Outcome of sickle cell anemia: a 4-decade observational study of 1056 patients

The medication usage pattern and prevalence of polypharmacy among patients with sickle cell disease: a population-based study in southern Iran

BACKGROUND

Due to the numerous complications associated with sickle cell disease (SCD), patients often receive a variety of medications alongside their SCD treatment. However, a notable gap exists in the current literature regarding medication use patterns among them. This study aimed to investigate medication usage patterns in patients with SCD.

RESEARCH DESIGN AND METHODS

This cross-sectional study, conducted in Bushehr Province, employed a stratified random sampling method to select eligible participants with SCD. A thorough interview gathered various information, including details about the medications. The Anatomical Therapeutic Chemical classification system was utilized for drug classification. Polypharmacy was defined as the concurrent use of at least five medications.

RESULTS

A total of 300 individuals with SCD were included in this study. Polypharmacy was observed in 26.3% (95% CI: 20.8%-32.8%) of the study population. The analyses revealed positive associations between the use of more concurrent medication use and higher age groups and having multimorbidity. Antianemic preparations (86.7%), antineoplastic agents (58.3%), and vitamins (41.0%) were the most frequent medication classes used by the study participants.

CONCLUSIONS

Our study revealed notable underutilization of hydroxyurea and a high rate of polypharmacy, associated with age and multimorbidity, among patients with SCD in southern Iran.

Costs and impact of disease in adults with sickle cell disease: a pilot study

ABSTRACT

We assessed the feasibility to estimate illness burden in adults with SCD, investigated factors associated with health-related quality of life (HRQoL), and estimated societal burden. We recruited 32 participants and collected data on fatigue, HRQoL, and work productivity and activity impairment via patient survey. Health care utilization was abstracted for the 12 months before enrollment using medical chart review. Mean age was 36.7 years; 84.4% of participants had hemoglobin SS or Sβthal0 disease, and 81.3% reported chronic pain (experiencing pain on ≥3 days per week in the past 6 months). Mean EQ-5D-3L visual analogue scale score was 63.4 and the index score was 0.79. The mean fatigue score was 57.9. Higher fatigue score was correlated with lower EQ-5D index score (correlation coefficient r = -0.35; P = .049) and Adult Sickle Cell Quality of Life Measurement Information System (ASCQ-Me) scores, including pain (r = -0.47; P = .006), sleep (r = -0.38; P = .03), and emotion scores (r = -0.79; P < .0001). The number of hospitalizations was negatively correlated with HRQoL (all P < .05). Patients who reported chronic pain had significantly lower mean ASCQ-Me sleep scores (48.3 vs 57.1; P = .04) and EQ-5D index scores (0.72 vs 0.89; P = .002) than those without chronic pain. Mean estimated annual per person costs were $51 779 (median, $36 366) for total costs, $7619 ($0) for indirect costs (estimated from lost earnings of participants), and $44 160 ($31 873) for medical costs. Fatigue, SCD complications, hospitalization, and chronic pain negatively affected HRQoL. This sample experienced a high economic burden, largely from outpatient doctor visits.

Health Supervision for Children and Adolescents With Sickle Cell Disease: Clinical Report

Sickle cell disease (SCD) is a group of complex genetic disorders of hemoglobin with multisystem manifestations. The scope of this clinical report is such that in-depth recommendations for management of all complications is not possible. Rather, the authors present an overview focused on the practical management of children and adolescents with SCD and the complications that are of particular relevance to pediatric primary care providers. References with detailed commentary provide further information. Timely and appropriate treatment of acute illness is critical, because life-threatening complications may develop rapidly. Specialized comprehensive medical care decreases morbidity and mortality during childhood. The provision of comprehensive care is a time-intensive endeavor that includes ongoing patient and family education, periodic comprehensive evaluations and other disease-specific health maintenance services, nursing support, psychosocial care, and genetic counseling. Ideally, this care includes comanagement by the pediatrician or other pediatric primary care provider and a team of specialist SCD experts: Hematologist, other pediatric specialists, advanced practice providers, nurse specialists, social workers, patient navigators, and educational liaisons.

Prevalence, Mortality, and Access to Care for Chronic Kidney Disease in Medicaid-Enrolled Adults With Sickle Cell Disease in California: Retrospective Cohort Study

BACKGROUND

Chronic kidney disease (CKD) is a significant complication in patients with sickle cell disease (SCD), leading to increased mortality.

OBJECTIVE

This study aims to investigate the burden of CKD in Medicaid-enrolled adults with SCD in California, examine differences in disease burden between male and female individuals, and assess mortality rates and access to specialized care.

METHODS

This retrospective cohort study used the California Sickle Cell Data Collection program to identify and monitor individuals with SCD. Medicaid claims, vital records, emergency department, and hospitalization data from 2011 to 2020 were analyzed. CKD prevalence was assessed based on ICD (International Classification of Diseases) codes, and mortality rates were calculated. Access to specialized care was examined through outpatient encounter rates with hematologists and nephrologists.

RESULTS

Among the 2345 adults with SCD, 24.4% (n=572) met the case definition for CKD. The SCD-CKD group was older at the beginning of this study (average age 44, SD 14 vs 34, SD 12.6 years) than the group without CKD. CKD prevalence increased with age, revealing significant disparities by sex. While the youngest (18-29 years) and oldest (>65 years) groups showed similar CKD prevalences between sexes (female: 12/111, 10.8% and male: 12/101, 11.9%; female: 74/147, 50.3% and male: 34/66, 51.5%, respectively), male individuals in the aged 30-59 years bracket exhibited significantly higher rates than female individuals (30-39 years: 49/294, 16.7%, P=.01; 40-49 years: 52/182, 28.6%, P=.02; and 50-59 years: 76/157,48.4%, P<.001). During this study, of the 2345 adults, 435 (18.5%) deaths occurred, predominantly within the SCD-CKD cohort (226/435, 39.5%). The median age at death was 53 (IQR 61-44) years for the SCD-CKD group compared to 43 (IQR 33-56) years for the SCD group, with male individuals in the SCD-CKD group showing significantly higher mortality rates (111/242, 45.9%; P=.009) than female individuals (115/330, 34.9%). Access to specialist care was notably limited: approximately half (281/572, 49.1%) of the SCD-CKD cohort had no hematologist visits, and 61.9% (354/572) did not see a nephrologist during this study's period.

CONCLUSIONS

This study provides robust estimates of CKD prevalence and mortality among Medicaid-enrolled adults with SCD in California. The findings highlight the need for improved access to specialized care for this population and increased awareness of the high mortality risk and progression associated with CKD.

Durable engraftment after pharmacological pre-transplant immune suppression followed by reduced-toxicity myeloablative haploidentical stem cell transplantation in highly HLA-immunized adults with sickle cell disease

Allogeneic stem cell transplantation (Allo-SCT) is the only rapidly available curative treatment modality in patients with severe sickle cell disease (SCD). The development of reduced-toxicity myeloablative conditioning (RT-MAC) regimen and the use of partially matched family donors with post-transplantation cyclophosphamide (PT-Cy) have widened the access to Allo-SCT. Antibodies against donor-specific HLA (DSA) increase the risk of engraftment failure in HLA mismatched Allo-SCT. We report the results of five patients with SCD, whereas three with DSA, who underwent an unmanipulated haploidentical stem cell transplantation (Haplo-SCT) after a busulfan-based RT-MAC regimen with PT-Cy. To reduce the risk of engraftment failure, a sequential two courses pharmacological pre-transplant immune suppression (PTIS) phase was added prior to the conditioning regimen. All patients engrafted successfully. The procedure was well tolerated. None of the patients developed acute GVHD, whereas one developed moderate chronic GVHD. After a median follow-up of 5 years (range, 2.2-9), all patients are free of pain with excellent quality of life. Our report shows that Haplo-SCT after a RT-MAC regimen is feasible and safe with stable long-term engraftment and excellent disease control. The risk of graft failure can be abrogated by adding a PTIS phase prior to initiating the conditioning regimen.

Chronic kidney disease and outcomes in hospitalized sickle cell disease patients: A National Inpatient Sample analysis

OBJECTIVES

To examine the association between chronic kidney disease (CKD) and outcomes in sickle cell disease (SCD) patients.

METHODS

Patients ≥18 years with SCD in the National Inpatient Sample database between 2016 and 2018 were identified using ICD-10-CM diagnosis codes. A 1:1 propensity-score matched analysis was performed to compare in-hospital outcomes of patients with and without CKD.

RESULTS

Of the 366 240 SCD admissions, 19 365 (5.3%) had CKD. The CKD group had higher odds of in-hospital mortality (odds ratio [OR] 2.59, 95% confidence interval [CI]: 1.63-4.12, p = <.01), blood transfusion (OR 1.67, 95% CI: 1.47-1.90, p < .01), mechanical ventilation (OR 2.20, 95% CI: 1.56-3.12, p = <.01), sepsis (OR 1.75, 95% CI: 1.46-2.10, p < .01), incurred higher costs ($53 255 vs. $47 294, p < .001), but had lower odds of acute chest syndrome (OR 0.71, 95% CI: 0.54-0.95, p = 0.02) and pulmonary embolism (OR 0.45, 95% CI: 0.31-0.67, p < .01).

