In conjunction with the polymerization of hemoglobin S (HbS), intravascular hemolysis, which releases free heme, HbS, and hemoglobin-related damage-associated molecular patterns, initiates multiple inflammatory pathways that are not yet fully comprehended. These complex phenomena lead to a vicious cycle that perpetuates vaso-occlusion, hemolysis, and inflammation. To date, few inflammatory biomarkers can predict disease complications; conversely, there is a plethora of therapies that reduce inflammation in SCD, although clinical outcomes vary widely. Importantly, whether the clinical heterogeneity and complications are related to the degree of inflammation is not known. This review aims to further our understanding of the roles of main immune cells, and other inflammatory factors, as potential prognostic biomarkers for predicting clinical outcomes or identifying novel treatments for SCD.

Effects of Air Pollution on Respiratory Events and Pain Crises among Children with Sickle Cell Disease in New York City

Rationale: The disease burden of sickle cell disease (SCD) is highest among U.S. Black and Hispanic populations, which are often disproportionately represented in communities with poor air quality. There are limited data on the effects of air pollution exposure and social environmental factors on health outcomes in children with SCD. Objectives: The objectives of our study were to examine the associations between air pollution exposure and acute respiratory and vaso-occlusive pain crises (VOCs) and to further study the associations when stratifying by asthma status and neighborhood disadvantages. Methods: We conducted a retrospective study, collecting data on outpatient sick and emergency department visits, hospital admissions for respiratory events (i.e., respiratory tract infections, asthma exacerbation, acute chest syndrome), and hospitalizations for VOCs among children with SCD in a tertiary care center in New York City from 2015 to 2018. Modeled data from the New York City Community Air Survey data using home addresses' estimated street-level annual average exposure to air pollution (i.e., black carbon, particulate matter with an aerodynamic diameter ≤2.5 μm, and nitrogen dioxide). The area deprivation index (ADI) continuous national ranking percentile (1-100) was used, representing a composite index for neighborhood-level social disadvantage. We further dichotomized study participants at the upper tertile (high vs. low ADI). Multivariable Poisson regression in generalized estimating equation models were used to estimate relative risks (RRs) after adjusting for potential covariates. Results: A total of 114 children with SCD were included in this study and had between one and four annual repeated measures of annual average air pollutants over a total of 425 visits. Overall, there were no significant associations between air pollution levels and acute respiratory pain crises and VOCs among children with SCD and when stratified by asthma status. We found significant interactions between air pollution levels and the continuous ADI variable on respiratory outpatient and frequent respiratory outpatient/ED visits (P < 0.1). When stratified by high ADI, increased exposure to particulate matter with an aerodynamic diameter ≤2.5 μm was significantly associated with more frequent respiratory outpatient/emergency department visits among children residing in higher ADI neighborhoods (RR [95% confidence interval], 1.13 [1.01, 1.27]; P < 0.05), but not among those in lower ADI neighborhoods. Increased exposure to nitrogen dioxide was associated with more outpatient respiratory events for children in high ADI neighborhoods (RR [95% confidence interval], 2.74 [1.24, 6.08]; P < 0.05) compared with low ADI neighborhoods. Conclusions: Air pollution exposures increased respiratory complications among children with SCD living in deprived neighborhoods.

Protocol for a multicentric, double-blind, randomised controlled trial of hyperbaric oxygen therapy (HBOT) versus sham for treating vaso-occlusive crisis (VOC) in sickle cell disease (SCD) in patients aged 8 years or older (HBOT-SCD study)

INTRODUCTION

Sickle cell disease (SCD) is one of the most common genetic diseases in the world, annually affecting approximately 310 000 births and causing >100 000 deaths. Vaso-occlusive crisis (VOC) is the most frequent complication of SCD, leading to bone pain, thoracic pain (acute chest syndrome) and/or abdominal spasms. It is the main cause of mortality in patients with SCD, reducing life expectancy. Hyperbaric oxygen therapy (HBOT) is a safe and well-established method of increasing tissue oxygen delivery immediately by up to 10-fold to 20-fold. In the context of VOC, HBOT has the potential to limit sickling. A previous pilot study of nine patients showed the safety and potential benefits of HBOT on VOC-induced pain. Our study aimed to assess the clinical safety and effectiveness of HBOT for treating VOC, its biological mechanisms of actions and its cost-effectiveness.

