Sickle Cell Disease and Acute Chest Syndrome: Epidemiology, Diagnosis, Management, Outcomes

Haplotype-Specific Genetic Epidemiology of Sickle Cell Anemia Patients in Accra, Ghana: Patterns, Clinical Implications, and Public Health Responses

Sickle cell disease (SCD) is a genetic disorder with a diverse spectrum of clinical presentation, often determined by inherited βS gene haplotypes. Ghana, a country with a significant SCD burden, lacks population haplotype frequency data, hindering anthropological, genetic, and clinical understanding and management of the disease. A prospective sample of 191 SCD patients (sickle cell anemia; homozygous HbSS) was recruited at the Korle-Bu Teaching Hospital, Accra. Identification of βS gene haplotypes was performed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Hematological tests were performed using routine laboratory procedures. Kruskal-Wallis ANOVA with Dunn post-hoc was used to compare the hematological parameters. Multinomial probability models were used to compare the frequencies of the observed haplotypes with those reported in other African countries. The Atypical haplotype was disproportionately prevalent (58%), followed by the Bantu/CAR (20%) and Benin (10%) haplotypes. Significant differences were observed between the haplotypes in lymphocyte count, platelet count, sodium and potassium levels (P < 0.001). In addition, disease severity varied significantly between haplotypes (P = 0.010), with notable differences between the Atypical and Bantu/CAR haplotypes (PFDR = 0.020). Multinomial probability testing revealed a substantial deviation from the expected haplotype distribution, highlighting significant differences in haplotype frequencies between Ghana and other African countries. The Wright-Fisher model showed that the variation in Arab-Indian haplotype frequency reached zero by the 100th generation. Our findings highlight the need to study haplotype composition in Ghana to identify population-specific risk factors and tailor public health interventions to better manage patient needs.

Physician perspectives about the diagnosis and management of acute chest syndrome

BACKGROUND

Acute chest syndrome (ACS) is the leading cause of mortality, accounting for 25% of all deaths among individuals with sickle cell disease (SCD). There is a lack of evidence-based laboratory and clinical risk stratification guidelines for the diagnosis and management of ACS.

STUDY DESIGN AND METHODS

To better understand physician practices for the management of ACS in the United States, we created an ACS Working Group including hematology and transfusion medicine physicians from four different SCD treatment centers in the United States. The working group created a physician survey that included physician demographics and ACS diagnostic criteria that they had to rate. The survey also included three case scenarios to assess physician attitudes about the management of ACS. Management options included supportive and preventive strategies in addition to transfusion therapy options.

RESULTS

Out of 455 physicians who received the survey, 195 responded (response rate = 43%). The respondents were primarily hematology/oncology physicians. The responses showed wide variability among physicians in how diagnostic criteria for ACS are used and how physicians risk-stratify ACS patients in their practice. The responses also reflected variability in the use of transfusions for ACS.

DISCUSSION

Based on our results, we conclude that ACS is diagnosed and managed inconsistently among expert physicians, especially in their transfusion practices due to a lack of consensus on risk stratification criteria. Our data suggest an urgent need for well-designed prospective studies to provide evidence-based guidelines and minimize management variability among physicians who care for individuals with SCD and ACS.

Budget Impact of Disease-Modifying Treatments and a CRISPR Gene-Edited Therapy for Sickle Cell Disease

BACKGROUND AND OBJECTIVE

Treatment of sickle cell disease (SCD) has traditionally focused on symptomatic and preventative care. Recent advances in novel therapeutic developments, likely to be orphan-designated, are anticipated to carry a substantial price tag. This study assesses the potential budget impact of adopting disease-modifying treatments, crizanlizumab and voxelotor, and pioneering CRISPR gene-edited therapy, CTX001, in the Belgian healthcare system.

METHODS

The perspective of the Belgian healthcare payer (RIZIV-INAMI including patient copayments), a 5-year horizon with a 2-10% uptake of disease-modifying interventions, and a 2% uptake of CTX001 were considered. Data, encompassing target population, current (chronic and acute management, curative hematopoietic stem cell transplantation) and new (crizanlizumab, voxelotor, and CTX001) interventions, clinical effectiveness, adverse events, healthcare resource utilization, and associated costs, were gathered through a comprehensive literature review (first phase) and two Delphi panels involving hematologists (second phase). The cost difference between a "world with and without crizanlizumab, voxelotor, and CTX001" was calculated to obtain the budget impact. Three scenario analyses were conducted: a 5-13% and 4% uptake analysis, a 10-18% and 8% uptake analysis, respectively for disease-modifying treatments (crizanlizumab and voxelotor) and CTX001, and a 0% crizanlizumab uptake and managed entry agreements analysis . A ± 20% univariate sensitivity analysis was performed to test the robustness of the analysis.