CONCLUSIONS

CKD was associated with higher mortality, higher costs, blood transfusion, sepsis, and mechanical ventilation in SCD patients. Further studies are needed to explore the reasons for the reduced odds of pulmonary embolism and acute chest syndrome.

Iron restriction in sickle cell disease: When less is more

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

Controversies in the pathophysiology of leg ulcers in sickle cell disease

Patients with sickle cell disease (SCD) often experience painful vaso-occlusive crises and chronic haemolytic anaemia, as well as various acute and chronic complications, such as leg ulcers. Leg ulcers are characterized by their unpredictability, debilitating pain and prolonged healing process. The pathophysiology of SCD leg ulcers is not well defined. Known risk factors include male gender, poor social conditions, malnutrition and a lack of compression therapy when oedema occurs. Leg ulcers typically start with spontaneous pain, followed by induration, hyperpigmentation, blister formation and destruction of the epidermis. SCD is characterized by chronic haemolysis, increased oxidative stress and decreased nitric oxide bioavailability, which promote ischaemia and inflammation and consequently impair vascular function in the skin. This cutaneous vasculopathy, coupled with venostasis around the ankle, creates an ideal environment for local vaso-occlusive crises, which can result in the development of leg ulcers that resemble arterial ulcers. Following the development of the ulcer, healing is hindered as a result of factors commonly observed in venous ulceration, including venous insufficiency, oedema and impaired angiogenesis. All of these factors are modulated by genetic factors. However, our current understanding of these genetic factors remains limited and does not yet enable us to accurately predict ulceration susceptibility.

Cost-Effectiveness of Lovotibeglogene Autotemcel (Lovo-Cel) Gene Therapy for Patients with Sickle Cell Disease and Recurrent Vaso-Occlusive Events in the United States

BACKGROUND AND OBJECTIVE

Gene therapies for sickle cell disease (SCD) may offer meaningful benefits for patients and society. This study evaluated the cost-effectiveness of lovotibeglogene autotemcel (lovo-cel), a one-time gene therapy administered via autologous hematopoietic stem cell transplantation, compared with common care for patients in the United States (US) with SCD aged ≥ 12 years with ≥ 4 vaso-occlusive events (VOEs) in the past 24 months.

METHODS

We developed a patient-level simulation model accounting for lovo-cel and SCD-related events, complications, and mortality over a lifetime time horizon. The pivotal phase 1/2 HGB-206 clinical trial (NCT02140554) served as the basis for lovo-cel efficacy and safety. Cost, quality-of-life, and other clinical data were sourced from HGB-206 data and the literature. Analyses were conducted from US societal and third-party payer perspectives. Uncertainty was assessed through probabilistic sensitivity analysis and extensive scenario analyses.

RESULTS

Patients treated with lovo-cel were predicted to survive 23.84 years longer on average (standard deviation [SD], 12.80) versus common care (life expectancy, 62.24 versus 38.40 years), with associated discounted patient quality-adjusted life-year (QALY) gains of 10.20 (SD, 4.10) and direct costs avoided of $1,329,201 (SD, $1,346,446) per patient. Predicted societal benefits included discounted caregiver QALY losses avoided of 1.19 (SD, 1.38) and indirect costs avoided of $540,416 (SD, $262,353) per patient. Including lovo-cel costs ($3,282,009 [SD, $29,690] per patient) resulted in incremental cost-effectiveness ratios of $191,519 and $124,051 per QALY gained from third-party payer and societal perspectives, respectively. In scenario analyses, the predicted cost-effectiveness of lovo-cel also was sensitive to baseline age and VOE frequency and to the proportion of patients achieving and maintaining complete resolution of VOEs.

CONCLUSIONS

Our analysis of lovo-cel gene therapy compared with common care for patients in the US with SCD with recurrent VOEs estimated meaningful improvements in survival, quality of life, and other clinical outcomes accompanied by increased overall costs for the health care system and for broader society. The predicted economic value of lovo-cel gene therapy was influenced by uncertainty in long-term clinical effects and by positive spillover effects on patient productivity and caregiver burden.

End Organ Affection in Sickle Cell Disease

Sickle cell disease is an orphan disease affecting ethnic minorities and characterized by profound systemic manifestations. Although around 100,000 individuals with SCD are living in the US, the exact number of individuals is unknown, and it is considered an orphan disease. This single-gene disorder leads to red blood cell sickling and the deoxygenation of hemoglobin, resulting in hemolysis. SCD is associated with acute complications such as vaso-occlusive crisis, infections, and chronic target organ complications such as pulmonary disease and renal failure. While genetic therapy holds promise to alter the fundamental disease process, the major challenge in the field remains the target end organ damage and ways to mitigate or reverse it. Here, we provide an overview of the clinical manifestations and pathogenesis with a focus on end-organ damage and current therapeutic options, including recent FDA-approved stem cell and gene editing therapies.

Systematic Review of Genetic Modifiers Associated with the Development and/or Progression of Nephropathy in Patients with Sickle Cell Disease

Sickle cell nephropathy (SCN) is a common complication of sickle cell disease (SCD) that significantly contributes to morbidity and mortality. In addition to clinical and life-style factors, genetic variants influence this risk. We performed a systematic review, searching five databases. Studies evaluating the effect of genetic modifiers on SCN were eligible. Twenty-eight studies (fair-to-good quality) were included: one genome-wide association study, twenty-six case-control studies, and one article combining both approaches. APOL1 was significantly associated with albuminuria and hyperfiltration in children and with worse glomerular filtration in adults. On the other hand, alpha-thalassemia protected patients against albuminuria and hyperfiltration, while BCL11A variants were protective against albuminuria alone. The HMOX1 long GT-tandem repeat polymorphism led to a lower glomerular filtration rate. No modifiers for the risk of hyposthenuria were identified. A genome-wide association approach identified three new loci for proteinuria (CRYL1, VWF, and ADAMTS7) and nine loci were linked with eGFR (PKD1L2, TOR2A, CUBN, AGGF1, CYP4B1, CD163, LRP1B, linc02288, and FPGT-TNNI3K/TNNI3K). In conclusion, this systematic review supports the role of genetic modifiers in influencing the risk and progression of SCN. Incorporating and expanding this knowledge is crucial to improving the management and clinical outcomes of patients at risk.

Therapy with bone marrow mesenchymal stem cells in bone regeneration in children with osteonecrosis secondary to sickle cell disease

Introduction

This study aimed to describe the evolution of bone regeneration in children with hip osteonecrosis associated with sickle cell disease, treated with bone marrow-derived mesenchymal stem cell implants at the Professor Edgar Santos University Hospital Complex.

Materials and methods

A non-randomized clinical trial was conducted with 48 patients of both sexes, aged between 11 and 18 years, diagnosed with femoral head osteonecrosis secondary to sickle cell disease. Patient selection was based on strict criteria, including confirmed diagnosis of sickle cell anemia and a stage of osteonecrosis compatible with the proposed treatment. Bone regeneration assessment was performed through radiographic examinations and magnetic resonance imaging, following the Ficat & Arlet criteria and the Salter-Thompson classification.

Results

Statistical analysis revealed a significant association between the patients' age and positive treatment outcomes, suggesting that autologous bone marrow cell implantation is a safe and effective approach in the early stages of osteonecrosis. The majority of patients (87.5%) reported complete pain relief, while 10.42% experienced significant symptom improvement. Only one patient (2.08%) did not observe improvement. The results indicate that cell therapy can regenerate or slow the progression of bone necrosis, reducing the need for more invasive surgical procedures.

Conclusion

The study demonstrates the potential of bone marrow-derived mesenchymal stem cell implantation in treating hip osteonecrosis in children with sickle cell disease, emphasizing the importance of long-term monitoring of bone structure stability.

Sickle cell disease in Australia: a snapshot from the Australian Haemoglobinopathy Registry

BACKGROUND

Sickle cell disease (SCD) is the most common monogenic disorder worldwide. In deoxygenated conditions, the altered beta chain (haemoglobin S [HbS]) polymerises and distorts the erythrocyte, resulting in pain crises, vasculopathy and end-organ damage. Clinical complications of SCD cause substantial morbidity, and therapy demands expertise and resources. Optimising care for patients and planning resource allocation for the future requires an understanding of the disease in the Australian population. The Australian Haemoglobinopathy Registry (HbR) is a collaborative initiative of specialist centres collating and analysing data on patients with haemoglobin disorders.

AIMS

To provide a snapshot of SCD in Australia over a 12-month period based on data from the HbR.

