Impact of hydroxyurea on clinical events in the BABY HUG trial

Prophylactic red cell transfusions for sickle cell disease pregnancy: increased use of therapy could transform outcomes

PURPOSE OF REVIEW

Pregnancy for people with sickle cell disease (SCD) is high risk with persistently high rates of severe maternal and fetal mortality and morbidity. Transfusion therapy is the best-studied treatment for SCD in pregnancy; hydroxyurea is not usually used because of teratogenicity concerns. In high-resource settings, red cell transfusions are likely underutilized, while in low-resource settings, they may be altogether unavailable.

RECENT FINDINGS

A randomized controlled trial and meta-analysis, two of the strongest forms of clinical research, show transfusion significantly reduces maternal and fetal death, painful crisis, thrombosis, and acute respiratory failure. Downstream benefits of treatment are less well measured and may include improving maternal anemia, reducing opioid exposure, and avoiding hospitalization, which presents risk for additional complications. Alloimmunization is a particular transfusion risk in SCD. However, many strategies can mitigate this risk. Accordingly, the American Society of Hematology classifies chronic transfusion in pregnancy as low risk.

SUMMARY

Given the low risk classification, lack of alternative therapies, dismal, stagnant pregnancy outcomes and the potential for profound treatment benefit, wider use of chronic transfusion therapy for SCD pregnancy is likely indicated. This review discusses the benefits and potential risks of prophylactic transfusions for SCD pregnancy. Use of chronic transfusions during pregnancy is indicated to help urgently transform outcomes.

Newborn Screening for Sickle Cell Disease in Catalonia between 2015 and 2022-Epidemiology and Impact on Clinical Events

In 2015, Catalonia introduced sickle cell disease (SCD) screening in its newborn screening (NBS) program along with standard-of-care treatments like penicillin, hydroxyurea, and anti-pneumococcal vaccination. Few studies have assessed the clinical impact of introducing NBS programs on SCD patients. We analyzed the incidence of SCD and related hemoglobinopathies in Catalonia and the change in clinical events occurring after introducing NBS. Screening 506,996 newborns from 2015 to 2022, we conducted a retrospective multicenter study including 100 screened (SG) and 95 unscreened (UG) SCD patients and analyzed SCD-related clinical events over the first six years of life. We diagnosed 160 cases of SCD, with an incidence of 1 in 3169 newborns. The SG had a significantly lower median age at diagnosis (0.1 y vs. 1.68 y, p < 0.0001), and initiated penicillin prophylaxis (0.12 y vs. 1.86 y, p < 0.0001) and hydroxyurea treatment earlier (1.42 y vs. 4.5 y, p < 0.0001). The SG experienced fewer median SCD-related clinical events (vaso-occlusive crisis, acute chest syndrome, infections of probable bacterial origin, acute anemia requiring transfusion, acute splenic sequestration, and pathological transcranial Doppler echography) per year of follow-up (0.19 vs. 0.77, p < 0.0001), a reduced number of annual emergency department visits (0.37 vs. 0.76, p < 0.0001), and fewer hospitalizations (0.33 vs. 0.72, p < 0.0001). SCD screening in Catalonia's NBS program has effectively reduced morbidity and improved affected children's quality of life.

Sickle Cell Disease

Background

Sickle cell disease (SCD) is among the most frequent hereditary disorders globally and its prevalence in Europe is increasing due to migration movements.

Summary

The basic pathophysiological event of SCD is polymerization of deoxygenated sickle hemoglobin, resulting in hemolysis, vasoocclusion, and multiorgan damage. While the pathophysiological cascade offers numerous targets for treatment, currently only two disease-modifying drugs have been approved in Europe and transfusion remains a mainstay of both preventing and treating severe complications of SCD. Allogeneic stem cell transplantation and gene therapy offer a curative option but are restricted to few patients due to costs and limited availability of donors.

Key Message

Further efforts are needed to grant patients access to approved treatments, to explore drug combinations and to establish new treatment options.

Hydroxyurea in Sickle Cell Disease and Invasive Bacterial Infections: A Case-Control Study

Hydroxyurea decreases painful events among children with sickle cell disease (SCD) but could increase the risk of infections in treated patients through leucopenia. We performed a case-control study, comparing hydroxyurea treatment for SCD in cases with an invasive bacterial infection and in controls without infection. No difference was found.

Sickle cell disease and infertility risks: implications for counseling and care of affected girls and women

INTRODUCTION

Sickle cell disease (SCD), its treatments and cures present infertility risks. Fertility counseling is broadly indicated for affected girls and women and fertility preservation may appeal to some. Several streams of evidence suggest that the reproductive lifespan of women with SCD is reduced. Pregnancy is associated with high miscarriage rates. There are enduring questions about the effects of highly effective hydroxyurea treatment on female fertility. Current conditioning regimens for gene therapy or hematopoietic stem cell transplant are gonadotoxic. Fertility preservation methods exist as non-experimental standards of care for girls and women. Clinicians are challenged to overcome multifactorial barriers to incorporate fertility counseling and fertility preservation care into routine SCD care.

AREAS COVERED

Here we provide a narrative review of existing evidence regarding fertility and infertility risks in girls and women with SCD and consider counseling implications of existing evidence.

EXPERT OPINION

Addressing fertility for girls and women with SCD requires engaging concerns that emerge across the lifespan, acknowledging uncertainty and identifying barriers to care, some of which may be insurmountable without public policy changes. The contemporary SCD care paradigm can offer transformative SCD treatments alongside comprehensive counselling that addresses fertility risks and fertility preservation opportunities.

Current and emerging drug treatment strategies to tackle sickle cell anemia

INTRODUCTION

Since its discovery in the early 1900s, sickle cell disease (SCD) has contributed significantly to the scientific understanding of hemoglobin and hemoglobinopathies. Despite this, now almost a century later, optimal medical management and even curative options remain limited. Encouragingly, in the last decade, there has been a push toward advancing the care for individuals with SCD and a diversifying interest in options to manage this disorder.

AREAS COVERED

Here, we review the current state of disease modifying therapies for SCD including fetal hemoglobin inducers, monoclonal antibodies, anti-inflammatory modulators, and enzyme activators. We also discuss current curative strategies with specific interest in transformative gene therapies.

EXPERT OPINION

SCD is a chronic, progressive disease that despite a century of clinical description, only now is seeing a growth and advance in therapeutic options to improve the lifespan and quality of life for individuals with SCD. We anticipate newly designed and even repurposed therapies that may work as a single agent or combination agents to tackle the progression of SCD. The vast majority of individuals living with SCD are unlikely to receive gene therapy, therefore improved disease management is critical even for those that may ultimately chose to pursue a potentially curative strategy.

Study protocol for ADHERE (Applying Directly observed therapy to HydroxyurEa to Realize Effectiveness): Using small business partnerships to deliver a scalable and novel hydroxyurea adherence solution to youth with sickle cell disease

Sickle cell disease (SCD) is an inherited blood disorder that affects approximately 100,000 Americans, primarily from underrepresented racial minority populations, and results in costly, multi-organ complications. Hydroxyurea, the primary disease-modifying therapy for SCD, is effective at reducing most complications; however, adherence to hydroxyurea remains suboptimal and is the primary barrier to clinical effectiveness. Video directly observed therapy (VDOT) has shown promise as an adherence-promoting intervention for hydroxyurea, yet previous VDOT trials were limited by high attrition from gaps in technology access, use of unvalidated adherence measures, and healthcare system limitations of delivering VDOT to patients. As such, we fostered a small business partnership to compare VDOT for hydroxyurea to attention control to address previous shortcomings, promote equitable trial participation, and maximize scalability. VDOT will be administered by Scene Health (formerly emocha Health) and adherence monitoring will be performed using a novel electronic adherence monitor developed to meet the unique needs of the target population. Adolescent and young adult patients as well as caregivers of younger patients (<11 years of age) will be recruited. In addition to visit incentives, all participants will be offered a smartphone with a data plan to ensure all participants have equal opportunity to complete study activities. The primary objectives of this pilot, multi-center, randomized controlled trial (RCT) are to assess retention and sustained engagement and to explore needs and preferences for longer-term adherence monitoring and interventions. This RCT is registered with the National Institutes of Health (NCT06264700). Findings will inform a future efficacy RCT applying VDOT to hydroxyurea to address adherence gaps and improve outcomes within this vulnerable population.