RESULTS

The total five-year cumulative budget impact was estimated at €30,024,968, with 91% attributed to drug acquisition costs. The largest budget impact share was for CTX001 (€25,575,150), while crizanlizumab (€2,301,095) and voxelotor (€2,148,723) was relatively small. In scenarios one and three, a two-fold increase of the cumulative budget impact to €60,731,772 and a four-fold increase to €120,846,256 from the base case was observed. In scenario three, this budget impact decreased by 63% to €11,212,766. Patient population size, number of treated patients, and drug costs influenced the analysis the most, while discontinuation, acute crisis, and adverse event rates had comparatively minimal impact.

CONCLUSIONS

Belgian decision-makers may consider alternative financing models, such as outcome-based risk-sharing agreements or annuities, to ensure sustainable coverage of these treatments. This study adheres to recommended practices for assessing budget impact of orphan drugs, distinguishing it from earlier studies with potentially weaker methodologies.

The Bias of Medicine in Sickle Cell Disease

Sickle cell disease (SCD) is the most common monogenetic condition in the United States (US) and one that has been subjected to a history of negative bias. Since SCD was first described approximately 120 years ago, the medical establishment has, directly and indirectly, harmed patients by reinforcing biases and assumptions about the disease. Furthermore, negative biases and stigmas have been levied upon patients with SCD by healthcare providers and society, researchers, and legislators. This article will explore the historical context of SCD in the US; discuss specific issues in care that lead to biases, social and self-stigma, inequities in access to care, and research funding; and highlight interventions over recent years that address racial biases and stigma.

Acute Chest Syndrome in Sickle Cell Disease

Acute chest syndrome (ACS) is the leading cause of mortality among individuals with sickle cell disease (SCD) accounting for 25% of all deaths. The etiologies and clinical manifestations of ACS are variable among children and adults, with a lack of clear risk stratification guidelines for the practicing clinician. In addition, the management of ACS is based on limited evidence and is currently guided primarily by expert opinion. This manuscript reviews the pathophysiology, risk factors, and current management strategies for ACS through a review of published data on this subject between 1988 and 2022. Blood transfusion is often used as a therapeutic intervention for ACS to increase blood's oxygen-carrying capacity and reduce complications by reducing hemoglobin S (HbS) percentage, based on the very low quality of the evidence about its efficacy. The benefit of RBC transfusion for ACS has been described in case series and observational studies, but randomized studies comparing simple transfusion vs. exchange transfusions for ACS are lacking. In this review, we conclude that the development of clinical and laboratory risk stratification is necessary to further study an optimal management strategy for individuals with ACS to avoid transfusion-related complications while minimizing mortality.

A case of autopsy discovery of acute chest syndrome triggered by pulmonary embolism in a sickle cell patient

This is a case report about a 7-year-old male child with sickle cell anemia (S/β⁺) who died unexpectedly during hospitalization, justifying the performance of a forensic autopsy completed by histological examination of organ fragments and toxicological analyses of biological fluids. The diagnosis retained was pulmonary thromboembolism as the cause of death occurring in the context of an acute chest syndrome (ACS). The mechanism of occurrence of this pulmonary embolism was vascular stasis caused by sickle cell disease. The search for etiologies of ACS complicating sickle cell disease should not exclude pulmonary embolism with red cell dense fibrin clot..

Role of Steroids in Sickle Cell Patients With Acute Chest Syndrome

Background

The role of corticosteroids to treat acute chest syndrome (ACS) in patients with sickle cell disease (SCD) has always been a matter of debate. In clinical practice, systemic steroids were given for ACS with more severe disease. With the lack of standard treatment guidelines, their use to treat ACS is highly physician-dependent and varies widely across different hospitals. The utility of corticosteroids in ACS remains unclear. The objective of our study was to describe the differences between SCD patients treated with corticosteroids for ACS and those who were not and to evaluate the association between corticosteroid use, length of stay, and readmission rates.

Methodology

We performed a retrospective chart review of patients with SCD ≤18 years of age hospitalized for ACS at Brookdale University Hospital Medical Center between January 2016 and May 2021.

Results

We identified 43 patients with 60 episodes of ACS (median age was 11 years and 55% were males). In total, 32 such episodes were treated with corticosteroids. The use of bronchodilators (p = 0.23), hydroxyurea (p = 0.13), and the presence of fever (p = 0.86) showed no significant difference between the two groups. The need for blood transfusions (p = 0.005), intensive care unit admission (p = 0.031), respiratory support (p = 0.011), and chest X-ray finding with more than one lobe involvement (p = 0.003) all point to moderate or severe ACS, which has been linked to steroid use. The length of hospital stay (p = 0.07) and the readmission rate (p = 0.31) were not statistically significant between the groups. Even in the subgroup with asthma, the length of stay was not different between the groups (p = 0.44).

Conclusions

Our results show that treatment with systemic steroids for ACS is associated with more severe disease. The length of hospital stay was not different between the steroid-treated and untreated groups. Corticosteroids were not associated with a higher readmission rate in our study population, even in ACS patients with comorbid asthma. Further adequately powered prospective trials are needed to investigate the efficacy of corticosteroids in ACS.