Genetic Modifiers of White Blood Cell Count, Albuminuria and Glomerular Filtration Rate in Children with Sickle Cell Anemia

<div><p>Discovery and validation of genetic variants that influence disease severity in children with sickle cell anemia (SCA) could lead to early identification of high-risk patients, better screening strategies, and intervention with targeted and preventive therapy. We hypothesized that newly identified genetic risk factors for the general African American population could also impact laboratory biomarkers known to contribute to the clinical disease expression of SCA, including variants influencing the white blood cell count and the development of albuminuria and abnormal glomerular filtration rate. We first investigated candidate genetic polymorphisms in well-characterized SCA pediatric cohorts from three prospective NHLBI-supported clinical trials: HUSTLE, SWiTCH, and TWiTCH. We also performed whole exome sequencing to identify novel genetic variants, using both a discovery and a validation cohort. Among candidate genes, <i>DARC</i> rs2814778 polymorphism regulating Duffy antigen expression had a clear influence with significantly increased WBC and neutrophil counts, but did not affect the maximum tolerated dose of hydroxyurea therapy. The <i>APOL1</i> G1 polymorphism, an identified risk factor for non-diabetic renal disease, was associated with albuminuria. Whole exome sequencing discovered several novel variants that maintained significance in the validation cohorts, including <i>ZFHX4</i> polymorphisms affecting both the leukocyte and neutrophil counts, as well as <i>AGGF1</i>, <i>CYP4B1</i>, <i>CUBN</i>, <i>TOR2A</i>, <i>PKD1L2</i>, and <i>CD163</i> variants affecting the glomerular filtration rate. The identification of robust, reliable, and reproducible genetic markers for disease severity in SCA remains elusive, but new genetic variants provide avenues for further validation and investigation.</p></div

Genetic variants identified by WES associated with either WBC or ANC.

<p>Genetic variants identified by WES associated with either WBC or ANC.</p

Coding variants associated with glomerular filtration rate.

<p>Coding variants associated with glomerular filtration rate.</p

Association of candidate genes with WBC and ANC.

<p>Association of candidate genes with WBC and ANC.</p

Global geographic differences in healthcare utilization for sickle cell disease pain crises in the CASiRe cohort

Background: Sickle cell disease (SCD) is characterized by frequent, unpredictable pain episodes and other vasoocclusive crises (VOCs) leading to significant healthcare utilization. VOC frequency is often an endpoint in clinical trials investigating novel therapies for this devastating disease. Procedure: The Consortium for the Advancement of Sickle Cell Research (CASiRe) is an international collaboration investigating clinical severity in SCD using a validated questionnaire and medical chart review standardized across four countries (United States, United Kingdom, Italy and Ghana). Results: This study, focused on pain crisis incidence and healthcare utilization, included 868 patients, equally represented according to age and gender. HgbSS was the most common genotype. Patients from Ghana used the Emergency Room/Day Hospital for pain more frequently (annualized mean 2.01) than patients from other regions (annualized mean 1.56 U.S.; 1.09 U.K.; 0.02 Italy), while U.K. patients were hospitalized for pain more often (annualized mean: U.K. 2.98) than patients in other regions (annualized mean 1.98 U.S.; 1.18 Ghana; Italy 0.54). Italy's hospitalization rate for pain (annualized mean: 0.57) was nearly 20 times greater than its emergency room/day hospital only visits for pain (annualized mean: 0.03). When categorized by genotype and age, similar results were seen

Pain Burden in the CASiRe International Cohort of Sickle Cell Patients: United States and Ghana

Objectives: Sickle Cell Disease (SCD) is a genetic blood disorder affecting over 1 million people globally. The aim of this analysis is to explore the pain burden of patients with SCD in two countries: the United States and Ghana. Methods: The Consortium for the Advancement of Sickle Cell Research (CASiRe) was created to better understand the clinical severity of patients with SCD worldwide. Data regarding gender, SCD genotype, prior medical diagnoses, and validated pain burden measures were analyzed from the CASiRe database. The Sickle Cell Pain Burden Interview (SCPBI) was used to assess pain burden, the impact of pain on physical, emotional, and social function. Results: Most subjects identified as Black/African American (n = 298, 97.0%). Patient ages ranged from 6 to 73 years. 35.9% resided in the United States, 64.1% resided in Ghana, 40.9% were men, and 58.7% were women. The mean SCPBI score for US SCD patients was 6.53(±5.89) vs 4.04(±5.10) for Ghanaian patients, P <0.001. Pain burden was higher in US men vs Ghanaian men (6.74(±5.68) vs 3.54(±4.46), P = .003) and in US women vs Ghanaian women (6.37 ± 6.06 vs 4.44(±5.54), P = .032). Pain burden was higher in US patients than Ghanaian patients for both the Hb SC/SBeta+ genotype (5.40(±5.29) vs 2.82(±4.86), P = .054) and Hb SS/SBeta0 genotype (6.79(±6.01) vs 4.49(±5.13), P = .003). Pain burden was significantly higher in SCD patients with comorbid conditions independent of geographic origin including stroke, cholecystectomy, gallstones, depression, and headache. Discussion: US patients with SCD have a higher pain burden than Ghanaian patients. Further studies should investigate underlying contributors to pain burden in these populations and further explore the etiology of geographic differences in pain