Effects of hydroxyurea on fertility in male and female sickle cell disease patients. A systemic review and meta-analysis

BACKGROUND

Evidence supports the benefits of hydroxyurea (HU) in adults with sickle cell disease (SCD), but reservations remain due to long-term concerns of fertility. Retrospective analysis of clinical records of SCD patients (haemoglobin SS genotype) have identified gender-related differences in disease progression. This could inform risk stratification during SCD at diagnosis with the possibility to guide therapeutic decisions.

METHODS

This systemic review and meta-analysis evaluated fertility parameters in both children (aged ≥ 6 years) and adults with SCD receiving HU therapy. Studies were sourced from PubMed and EMBASE from inception to July 2023. A total of 160 potentially relevant articles were identified.

RESULTS

Four studies were included that evaluated the effects of HU on sperm parameters in males. A further 4 studies assessed anti-mullerian hormone (AMH) levels and ovarian reserves in females. Differences from baseline values were used to identify compromised fertility. Amongst males, HU treatment negatively impacted the concentration of spermatozoa (MD = -15.48 million/mL; 95% CI: [-20.69, -10.26]; p< 0.001), which continued following treatment cessation (MD = -20.09 million/mL; 95% CI: [-38.78, -1.40]; P = 0.04). HU treatment also led to lower total sperm counts (MD = -105.87 million; 95% CI: [-140.61, -71.13]; P< 0.001) which persisted after treatment (MD = -53.05 million; 95% CI: [-104.96, -1.14]; P = 0.05). Sperm volume, initial forward motility and morphology were unaffected by HU treatment. In females, HU treatment decreased the mean AMH levels 1.83 (95% CI [1.42, 2.56]. A total of 18.2.% patients treated with HU showed reduced ovarian reserves.

INTERPRETATION & CONCLUSIONS

This systemic review and meta-analysis suggest that the use of HU for SCD impacts seminal fluid parameters in males and can diminish AMH levels and ovarian reserves in females.

Positive impacts of universal newborn screening on the outcome of children with sickle cell disease in the province of Quebec: A retrospective cohort study

A universal newborn screening program for sickle cell disease (uNS-SCD) was implemented in the province of Québec (Qc) in November 2013, close in time to the recommendation of early initiation of hydroxyurea (HU) therapy for children. This retrospective cohort study evaluated the impact of such a program on children first seen between January 2000 and December 2019. Cohorts pre-SCD-uNS in Qc (pre-QcNS) (n = 253) and post-QcNS (n = 157) for patients seen prior to or after Nov 2013 were compared. Kaplan-Meier curves, Poisson regression, and logistic regressions were used for statistical analysis, using Software R version 4.2.1. Median age at first visit decreased significantly from 14.4 [interquartile range: 2.4-72.0] to 1.2 months [1.2-57.6] (p < 0.001). The percentage of children born in Qc undiagnosed at birth and referred after a first SCD-related complication dropped from 42.6% to 0.0% (p < 0.0001). The median age of HU introduction for patients with SS/Sβ°-thalassemia decreased from 56.4 [31.2-96.0] to 9.0 months post-QcNS [8.0-12.1] (p < 0.001). Event-free survival improved significantly for any type of hospitalization as well as for vaso-occlusive crisis (VOC) (140-257 days (p < 0.001) and 1320 vs. 573 days (p < 0.002), respectively), resulting in a reduction from 2 [interquartile range: 1.0-3.0] to 1.0 hospitalizations/patient-year [0.6-1.4] (p < 0.001). Children with SS/Sβ°-thalassemia referred post-QcNS also had fewer emergency department visits for VOC (RR: 0.69, 95% confidence interval: 0.54-0.88). The Universal NS program allows early detection and referral of children with SCD to comprehensive care centers. Earlier access ensures that children benefit from essential preventive interventions, reducing disease burden. This cohort study highlights that uNS-SCD is an essential public health measure.

Transfusing children with sickle cell disease using blood group genotyping when the pool of Black donors is limited

BACKGROUND

Red blood cell transfusion is an effective treatment for patients with sickle cell disease (SCD). Alloimmunization can occur after a single transfusion, limiting further usage of blood transfusion. It is recommended to match for the ABO, D, C, E, and K antigens to reduce risks of alloimmunization. However, availability of compatible blood units can be challenging for blood providers with a limited number of Black donors.

STUDY DESIGN AND METHODS

A prospective cohort of 205 pediatric patients with SCD was genotyped for the RH and FY genes. Transfusion and alloimmunization history were collected. Our capacity to find RhCE-matched donors was evaluated using a database of genotyped donors.

RESULTS

Nearly 9.8% of patients carried a partial D variant and 5.9% were D-. Only 45.9% of RHCE alleles were normal, with the majority of variants affecting the RH5 (e) antigen. We found an alloimmunization prevalence of 20.7% and a Rh alloimmunization prevalence of 7.1%. Since Black donors represented only 1.40% of all blood donors in our province, D- Caucasian donors were mostly used to provide phenotype matched products. Compatible blood for patients with rare Rh variants was found only in Black donors. A donor with compatible RhCE could be identified for all patients.

CONCLUSION

Although Rh-compatible donors were identified, blood units might not be available when needed and/or the extended phenotype or ABO group might not match the patient. A greater effort has to be made for the recruitment of Black donors to accommodate patients with SCD.

Role of hydroxyurea therapy in the prevention of organ damage in sickle cell disease: a systematic review and meta-analysis

BACKGROUND

Hydroxyurea is an affordable drug that reduces vaso-occlusive crises and transfusion requirements in sickle cell disease. However, its effectiveness in preventing chronic organ damage is still unclear. This systematic review and meta-analysis aimed to evaluate the role of hydroxyurea in preventing organ morbidity.

METHOD

We included original articles published in English from 1st January 1990 to 31st January 2023, reporting hydroxyurea therapy and organ damage from PubMed, Google Scholar, Scopus, and CrossRef databases. A total of 45 studies with 4681 sickle cell disease patients were evaluated for organ damage.

RESULTS

Our analysis showed that hydroxyurea intervention significantly lowered transcranial Doppler and tricuspid regurgitant velocity, with a standardized mean difference of - 1.03 (- 1.49; - 0.58); I 2 = 96% and - 1.37 (CI - 2.31, - 0.42); I 2 = 94%, respectively. Moreover, the pooled estimate for albuminuria showed a beneficial effect post-hydroxyurea therapy by reducing the risk of albuminuria by 58% (risk ratio of 0.42 (0.28; 0.63); I 2 = 28%).

CONCLUSION

Our study found that a hydroxyurea dose above 20 mg/kg/day with a mean rise in HbF by 18.46% post-hydroxyurea therapy had a beneficial role in reducing transcranial doppler velocity, tricuspid regurgitant velocity, albuminuria, and splenic abnormality.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42023401187.

Sickle Cell Disease and CKD: An Update

BACKGROUND

Sickle cell disease is an inherited red blood cell disorder that affects approximately 100,000 people in the USA and 25 million people worldwide. Vaso-occlusion and chronic hemolysis lead to dysfunction of vital organ systems, with the kidneys being among the most commonly affected organs.