METHODS

Patients with a clinically significant sickling disorder across 12 clinical sites were included for analysis. Data include demographic and diagnostic details, as well as details of the clinical management of the condition over a 12-month period.

RESULTS

Data on 359 SCD patients demonstrate a shift in the demographic of patients in Australia, with a growing proportion of sub-Saharan African ethnicities associated with the HbSS genotype. Acute and chronic complications are common, and patients require significant outpatient and inpatient support. Prevalence of disease complications and therapeutic trends are in keeping with other high-income countries.

CONCLUSIONS

This study provides the first national picture of SCD in Australia, describing the characteristics and needs of SCD patients, elucidating demand for current and novel therapy and facilitating the planning of services for this vulnerable population.

Nontargeted Plasma Proteomic Analysis of Renal Disease and Pulmonary Hypertension in Patients with Sickle Cell Disease

Sickle cell disease (SCD) is characterized by red blood cell sickling, vaso-occlusion, hemolytic anemia, damage to multiple organ systems, and, as a result, shortened life expectancy. Sickle cell disease nephropathy (SCDN) and pulmonary hypertension (pHTN) are common and frequently co-occurring complications of SCD; both are associated with markedly accelerated mortality. To identify candidate circulating biomarkers of SCDN and pHTN, we used mass spectrometry to quantify the relative abundance of >1000 proteins in plasma samples from 189 adults with SCD from the Outcome Modifying Genes in SCD (OMG-SCD) cohort (ProteomeXchange identifier PXD048716). Forty-four proteins were differentially abundant in SCDN, most significantly cystatin-C and collagen α-1(XVIII) chain (COIA1), and 55 proteins were dysregulated in patients with SCDN and pHTN, most significantly insulin-like growth factor-binding protein 6 (IBP6). Network analysis identified a module of 133 coregulated proteins significantly associated with SCDN, that was enriched for extracellular matrix proteins, insulin-like growth factor binding proteins, cell adhesion proteins, EGF-like calcium binding proteins, and several cadherin family members. Collectively, these data provide a comprehensive understanding of plasma protein changes in SCDN and pHTN which validate numerous studies of chronic kidney disease and suggest shared profiles of protein disruption in kidney dysfunction and pHTN among SCD patients.

Homozygous Sickle Cell Disease after Age of 40: Follow-Up of a Cohort of 209 Patients in Senegal, West Africa

Objectives

The aim of this study was to describe the morbidity and mortality of homozygous sickle cell disease after the age of 40.

Methods

This was a cohort study of 209 patients followed from 1994 to 2022. All hemoglobin electrophoresis-confirmed SS sickle cell patients over 40 years were included. A descriptive study of epidemiological, diagnostic, therapeutic, and evolutionary data was used to assess morbidity and mortality.

Results

Sex ratio (M/F) was 0.6. Median age was 47 (41-75). According to morbidity, 95.1% had less than 3 vaso-occlusive crises/year. Acute anemia was the most frequent complication (52.63%). Chronic complications were noted in 32.5%. At diagnosis, mean hemoglobin was 8.1 g/dl ± 1.9, HbS was 86.5 ± 10, and HbF was 9.4 ± 7.6. Number of patients transfused was 66%. We noted that 8.1% of patients died, 29.2% were lost to follow-up, and 62.7% were still being followed up. The risk factors identified for death were geographical origin, comorbidity, high HbS, low HbF, and thrombocytosis.

Conclusion

This study shows that homozygous SCD is increasingly becoming an adult disease and that it can be carried into old age in Africa. Advanced age over 40 is marked by an upsurge in chronic complications, making it essential to set up a screening program and to organize multidisciplinary follow-up.

Neurological abnormalities among pediatric patients with sickle cell disease in Saudi Arabia: a single-center retrospective study

Introduction

Sickle cell disease (SCD) is a common inherited blood disorder characterized by the production of abnormal sickle-shaped red blood cells. SCD can lead to various complications including neurological issues. Early detection and treatment are crucial for preventing these complications. This study aimed to describe the neurological manifestations, radiological findings, and neurological diagnosis related to SCD in Saudi children with the aim of contributing to the formulation of population-based guidelines for screening and treating SCD-related neurological complications.

Methods

This descriptive retrospective study included pediatric patients aged < 14 years diagnosed with SCD who were regularly followed up at the hematology clinic in KAMC, Jeddah, Saudi Arabia, from January 2008 to January 2022. Demographic and clinical data were collected from the clinical charts of 101 participants.

Results

This study included 101 patients with SCD with a mean age of 23 months at diagnosis. Among these, 59% had SCD and high fetal hemoglobin (HbF) levels. Neurological sequelae, including seizures, stroke, and other abnormalities, were observed in 26.7% of patients. There were no significant differences in the onset of neurological issues between the patients with SCD-high HbF and those with other SCD phenotypes.

Discussion

This study highlights the increased risk of brain injury and neurocognitive deficits in children with SCD. The occurrence of neurological sequelae in many patients emphasizes the need for early detection and intervention. Some patients experience neurological complications despite having high HbF levels, suggesting that further interventions are needed. This study has some limitations, including its small sample size and retrospective nature.

Conclusion

Early detection and intervention are crucial for neurological complications in patients with SCD. This study emphasizes the need for further research and effective treatment strategies considering the presence of neurological complications despite the presence of high HbF levels. Large-scale studies and population-specific guidelines are warranted for better understanding and management of SCD-related neurological complications in the Saudi population.

Euvolemic automated transfusion to treat severe anemia in sickle cell disease patients at risk of circulatory overload

BACKGROUND

Red blood cell (RBC) transfusion remains a major treatment for sickle cell disease (SCD). Patients with SCD have a high prevalence of renal impairment and cardiorespiratory disease, conferring risk of transfusion-associated circulatory overload (TACO).

STUDY DESIGN AND METHODS

We describe an approach, titled euvolemic automated transfusion (EAT), to transfuse SCD patients with severe anemia who are at risk of TACO. In EAT, plasmapheresis is performed using donor RBCs, rather than albumin or plasma, as replacement fluid. Euvolemia is maintained. A retrospective analysis was conducted of patients with SCD who underwent EAT at our institution over a 10-year period, to evaluate the efficacy and safety of EAT.

RESULTS

Eleven SCD patients underwent 109 EAT procedures (1-59 procedures per patient). The median age was 42 years (IQR = [30-49]) and 82% (n = 9) were female. Most (82%; n = 9) patients had severe chronic kidney disease and 55% (n = 6) had heart failure. One (9%) patient had a history of life-threatening TACO. Mean pre- and post-procedure Hct values were 19.8% (SD ± 1.6%) and 29.1% (SD ± 1.4%), respectively. The average Hct increment was 3.2% per RBC unit. Only two EAT-related complications were recorded during the 109 procedures: central line-associated infection and citrate toxicity (muscle cramping). EAT used an average of two RBC units less than that projected for standard automated RBC exchange.

CONCLUSION

Our findings suggest that EAT is safe and effective to treat patients with SCD and severe anemia, who are at risk for TACO. EAT requires fewer RBC units compared to automated RBC exchange.

Terminology for Retinal Findings in Sickle Cell Disease Research: A Scoping Review

OBJECTIVE

To review the current sickle cell disease (SCD) literature to assess how "retinopathy" has been defined and to identify ocular outcomes that have been measured and described.

DESIGN

A systematic scoping review of SCD literature was completed regarding ocular manifestations of SCD and vision outcomes across all medical specialties.

SUBJECTS

Participants with SCD and control patients were included in our data extraction.

METHODS

We reviewed English-language literature from 2000 to 2021 for eligible studies by searching PubMed, Google Scholar, Embase, and the Cochrane library using terms to encompass SCD and ocular findings.

MAIN OUTCOME MEASURES

Data collection included study information, patient characteristics, vision-related findings (inclusion criteria and/or study outcomes), and retinopathy characteristics (definition, when, how and by whom diagnosed).

RESULTS

We identified 4006 unique citations and 111 were included in the analysis. Ophthalmologists were senior authors of about half (59/111; 53.2%) of the articles; most articles were published between 2016 and 2021 (71/111; 70.0%). The studies had been conducted primarily in North America (54/111; 48.6%) or Europe (23/111; 20.7%); designs were cross-sectional (51/111; 45.9%), prospective cohort (28/111; 25.2%), retrospective cohort (27/111; 24.3%), and case-control (4/111; 3.6%). Among studies reporting any retinopathy, it was commonly defined as a combination of nonproliferative sickle cell retinopathy and proliferative sickle cell retinopathy (PSR; 52/87; 59.8%), infrequently as PSR only (6/87; 6.9%), or not defined at all (23/87; 26.4%). The Goldberg classification was used to grade retinopathy in almost half of the studies (41/87; 47.1%). Investigators reporting diagnostic methods used clinical fundus examination (56/111; 50.4%), OCT (24/111; 21.6%), fluorescein angiography (20/111; 18.0%), ultrawidefield fundus photographs (15/111; 13.5%), and OCT angiography (10/111; 9.0%), or did not report methods (28/111; 25.2%).