METHODS AND ANALYSIS

This is a multicentric, triple-blinded, randomised controlled trial. Patients aged 8 years or above with a diagnosed major form of SCD, presenting at one of the participating centres' emergency departments (EDs) with a VOC requiring level 3 analgesia (according to WHO definition), will be eligible. Exclusion criteria are pregnancy, mechanical ventilation, previous history of stroke or prior transcranial Doppler ultrasound anomaly, contraindication to HBOT and the need for above 2 L/min of oxygen. All patients will receive the usual care for VOCs, including hydration, analgesics, normobaric oxygen therapy and when medically indicated, antibiotic therapy and/or transfusions. Within 24 hours of their arrival in the ED (or longer in specific cases), and after obtaining informed consent, patients will be randomised into the HBOT intervention group (2.0 atmosphere absolute (ATA), 90 min, FIO2=1) or the sham group (1.3 ATA, 90 min, FIO2=0.21). After their first HBOT session, patients will return to their acute-care ward. Patients in both arms will undergo a second and third session within 24-36 hours of the first, unless their Visual Analogue Scale (VAS)-pain is ≤2 without use of level 3 analgesics. The difference in the pain-VAS before and after HBOT and other outcomes will be compared between the intervention and sham groups. Our composite primary outcome will be (1) the change in global VAS-pain 6 hours after initiation of HBOT; (2) the number of patients with a VAS-pain score >4 and/or a morphine dosage >1 mg/hour intravenous after the HBOT/sham session. Other outcomes to be reported are morphine usage, length of stay, biological parameters, satisfaction, complications and cost.

ETHICS AND DISSEMINATION

Ethical approval CER Geneva 2019-01707 (last submission V.5.1, 06.15.2023). The results of the studies will be disseminated by several media, including publications in peer-reviewed international medical journals, and presentations at national and/or international conferences.

TRIAL REGISTRATION NUMBER

NCT04978116.

Atrial arrhythmia in adults with sickle cell anemia: a missing link toward understanding and preventing strokes

ABSTRACT

Although patients with homozygous sickle cell anemia (SCA) carry both significant left atrial (LA) remodeling and an increased risk of stroke, the prevalence of atrial arrhythmia (AA) has never been prospectively evaluated. The aim of this study was to identify the prevalence and predictors of atrial arrhythmia in SCA. From 2018 to 2022, consecutive adult patients with SCA were included in the DREPACOEUR prospective registry and referred to the physiology department for cardiac evaluation, including a 24-hour electrocardiogram monitoring (ECG-Holter). The primary endpoint was the occurrence of AA, defined by the presence of excessive supraventricular ectopic activity (ESVEA) on ECG-Holter (ie >720 premature atrial contractions [PACs] or any run ≥ 20 PACs) or any recent history of atrial fibrillation. Overall, 130 patients with SCA (mean age: 45±12 years, 48% of male) were included. AA was found in 34 (26%) patients. Age (52±9 vs. 42±12 years, P=0,002), LA dilation (LAVi, 71±24 vs. 52±14 mL/m², P<0.001) and history of stroke without underlying cerebral vasculopathy (26% vs. 5%, P=0.009, OR=6.6 (95%CI 1.4-30.3]) were independently associated with AA. Age and LAVi correlated with PAC load per 24 hours on ECG-Holter. An age over 47 years or a LAVi >55mL/m² could predict AA with a PPV of 33% and a NPV of 92%. AAs are frequent in middle-aged patients with SCA and increase with age and LA remodeling, leading to a major additional risk factor for ischemic stroke. This study provides arguments and means to early screen for AA and potentially prevent cerebral complications.

The Association between Sickle Cell Disease and Postpartum Severe Maternal Morbidity

OBJECTIVE

 To compare the risk of severe maternal morbidity (SMM) from the delivery admission to 42 days' postdischarge among persons with sickle cell disease (SCD) to those without SCD.

STUDY DESIGN

 This retrospective cohort study included deliveries ≥20 weeks' gestation at an urban safety net hospital in Atlanta, GA from 2011 to 2019. The exposure was SCD diagnosis. The outcome was a composite of SMM from the delivery admission to 42 days' postdischarge. SMM indicators as defined by the Centers for Disease Control and Prevention were identified using the International Classification of Diseases, Ninth and Tenth Revisions (ICD-9/10) codes; transfusion of blood products and sickle cell crisis were excluded.

