Association of elevated tricuspid regurgitation velocity with cerebrovascular and kidney disease in children with sickle cell disease.

BACKGROUND: Tricuspid regurgitation velocity (TRV), measured by echocardiography, is a surrogate marker for pulmonary hypertension. Limited pediatric studies have considered the association between TRV and surrogate markers of end-organ disease. METHODS: We conducted a cross-sectional study that evaluated the prevalence of elevated TRV ≥2.5 m/s and its associations with renal and cerebrovascular outcomes in children with sickle cell disease (SCD) 1-21 years of age in two large sickle cell cohorts, the University of Alabama at Birmingham (UAB) sickle cell cohort, and the Sickle Cell Clinical Research and Intervention Program (SCCRIP) cohort at St. Jude Children's Research Hospital. We hypothesized that patients with SCD and elevated TRV would have higher odds of having either persistent albuminuria or cerebrovascular disease. RESULTS: We identified 166 children from the UAB cohort (mean age: 13.49 ± 4.47 years) and 325 children from the SCCRIP cohort (mean age: 13.41 ± 3.99 years) with echocardiograms. The prevalence of an elevated TRV was 21% in both UAB and SCCRIP cohorts. Elevated TRV was significantly associated with cerebrovascular disease (odds ratio [OR] 1.88, 95% confidence interval [CI]: 1.12-3.15; p = .017) and persistent albuminuria (OR 1.81, 95% CI: 1.07-3.06; p = .028) after adjusting for age, sex, treatment, and site. CONCLUSION: This cross-sectional, multicenter study identifies associations between surrogate markers of pulmonary hypertension with kidney disease and cerebrovascular disease. A prospective study should be performed to evaluate the longitudinal outcomes for patients with multiple surrogate markers of end-organ disease.

Birth Prevalence of Sickle Cell Disease and County-Level Social Vulnerability - Sickle Cell Data Collection Program, 11 States, 2016-2020.

Sickle cell disease (SCD) remains a public health priority in the United States because of its association with complex health needs, reduced life expectancy, lifelong disabilities, and high cost of care. A cross-sectional analysis was conducted to calculate the crude and race-specific birth prevalence for SCD using state newborn screening program records during 2016-2020 from 11 Sickle Cell Data Collection program states. The percentage distribution of birth mother residence within Social Vulnerability Index quartiles was derived. Among 3,305 newborns with confirmed SCD (including 57% with homozygous hemoglobin S or sickle ß-null thalassemia across 11 states, 90% of whom were Black or African American [Black], and 4% of whom were Hispanic or Latino), the crude SCD birth prevalence was 4.83 per 10,000 (one in every 2,070) live births and 28.54 per 10,000 (one in every 350) non-Hispanic Black newborns. Approximately two thirds (67%) of mothers of newborns with SCD lived in counties with high or very high levels of social vulnerability; most mothers lived in counties with high or very high levels of vulnerability for racial and ethnic minority status (89%) and housing type and transportation (64%) themes. These findings can guide public health, health care systems, and community program planning and implementation that address social determinants of health for infants with SCD. Implementation of tailored interventions, including increasing access to transportation, improving housing, and advancing equity in high vulnerability areas, could facilitate care and improve health outcomes for children with SCD.

Current Methods of Newborn Screening Follow-Up for Sickle Cell Disease Are Highly Variable and without Quality Assurance: Results from the ENHANCE Study.

Newborn screening (NBS) for sickle cell disease (SCD) has significantly improved childhood survival but there are still gaps resulting in delayed care for affected infants. As a state-run program, there are no national quality assurance programs to ensure each state achieves consistent, reliable outcomes. We performed this qualitative study of NBS follow-up practices to better evaluate and understand the multi-level, state-specific processes of how each state's public health department delivers the NBS results to families, how/if they ensure affected infants are seen quickly by sickle cell specialists, and to determine the close-out processes used in each state. This project used semi-structured interviews conducted with 29 participants across eight states to explore these NBS follow-up processes in each state. Participants included SCD providers, NBS coordinators, or personnel associated with state health departments and community-based SCD organizations (CBO). Our results show significant state-dependent variations in the NBS processes of information delivery and patient management. Specifically, programs differed in how they communicated results to affected families and which other organizations were informed of the diagnosis. There was also state-based (and intrastate) variation in who should assume responsibility for ensuring that infants receive confirmatory testing and are promptly started on penicillin prophylaxis. Case closure was also highly variable and poorly validated. Our results also yielded identifiable challenges and facilitators to NBS which were highly variable by state but potentially addressable in the future. This information suggests opportunities for systematic improvement in NBS follow-up processes.

Transcranial doppler velocity in iron-deficient Nigerian children with sickle cell anemia.

Oral iron supplementation in iron deficient children with sickle cell anemia and normal transcranial Doppler ultrasound (TCD) velocities does not reduce arterial flow in the middle cerebral artery.