SUMMARY

Early renal manifestations include medullary ischemia with the loss of urine-concentrating ability and hyperfiltration. This can be followed by progressive damage characterized by persistent albuminuria and a decline in the estimated glomerular filtration rate. The risk of sickle nephropathy is greater in those with the APOL1 G1 and G2 kidney risk variants and variants in HMOX1 and lower in those that coinherit α-thalassemia. Therapies to treat sickle cell disease-related kidney damage focus on sickle cell disease-modifying therapies (e.g., hydroxyurea) or those adopted from the nonsickle cell disease kidney literature (e.g., renin-angiotensin-aldosterone system inhibitors), although data on their clinical efficacy are limited to small studies with short follow-up periods. Kidney transplantation for end-stage kidney disease improves survival compared to hemodialysis but is underutilized in this patient population.

KEY MESSAGES

Kidney disease is a major contributor to early mortality, and more research is needed to understand the pathophysiology and develop targeted therapies to improve kidney health in sickle cell disease.

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.

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 Critical Review of Sickle Cell Disease Burden and Challenges in Sub-Saharan Africa

Sickle cell disease is caused by an abnormality of the β-globin gene and is characterised by sickling of the red blood cells. Globally, sub-Saharan African countries share the highest burden of the disease. This study aimed at critically reviewing studies focusing on challenges of sickle cell anaemia in sub-Saharan Africa. A literature search was carried out in five major databases. Articles that met the inclusion criteria were included in the bibliometric review and critical analysis. A majority of the studies were undertaken in the West African region (85.5%), followed by Central Africa (9.1%). Very few studies had been undertaken in East Africa (3.6%), whilst the Southern African region had the fewest studies (1.8%). Distribution in relation to country revealed that three quarters of the studies were carried out in Nigeria (74.5%), followed by the Democratic Republic of the Congo (9.1%). According to healthcare settings, a strong majority of the studies were undertaken in tertiary health care facilities (92.7%). Major themes that emerged from the review include interventions, cost of treatment, and knowledge about sickle cell disease. Public health awareness and promotion as well as improving the quality of sickle cell centers for prompt management of patients with sickle cell disorder was identified as a critical strategy towards reducing the burden of the disease in sub-Saharan Africa. To achieve this, governments in countries located in this region need to adopt a proactive strategy in addressing gaps that have been identified in this study, as well as instituting other relevant measures, such as continuous media engagement and public health interventions relating to genetic counselling. Reforms in other areas that can help reduce the disease burden, include training of practitioners and equipping sickle cell disease treatment centers according to World Health Organization specifications.

Efficacy and safety of pharmacological interventions for managing sickle cell disease complications in children and adolescents: Systematic review with network meta-analysis

This study aimed to synthesize the evidence on the effects of disease-modifying agents for managing sickle cell disease (SCD) in children and adolescents by means of a systematic review with network meta-analyses, surface under the cumulative ranking curve (SUCRA) and stochastic multicriteria acceptability analyses (SMAA) (CRD42022328471). Eightteen randomized controlled trials (hydroxyurea [n = 7], l-arginine [n = 3], antiplatelets [n = 2], immunotherapy/monoclonal antibodies [n = 2], sulfates [n = 2], docosahexaenoic acid [n = 1], niprisan [n = 1]) were analyzed. SUCRA and SMAA demonstrated that hydroxyurea at higher doses (30 mg/kg/day) or at fixed doses (20 mg/kg/day) and immunotherapy/monoclonal antibodies are more effective for preventing vaso-occlusive crisis (i.e., lower probabilities of incidence of this event; 14, 25, and 30%, respectively), acute chest syndrome (probabilities ranging from 8 to 30%), and needing of transfusions (11-31%), while l-arginine (100-200 mg/kg) and placebo were more prone to these events. Therapies were overall considered safe; however, antiplatelets and sulfates may lead to more severe adverse events. Although the evidence was graded as insufficient and weak, hydroxyurea remains the standard of care for this population, especially if a maximum tolerated dose schedule is considered.

Higher hydroxyurea adherence among young adults with sickle cell disease compared to children and adolescents

BACKGROUND

Sickle cell disease (SCD) results in severe complications, such as anaemia and pain episodes. Hydroxyurea (HU) is efficacious in SCD, yet adherence remains low.

OBJECTIVE

To assess the relationship of HU adherence to health care utilization and patients' characteristics.

METHODS

This is a 5-year retrospective chart review. Patients' demographics and medical history were collected from the electronic medical record (EMR). HU adherence was evaluated using foetal haemoglobin "HbF%", mean corpuscular volume "MCV", and absolute neutrophil count "ANC". Age groups included children (<12 years), adolescents (12-17 years), and young adults (≥18 years).

RESULTS

A total of 113 SCD patients on HU were included (median age 14 years, IQR 10-20; 50% female; 88% HbSS). Young adults had significantly higher HU adherence compared to adolescents and children, including higher median HbF% (24.2 vs. 12.4 vs. 8.6, p = .003), MCV (fl) (106.4 vs. 96.2 vs. 95.4, p = .01) and lower ANC (10³/ml) (3.25 vs. 4.9 vs. 4.2, p = .01), respectively. Patients with chronic pain had lower HU adherence (HbF% 15.3 vs. 10.7, p = .04; ANC 3.6 vs. 6.3, p = .002; MCV 102.3 vs. 93.1, p = .1). Patients with higher HbF or MCV and lower ANC had significantly less frequent emergency room visits (r_s=-0.26, p = .01; r_s=-0.23, p = .01; r_s=0.24, p = .01) and hospitalizations (r_s=-0.27, p = .01; r_s=-0.31, p = .01; r_s=0.21, p = .02) as well as shorter length of stays (r_s=-0.27, p = .0045; r_s=-.34, p = 0.004; r_s=0.23, p = .02), respectively. Similar trends in HU adherence and health care utilization were seen in subgroup analysis of only HbSS patients. There was no significant association of HU adherence to patients' sex, socio-economic status, distance from hospital, and HU duration.

CONCLUSIONS

Young adults with SCD had significantly higher HU adherence compared to children and adolescents. Patients with lower HU adherence and/or chronic pain had increased health care utilization. Future studies examining barriers to adherence and evaluating interventions to optimize HU adherence in SCD are warranted.KEY MESSAGESYoung adults with SCD had significantly higher HU adherence, as reflected in their laboratory markers, compared to children and adolescents.Patients with higher HU adherence and/or those without chronic pain had lower or less frequent health care utilization.No significant association of HU adherence to patients' sex, socio-economic status and distance from hospital.

Incidence, kinetics, and risk factors for intra- and extracranial cerebral arteriopathies in a newborn sickle cell disease cohort early assessed by transcranial and cervical color Doppler ultrasound