CONCLUSIONS

There are inconsistencies in documentation of methods and outcomes in studies of SCD ophthalmic findings. Particularly concerning is the lack of documentation of ophthalmic examination methods, qualifications of examiners, and clarity and specificity of sickle cell retinopathy definitions. With the increase in SCD treatment research and novel systemic therapies available, it is important to adopt clear and consistent descriptions and rigorous data collection and reporting of ophthalmic outcomes in SCD studies.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any materials discussed in this article.

Renal outcomes in pediatric patients with sickle cell disease: a single center experience in Saudi Arabia

Background

Sickle cell nephropathy (SCN) is a significant complication of sickle cell disease (SCD) with an asymptomatic onset in childhood and potential progression to chronic kidney disease (CKD). The clinical findings of SCN include hyposthenuria, hematuria, proteinuria, hyperfiltration, and CKD. Data on renal manifestation among patients with SCD in Saudi Arabia is lacking. Therefore, this study aimed to evaluate renal outcomes in patients with SCD who visited a hematology clinic at the National Guard Hospital, Jeddah.

Methods

We conducted a retrospective chart review of renal complications in patients with SCD who are within 0-14 years of age and on regular follow-ups at the pediatric hematology clinic in King Abdulaziz Medical City-Jeddah, Saudi Arabia.

Results

Among the 140 patients with SCD, 99 met the inclusion criteria. The median age at diagnosis was 18 (1-108) months. Two SCD phenotypes were observed, with 82 (83%) patients having sickle cell anemia (HbSS) and 17 (17%) having HbS/B+ thalassemia. Of the total patients, 92 (93%) were administered hydroxyurea (HU), with a median starting age of 48 (9-168) months. The most common renal complication observed during routine urinalysis was hematuria (38%), followed by proteinuria (11%). After stratifying the sample into four age groups (0-3 years old, 4-7 years old, 8-11 years old, and 12-14 years old), the mean glomerular filtration rate (GFR) values were 96.16, 101.36, 112.69, and 120.11 ml/min/1.73 m2 respectively. Renal imaging revealed abnormal findings in 27 (29%) patients. The most common abnormality observed on US was increased echogenicity (43%).

Conclusion

SCN is a significant complication of SCD. In this study, we assessed the renal outcomes in pediatric patients with SCD. After analyzing the clinical findings of SCN, we concluded that the presence of renal complications in pediatric patients presented a progressive pattern.

Racial and Ethnic Disparities in Metabolic Bone Disease

Racial and ethnic disparities exist in the prevalence and management of osteoporosis, metastatic cancer, and sickle cell disease. Despite being the most common metabolic bone disease, osteoporosis remains underscreened and undertreated among Black women. Skeletal-related events in metastatic cancer include bone pain, pathologic fractures, and spinal cord compression. Disparities in screening for and treating skeletal-related events disproportionately affect Black patients. Metabolic bone disease contributes significantly to morbidity in sickle cell disease; however, clinical guidelines for screening and treatment do not currently exist. Clinical care recommendations are provided to raise awareness, close health care gaps, and guide future research efforts.

Incidence and risk factors for osteonecrosis of the femoral head in five hundred and ten sickle cell disease paediatric patients

PURPOSE

Osteonecrosis of the femoral head (ONFH) is a degenerative and progressive disorder that mainly affects people with sickle cell disease (SCD). Herein, we aimed to search for a better understanding of markers that can act as risk factors for ONFH in patients with SCD.

METHODS

We conducted a retrospective study including 510 SCD patients followed over 23 years. Patients were divided into the ONFH group and the no-ONHF control group. Univariate and multivariate logistic regression analyses were performed to identify risk factors.

RESULTS

Among 510 SCD patients, 41(8%) were diagnosed with ONFH at a mean age of 167 months ± 64 (72-288). The cumulative incidence of ONHF increased from 2.3% at ten years to 18.3% at 20 years of age. The radiological grade 3 ONHF was predominant. No significant differences in sex, age at diagnosis of SCD, and Hb genotype were found between groups. The patient age and the time since diagnosis of SCD were statistically higher in patients with ONHF in univariate and multivariate analysis. ONHF was also associated with higher creatinine level (p = 0.001) lower LDH level (p = 0.006), and higher number of vaso-occlusive crisis (VOC)/patient/year (p < 0.001). The cumulative incidence of ONHF in patients having more than 3 VOC/year was significantly higher (43% versus 18.9% at 20 years, p < 0.001). In addition, infections, gallstones, growth delay, delayed initiation of hydroxyurea, and a higher transfusion rate were significantly associated with ONFH.

CONCLUSION

These findings confirm that ONFH is closely related to the age, severity, and duration of SCD. Better management of this disease prevents acute and chronic complications, and early screening of the ONFH as soon as the first signs of the severity of the disease are detected provides a better functional prognosis.

From Stress to Sick(le) and Back Again-Oxidative/Antioxidant Mechanisms, Genetic Modulation, and Cerebrovascular Disease in Children with Sickle Cell Anemia

Sickle cell anemia (SCA) is a genetic disease caused by the homozygosity of the HBB:c.20A>T mutation, which results in the production of hemoglobin S (HbS). In hypoxic conditions, HbS suffers autoxidation and polymerizes inside red blood cells, altering their morphology into a sickle shape, with increased rigidity and fragility. This triggers complex pathophysiological mechanisms, including inflammation, cell adhesion, oxidative stress, and vaso-occlusion, along with metabolic alterations and endocrine complications. SCA is phenotypically heterogeneous due to the modulation of both environmental and genetic factors. Pediatric cerebrovascular disease (CVD), namely ischemic stroke and silent cerebral infarctions, is one of the most impactful manifestations. In this review, we highlight the role of oxidative stress in the pathophysiology of pediatric CVD. Since oxidative stress is an interdependent mechanism in vasculopathy, occurring alongside (or as result of) endothelial dysfunction, cell adhesion, inflammation, chronic hemolysis, ischemia-reperfusion injury, and vaso-occlusion, a brief overview of the main mechanisms involved is included. Moreover, the genetic modulation of CVD in SCA is discussed. The knowledge of the intricate network of altered mechanisms in SCA, and how it is affected by different genetic factors, is fundamental for the identification of potential therapeutic targets, drug development, and patient-specific treatment alternatives.

Genome-wide meta-analysis identifies new candidate genes for sickle cell disease nephropathy

Sickle cell disease nephropathy (SCDN), a common SCD complication, is strongly associated with mortality. Polygenic risk scores calculated from recent transethnic meta-analyses of urinary albumin-to-creatinine ratio and estimated glomerular filtration rate (eGFR) trended toward association with proteinuria and eGFR in SCD but the model fit was poor (R2 < 0.01), suggesting that there are likely unique genetic risk factors for SCDN. Therefore, we performed genome-wide association studies (GWAS) for 2 critical manifestations of SCDN, proteinuria and decreased eGFR, in 2 well-characterized adult SCD cohorts, representing, to the best of our knowledge, the largest SCDN sample to date. Meta-analysis identified 6 genome-wide significant associations (false discovery rate, q ≤ 0.05): 3 for proteinuria (CRYL1, VWF, and ADAMTS7) and 3 for eGFR (LRP1B, linc02288, and FPGT-TNNI3K/TNNI3K). These associations are independent of APOL1 risk and represent novel SCDN loci, many with evidence for regulatory function. Moreover, GWAS SNPs in CRYL1, VWF, ADAMTS7, and linc02288 are associated with gene expression in kidney and pathways important to both renal function and SCD biology, supporting the hypothesis that SCDN pathophysiology is distinct from other forms of kidney disease. Together, these findings provide new targets for functional follow-up that could be tested prospectively and potentially used to identify patients with SCD who are at risk, before onset of kidney dysfunction.

Interventions for chronic kidney disease in people with sickle cell disease

BACKGROUND

Sickle cell disease (SCD), one of the commonest severe monogenic disorders, is caused by the inheritance of two abnormal haemoglobin (beta-globin) genes. SCD can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Kidney disease is a frequent and potentially severe complication in people with SCD. Chronic kidney disease (CKD) is defined as abnormalities of kidney structure or function present for more than three months. Sickle cell nephropathy refers to the spectrum of kidney complications in SCD. Glomerular damage is a cause of microalbuminuria and can develop at an early age in children with SCD, with increased prevalence in adulthood. In people with sickle cell nephropathy, outcomes are poor as a result of the progression to proteinuria and chronic kidney insufficiency. Up to 12% of people who develop sickle cell nephropathy will develop end-stage renal disease. This is an update of a review first published in 2017.

OBJECTIVES

To assess the effectiveness of any intervention for preventing or reducing kidney complications or chronic kidney disease in people with sickle cell disease. Possible interventions include red blood cell transfusions, hydroxyurea, and angiotensin-converting enzyme inhibitors (ACEIs), either alone or in combination.