RESULTS

 Of N = 17,354 delivery admissions, n = 92 (0.53%) had SCD. Persons with SCD versus without SCD had an increased risk of composite SMM (15.22 vs. 2.29%, p < 0.001), acute renal failure (6.52 vs. 0.71%, p < 0.001), acute respiratory distress syndrome (4.35 vs. 0.17%, p < 0.001), puerperal cerebrovascular disorders (3.26 vs. 0.10%, p < 0.001), sepsis (4.35 vs. 0.42%, p < 0.01), air and thrombotic embolism (5.43 vs. 0.10%, p < 0.001), and ventilation (2.17 vs. 0.09%, p < 0.01). Ultimately, those with SCD had an approximately 6-fold higher incidence risk ratio of SMM, which remained after adjustment for confounders (adjusted incidence risk ratio [aIRR]: 5.96, 95% confidence interval [CI]: 3.4-9.19, p < 0.001). Persons with SCD in active vaso-occlusive crisis at the delivery admission had an approximately 9-fold higher risk of SMM up to 42 days' postdischarge compared with those with SCD not in crisis at the delivery admission (incidence: 25.71 vs. 8.77%, p < 0.05; aIRR: 8.92, 95% CI: 4.5-10.04, p < 0.05). Among those with SCD, SMM at the delivery admission was primarily related to renal and cerebrovascular events, whereas most postpartum SMM was related to respiratory events or sepsis.

CONCLUSION

 SCD is significantly associated with an increased risk of SMM during the delivery admission and through 42 days' postdischarge. Active crisis at delivery further increases the risk of SMM.

KEY POINTS

· Sickle cell disease was associated with an approximately 6-fold increased risk of SMM.. · Active vaso-occlusive crisis at delivery was associated with an approximately 9-fold increased risk of SMM.. · 48% of SMM events in persons with SCD occurred postpartum and were respiratory- or sepsis-related..

Black Americans With Sickle Cell Disease (SCD) Demonstrate Accelerated Epigenetic Pace of Aging Compared to Black Americans Without SCD

BACKGROUND

Sickle cell disease (SCD) is a chronic medical condition characterized by red blood cell sickling, vaso-occlusion, hemolytic anemia, and subsequently, end-organ damage and reduced survival. Because of this significant pathophysiology and early mortality, we hypothesized that patients with SCD are experiencing accelerated biological aging compared with individuals without SCD.

METHODS

We utilized the DunedinPACE measure to compare the epigenetic pace of aging in 131 Black Americans with SCD to 1391 Black American veterans without SCD.

RESULTS

SCD patients displayed a significantly accelerated pace of aging (DunedinPACE mean difference of 0.057 points) compared with the veterans without SCD, whereby SCD patients were aging ≈0.7 months more per year than those without SCD (p = 4.49 × 10-8). This was true, even though the SCD patients were significantly younger according to chronological age than the individuals without SCD, making the epigenetic aging discrepancy even more apparent. This association became stronger when we removed individuals with posttraumatic stress disorder from the non-SCD group (p = 2.18 × 10-9), and stronger still when we restricted the SCD patients to those with hemoglobin SS and Sβ0 thalassemia genotypes (p = 1.61 × 10-10).

CONCLUSIONS

These data support our hypothesis that individuals with SCD experience accelerated biological aging as measured by global epigenetic variation. The assessment of epigenetic measures of biological aging may prove useful to identify which SCD patients would most benefit from clinical interventions to reduce mortality.

Genetic variants associated with white blood cell count amongst individuals with sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is a Mendelian disorder characterized by a point mutation in the β-globin gene that leads to sickling of erythrocytes. Several studies have shown that absolute neutrophil count is strongly associated with clinical severity of SCD, suggesting an apparent role of white blood cells (WBC) in SCD pathology. However, the mechanism by which genetic variants lead to WBC count differences in SCD patients remains unclear.

METHODS

Genome-wide association (GWA) analyses were carried out amongst a cohort of 2409 Brazil SCD participants. Association of WBC count and genetic markers were investigated in homozygous sickle cell anaemia participants and compound heterozygous sickle cell haemoglobin C participants.

RESULTS

GWA analysis showed that variants in genes TERT, ACKR1, and FAM3C are associated with WBC count variation. The well-studied association between WBC count and Duffy null phenotype (variant in ACKR1) in healthy populations was replicated, reinforcing the influence of the SNP rs2814778 (T>C) in WBC count.