The risk of stroke in children with sickle cell disease (SCD) is detected by abnormal intracranial arterial time-averaged mean of maximum velocities (TAMVs ≥200 cm/s). Recently, extracranial internal carotid artery (eICA) arteriopathy has been reported, and a cross-sectional study showed that eICA-TAMVs ≥160 cm/s are significantly associated with eICA kinkings and stenosis. The cumulative incidence of and predictive risk factors for intracranial arteriopathy are well described in sickle cell anemia (SCA=SS/Sβ0) but are lacking for SC/Sβ+ children, as is the cumulative incidence of eICA arteriopathy. We report a prospective longitudinal cohort study including 493 children with SCD (398 SCA, 95 SC/Sβ+), all assessed by transcranial and cervical color Doppler ultrasound. Cerebral MRI/MRA data were available in 375 children with SCD and neck MRA in 365 children. eICA kinkings were defined as eICA tortuosities on neck MRA, with an internal acute angle between the two adjacent segments <90°. The median follow-up was 10.6 years. The cumulative incidence of kinkings was significantly lower in SC/Sβ+ children than in children with SCA, and no SC/Sβ+ child developed intra- or extracranial stenotic arteriopathy. The 10-year KM estimate of cumulative incidence (95% CI) for eICA-TAMVs ≥160 cm/s revealed its development in the 2nd year of life in children with SCA, reaching a plateau of 17.4% (13.2–21.6%) by about 10 years of age, while the plateau for eICA stenosis was 12.3% (8.3–16.3%). eICA assessment identified 13.5% (9.3–17.7%) patients at risk of stroke who were not detected by transcranial color Doppler ultrasound. We also show, for the first time, that in addition to a congenital origin, eICA kinkings sin patients with SCD can develop progressively with aging as a function of eICA-TAMVs, themselves related to anemia severity. Ongoing hydroxyurea treatment was significantly associated with a lower risk of abnormal intracranial arteriopathy and eICA kinkings. After adjustment with hydroxyurea, baseline low hemoglobin, high reticulocyte, and WBC counts remained independent risk factors for intracranial arteriopathy, while low hemoglobin and SEN β-haplotype number were independent risk factors for extracranial arteriopathy. The association between extracranial arteriopathy and SEN β-haplotype number suggested a genetic link between the ethnic origin and incidence of eICA kinkings. This prospective cohort study shows the importance of systematically assessing the eICA and of recording biological parameters during the 2nd year of life before any intensive therapy to predict the risk of cerebral arteriopathy and treat patients with severe baseline anemia.

Hydroxyurea (hydroxycarbamide) for sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is one of the most common inherited diseases worldwide. It is associated with lifelong morbidity and a reduced life expectancy. Hydroxyurea (hydroxycarbamide), an oral chemotherapeutic drug, ameliorates some of the clinical problems of SCD, in particular that of pain, by raising foetal haemoglobin (HbF). This is an update of a previously published Cochrane Review.

OBJECTIVES

The aims of this review are to determine through a review of randomised or quasi-randomised studies whether the use of hydroxyurea in people with SCD alters the pattern of acute events, including pain; prevents, delays or reverses organ dysfunction; alters mortality and quality of life; or is associated with adverse effects. In addition, we hoped to assess whether the response to hydroxyurea in SCD varies with the type of SCD, age of the individual, duration and dose of treatment, and healthcare setting.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Haemoglobinopathies Register, comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also searched online trial registries. The date of the most recent search was 17 February 2022.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials (RCTs and quasi-RCTs), of one month or longer, comparing hydroxyurea with placebo or standard therapy in people  with SCD.

DATA COLLECTION AND ANALYSIS

Authors independently assessed studies for inclusion, carried out data extraction, assessed the risk of bias and assessed the quality of the evidence using GRADE.

MAIN RESULTS

We included nine RCTs recruiting 1104 adults and children with SCD (haemoglobin SS (HbSS), haemoglobin SC (HbSC) or haemoglobin Sβºthalassaemia (HbSβºthal) genotypes). Studies lasted from six to 30 months. We judged the quality of the evidence for the first two comparisons below as moderate to low as the studies contributing to these comparisons were mostly large and well-designed (and at low risk of bias); however, the evidence was limited and imprecise for some outcomes such as quality of life, deaths during the studies and adverse events, and the results are applicable only to individuals with HbSS and HbSβºthal genotypes. We judged the quality of the evidence for the third and fourth comparisons to be very low due to the limited number of participants, the lack of statistical power (both studies were terminated early with approximately only 20% of their target sample size recruited) and the lack of applicability to all age groups and genotypes. Hydroxyurea versus placebo Five studies (784 adults and children with HbSS or HbSβºthal) compared hydroxyurea to placebo; four recruited individuals with only severe disease and one recruited individuals with all disease severities. Hydroxyurea probably improves pain alteration (using measures such as pain crisis frequency, duration, intensity, hospital admissions and opoid use) and life-threatening illness, but we found no difference in death rates (10 deaths occurred during the studies, but the rates did not differ by treatment group) (all moderate-quality evidence). Hydroxyurea may improve measures of HbF (low-quality evidence) and probably decreases neutrophil counts (moderate-quality evidence). There were no consistent differences in terms of quality of life and adverse events (including serious or life-threatening events) (low-quality evidence). There were fewer occurrences of acute chest syndrome and blood transfusions in the hydroxyurea groups.  Hydroxyurea and phlebotomy versus transfusion and chelation Two studies (254 children with HbSS or HbSβºthal also with risk of primary or secondary stroke) contributed to this comparison. There were no consistent differences in terms of pain alteration, death or adverse events (low-quality evidence) or life-threatening illness (moderate-quality evidence). Hydroxyurea with phlebotomy probably increased HbF and decreased neutrophil counts (moderate-quality evidence), but there were more occurrences of acute chest syndrome and infections. Quality of life was not reported. In the primary prevention study, no strokes occurred in either treatment group but in the secondary prevention study, seven strokes occurred in the hydroxyurea and phlebotomy group (none in the transfusion and chelation group) and the study was terminated early.  Hydroxyurea versus observation One study (22 children with HbSS or HbSβºthal also at risk of stoke) compared hydroxyurea to observation. Pain alteration and quality of life were not reported. There were no differences in life-threatening illness, death (no deaths reported in either group) or adverse events (very low-quality evidence). We are uncertain if hydroxyurea improves HbF or decreases neutrophil counts (very low-quality evidence). Treatment regimens with and without hydroxyurea One study (44 adults and children with HbSC) compared treatment regimens with and without hydroxyurea. Pain alteration, life-threatening illness and quality of life were not reported. There were no differences in death rates (no deaths reported in either group), adverse events or neutrophil levels (very low-quality evidence). We are uncertain if hydroxyurea improves HbF (very low-quality evidence).

AUTHORS' CONCLUSIONS

There is evidence to suggest that hydroxyurea may be effective in decreasing the frequency of pain episodes and other acute complications in adults and children with sickle cell anaemia of HbSS or HbSβºthal genotypes and in preventing life-threatening neurological events in those with sickle cell anaemia at risk of primary stroke by maintaining transcranial Doppler velocities. However, there is still insufficient evidence on the long-term benefits of hydroxyurea, particularly with regard to preventing chronic complications of SCD, or recommending a standard dose or dose escalation to maximum tolerated dose. There is also insufficient evidence about the long-term risks of hydroxyurea, including its effects on fertility and reproduction. Evidence is also limited on the effects of hydroxyurea on individuals with the HbSC genotype. Future studies should be designed to address such uncertainties.

Advanced Clinical Parameters: a complementary hydroxyurea adherence evaluation in sickle cell anemia treatment

OBJECTIVES

Given the complex pathology of sickle cell anemia (SCA) and low adherence to Hydroxyurea (HU) treatment, there is a need to seek parameters that identify recent changes in patient status. The Advanced Clinical Parameters (ACPs) allow an early analysis of hematopoiesis. We aimed to draw the demographic profile of non-adherent SCA patients and to verify the use of ACPs as a measure of HU treatment adherence.

METHOD

In a cross-sectional study, we divided 83 SCA subjects treated with HU into Children (<12 years old) and Adolescents/Adults (≥12 years old). Their haemogram with the ACPs, electronic medical charts and pharmacy claim data were analyzed.

RESULTS

Non-adherent ≥12 years old patients had significantly increased WBC, absolute neutrophil, lymphocyte, monocyte, and basophil counts, RBC, RET, RDW, and PLT, and significantly decreased MCV and MCH. Subjects in the Adolescent/Adult group with IG† ≥0.035 cells/mm³ had the RR for non-adherence increased by 4.6 times (p=0.014), and the systemic immune inflammation index (SII) of non-adherent patients was also significantly higher (p=0.042).

CONCLUSION

IG† presents clinical utility in early identification of non-adherence to HU, especially when combined with other parameters, suggesting the evaluation of ACPs in laboratory routine, as they can be easily implemented. This article is protected by copyright. All rights reserved.