SEARCH METHODS

We searched for relevant trials in the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, CENTRAL, MEDLINE, Embase, seven other databases, and two other trials registers.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing interventions to prevent or reduce kidney complications or CKD in people with SCD. We applied no restrictions related to outcomes examined, language, or publication status.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility, extracted data, assessed the risk of bias, and assessed the certainty of the evidence (GRADE).

MAIN RESULTS

We included three RCTs with 385 participants. We rated the certainty of the evidence as low to very low across different outcomes according to GRADE methodology, downgrading for risk of bias concerns, indirectness, and imprecision. Hydroxyurea versus placebo One RCT published in 2011 compared hydroxyurea to placebo in 193 children aged nine to 18 months. We are unsure if hydroxyurea compared to placebo reduces or prevents progression of kidney disease assessed by change in glomerular filtration rate (mean difference (MD) 0.58 mL/min /1.73 m2, 95% confidence interval (CI) -14.60 to 15.76; 142 participants; very low certainty). Hydroxyurea compared to placebo may improve the ability to concentrate urine (MD 42.23 mOsm/kg, 95% CI 12.14 to 72.32; 178 participants; low certainty), and may make little or no difference to SCD-related serious adverse events, including acute chest syndrome (risk ratio (RR) 0.39, 99% CI 0.13 to 1.16; 193 participants; low certainty), painful crisis (RR 0.68, 99% CI 0.45 to 1.02; 193 participants; low certainty); and hospitalisations (RR 0.83, 99% CI 0.68 to 1.01; 193 participants; low certainty). No deaths occurred in either trial arm and the RCT did not report quality of life. Angiotensin-converting enzyme inhibitors versus placebo One RCT published in 1998 compared an ACEI (captopril) to placebo in 22 adults with normal blood pressure and microalbuminuria. We are unsure if captopril compared to placebo reduces proteinuria (MD -49.00 mg/day, 95% CI -124.10 to 26.10; 22 participants; very low certainty). We are unsure if captopril reduces or prevents kidney disease as measured by creatinine clearance; the trial authors stated that creatinine clearance remained constant over six months in both groups, but provided no comparative data (very low certainty). The RCT did not report serious adverse events, all-cause mortality, or quality of life. Angiotensin-converting enzyme inhibitors versus vitamin C One RCT published in 2020 compared an ACEI (lisinopril) with vitamin C in 170 children aged one to 18 years with normal blood pressure and microalbuminuria. It reported no data we could analyse. We are unsure if lisinopril compared to vitamin C reduces proteinuria in this population: the large drop in microalbuminuria in both arms of the trial after only one month on treatment may have been due to an overestimation of microalbuminuria at baseline rather than a true effect. The RCT did not report serious adverse events, all-cause mortality, or quality of life.

AUTHORS' CONCLUSIONS

We are unsure if hydroxyurea improves glomerular filtration rate or reduces hyperfiltration in children aged nine to 18 months, but it may improve their ability to concentrate urine and may make little or no difference to the incidence of acute chest syndrome, painful crises, and hospitalisations. We are unsure if ACEI compared to placebo has any effect on preventing or reducing kidney complications in adults with normal blood pressure and microalbuminuria. We are unsure if ACEI compared to vitamin C has any effect on preventing or reducing kidney complications in children with normal blood pressure and microalbuminuria. No RCTs assessed red blood cell transfusions or any combined interventions to prevent or reduce kidney complications. Due to lack of evidence, we cannot comment on the management of children aged over 18 months or adults with any known genotype of SCD. We have identified a lack of adequately designed and powered studies, although we found four ongoing trials since the last version of this review. Only one ongoing trial addresses renal function as a primary outcome in the short term, but such interventions have long-term effects. Trials of hydroxyurea, ACEIs or red blood cell transfusion in older children and adults are urgently needed to determine any effect on prevention or reduction of kidney complications in people with SCD.

Emerging Therapies and Advances in Sickle Cell Disease with a Focus on Renal Manifestations

The underlying mechanisms of disease in sickle cell disease (SCD) contribute to a multifaceted nephropathy, commonly manifested as albuminuria. In severe SCD genotypes ( e.g. , Hemoglobin SS [HbSS]), albuminuria and CKD are major predictors of mortality in this population. Therefore, the monitoring and management of renal function is an intrinsic part of comprehensive care in SCD. Management of nephropathy in SCD can be accomplished with SCD-directed therapies and/or CKD-directed therapies. In the past 5 years, novel disease-modifying and palliative therapies have been approved in SCD to target aspects of the disease, such as anemia, inflammation, and vasculopathy. Along with conventional hydroxyurea and chronic transfusion, l -glutamine, crizanlizumab, and voxelotor have all been shown to mitigate some adverse effect of SCD, and their effect on nephropathy is being investigated. CKD-directed therapies such as renin-angiotensin-aldosterone system blockers have long been used in SCD nephropathy; however, more complete long-term studies on benefits are needed. Given the effect of renal disease on survival, further assessment of the mechanisms and efficacy of these SCD-directed or CKD-directed therapeutic agents is essential.

Sickle cell disease in Ontario, Canada: an epidemiologic profile based on health administrative data

BACKGROUND

The number of patients with sickle cell disease in Ontario, Canada, is unknown. In the absence of a formal registry, we performed a study to determine an approximate census via analysis of health administrative databases.

METHODS

We identified Ontario patients with a diagnosis of sickle cell disease through queries of the Discharge Abstract Database, National Ambulatory Care Reporting System and Newborn Screening Ontario database. The period of inquiry was Apr. 1, 2007, through Mar. 31, 2017. We identified repeat interactions by the same patient by cross-referencing provincial health insurance plan numbers.

RESULTS

We documented health care system interactions for 3418 unique patients (1912 [55.9%] female, median age at the time of identification 24 yr). Over the 10-year study period, patients visited the emergency department a median of 2 (interquartile range [IQR] 1-7) times and an average of 6.69 (standard deviation [SD] 26.71) times, and were admitted to hospital a median of 1 (IQR 1-5) time and an average of 4.38 (SD 8.53) times for treatment related to sickle cell disease. A total of 229 patients (6.7%) died during the study period, with an average age at death of 55 years. Even without accounting for the effects of immigration, the rate of natural increase slowed slightly over the study period owing to a decrease in the annual number of affected births.

INTERPRETATION

The estimated prevalence of patients with sickle cell disease in Ontario in 2007/08-2016/17 was 1 in 4200, and affected patients' need for hospital-based care was substantial, although highly variable. Similar queries of health administrative databases may be feasible in other Canadian provinces.

Sickle cell leg ulcer successfully managed by hyperbaric oxygen: a case report

Sickle cell leg ulcers (SCLUs) are usually chronic, painful, and devastating complications of sickle cell disease. Skin vaso-occlusion with compromised blood flow, chronic inflammation, and endothelial dysfunction is thought to be the underlying mechanism. It is usually slow to heal, and it may become chronic and superinfected. The management of SCLUs is usually challenging and requires a multidisciplinary team. Multiple systemic and local therapies have been tried in SCLU treatment. However, the outcome is variable: currently, there are no official recommendations for the best effective treatment. Herein, we report a 34-year-old male patient with non-transfusion-dependent sickle cell disease who was suffering from a chronic left ankle ulcer and was successfully managed with hyperbaric oxygen therapy, resulting in a complete resolution of this devastating complication.

Urinary angiotensinogen is associated with albuminuria in adults with sickle cell anaemia

We explored the association of novel urinary biomarkers with albumin-creatinine ratio (ACR) in adults with sickle cell anaemia. Of 37 participants, 13 (35.2%) had persistent albuminuria (PA). Urinary levels of clusterin (p = 0.002), retinol-binding protein 4 (p = 0.008), alpha-1 microglobulin (p = 0.002) and angiotensinogen (p = 0.006) were significantly higher in participants with PA than in those without PA. Although univariate analysis showed significant associations between both alpha-1 microglobulin (p = 0.035) and angiotensinogen (p = 0.0021) with ACR, only angiotensinogen was associated with ACR in multivariable analysis (p = 0.04). Our results suggest that urinary angiotensinogen may identify sickle cell anaemia patients at risk for kidney disease.