CONCLUSION

Genetics plays an important role in regulating WBC count in patients with SCD. Our results point to possible mechanisms involved in WBC count variation and as increased WBC count is associated with more severe SCD, these results could suggest potential therapeutic targets for individuals with SCD.

Association of biomarkers of endothelial function, coagulation activation and kidney injury with persistent albuminuria in sickle cell anaemia

Persistent albuminuria (PA) is common in sickle cell anaemia (SCA). With the association of chronic kidney disease (CKD) with increased mortality, biomarkers that predict its development or progression are needed. We evaluated the association of select biomarkers with PA in adults with SCA using Kruskal-Wallis rank-sum test and logistic regression models, with adjustment for multiple testing. Of 280 subjects, 100 (35.7%) had PA. Median plasma levels of soluble vascular cell adhesion molecule-1 (VCAM-1) (1176.3 vs. 953.4 ng/mL, false discovery rate [FDR] q-value <0.003), thrombin-antithrombin complex (5.5 vs. 4.7 ng/mL, FDR q-value = 0.04), and urinary angiotensinogen (AGT) (12.2 vs. 5.3 ng/mg, FDR q-value <0.003), urinary nephrin (30.6 vs. 27.2 ng/mg, FDR q-value = 0.04), and urinary kidney injury molecule-1 (KIM-1) (0.8 vs. 0.5 ng/mg, FDR q-value <0.003), normalized to urine creatinine, were significantly higher in subjects with PA. In multivariable analysis, only urinary AGT (odds ratio = 1.058, FDR q-value <0.0001) remained a significant predictor of PA. In addition, soluble VCAM-1 (FDR q-value <0.0001), D-dimer (FDR q-value <0.0001), urinary AGT (FDR q-value <0.0001), KIM-1 (FDR q-value <0.0001), and nephrin (FDR q-value <0.0001) were significantly associated with urine albumin-creatinine ratio in multivariable analyses. Longitudinal studies to evaluate the predictive capacity of biomarkers for the development and progression of CKD in SCA are warranted.

Δ9-Tetrahydrocannabinol Alleviates Hyperalgesia in a Humanized Mouse Model of Sickle Cell Disease

People with sickle cell disease (SCD) often experience chronic pain as well as unpredictable episodes of acute pain, which significantly affects their quality of life and life expectancy. Current treatment strategies for SCD-associated pain primarily rely on opioid analgesics, which have limited efficacy and cause serious adverse effects. Cannabis has emerged as a potential alternative, yet its efficacy remains uncertain. In this study, we investigated the antinociceptive effects of Δ9-tetrahydrocannabinol (THC), cannabis' intoxicating constituent, in male HbSS mice, which express >99% human sickle hemoglobin, and male HbAA mice, which express normal human hemoglobin A, as a control. Acute THC administration (0.1-3 mg/kg-1, i.p.) dose-dependently reduced mechanical and cold hypersensitivity in human sickle hemoglobin (HbSS) but not human normal hemoglobin A (HbAA) mice. In the tail-flick assay, THC (1 and 3 mg/kg-1, i.p.) produced substantial antinociceptive effects in HbSS mice. By contrast, THC (1 mg/kg-1, i.p.) did not alter anxiety-like behavior (elevated plus maze) or long-term memory (24-hour novel object recognition). Subchronic THC treatment (1 and 3 mg/kg-1, i.p.) provided sustained relief of mechanical hypersensitivity but led to tolerance in cold hypersensitivity in HbSS mice. Together, the findings identify THC as a possible therapeutic option for the management of chronic pain in SCD. Further research is warranted to elucidate its mechanism of action and possible interaction with other cannabis constituents. SIGNIFICANCE STATEMENT: The study explores Δ9-tetrahydrocannabinol (THC)'s efficacy in alleviating pain in sickle cell disease (SCD) using a humanized mouse model. Findings indicate that acute THC administration reduces mechanical and cold hypersensitivity in SCD mice without impacting emotional and cognitive dysfunction. Subchronic THC treatment offers sustained relief of mechanical hypersensitivity but leads to cold hypersensitivity tolerance. These results offer insights into THC's potential as an alternative pain management option in SCD, highlighting both its benefits and limitations.