Engaging caregivers and providers of children with sickle cell anemia in shared decision making for hydroxyurea: Protocol for a multicenter randomized controlled trial

Background: Sickle cell anemia (SCA) is a genetic blood disorder that puts children at a risk of serious medical complications, early morbidity and mortality, and high health care utilization. Until recently, hydroxyurea was the only disease-modifying treatment for this life-threatening disease and has remained the only option for children younger than 5 years. Evidence-based guidelines recommend using a shared decision-making (SDM) approach for offering hydroxyurea to children with SCA (HbSS or HbS/β0 thalassemia) aged as early as 9 months. However, the uptake remains suboptimal, likely because caregivers lack information about hydroxyurea and have concerns about its safety and potential long-term side effects. Moreover, clinicians do not routinely receive training or tools, especially those that provide medical evidence and consider caregivers\u27 preferences and values, to facilitate a shared discussion with caregivers. Objective: The aim of this study is to understand how best to help parents of young children with sickle cell disease and their clinicians have a shared discussion about hydroxyurea (one that considers medical evidence and parent values and preferences). Methods: We designed our study to compare the effectiveness of two methods for disseminating hydroxyurea guidelines to facilitate SDM: a clinician pocket guide (ie, usual care) and a clinician hydroxyurea SDM toolkit (H-SDM toolkit). Our primary outcomes are caregiver reports of decisional uncertainty and knowledge of hydroxyurea. The study also assesses the number of children (aged 0-5 years) who were offered and prescribed hydroxyurea and the resultant health outcomes. Results: The Ethics Committee of the Cincinnati Children\u27s Hospital Medical Center approved this study in November 2017. As of February 2021, we have enrolled 120 caregiver participants. Conclusions: The long-term objective of this study is to improve the quality of care for children with SCA. Using multicomponent dissemination methods developed in partnership with key stakeholders and designed to address barriers to high-quality care, caregivers of patients with SCA can make informed and shared decisions about their health

Engaging Caregivers and Providers of Children With Sickle Cell Anemia in Shared Decision Making for Hydroxyurea:Protocol for a Multicenter Randomized Controlled Trial

BACKGROUND: Sickle cell anemia (SCA) is a genetic blood disorder that puts children at a risk of serious medical complications, early morbidity and mortality, and high health care utilization. Until recently, hydroxyurea was the only disease-modifying treatment for this life-threatening disease and has remained the only option for children younger than 5 years. Evidence-based guidelines recommend using a shared decision-making (SDM) approach for offering hydroxyurea to children with SCA (HbSS or HbS/β0 thalassemia) aged as early as 9 months. However, the uptake remains suboptimal, likely because caregivers lack information about hydroxyurea and have concerns about its safety and potential long-term side effects. Moreover, clinicians do not routinely receive training or tools, especially those that provide medical evidence and consider caregivers’ preferences and values, to facilitate a shared discussion with caregivers. OBJECTIVE: The aim of this study is to understand how best to help parents of young children with sickle cell disease and their clinicians have a shared discussion about hydroxyurea (one that considers medical evidence and parent values and preferences). METHODS: We designed our study to compare the effectiveness of two methods for disseminating hydroxyurea guidelines to facilitate SDM: a clinician pocket guide (ie, usual care) and a clinician hydroxyurea SDM toolkit (H-SDM toolkit). Our primary outcomes are caregiver reports of decisional uncertainty and knowledge of hydroxyurea. The study also assesses the number of children (aged 0-5 years) who were offered and prescribed hydroxyurea and the resultant health outcomes. RESULTS: The Ethics Committee of the Cincinnati Children’s Hospital Medical Center approved this study in November 2017. As of February 2021, we have enrolled 120 caregiver participants. CONCLUSIONS: The long-term objective of this study is to improve the quality of care for children with SCA. Using multicomponent dissemination methods developed in partnership with key stakeholders and designed to address barriers to high-quality care, caregivers of patients with SCA can make informed and shared decisions about their health. TRIAL REGISTRATION: ClinicalTrials.gov NCT03442114; https://clinicaltrials.gov/ct2/show/NCT03442114 INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/2765