Predictors of Mortality in Adults With Sickle Cell Disease Admitted to the Intensive Care Unit in King Saud Medical City, Saudi Arabia

Background Sickle cell disease (SCD) is the most common genetic blood disorder in Saudi Arabia. A limited number of studies have been conducted on SCD patients regarding their intensive care unit (ICU) admissions. We aimed to identify the cause of ICU admission in SCD patients and to identify predictors of mortality. Methodology We identified 64 patients with SCD, aged 14 years and older, who were admitted to the ICU of King Saud Medical City, Riyadh, Kingdom of Saudi Arabia, from January 1, 2017, to December 31, 2020. Results Acute chest syndrome was the most frequent primary diagnosis for ICU admission in 29 (45.3%) patients followed by vaso-occlusive crisis in 23 (35.9%) patients. Pregnancy in eight (12.5%) patients was the most prevalent co-existing condition. The median age was 29 years, with males comprising 45.3% and females comprising 54.7% of the study population. Arterial blood gas pH less than 7.2 on ICU admission (p= <0.001), hemodialysis support (p= 0.049), the use of vasopressors (p= 0.016), intubation (p= <0.001), and being intubated within the first 24 hours of ICU stay (p= 0.04) had a statistically significant association with mortality at ICU discharge out of all the variables tested. Mortality on ICU discharge was 7 (10.9%). Conclusion This was a retrospective study carried out in King Saud Medical City. Comparing the results of the study to those of similar ones conducted around the world revealed a low SCD ICU mortality rate. This low mortality may be a result of improved overall ICU care. We recommend a multi-center, prospective study in future.

Self-management interventions for children and young people with sickle cell disease: A systematic review

BACKGROUND

Increasing numbers of interventions are being developed to support self-management for children and young people (CYP) with sickle cell disease (SCD), but no systematic review has systematically synthesized this evidence regarding their characteristics, effectiveness, acceptability and feasibility for all published intervention types.

METHODS

The Joanna Briggs Institute guidelines for mixed-method reviews were followed. A systematic search of eight databases and key journals was conducted from their inception to November 2021. Primary research of self-management interventions targeting CYP with SCD aged 8-24 years and reporting any health/social outcome and acceptability data were included. Design-specific standardized critical appraisal instruments were used. Two independent reviewers screened and appraised the articles. A third reviewer resolved disagreements.

RESULTS

Of 1654 articles identified, 38 studies were included. Methodological quality was moderate. Most studies evaluated SCD education, psycho-behavioural, psychosocial and skills training and/or social support interventions. They appear to demonstrate short-term improvements in knowledge, social functioning and medical adherence outcomes. Interventions that were multifaceted in content, combined technological platforms and in-person group-based formats and involved peers, family and care providers were more acceptable and effective. The long-term impact of interventions was limited, including CYP's involvement in the intervention development and implementation.

CONCLUSIONS

There is inconclusive evidence for any self-management programme. Nonetheless, support from family, peers and care providers appears to be important for self-management interventions' effectiveness and acceptability. Future research needs to prioritize CYP involvement in both intervention design and delivery, their wider social context and include CYP with SCD from non-Black backgrounds.

PATIENT AND PUBLIC CONTRIBUTION

Three young people with SCD recruited acted as the review advisors. They were formally trained in the review process and involved in every aspect of the review: the design, conduct and interpretation of the findings. CYP involvement in the interventions' development and implementation was analysed as part of the review. This systematic review was conducted as part of a wider research project titled: Understanding fatigue experiences of CYP with SCD to guide the co-development of a fatigue self-management intervention. Two of the young advisors involved in the review were also involved in the development of the project funding application.

Acute chest syndrome in adult patients with sickle cell disease: The relationship with the time to onset after hospital admission

Data on acute chest syndrome (ACS) in adult sickle cell disease patients are scarce. In this study, we describe 105 consecutive ACS episodes in 81 adult patients during a 32-month period and compare the characteristics as a function of the time to onset after hospital admission for a vaso-occlusive crisis (VOC), that is early-onset episodes (time to onset ≤24 h, 42%) versus secondary episodes (>24 h, 58%; median [interquartile range] time to onset: 2 [2-3] days). The median age was 27 [22-34] years, 89% of the patients had an S/S or S/β⁰ -thalassaemia genotype; 81% of the patients had a history of ACS (median: 3 [2-5] per patient), only 61% were taking a disease-modifying treatment at the time of the ACS. Fever and chest pain were noted in respectively 54% and 73% of the episodes. Crackles (64%) and bronchial breathing (32%) were the main abnormal auscultatory findings. A positive microbiological test was found for 20% of episodes. Fifty percent of the episodes required a blood transfusion; ICU transfer and mortality rates were respectively 29% and 1%. Secondary and early-onset forms of ACS did not differ significantly. Disease-modifying treatments should be revaluated after each ACS episode because the recurrence rate is high.

Real-world characteristics of patients with sickle cell disease who initiated crizanlizumab therapy

OBJECTIVE

To provide real-word evidence of patients with SCD initiating crizanlizumab, their use of other SCD treatments, and crizanlizumab treatment patterns.

METHODS

Using IQVIA's US-based, Longitudinal Patient-Centric Pharmacy and Medical Claims Databases patients with a diagnosis of SCD between November 1, 2018, and April 30, 2021, and ≥1 claim for crizanlizumab (date of first claim = index date) between November 1, 2019, and January 31, 2021 who were ≥16 years of age, and had ≥12 months of pre-index data were selected for analysis. Two cohorts were identified based on available follow-up time (3- and 6-month cohorts). Patient characteristics were reported along with pre- and post-index SCD treatments and crizanlizumab treatment patterns (e.g. total doses received, gap-days between doses, days on therapy, discontinuation, and restarts).

RESULTS

540 patients met the base inclusion criteria (345 in the 3-month cohort and 262 in the 6-month cohort. Most patients (64%) were female with a mean (SD) age of 35 (12) years overall. Concomitant hydroxyurea use was observed in 19-39% of patients, while concomitant L-glutamine use was observed for 4-8% of patients. 85% of 3-month cohort patients received at least two doses of crizanlizumab, while 66% of the 6-month cohort received at least 4 doses of crizanlizumab. The median number of gap days between doses was 1 or 2.

CONCLUSIONS

66% of patients who receive crizanlizumab receive at least 4 doses within 6-months. The low median number of gap days suggests high adherence.

Estimated glomerular filtration rate in Brazilian adults with sickle cell disease: results from the REDS-III multicenter cohort study

Chronic kidney disease (CKD) has a significant impact on sickle cell disease (SCD) morbidity and mortality. Early identification of individuals at highest risk of developing CKD may allow therapeutic intervention to prevent worse outcomes. This study aimed to evaluate the prevalence and risk factors for reduced estimated glomerular filtration rate (eGFR) among adults with SCD in Brazil. Participants in the REDS-III multicenter SCD cohort with more severe genotypes aged ≥ 18 years with at least two serum creatinine values were analyzed. The eGFR was calculated using the Jamaica Sickle Cell Cohort Study GFR equation. The eGFR categories were defined according to the K/DOQI. Participants with eGFR ≥ 90 were compared to those with those with eGFR < 90. Among the 870 participants, 647 (74.4%) had eGFR ≥ 90, 211 (24.3%) had eGFR 60 to 89, six (0.7%) had eGFR 30 to 59, and six (0.7%) had ESRD. Male sex (OR: 37.3; 95%CI: 22.4-65.1), higher age (OR: 1.04; 95%CI: 1.02-1.06), higher diastolic blood pressure (OR: 1.03; 95%CI: 1.009-1.06), lower Hb (OR: 0.80; 95%CI: 0.68-0.93), and lower reticulocytes (OR: 0.94; 95%CI: 0.89-0.99) levels were independently associated with eGFR < 90. There was a trend towards higher odds of death in participants with eGFR < 90 (OR: 1.8; 95%CI: 0.95-3.32; p = 0.065). In turn, participants with eGFR < 60 had a 12.2 (95%CI: 2.1-96.9) times higher odds for death when compared to those with eGFR ≥ 60. In this study, eGFR < 90 was observed in one-quarter of adults. Older age, male sex, higher diastolic blood pressure, lower hemoglobin, and lower reticulocyte levels were associated with occurrence of eGFR < 90. Estimated GFR < 60 increased the risk of mortality.

In Humanized Sickle Cell Mice, Imatinib Protects Against Sickle Cell-Related Injury

Drug repurposing is a valuable strategy for rare diseases. Sickle cell disease (SCD) is a rare hereditary hemolytic anemia accompanied by acute and chronic painful episodes, most often in the context of vaso-occlusive crisis (VOC). Although progress in the knowledge of pathophysiology of SCD have allowed the development of new therapeutic options, a large fraction of patients still exhibits unmet therapeutic needs, with persistence of VOCs and chronic disease progression. Here, we show that imatinib, an oral tyrosine kinase inhibitor developed for the treatment of chronic myelogenous leukemia, acts as multimodal therapy targeting signal transduction pathways involved in the pathogenesis of both anemia and inflammatory vasculopathy of humanized murine model for SCD. In addition, imatinib inhibits the platelet-derived growth factor-B-dependent pathway, interfering with the profibrotic response to hypoxia/reperfusion injury, used to mimic acute VOCs. Our data indicate that imatinib might be considered as possible new therapeutic tool for chronic treatment of SCD.