Detection of Subclinical Cardiac Dysfunction in Patients With Sickle Cell Disease Using Speckle-Tracking Echocardiography

Sickle cell disease (SCD) is characterized by chronic anemia and recurrent ischemia-reperfusion episodes, which can lead to high-output heart failure. The impact of SCD on cardiac structure and function remains underinvestigated. We conducted a single-institution retrospective analysis of clinical and echocardiographic data from patients with hemoglobin SS SCD (SCD-SS) between January 2016 and June 2022. Patients with known heart failure, left ventricular (LV) ejection fraction <50%, moderate or severe valvular heart disease, congenital heart disease, established coronary artery disease, diabetes mellitus, hypertension, or coexistent lung disease were excluded. Compared with healthy controls (n = 28), patients with SCD-SS (n = 66) had a significantly higher left atrial (LA) volume index (35.7 vs 23.9 ml/m², p <0.001) and average E/e' (7.4 vs 6.5, p = 0.003) but lower average e' (12.3 vs 13.6 cm/s, p = 0.047) and LA reservoir strain (32.9% vs 42.4%, p <0.001). Patients with SCD-SS had higher LV end-diastolic (132.5 vs 104.1 ml, p <0.001) and LV end-systolic volumes (51.0 vs 43.8 ml, p = 0.017) with reduced LV global longitudinal strain (17.6% vs 20.0%, p <0.001). In addition, patients with SCD-SS showed reduced right ventricular (RV) global longitudinal strain (19.7% vs 22.8%, p <0.001) in the setting of normal RV tricuspid annular plane systolic excursion. Maximal systolic tricuspid regurgitation velocity (231 vs 202 cm/s, p <0.001) and right atrial area (16.6 vs 12.8 cm², p <0.001) were statistically greater in SCD-SS. Hemoglobin and hematocrit negatively correlated with LA volume index, average E/e', LV end-diastolic and LV end-systolic volumes. In conclusion, patients with SCD-SS had notable differences in cardiac chamber size and impaired LV, RV, and LA strain compared with healthy controls. Further investigations are needed to assess the impact of these variables on SCD clinical course and prognosis.

Impact of hydroxyurea on follicle density in patients with sickle cell disease

ABSTRACT

The impact of hydroxyurea (HU) on the ovarian reserve of female patients with sickle cell disease (SCD) remains poorly elucidated. Only direct histological analysis of ovarian follicle density can effectively evaluate HU's effect on ovarian reserve. By analyzing digitized slides of ovarian tissue from girls and young women with SCD who underwent ovarian tissue cryopreservation (OTC) before hematological stem cell transplantation, we meticulously counted follicles and categorized them based on their growth stage. We then calculated the densities of different follicle types and assessed their correlation with patient characteristics, clinical manifestations, and treatments extracted from medical records. Seventy-six patients with SCD participated in the study, with a median age at OTC of 10.2 years (interquartile range [IQR], 7.5-14.6), and 50 (65.8%) were prepubertal. Of these, 35 patients (46.1%) had received HU, with a median daily dosage of 23.0 mg/kg (IQR, 20.0-25.0) and median exposure time of 44 months (IQR, 24.0-54.0). Primordial follicle density was comparable between the HU and non-HU groups (5.8 follicles per mm2 [IQR, 1.0-13.3] vs 4.2 follicles per mm2 [IQR, 1.1-14.4], respectively; P = .95). However, in the HU group, after adjusting for age, the density of growing follicles was marginally lower than that in the non-HU group (P = .09). Notably, other parameters such as vaso-occlusive crisis did not affect follicular density. In conclusion, exposure to HU did not demonstrate a reduction in ovarian reserve in girls or women with SCD. Therefore, fertility preservation measures before initiating HU treatment do not seem necessary.

Consultation Liaison Case Conference: Inpatient Psychiatric Consultation for Patients With Sickle Cell Disease

We present the fictional case of a 29-year-old man with sickle cell disease referred to psychiatry for evaluation of depression during an acute pain episode. Consultation-liaison psychiatrists with expertise in sickle cell disease provide guidance for this commonly encountered clinical case based on their experience and a review of the available literature. Key teaching points include the high prevalence of mood and cognitive disorders in this population, as well as pertinent issues related to chronic pain, opioids, and stigma.