Barriers to hydroxyurea use from the perspectives of providers, individuals with sickle cell disease, and families: Report from a U.S. regional collaborative

Sickle cell disease (SCD) is an inherited blood disorder that affects about 100,000 people in the U.S., primarily Blacks/African-Americans. A multitude of complications negatively impacts quality of life. Hydroxyurea has been FDA approved since 1998 as a disease-modifying therapy for SCD, but is underutilized. Negative and uninformed perceptions of hydroxyurea and barriers to its use hinder adherence and promotion of the medication. As the largest real-world study to date that assessed hydroxyurea use for children and adults with SCD, we gathered and analyzed perspectives of providers, individuals with SCD, and families. Participants provided information about socio-demographics, hospital and emergency admissions for pain, number of severe pain episodes interfering with daily activities, medication adherence, and barriers to hydroxyurea. Providers reported on indications for hydroxyurea, reasons not prescribed, and current laboratory values. We found that hydroxyurea use was reported in over half of eligible patients from this large geographic region in the U.S., representing a range of sickle cell specialty clinical settings and practices. Provider and patient/caregiver reports about hydroxyurea use were consistent with one another; adults 26 years and older were least likely to be on hydroxyurea; and the likelihood of being on hydroxyurea decreased with one or more barriers. Using the intentional and unintentional medication nonadherence framework, we found that, even for patients on hydroxyurea, challenges to taking the medicine at the right time and forgetting were crucial unintentional barriers to adherence. Intentional barriers such as worry about side effects and “tried and it did not work” were important barriers for young adults and adults. For providers, diagnoses other than HgbSS or HgbS-β0 thalassemia were associated with lower odds of prescribing, consistent with evidence-based guidelines. Our results support strengthening provider understanding and confidence in implementing existing SCD guidelines, and the importance of shared decision making. Our findings can assist providers in understanding choices and decisions of families; guide individualized clinical discussions regarding hydroxyurea therapy; and help with developing tailored interventions to address barriers. Addressing barriers to hydroxyurea use can inform strategies to minimize similar barriers in the use of emerging and combination therapies for SCD.

How Hydroxyurea Alters the Gut Microbiome: A Longitudinal Study Involving Angolan Children with Sickle Cell Anemia

Sickle cell anemia (SCA) is an inherited hematological disorder and a serious global health problem, especially in Sub-Saharan Africa. Although hydroxyurea (HU) is the leading treatment for patients with SCA, its effects on the gut microbiome have not yet been explored. In this context, the aim of this study was to investigate this association by characterizing the gut microbiome of an Angolan SCA pediatric population before and after 6 months of HU treatment. A total of 66 stool samples were obtained and sequenced for the 16S rRNA gene (V3-V4 regions). Significant associations were observed in alpha and beta-diversity, with higher values of species richness for the children naïve for HU. We also noticed that children after HU had higher proportions of several beneficial bacteria, mostly short-chain fatty acids (SCFAs) producing species, such as Blautia luti, Roseburia inulinivorans, Eubacterium halli, Faecalibacterium, Ruminococcus, Lactobacillus rogosae, among others. In addition, before HU there was a higher abundance of Clostridium_g24, which includes C. bolteae and C. clostridioforme, both considered pathogenic. This study provides the first evidence of the HU effect on the gut microbiome and unravels several microorganisms that could be considered candidate biomarkers for disease severity and HU efficacy.

Sickle Cell Disease: A Review

IMPORTANCE

Sickle cell disease (SCD) is an inherited disorder of hemoglobin, characterized by formation of long chains of hemoglobin when deoxygenated within capillary beds, resulting in sickle-shaped red blood cells, progressive multiorgan damage, and increased mortality. An estimated 300 000 infants are born annually worldwide with SCD. Most individuals with SCD live in sub-Saharan Africa, India, the Mediterranean, and Middle East; approximately 100 000 individuals with SCD live in the US.

OBSERVATIONS

SCD is diagnosed through newborn screening programs, where available, or when patients present with unexplained severe atraumatic pain or normocytic anemia. In SCD, sickling and hemolysis of red blood cells result in vaso-occlusion with associated ischemia. SCD is characterized by repeated episodes of severe acute pain and acute chest syndrome, and by other complications including stroke, chronic pain, nephropathy, retinopathy, avascular necrosis, priapism, and leg ulcers. In the US, nearly all children with SCD survive to adulthood, but average life expectancy remains 20 years less than the general population, with higher mortality as individuals transition from pediatric to adult-focused health care systems. Until 2017, hydroxyurea, which increases fetal hemoglobin and reduces red blood cell sickling, was the only disease-modifying therapy available for SCD and remains first-line therapy for most individuals with SCD. Three additional therapies, L-glutamine, crizanlizumab, and voxelotor, have been approved as adjunctive or second-line agents. In clinical trials, L-glutamine reduced hospitalization rates by 33% and mean length of stay from 11 to 7 days compared with placebo. Crizanlizumab reduced pain crises from 2.98 to 1.63 per year compared with placebo. Voxelotor increased hemoglobin by at least 1 g/dL, significantly more than placebo (51% vs 7%). Hematopoietic stem cell transplant is the only curative therapy, but it is limited by donor availability, with best results seen in children with a matched sibling donor. While SCD is characterized by acute and chronic pain, patients are not more likely to develop addiction to pain medications than the general population.

CONCLUSIONS AND RELEVANCE

In the US, approximately 100 000 people have SCD, which is characterized by hemolytic anemia, acute and chronic pain, acute chest syndrome; increased incidence of stroke, nephropathy, and retinopathy; and a life span that is 20 years shorter than the general population. While hydroxyurea is first-line therapy for SCD, L-glutamine, crizanlizumab, and voxelotor have been approved in the US since 2017 as adjunctive or second-line treatments, and hematopoietic stem cell transplant with a matched sibling donor is now standard care for severe disease.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Predictors of Recurrent Acute Chest Syndrome in Pediatric Sickle Cell Disease: A Retrospective Case-Control Study

Acute chest syndrome (ACS) is a common cause of death in sickle cell disease (SCD) patients. Multiple studies investigated the risk factors of developing ACS; however, predictors of recurrent ACS episodes have not been thoroughly investigated. We aim to examine the clinical and laboratory predictors of recurrent ACS in pediatric patients with SCD. A retrospective case-control study included pediatric patients with SCD (˂14 years) admitted with ACS or developed ACS during admission for another indication. Patients were classified into recurrent ACS episodes (≥2 episodes) and a single ACS episode groups. Ninety-one ACS episodes (42 patients) were included, with a mean age at diagnosis of 7.18 ± 3.38 years. Twenty-two (52.4%) patients were male, and twenty-five (59.5%) patients had recurrent ACS. Younger age at first ACS was significantly associated with recurrence (p = 0.003), with an optimal cutoff at 7.5 years (area under the receiver operating characteristic curve [AUROC] = 0.833; p < 0.001). Higher SCD-related hospitalizations were significantly associated with recurrence (p = 0.038). Higher mean values of baseline white blood count (WBC) (p = 0.009), mean corpuscular volume (MCV) (p = 0.011), and reticulocyte (p = 0.036) were significantly associated with recurrence. Contrarily, lower baseline hematocrit values (p = 0.016) were significantly associated with recurrence. The ACS frequencies were significantly lower after hydroxyurea (p = 0.021). The odds of ACS recurrence increased with a positive C-reactive protein (CRP) at admission (p = 0.006). In conclusion, several baseline and admission laboratory data showed significant associations with recurrence. Hydroxyurea therapy demonstrated reduced ACS episodes.