An Overview of Solid Organ Transplantation in Patients With Sickle Cell Disease

Sickle cell disease is a common genetic disorder affecting >300 000 people across the world. The vast majority of patients cared for in high-resource settings live well into adulthood, but many develop a high burden of disease complications. Good standard of care including disease-modifying agents and transfusion programs limits the number of patients who develop end-stage organ disease, but for those that do, the prognosis can be very poor. Solid organ transplantation is a well-established mode of treatment for patients with sickle cell disease and kidney or liver failure, but appropriate patient selection and perioperative management are important for achieving good outcomes. Hematopoietic stem cell transplantation and gene therapy may offer novel treatment options for adult patients with chronic organ damage in the future, but these are not yet widely available. For now, good, holistic care and early intervention of end-organ complications can minimize the number of patients requiring solid organ transplantation later in life.

Insulin-like Growth Factor-1 Prevents Hypoxia/Reoxygenation-Induced White Matter Injury in Sickle Cell Mice

Occlusion of cerebral blood vessels causes acute cerebral hypoxia—an important trigger of ischemic white matter injury and stroke in sickle cell disease (SCD). While chronic hypoxia triggers compensatory neuroprotection via insulin-like growth factor-1 (IGF-1) and hypoxia inducible factor-1α (HIF-1α), severe bouts of acute hypoxia and subsequent restoration of blood flow (hypoxia/reoxygenation, H/R) overwhelm compensatory mechanisms and cause neuroaxonal damage–identified as white matter lesions–in the brain. The neuroprotective role of IGF-1 in the pathogenesis of white matter injury in SCD has not been investigated; however, it is known that systemic IGF-1 is reduced in individuals with SCD. We hypothesized that IGF-1 supplementation may prevent H/R-induced white matter injury in SCD. Transgenic sickle mice homozygous for human hemoglobin S and exposed to H/R developed white matter injury identified by elevated expression of non-phosphorylated neurofilament H (SMI32) with a concomitant decrease in myelin basic protein (MBP) resulting in an increased SMI32/MBP ratio. H/R-challenge also lowered plasma and brain IGF-1 expression. Human recombinant IGF-1 prophylaxis significantly induced HIF-1α and averted H/R-induced white matter injury in the sickle mice compared to vehicle-treated mice. The expression of the IGF-1 binding proteins IGFBP-1 and IGFBP-3 was elevated in the IGF-1-treated brain tissue indicating their potential role in mediating neuroprotective HIF-1α signaling. This study provides proof-of-concept for IGF-1-mediated neuroprotection in SCD.

Access to healthcare for people with sickle cell disease: Views of healthcare professionals on policies and practices

INTRODUCTION

Sickle cell disease is a genetic disorder with its highest prevalence in Nigeria. The condition causes red blood cells to turn rigid, and consequently, results to several complications including organ damage. This study aimed at assessing views of health practitioners in Nigeria on policies and practices in the area of access to healthcare services for sickle cell disease.

METHODS

A cross-sectional study was undertaken amongst healthcare professionals in Nigeria. Data were collected using a self-administered questionnaire, and analyses were undertaken using Statistical Package for Social Sciences software.

RESULTS

A significant proportion of the participants (42.8%) disagreed that relevant legislative framework exists to facilitate optimal access to high-quality healthcare services for persons with sickle cell disorder in Nigeria. Two-thirds of the study cohort were of the opinion that public health surveillance towards sickle cell disease was suboptimal (61.2%). Also, more than three-quarters of the respondents (78.7%) indicated that the cost of managing sickle cell disease was not affordable to majority of affected Nigerians.

CONCLUSION

This study provides critical insights into access to healthcare services for sickle cell disease. As such, challenges preventing access to healthcare services for sickle cell patients which have been identified in this study can underpin the development of contextual policies to address them.

Hemoglobinopathy Patterns in Anemic Patients with a Strong History of Sickle Cell Disease in Eastern Province, Saudi Arabia: A Cross-Sectional Study

&lt;b&gt;Background and Objective:&lt;/b&gt; The most common genetic disease in humans is hemoglobinopathies, also known as hemoglobin hereditary diseases. The purpose of this study was to look at the hemoglobinopathy patterns in anemic patients with a history of sickle cell disease in Saudi Arabia's Eastern Province. &lt;b&gt;Materials and Methods:&lt;/b&gt; This prospective cross-sectional study was conducted on anemic patients attending the hospital with a strong family history of hemoglobinopathy and general signs and symptoms, as well as mild to moderate anemia crises. One hundred and ten people were chosen to participate in this study. The research was carried out between September, 2019 and October, 2020. &lt;b&gt;Results:&lt;/b&gt; The sickle cell trait was the most common hemoglobinopathy in males (31.1%) and sickle cell trait+beta thalassemia minor was the most common in females (18%). The gender of patients and the distribution of hemoglobinopathy types were found to have a significant relationship (p-value of 0.001). &lt;b&gt;Conclusion:&lt;/b&gt; A significant correlation was discovered between the gender of patients and the distribution of hemoglobinopathy types. More efforts must be made to raise the prevention of endogamy awareness among Saudis.

Organ function indications and potential improvements following curative therapy for sickle cell disease

Curative therapies for sickle cell disease include allogeneic hematopoietic stem cell transplantation (HSCT) and gene-modified autologous stem cell transplantation. HSCT has been used for 30 years with success measured by engraftment, symptom control, graft-vs-host disease (GVHD) risk, organ toxicity, and immune reconstitution. While human leukocyte antigen-matched sibling donor (MSD) transplants have excellent outcomes, alternate donor transplants (unrelated/haploidentical) are just beginning to overcome GVHD and engraftment hurdles to match MSD. Gene therapy, a newly developed treatment, is undergoing careful evaluation in many trials with varying approaches. The risk/benefit ratio to the patient in relation to outcomes, toxicities, and mortality risk drives eligibility for curative interventions. Consequently, eligibility criteria for MSD transplants can be less stringent, especially in the young. Posttransplant outcome analysis after the "cure" with respect to organ function recovery is essential. While established damage such as stroke is irreversible, transplant can help stabilize (pulmonary function), prevent further deterioration (stroke), improve (neurocognition), and protect unaffected organs. Tracking organ functions postintervention uniformly between clinical trials and for adequate duration is essential to answer safety and efficacy questions related to curative therapies. Age-appropriate application/outcome analyses of such therapies will be the ultimate goal in overcoming this disease.

Satisfaction and access to care for adults and adolescents with sickle cell disease: ASCQ-Me quality of care and the SHIP-HU study

A lack of adult sickle cell providers has long been blamed for poor satisfaction and access to specialty care for adults with sickle cell disease (SCD). We were interested in comparing how adolescent and adult patients already in established SCD centers perceived access and quality of care. Hydroxyurea-eligible patients aged 15 years and older were enrolled in the Start Healing in Patients with Hydroxyurea trial, which required them to be affiliated with a SCD specialist. Patients were seen in one of three adult-oriented specialty clinic sites or one of three pediatric-oriented sites. At baseline, patients completed the Adult Sickle Cell Quality of Life Measurement Information System measure as part of a survey battery. Patients treated at adult clinic sites reported being less able to get timely ambulatory appointments (p = .004). They reported emergency department (ED) wait times of >1 h far more often (47.7 vs. 19.3%, p = .0048). They reported less overall satisfaction with care (7.47 vs. 8.77, p < .0001), and less satisfaction with care in the ED (2.88 vs. 3.4, p = .0068. Ambulatory satisfaction was no different between pediatric site versus adult site patients. Poorer systems of care appeared to underlie reported differences, rather than differences in biopsychosocial determinants. Even among specialty-care-affiliated SCD patients, those seen in adult clinics reported worse access to care and lower satisfaction with care than patients seen in pediatric clinics. In addition to increasing the number of adult SCD providers and better preparing pediatric SCD patients to transfer to adult programs, SCD clinical caregivers must also improve aspects of adult care quality to meet reasonable patient expectations of timeliness and interpersonal aspects of care quality.

Biomarkers of sickle cell nephropathy in Senegal

Sickle cell anemia (SCA) is caused by a single point variation in the β-globin gene (HBB): c.20A> T (p.Glu7Val), in homozygous state. SCA is characterized by sickling of red blood cells in small blood vessels which leads to a range of multiorgan complications, including kidney dysfunction. This case-control study aims at identifying sickle cell nephropathy biomarkers in a group of patients living with SCA from Senegal. A total of 163 patients living with SCA and 177 ethnic matched controls were investigated. Biological phenotyping included evaluation of glycemia, glucosuria, albuminuria, proteinuria, tubular proteinuria, serum creatinine, urine creatinine, urine specific gravity and glomerular filtration rate. Descriptive statistics of biomarkers were performed using the χ2 -test, with the significance level set at p<0.05. Patients living with SCA had a median age of 20 years (range 4 to 57) with a female sex frequency of 53.21%. The median age of the control participants was 29 years (range: 4-77) with a female sex frequency of 66.09%. The following proportions of abnormal biological indices were observed in SCA patients versus (vs.) controls, as follows: hyposthenuria: 35.3%vs.5.2% (p<0.001); glomerular hyperfiltration: 47.66%vs.19.75% (p<0.001), renal insufficiency: 5.47%vs.3.82% (p = 0.182); microalbuminuria: 42.38%vs.5.78% (p<0.001); proteinuria: 39.33%vs.4.62% (p<0.001); tubular proteinuria: 40.97%vs.4.73% (p<0.001) and microglucosuria: 22.5%vs.5.1% (p<0.001). This study shows a relatively high proportion of SCA nephropathy among patients living with SCA in Senegal. Microglucosuria, proteinuria, tubular proteinuria, microalbuminuria, hyposthenuria and glomerular hyperfiltration are the most prevalent biomarkers of nephropathy in this group of Senegalese patients with SCA.