Exploring Novel Strategies to Alleviate Symptoms of β-Globinopathies: Examining the Potential Role of Embryonic ε-globin Induction

β-thalassemia and sickle cell disease are among the most prevalent genetic blood disorders globally. These conditions arise from mutations in the β-globin gene, leading to defective hemoglobin production and resulting in anemia. Current treatments include γ-globin inducers (eg, Hydroxyurea), blood transfusions, iron chelation therapy, and bone marrow transplantation. Recently approved disease-modifying agents and promising gene therapies offer hope, yet their broad application is constrained by scalability challenges. Traditionally, research and development for β-globinopathies have focused on γ-globin induction. However, the ε-globin variant, which is active during early embryonic development and subsequently silenced prenatally, was once considered noninducible by postnatal pharmacological means. Recent studies indicate that, akin to γ-globin, enhancing ε-globin expression could compensate for impaired β-globin synthesis, potentially ameliorating the clinical manifestations of β-globinopathies. This review critically examines the viability of ε-globin induction as a therapeutic strategy for β-thalassemia and sickle cell diseases. It also delves into the burgeoning research on the mechanisms governing ε-globin silencing and its pharmacological reactivation. We conclude with a discussion of prospective research directions and drug development initiatives aimed at exploiting ε-globin's therapeutic promise.

The epidemiology of very severe anaemia in sickle cell disease in Tanzania: a prospective cohort study

Background

Anaemia in sickle cell disease (SCD) is a significant cause of morbidity and mortality, but few studies have reported on the burden and outcome of very severe anaemia. This study described the epidemiology of very severe anaemia by determining the prevalence and incidence, investigating associated clinical and laboratory factors, and assessing outcomes in SCD.

Methods

A 10-year prospective cohort study involving SCD patients of all ages was conducted at Muhimbili National Hospital in Tanzania between 2004 and 2013. SCD included Homozygous SS-Sickle cell anaemia and Sβ0 thalassemia at clinics and during hospitalization visits. Very severe anaemia was defined as Haemoglobin <5 g/dL at steady-state which was a period when a patient was stable with no blood transfusion in past 3 months or accute pain report in the previous month.

Findings

There were 28,293 (92.9%) clinic visits and 2158 hospitalisations amongst 3586 patients. Mean haemoglobin concentration at clinic was 7.4 g/dL, (95% CI: 7.4-7.5) compared to hospitalisation [6.4 g/dL, 95% CI: 6.3-6.5], p < 0.001. Prevalence of very severe anaemia at the clinic was 4.1%, and 23.8% during hospitalization, while the overall incidence was 114.1 (95% CI: 108.2-120.2) events per 1000 person years. Risk ratio of dying for patients with very severe anaemia was 4.78 times higher (95% CI: 3.65-6.25, p < 0.001) than in individuals without very severe anaemia. The risk ratio for mortality was highest in children aged <2 years, and was decreasing steadily with increase in age, from HR = 0.73 (95% CI: 0.39-1.35) in children aged 2-4 years to HR of 0.38 (95% CI: 0.20-0.71) in patients in age group 10-17 years when compared to those aged 0-1 years. Mortality risk ratio was higher (HR = 6.76 [95% CI: 4.31-10.62, p < 0.001]) in patients with steady-state haemoglobin <5 g/dL and presenting with very severe anaemia before death compared to those with steady state haemoglobin ≥5 g/dL and haemoglobin ≥5 g/dL before death.

Interpretation

The burden of very severe anaemia in SCD was high, especially during hospitalization, and was independent predictor of mortality. There is an urgent need to improve prevention, diagnosis, and interventions for very severe anaemia in SCD in Africa. More research to elucidate the aetiology and mechanisms of anaemia in this population is required.

Funding

Government of the United Republic of Tanzania, Wellcome Trust, United Kingdom (JKM 072064; Project grant 080025, Strategic award 084538).

Stroke without cerebral arteriopathy in sickle cell disease children: causes and treatment

Cerebral arteriopathy (CA) in children with sickle cell disease (SCD) is classically described as chronic stenosis of arteries in the anterior brain circulation, leading to ischemic stroke. Some studies have, however, reported strokes in children with SCD but without CA. In order to better understand the etiology and risk factors of these strokes, we retrospectively analyzed ischemic strokes occurring in a large cohort of children over a 13-year period. Between 2007 and 2020, 25 of 1,500 children with SCD had an ischemic stroke in our center. Among them, 13 (52%) had CA, described as anatomical arterial stenosis, while 12 (48%) did not. Patients with stroke without CA were older than patients with stroke attributed to SCD-CA (9.0 years old vs. 3.6 years old; P=0.008), and more frequently had SC genotype (25% vs. 0%, respectively). Their strokes more frequently involved the posterior circulation, with cerebellar involvement in 42%. Retained stroke etiologies in patients without typical SCD-related CA were reversible cerebral vasoconstriction syndrome, cerebral fat embolism, arterial thrombosis or thromboembolism, hyperviscosity, vasculitis in a context of infectious meningo-encephalitis, and severe hemodynamic failure. No recurrence was observed in the 24 months following stroke, even though 67% of the patients in this group were no longer receiving exchange transfusions. In conclusion, in a cohort of pediatric SCD patients with an efficient stroke screening strategy, half of the ischemic strokes that occurred were related to causes other than CA. They affected a different population of SCD children and systematic long-term transfusion programs may not be necessary in these cases.