In-Depth Immunological Typization of Children with Sickle Cell Disease: A Preliminary Insight into Its Plausible Correlation with Clinical Course and Hydroxyurea Therapy

Sickle cell disease (SCD) is a condition of functional hypo-/a-splenism in which predisposition to bacterial infections is only a facet of a wide spectrum of immune-dysregulation disorders forming the clinical expression of a peculiar immunophenotype. The objective of this study was to perform an in-depth immunophenotypical characterization of SCD pediatric patients, looking for plausible correlations between immunological biomarkers, the impact of hydroxyurea (HU) treatment and clinical course. This was an observational case−control study including 43 patients. The cohort was divided into two main groups, SCD subjects (19/43) and controls (24/43), differing in the presence/absence of an SCD diagnosis. The SCD group was split up into HU+ (12/19) and HU− (7/19) subgroups, respectively receiving or not a concomitant HU treatment. The principal outcomes measured were differences in the immunophenotyping between SCD patients and controls through chi-squared tests, t-tests, and Pearson’s correlation analysis between clinical and immunological parameters. Leukocyte and neutrophil increase, T-cell depletion with prevalence of memory T-cell compartment, NK and B-naïve subset elevation with memory and CD21low B subset reduction, and IgG expansion, significantly distinguished the SCD HU− subgroup from controls, with naïve T cells, switched-memory B cells and IgG maintaining differences between the SCD HU+ group and controls (p-value of <0.05). The mean CD4+ central-memory T-cell% count was the single independent variable showing a positive correlation with vaso-occlusive crisis score in the SCD group (Pearson’s R = 0.039). We report preliminary data assessing plausible clinical implications of baseline and HU-related SCD immunophenotypical alterations, which need to be validated in larger samples, but potentially affecting hypo-/a-splenism immuno-chemoprophylactic recommendations.

Mathematical Modeling of Hydroxyurea Therapy in Individuals with Sickle Cell Disease

Sickle cell disease (SCD) is a chronic hemolytic anemia affecting millions worldwide with acute and chronic clinical manifestations and early mortality. While hydroxyurea (HU) and other treatment strategies managed to ameliorate disease severity, high inter-individual variability in clinical response and a lack of an ability to predict those variations need to be addressed to maximize the clinical efficacy of HU. We developed pharmacokinetics (PK) and pharmacodynamics (PD) models to study the dosing, efficacy, toxicity, and clinical response of HU treatment in more than eighty children with SCD. The clinical PK parameters were used to model the HU plasma concentration for a 24 h period, and the estimated daily average HU plasma concentration was used as an input to our PD models with approximately 1 to 9 years of data connecting drug exposure with drug response. We modeled the biomarkers mean cell volume and fetal hemoglobin to study treatment efficacy. For myelosuppression, we modeled red blood cells and absolute neutrophil count. Our models provided excellent fits for individuals with known or correctly inferred adherence. Our models can be used to determine the optimal dosing regimens and study the effect of non-adherence on HU-treated individuals.

Considerations When Aggregating Data to Measure Performance Across Levels of the Health Care System

BACKGROUND

Measuring quality at varying levels of the health care system requires attribution, a process of determining the patients and services for which each level is responsible. However, it is important to ensure that attribution approaches are equitable; otherwise, individuals may be assigned differentially based upon social determinants of health.

METHODS

First, we used Medicaid claims (2010-2018) from Michigan to assess the proportion of children with sickle cell anemia who had less than 12 months enrollment within a single Medicaid health plan and could therefore not be attributed to a specific health plan. Second, we used the Medicaid Analytic eXtract data (2008-2009) from 26 states to simulate adapting the 30-Day Pediatric All-Condition Readmission measure to the Accountable Care Organization (ACO) level and examined the proportion of readmissions that could not be attributed.

RESULTS

For the sickle cell measure, an average of 300 children with sickle cell anemia were enrolled in Michigan Medicaid each year. The proportion of children that could not be attributed to a Medicaid health plan ranged from 12.2% to 89.0% across years. For the readmissions measure, of the 1,051,365 index admissions, 22% were excluded in the ACO-level analysis because of being unable to attribute the patient to a health plan for the 30 days post discharge.

CONCLUSIONS

When applying attribution models, it is essential to consider the potential to induce health disparities. Differential attribution may have unintentional consequences that deepen health disparities, particularly when considering incentive programs for health plans to improve the quality of care.

La prévention et la prise en charge des complications aiguës de l'anémie falciforme

L'anémie falciforme est une maladie multisystémique chronique qui exige des soins globaux. La falciformation des globules rouges entraîne une hémolyse et une occlusion vasculaire. L'anémie hémolytique, les syndromes douloureux et les atteintes organiques en sont des complications. En raison des profils d'immigration et d'une augmentation du dépistage néonatal, les professionnels de la santé pédiatrique du Canada doivent connaître l'anémie falciforme, tant dans les petits que les grands centres. Le présent document de principes porte sur les principes de prévention, de défense d'intérêts et de traitement rapide des complications aiguës courantes de l'anémie falciforme. Les lignes directrices comprennent l'état actuel du dépistage néonatal, les recommandations en matière de vaccination et de prophylaxie antibiotique et une introduction à l'hydroxyurée, un médicament qui réduit à la fois la morbidité et la mortalité chez les enfants atteints d'anémie falciforme. Des scénarios cliniques démontrent les principes de soins en cas de complications aiguës courantes : les épisodes vaso-occlusifs, le syndrome thoracique aigu, la fièvre, la séquestration splénique, les crises aplasiques et les accidents vasculaires cérébraux. Enfin, les principes de transfusion sanguine sont présentés, de même que les indications de transfusion simple ou d'exsanguinotransfusion.

Acute complications in children with sickle cell disease: Prevention and management

Sickle cell disease (SCD) is a chronic, multi-system disease that requires comprehensive care. The sickling of red blood cells leads to hemolysis and vascular occlusion. Complications include hemolytic anemia, pain syndromes, and organ damage. Patterns of immigration and an increase in newborn screening mean that paediatric health care providers across Canada, in small and large centres alike, need to be knowledgeable about SCD. This statement focuses on principles of prevention, advocacy, and the rapid treatment of common acute complications. Guidance includes the current status of newborn screening, recommendations for immunizations and antibiotic prophylaxis, and an introduction to hydroxyurea, a medication that reduces both morbidity and mortality in children with SCD. Case vignettes demonstrate principles of care for common acute complications of SCD: vaso-occlusive episodes (VOE), acute chest syndrome (ACS), fever, splenic sequestration, aplastic crises, and stroke. Finally, principles of blood transfusion are highlighted, along with indications for both straight and exchange blood transfusions.

Incorporation of novel therapies for the management of sickle cell disease: A pharmacist's perspective

Patients with sickle cell disease (SCD) experience significant disease-related morbidity including multiorgan damage, chronic anemia, and debilitating pain crises. While hydroxyurea has been the primary disease modifying modality in SCD, novel therapies with unique mechanism of action have recently been approved. This review article examines the evidence surrounding the available SCD therapies to guide pharmacists on potential treatment selection and management strategies for patients with SCD. A systematic search of online databases was performed to identify literature on the management of SCD. While the newly approved novel agents have demonstrated clinical benefit it remains unclear how these agents fit into the treatment paradigm. Pharmacists should be aware of the data supporting the use of these novel agents to optimize use on a patient-specific basis.

Development and Validation of the Patient/Caregiver Reported Hydroxyurea Evaluation of Adherence for Life (HEAL) Scale

INTRODUCTION

Hydroxyurea reduces the incidence of vaso-occlusive episodes, stroke, and respiratory, cardiac, and renal damage in sickle cell disease by increasing fetal hemoglobin. However, because suboptimal adherence to hydroxyurea limits its effectiveness, understanding patient-specific barriers to hydroxyurea adherence could help improve adherence and health outcomes in patients with sickle cell disease. The aim of this single-site, prospective, IRB-approved study was to validate a 24-item patient- and caregiver-reported hydroxyurea treatment adherence questionnaire, the Hydroxyurea Evaluation of Adherence for Life (HEAL) scale.