Treatment patterns and burden of complications associated with sickle cell disease: A US retrospective claims analysis

Complications associated with sickle cell disease (SCD) that are highly impactful for patients but until recently have been less understood include priapism, nephropathy, and neurologic injury. We conducted a retrospective study using US administrative claims data from July 01, 2013 through March 31, 2020 to analyze incidence of these complications, SCD treatment patterns, and healthcare resource utilization (HCRU) and costs among 2524 pediatric and adult patients with SCD (mean [SD] age 43.4 [22.4] years). The most common treatments during follow-up were short-acting opioids (54.0% of patients), red blood cell transfusion (15.9%), and hydroxyurea (11.0%). SCD complications occurred frequently; in the overall population, the highest follow-up incidences per 1000 person-years were for acute kidney injury (53.1), chronic kidney disease (40.6), and stroke (39.0). Complications occurred across all age groups but increased in frequency with age; notably, acute kidney injury was 69.7 times more frequent among ages 65+ than ages 0-15 (p < 0.001). Follow-up per-patient-per-month HCRU also increased with age; however, all-cause healthcare costs were similarly high for all age groups and were driven primarily by inpatient stays. Patients with SCD across the age spectrum have a high burden of complications with the use of current treatments, suggesting unmet needs for treatment management.

Simultaneous quantification of blood rheology and oxygen saturation to evaluate affinity-modifying therapies in sickle cell disease

Sickle cell blood demonstrates oxygen-dependent flow behavior as a result of HbS polymerization during hypoxia, and these rheological changes provide a biophysical metric that can be used to quantify the pathological behavior of the blood. Relating these rheological changes directly to hemoglobin oxygen saturation would improve our understanding of SCD pathogenesis and the potential effects of therapeutic drugs. Towards this end, we have developed a microfluidic platform capable of spectrophotometric quantification of Hb-O2 saturation and simultaneous evaluation of the accompanying rheological changes in SCD blood flow. We demonstrated the ability to measure changes in Hb-O2 affinity and a restoration of oxygen-independent blood flow behavior after incubation with voxelotor, an oxygen affinity modifying drug approved for use in SCD. We also identified regimes in Hb-O2 saturation where the effects of HbS polymerization begin to take effect in contributing to pathological flow behavior, independent of voxelotor treatment. In contrast, incubation with voxelotor recovered oxygen-dependent blood flow over a range of PO2, providing a framework for understanding voxelotor's therapeutic effect in lowering the PO2 at which the requisite Hb-O2 saturation is reached to observe pathological blood flow. These results help explain the mechanistic effects of voxelotor and show the potential of this platform to identify affinity-modifying compounds and evaluate their therapeutic effect on blood flow.

Glomerular filtration rate abnormalities in sickle cell disease

Sickle cell disease (SCD) is a group of inherited blood disorders affecting the β-globin gene, resulting in the polymerization of hemoglobin and subsequent sickling of the red blood cell. Renal disease, the most common complication in SCD, begins in childhood with glomerular hyperfiltration and then progresses into albuminuria, a fast decline of glomerular filtration, and renal failure in adults. This mini-review focuses on glomerular filtration abnormalities and the mechanisms of hyperfiltration, explores genetic modifiers and methods of estimating glomerular filtration rates, and examines novel biomarkers of glomerular filtration in SCD.

Sickle cell disease in Gulf Cooperation Council countries: a systematic review

INTRODUCTION

Evidence related to the national burden of Sickle Cell Disease (SCD) in Gulf Cooperation Council (GCC) largely fragmented. Thus, the aim of this study is to systemically review studies from GCC countries to assess the epidemiological profile of SCD.

AREAS COVERED

We searched combinations of key terms in MEDLINE/PubMed, CINAHL, and EMBASE. We selected relevant observational studies reporting the frequency, incidence, prevalence, risk factors, mortality rate, and complications of SCD among the GCC population. Studies restricted to laboratory diagnostic tests, experimental and animal studies, review articles, case reports and series, and conference proceedings and editorials were excluded. A total of 1,347 articles were retrieved, out of which 98 articles were found to be eligible and included in the study. The total number of participants from all the included studies was 3496447. The prevalence of SCD ranged from 0.24%-5.8% across the GCC and from 1.02%-45.8% for the sickle cell trait. Consanguineous marriage was a risk factor for likely giving children affected with hemoglobinopathies.

EXPERT OPINION

The prevalence of SCD and its complications vary among GCC. Because of the high prevalence of SCD and its complications, health authorities should focus on more rigorous prevention and treatment strategies.

Development and characterization of a preclinical total marrow irradiation conditioning-based bone marrow transplant model for sickle cell disease

Sickle cell disease (SCD) is a serious global health problem, and currently, the only curative option is hematopoietic stem cell transplant (HCT). However, myeloablative total body irradiation (TBI)-based HCT is associated with high mortality/morbidity in SCD patients. Therefore, reduced-intensity (2–4 Gy) total body radiation (TBI) is currently used as a conditioning regimen resulting in mixed chimerism with the rescue of the SCD disease characteristic features. However, donor chimerism gradually reduces in a few years, resulting in a relapse of the SCD features, and organ toxicities remained the primary concern for long-term survivors. Targeted marrow irradiation (TMI) is a novel technique developed to deliver radiation to the desired target while sparing vital organs and is successfully used for HCT in refractory/relapsed patients with leukemia. However, it is unknown if TMI will be an effective treatment for a hematological disorder like SCD without adverse effects seen on TBI. Therefore, we examined preclinical feasibility to determine the tolerated dose escalation, its impact on donor engraftment, and reduction in organ damage using our recently developed TMI in the humanized homozygous Berkley SCD mouse model (SS). We show that dose-escalated TMI (8:2) (8 Gy to the bone marrow and 2 Gy to the rest of the body) is tolerated with reduced organ pathology compared with TBI (4:4)-treated mice. Furthermore, with increased SCD control (AA) mice (25 million) donor BM cells, TMI (8:2)-treated mice show successful long-term engraftment while engraftment failed in TBI (2:2)-treated mice. We further evaluated the benefit of dose-escalated TMI and donor cell engraftment in alleviating SCD features. The donor engraftment in SCD mice completely rescues SCD disease features including recovery in RBCs, hematocrit, platelets, and reduced reticulocytes. Moreover, two-photon microscopy imaging of skull BM of transplanted SCD mice shows reduced vessel density and leakiness compared to untreated control SCD mice, indicating vascular recovery post-BMT.

Contribution of ADAMTS13-independent VWF regulation in sickle cell disease

BACKGROUND

Von Willebrand factor (VWF) is elevated in sickle cell disease (SCD) and contributes to vaso-occlusion through its thrombogenic properties. VWF is regulated by ADAMTS13, a plasma protease that cleaves VWF into less bioactive multimers. Independent investigations have shown VWF to be elevated in SCD, whereas measurements of ADAMTS13 have been variable.

OBJECTIVES

We assessed ADAMTS13 activity using multiple activity assays and measured levels of alternative VWF-cleaving proteases in SCD.

METHODS/ PATIENTS

Plasma samples were collected from adult patients with SCD (n = 20) at a single institution when presenting for routine red cell exchange transfusion therapy. ADAMTS13 activity was measured by FRETS-VWF73, Technozym ADAMTS-13 Activity ELISA kit and a full-length VWF digestion reaction. Alternative VWF-cleaving proteases were identified by ELISA. A cell culture model was used to study the impact of SCD stimuli on endothelial ADAMTS13 and alternative VWF-cleaving proteases.

RESULTS

ADAMTS13 activity was found to be moderately deficient across the SCD cohort as assessed by activity assays using a VWF A2 domain peptide substrate. However, SCD plasma showed preserved ability to digest full-length VWF, suggesting assay-discrepant results. Neutrophil and endothelial-derived proteases were found to be elevated in SCD plasma. Matrix metalloproteinase 9 specifically showed preferential cleavage of full-length VWF. Upregulation of alternative VWF-cleaving proteases occurred in endothelial cells exposed to SCD stimuli such as heme and hypoxia.

CONCLUSIONS

This is the first demonstration of accessory plasma enzymes contributing to the regulation of VWF in a specific disease state and may have implications for assessing the VWF/ADAMTS13 axis in other settings.