Diagnosis and Management of Cerebral Venous Thrombosis: A Scientific Statement From the American Heart Association.

Cerebral venous thrombosis accounts for 0.5% to 3% of all strokes. The most vulnerable populations include young individuals, women of reproductive age, and patients with a prothrombotic state. The clinical presentation of cerebral venous thrombosis is diverse (eg, headaches, seizures), requiring a high level of clinical suspicion. Its diagnosis is based primarily on magnetic resonance imaging/magnetic resonance venography or computed tomography/computed tomographic venography. The clinical course of cerebral venous thrombosis may be difficult to predict. Death or dependence occurs in 10% to 15% of patients despite intensive medical treatment. This scientific statement provides an update of the 2011 American Heart Association scientific statement for the diagnosis and management of cerebral venous thrombosis. Our focus is on advances in the diagnosis and management decisions of patients with suspected cerebral venous thrombosis. We discuss evidence for the use of anticoagulation and endovascular therapies and considerations for craniectomy. We also provide an algorithm to optimize the management of patients with cerebral venous thrombosis and those with progressive neurological deterioration or thrombus propagation despite maximal medical therapy.

Barriers and Facilitators of Premarital Genetic Counseling for Sickle Cell Disease in Northern Nigeria.

In high-income countries, premarital genetic counseling for Sickle Cell Disease (SCD) is a standard practice. However, in Nigeria, there is no formal premarital genetic counseling program available for SCD. We conducted a series of focus group discussions with health care professionals, patients with SCD, and parents of the patients with or without SCD to gain an understanding of their attitudes and beliefs towards SCD/Sickle Cell Trait and premarital genetic counseling for SCD. Data were analyzed using Charmaz's constructivist grounded theory approach. Two themes were highlighted in the analysis as follows: (1) the difference between the perception of premarital sickle cell screening among individuals with SCD versus the general population, and (2) the personal beliefs and physical challenges that could lead to the avoidance of premarital screening within the general community. Lack of disease-related knowledge, testing facilities, transportation, and stigma associated with the disease were the most commonly perceived barriers to premarital testing. Also, a willingness to receive premarital testing for SCD exists within our community to reduce the spread of the disease and advocate for improved health-related quality of life of patients with SCD. The content and structure of a premarital genetic counseling program in Kano, Northern Nigeria, needs to be developed.

Evaluating the Discriminatory Ability of the Sickle Cell Data Collection Program's Administrative Claims Case Definition in Identifying Adults With Sickle Cell Disease: Validation Study.

BACKGROUND: Sickle cell disease (SCD) was first recognized in 1910 and identified as a genetic condition in 1949. However, there is not a universal clinical registry that can be used currently to estimate its prevalence. The Sickle Cell Data Collection (SCDC) program, funded by the Centers for Disease Control and Prevention, funds state-level grantees to compile data within their states from various sources including administrative claims to identify individuals with SCD. The performance of the SCDC administrative claims case definition has been validated in a pediatric population with SCD, but it has not been tested in adults. OBJECTIVE: The objective of our study is to evaluate the discriminatory ability of the SCDC administrative claims case definition to accurately identify adults with SCD using Medicaid insurance claims data. METHODS: Our study used Medicaid claims data in combination with hospital-based medical record data from the Alabama, Georgia, and Wisconsin SCDC programs to identify individuals aged 18 years or older meeting the SCDC administrative claims case definition. In order to validate this definition, our study included only those individuals who were identified in both Medicaid's and the partnering clinical institution's records. We used clinical laboratory tests and diagnostic algorithms to determine the true SCD status of this subset of patients. Positive predictive values (PPV) are reported overall and by state under several scenarios. RESULTS: There were 1219 individuals (354 from Alabama and 865 from Georgia) who were identified through a 5-year time period. The 5-year time period yielded a PPV of 88.4% (91% for data from Alabama and 87% for data from Georgia), when only using data with laboratory-confirmed (gold standard) cases as true positives. With a narrower time period (3-year period) and data from 3 states (Alabama, Georgia, and Wisconsin), a total of 1432 individuals from these states were included in our study. The overall 3-year PPV was 89.4% (92%, 93%, and 81% for data from Alabama, Georgia, and Wisconsin, respectively) when only considering laboratory-confirmed cases as true cases. CONCLUSIONS: Adults identified as having SCD from administrative claims data based on the SCDC case definition have a high probability of truly having the disease, especially if those hospitals have active SCD programs. Administrative claims are thus a valuable data source to identify adults with SCD in a state and understand their epidemiology and health care service usage.

Factors associated with left ventricular hypertrophy in children with sickle cell disease: results from the DISPLACE study.