METHODS

A sample of 24 adults with sickle cell disease and 16 caregivers of children with sickle cell disease completed the HEAL scale, and a subset of the original sample provided a second HEAL scale for test-retest reliability. HEAL scale results were validated against global adherence ratings from participants and health-care providers, records of access to pill bottles, and laboratory values for fetal hemoglobin and absolute neutrophil count.

RESULTS AND DISCUSSION

Results demonstrated excellent internal consistency for the HEAL Total score and eight (3-item) subscale scores (Dose, Remember, Plan, Cost, Understand, Effectiveness, Laboratory, and Pharmacy), as well as strong test-retest reliability for all HEAL scores except the Cost subscale. HEAL Total scores correlated significantly with validity measures, including global adherence ratings and lab values. The HEAL scale offers significant clinical potential for understanding adherence in individual sickle cell disease patients and significant research potential for characterizing adherence in persons with sickle cell disease who are treated with hydroxyurea.

Influenza vaccination rates and hospitalizations among Medicaid enrollees with and without sickle cell disease, 2009-2015

BACKGROUND

Personswith sickle cell disease (SCD) face increased risks for pulmonary and infection-related complications. This study examines influenza vaccination coverage and estimates influenza-related morbidity among Medicaid enrollees with and without SCD.

PROCEDURE

Influenza vaccination coverage and hospitalizations related to influenza and pneumonia/acute chest syndrome (ACS) during each influenza season from 2009-2010 to 2014-2015 were assessed among enrollees in the IBM MarketScan® Multi-State Medicaid Database. Enrollees with SCD were identified as enrollees with greater than or equal to three claims listing SCD within a 5-year period during 2003-2017. Vaccinations were identified in outpatient claims. Hospitalizations associated with influenza or pneumonia/ACS were identified using inpatient claims. This study includes a series of cross-sectional assessments by season.

RESULTS

From 2009-2010 through 2014-2015 seasons, the SCD sample ranged from 5044 to 8651 enrollees; the non-SCD sample ranged from 1,841,756 to 3,796,337 enrollees. Influenza vaccination coverage was higher among enrollees with SCD compared with enrollees without SCD for all seasons (24.5%-33.6% and 18.2%-22.0%, respectively). Age-standardized rates of influenza-related hospitalizations were 20-42 times higher among SCD enrollees compared with non-SCD enrollees, and ACS/pneumonia hospitalizations were 18-29 times higher. Among enrollees with SCD, influenza-related hospitalization rates were highest among children aged 0-9 years. Among enrollees without SCD, influenza-related hospitalization rates were highest among adults aged 40-64 years.

CONCLUSIONS

Although vaccine coverage was higher in persons with versus without SCD, efforts to increase influenza coverage further are warranted for this high-risk group, who experienced markedly higher rates of influenza and ACS/pneumonia hospitalizations during each season.

Analyzing Effects of Sickle Cell Disease on Morphometric and Cranial Growth in Indian Population

BACKGROUND

Sickle cell disease is the most pervasive autosomal recessive hereditary blood diseases and is characterized by the presence of sickle hemoglobin (HbS), which in turn gives rise to pathophysiological consequences. This HbS reduces the agility of erythrocytes plummeting their ability to pass through small vascular channels, which in turn results in increased blood viscosity and congestion of vascular beds, causing ischemia, local infarction, and hemolysis.

OBJECTIVES

The current study was conducted to carry out the morphometric analysis in patients with sickle cell disease.

MATERIALS AND METHODS

This study was conducted on 75 subjects detected with sickle cell disease aged between 8 and 16.5 years. The study involved 38 males and 37 females. All the subjects were subjected to lateral cephalogram for the calculation of various angular and linear dimensions of the craniofacial structures. The linear measurements made were nasion-menton height, anterior nasal spine (ANS)-menton height, and nasion-ANS height, whereas the angular measurements made were Frankfurt mandibular plane angle, Frankfort mandibular incisor angle, and incisor mandibular plane angle.

RESULTS

Major chunk of the subjects had retruded mandible and vertical growth pattern. Few subjects exhibited with maxillary protrusion.

CONCLUSION

It is concluded that early diagnosis and management of dental malocclusion in patients with sickle cell disease plays a pivotal role in an attempt to endow with a better quality of life to these individuals.

Benefits of a Disease Management Program for Sickle Cell Disease in Germany 2011-2019: The Increased Use of Hydroxyurea Correlates with a Reduced Frequency of Acute Chest Syndrome

Sickle Cell Disease (SCD) is the most common monogenic disorder globally but qualifies as a rare disease in Germany. In 2012, the German Society for Paediatric Oncology and Haematology (GPOH) mandated a consortium of five university hospitals to develop a disease management program for patients with SCD. Besides other activities, this consortium issued treatment guidelines for SCD that strongly favour the use of hydroxyurea and propagated these guidelines in physician and patient education events. In order to quantify the effect of these recommendations, we made use of claims data that were collected by the research institute (WIdO) of the major German insurance company, the Allgemeine Ortskrankenkasse (AOK), and of publicly accessible data collected by the Federal Statistical Office (Statistisches Bundesamt, Destatis). While the number of patients with SCD in Germany increased from approximately 2200 in 2011 to approximately 3200 in 2019, important components of the recently issued treatment guidelines have been largely implemented. Specifically, the use of hydroxyurea has more than doubled, resulting in a proportion of approximately 44% of all patients with SCD being treated with hydroxyurea in 2019. In strong negative correlation with the use of hydroxyurea, the frequency of acute chest syndromes decreased. Similarly, the proportion of patients who required analgesics and hospitals admissions declined. In sum, these data demonstrate an association between the dissemination of treatment guidelines and changes in clinical practice. The close temporal relationship between the increased use of hydroxyurea and the reduction in the incidence of acute chest syndrome in a representative population-based analysis implies that these changes in clinical practice contributed to an improvement in key measures of disease activity.

American Society of Hematology 2021 guidelines for sickle cell disease: stem cell transplantation

BACKGROUND

Sickle cell disease (SCD) is a life-limiting inherited hemoglobinopathy that results in significant complications and affects quality of life. Hematopoietic stem cell transplantation (HSCT) is currently the only curative intervention for SCD; however, guidelines are needed to inform how to apply HSCT in clinical practice.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and health professionals in their decisions about HSCT for SCD.

METHODS

The multidisciplinary guideline panel formed by ASH included 2 patient representatives and was balanced to minimize potential bias from conflicts of interest. The Mayo Evidence-Based Practice Research Program supported the guideline development process, including performing systematic evidence reviews (through 2019). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE Evidence-to-Decision frameworks, to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 8 recommendations to help patients and providers assess how individuals with SCD should consider the timing and type of HSCT.

CONCLUSIONS

The evidence review yielded no randomized controlled clinical trials for HSCT in SCD; therefore, all recommendations are based on very low certainty in the evidence. Key recommendations include considering HSCT for those with neurologic injury or recurrent acute chest syndrome at an early age and to improve nonmyeloablative regimens. Future research should include the development of a robust SCD registry to serve as a comparator for HSCT studies.

American Society of Hematology 2021 guidelines for sickle cell disease: stem cell transplantation

BACKGROUND

Sickle cell disease (SCD) is a life-limiting inherited hemoglobinopathy that results in significant complications and affects quality of life. Hematopoietic stem cell transplantation (HSCT) is currently the only curative intervention for SCD; however, guidelines are needed to inform how to apply HSCT in clinical practice.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and health professionals in their decisions about HSCT for SCD.