Inpatient Management of Pain Episodes in Children with Sickle Cell Disease: A Review

Sickle cell disease (SCD) is the most common hemoglobinopathy in the world. Sickle cell vaso-occlusive episodes (VOEs) are very painful acute events and the most common complication as well as reason for hospitalization. SCD pain is best evaluated holistically with a pain functional assessment to aid in focusing pain management on reducing pain in addition to improving function. Patients with SCD have long endured structural racism and negative implicit bias surrounding the management of pain. Thus, it is important to approach the management of inpatient pain systematically with the use of multi-modal medications and nonpharmacologic treatments. Furthermore, equitable pain management care can be better achieved with standardized pain plans for an entire system and individualized pain plans for patients who fall outside the scope of the standardized pain plans. In this article, we discuss the best practices to manage SCD VOEs during an inpatient hospitalization.

Perceptions of Care and Perceived Discrimination: A Qualitative Assessment of Adults Living with Sickle Cell Disease

Sickle cell disease (SCD) is a major public health concern with significant associated economic costs. Although the disease affects all ethnic groups, about 90% of individuals living with sickle cell disease in the USA are Black/African American. The purpose of this study was to assess the health care discrimination experiences of adults living with SCD and the quality of the relationship with their health care providers. We conducted six focus groups from October 2018 to March 2019 with individuals receiving care at a specialized adult sickle cell program outpatient clinic at a private, nonprofit tertiary medical center and teaching hospital in the northeastern USA. The sample of 18 participants consisted of groups divided by gender and current use, past use, or never having taken hydroxyurea. Ten (56%) participants were males; most were Black/African American (83%) and had an average age of 39.4 years. This study reports a qualitative, thematic analysis of two of 14 areas assessed by a larger study: experiences of discrimination and relationships with providers. Participants described experiences of bias related to their diagnosis of SCD as well as their race, and often felt stereotyped as "drug-seeking." They also identified lack of understanding about SCD and poor communication as problematic and leading to delays in care. Finally, participants provided recommendations on how to address issues of discrimination.

Standardization of coding definitions for sickle cell disease complications: A systematic literature review

PURPOSE

Sickle cell disease (SCD) affects all organ systems and is characterized by numerous acute and chronic complications and comorbidities. Standardized codes are needed for complications/comorbidities used in real-world evidence (RWE) studies that rely on administrative and medical coding. This systematic literature review was conducted to produce a comprehensive list of complications/comorbidities associated with SCD, along with their diagnosis codes used in RWE studies.

METHODS

A search in MEDLINE and Embase identified studies published from 2016 to 2023. Studies were included if they were conducted in US SCD populations and reported complications/comorbidities and respective International Classification of Diseases, Clinical Modification (ICD-CM) codes. All identified complications/comorbidities and codes were reviewed by a certified medical coding expert and hematologist.

RESULTS

Of 1851 identified studies, 39 studies were included. The most reported complications/comorbidities were stroke, acute chest syndrome, pulmonary embolism, venous thromboembolism, and vaso-occlusive crisis. Most of the studies used ICD-9-CM codes (n = 21), while some studies used ICD-10-CM codes (n = 3) or both (n = 15), depending on the study period. Most codes reported in literature were heterogeneous across complications/comorbidities. The medical coding expert and hematologist recommended modifications for several conditions.

CONCLUSION

While many studies we identified did not report their codes and were excluded from this review, the studies with codes exhibited diverse coding definitions. By providing a standardized set of diagnosis codes that were reported by studies and reviewed by a coding expert and hematologist, our review can serve as a foundation for accurately identifying complications/comorbidities in future research, and may reduce heterogeneity, enhance transparency, and improve reproducibility. Future efforts focused on validating these code lists are needed.