METHODS

The multidisciplinary guideline panel formed by ASH included 2 patient representatives and was balanced to minimize potential bias from conflicts of interest. The Mayo Evidence-Based Practice Research Program supported the guideline development process, including performing systematic evidence reviews (through 2019). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE Evidence-to-Decision frameworks, to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 8 recommendations to help patients and providers assess how individuals with SCD should consider the timing and type of HSCT.

CONCLUSIONS

The evidence review yielded no randomized controlled clinical trials for HSCT in SCD; therefore, all recommendations are based on very low certainty in the evidence. Key recommendations include considering HSCT for those with neurologic injury or recurrent acute chest syndrome at an early age and to improve nonmyeloablative regimens. Future research should include the development of a robust SCD registry to serve as a comparator for HSCT studies.

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

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

Hydroxycarbamide treatment reduces transcranial Doppler velocity in the absence of transfusion support in children with sickle cell anaemia, elevated transcranial Doppler velocity, and cerebral vasculopathy: the EXTEND trial

EXpanding Treatment for Existing Neurological Disease (EXTEND) investigated whether hydroxycarbamide lowers transcranial Doppler (TCD) velocities in Jamaican children with sickle cell anaemia (SCA) and elevated TCD velocity with or without previous stroke. Forty-three children (age 2-17 years) with baseline maximum time-averaged mean velocity (TAMV) ≥ 170 cm/s were stratified into three risk categories based on treatment status and stroke history: Group 1 (no history of stroke, on hydroxycarbamide, n = 12); and Groups 2 (no stroke, no hydroxycarbamide, n = 21) and 3 (previous stroke, no hydroxycarbamide, n = 10). Open-label hydroxycarbamide at 20 mg/kg/day was commenced, with escalation to maximum tolerated dose (MTD) based on mild marrow suppression (average dose 25·4 ± 4·5 mg/kg/day). TCD was performed every six months with brain magnetic resonance imaging (MRI)/magnetic resonance angiography (MRA) at baseline and after 18-months of hydroxycarbamide. The maximum TAMV decreased significantly compared to baseline (24 ± 30 cm/s, P < 0·0001), with similar declines in all groups. Clinical stroke occurred in five children, one in Group 1, none in Group 2, and four in Group 3, P = 0·0032, comparing group incidence rates. Brain MRI/MRA was stable in children without clinical stroke. EXTEND documents the feasibility and benefits of hydroxycarbamide at MTD to lower TCD velocities and reduce stroke risk in children with SCA and no history of primary stroke in low-resource settings without transfusion management.

Effect of hydroxyurea exposure before puberty on sperm parameters in males with sickle cell disease

Sperm parameters are known to be impaired in men with sickle cell disease (SCD). Although treatment with hydroxyurea (HU) has an impact on sperm quality, sperm preservation is impossible before puberty. This study's primary objective was to analyze and compare sperm parameters in male patients with SCD exposed (or not) to HU before puberty. Twenty-six sperm samples from 15 patients (median age, 17 years; range, 16-23) treated with HU during childhood were compared with 46 samples from 23 HU-naïve patients (20 years; 16-24). The median age at HU initiation was 6 years (1-14 years), the median duration of HU treatment was 4 years (0.5-10), and the mean dose of HU was 22.4 ± 3.7 mg/kg per day. Although we observed substantial quantitative and qualitative semen abnormalities in all patients, there were no significant differences in semen volume, sperm concentration, total sperm count, or spermatozoa motility, morphology, and vitality between the HU-exposed and HU-naïve groups. At the time of the semen analysis, 100% of the patients in the HU-exposed group and 52% of the patients in the HU-naïve group received transfusion therapy. The specific effect of HU on spermatogenesis in very young infants and the putative value of transfusion for reversing the toxicity of HU warrant further investigation.

Level of utilization and provider-related barriers to the use of hydroxyurea in the treatment of sickle cell disease patients in Jos, North-Central Nigeria

BACKGROUND

Hydroxyurea is underutilized by sickle cell health-care providers in Nigeria despite available evidence of its effectiveness in reducing the manifestations and complications of sickle cell disease (SCD).

OBJECTIVES

To assess the level of utilization and provider-related barriers to the use of hydroxyurea in SCD therapy in Jos, Nigeria.

METHODS

A cross-sectional study conducted among 132 medical doctors providing care for SCD patients. Data on sociodemographics, utilization and barriers to hydroxyurea use were obtained. The barriers were fed cumulatively into the logistic regression model as predictors of utilization.

RESULTS

Of the 132 care providers, 88 (67%) had been in medical practice for ≥6years. The level of utilization of hydroxyurea was 24.2%. The significant barriers that predicted the non-utilization of hydroxyurea included lack of expertise (OR=5.1; 95% CI=2.65-9.05), lack of clinical guidelines (OR=3.84; 95% CI=2.37-14.33), fear of side-effects (OR=0.50; 95% CI=0.22-0.68) and doubt about its effectiveness (OR=0.30; 95% CI=0.20-0.90).

CONCLUSION

The level of utilization of hydroxyurea in the treatment of SCD among the care providers is sub-optimal with the lack of expertise in its use identified as the most prominent barrier. There is an urgent need for the training of sickle cell care-providers and the development of clinical guidelines on hydroxyurea use.

Management of sickle cell disease: current practices and challenges in a northeastern region of the Democratic Republic of the Congo

BACKGROUND

The Democratic Republic of the Congo (DRC) is the third most affected country worldwide by sickle cell disease (SCD). However, this disease is still orphaned in the country; large-scale control actions are rare, and little is known about its management.

OBJECTIVE

To assess current practices in the management of SCD in Kisangani, DRC.

METHODS

This cross-sectional study was conducted in six health facilities in Kisangani. It involved 198 presumed sickle cell patients attending the above health facilities. The study focused on the sociodemographic and clinical data of the participants, obtained through a clinical examination and their medical records. Diagnostic confirmation of SCD was made by high-performance liquid chromatography coupled to mass spectrometry. Data were analyzed using SPSS 20.0.

RESULTS

The diagnosis of SCD was confirmed in 194 (98.0%; 95% CI: 94.9-99.2) participants, while it was not confirmed in 4 (2.0%; 95% CI: 0.8-5.1) participants. The diagnosis was mainly made by the Emmel test (42.9%). 45.8% of participants had previously been transfused with the blood of their parents. Folic acid was taken by 48.5% of participants and the previous intake of hydroxyurea was reported in 5.1% of participants. The participants vaccinated against Pneumococcus were 13.6% and against Haemophilus influenzae type b 28.3%. Penicillin prophylaxis was received by only 1.5% and malaria prophylaxis by 11.6% of participants.

CONCLUSION

Standard-care practices for SCD patients in Kisangani are insufficient. The Congolese government should regard this disease as a health priority and consider actions to improve its management.

Nephrotic syndrome on sickle cell disease: the impact of Hydroxyurea

Nephropathy is a common under-recognised complication of sickle cell disease (SCD) and one of the main factors of poor prognosis in these patients. The association between nephrotic syndrome and SCD in children is rare. Strategies for sickle cell nephropathy prevention are still poorly established. Blood pressure control as well as monitoring of microalbuminuria and renal function are mandatory. The use of antiproteinuric drugs, such as anti-ACE inhibitors (ACEis) and hydroxyurea, should be considered in early stages. Here, we report a case of a female adolescent with SCD and inaugural nephrotic syndrome who, after an initial treatment failure with corticotherapy, had a remarkable recovery after treatment with hydroxyurea and ACEis.

Pulmonary Manifestations of Hematologic and Oncologic Diseases in Children

Pulmonary complications are common in children with hematologic or oncologic diseases, and many experience long-term effects even after the primary disease has been cured. This article reviews pulmonary complications in children with cancer, after hematopoietic stem cell transplant, and caused by sickle cell disease and discusses their management.