Cardiopulmonary complications remain a leading cause of morbidity and mortality in sickle cell disease (SCD). The overall goals of this study were to evaluate the relationship between left ventricular hypertrophy (LVH) and laboratory markers of hemolysis and determine the association between LVH and SCD-specific therapies (hydroxyurea and chronic red cell transfusion). Data from the DISPLACE (Dissemination and Implementation of Stroke Prevention Looking at the Care Environment) study cohort was used. LVH was defined based on the left ventricular mass indexed to the body surface area as left ventricular mass index >103.0 g/m2 for males and >84.2 g/m2 for females. There were 1,409 children included in the analysis and 20.3% had LVH. Results of multivariable analysis of LVH showed baseline hemoglobin levels were associated with the lower odds of having LVH (odds ratio [OR]: 0.71, 95% confidence interval [CI]: 0.60- 0.84). The odds of LVH increases for every 1-year increase in age (OR: 1.07, 95% CI: 1.02-1.13). Similarly, the odds of LVH were lower among males than females (OR: 0.59, 95% CI: 0.38-0.93). The odds of LVH were higher among those on hydroxyurea compared to no therapy (OR: 1.83, 95% CI: 1.41-2.37). Overall results of the study showed that LVH occurs early in children with SCD and the risk increases with increasing age and with lower hemoglobin. Further, we found higher use of hydroxyurea among those with LVH, suggesting that the need for hydroxyurea conveys a risk of cardiovascular remodeling.

Hydroxyurea for primary stroke prevention in children with sickle cell anaemia in Nigeria (SPRING): a double-blind, multicentre, randomised, phase 3 trial.

BACKGROUND: In high-income countries, standard care for primary stroke prevention in children with sickle cell anaemia and abnormal transcranial Doppler velocities results in a 92% relative risk reduction of strokes but mandates initial monthly blood transfusion. In Africa, where regular blood transfusion is not feasible for most children, we tested the hypothesis that initial moderate-dose compared with low-dose hydroxyurea decreases the incidence of strokes for children with abnormal transcranial Doppler velocities. METHODS: SPRING is a double-blind, parallel-group, randomised, controlled, phase 3 trial of children aged 5-12 years with sickle cell anaemia with abnormal transcranial Doppler velocities conducted at three teaching hospitals in Nigeria. For randomisation, we used a permuted block allocation scheme with block sizes of four, stratified by sex and site. Allocation was concealed from all but the pharmacists and statisticians. Participants were assigned in a 1:1 ratio to low-dose (10 mg/kg per day) or moderate-dose (20 mg/kg per day) oral hydroxyurea taken once daily with monthly clinical evaluation and laboratory monitoring. The primary outcome was initial stroke or transient ischaemic attack, centrally adjudicated. The secondary outcome was all-cause hospitalisation. We used the intention-to-treat population for data analysis. The trial was stopped early for futility after a planned minimum follow-up of 3·0 years to follow-up for participants. This trial was registered with ClinicalTrials.gov, number NCT02560935. FINDINGS: Between Aug 2, 2016, and June 14, 2018, 220 participants (median age 7·2 years [IQR 5·5-8·9]; 114 [52%] female) were randomly allocated and followed for a median of 2·4 years (IQR 2·0-2·8). All participants were Nigerian and were from the following ethnic groups: 179 (82%) people were Hausa, 25 (11%) were Fulani, and 16 (7%) identified as another ethnicity. In the low-dose hydroxyurea group, three (3%) of 109 participants had strokes, with an incidence rate of 1·19 per 100 person-years and in the moderate-dose hydroxyurea group five (5%) of 111 had strokes with an incidence rate of 1·92 per 100 person-years (incidence rate ratio 0·62 [95% CI 0·10-3·20], p=0·77). The incidence rate ratio of hospitalisation for any reason was 1·71 (95% CI 1·15-2·57, p=0·0071), with higher incidence rates per 100 person-years in the low-dose group versus the moderate-dose group (27·43 vs 16·08). No participant had hydroxyurea treatment stopped for myelosuppression. INTERPRETATION: Compared with low-dose hydroxyurea therapy, participants treated with moderate-dose hydroxyurea had no difference in the stroke incidence rate. However, secondary analyses suggest that the moderate-dose group could lower incidence rates for all-cause hospitalisations. These findings provide an evidence-based guideline for the use of low-dose hydroxyurea therapy for children with sickle cell anaemia at risk of stroke. FUNDING: National Institute of Neurological Disorders and Stroke.

Treatment-related Correlates of Growth in Children With Sickle Cell Disease in the DISPLACE Cohort.

Reduced growth and delayed maturation have been described in children with sickle cell disease (SCD). This study investigated growth and hemolysis in children with SCD in the DISPLACE (Dissemination and Implementation of Stroke Prevention Looking at the Care Environment) cohort. The database includes 5287 children, of which, 3305 had at least 2 growth measurements over a 5-year period. Body mass index was converted to z-scores (zBMI), and 19.8%, 66.1%, 14.2% of children were classified as underweight, normal, and overweight/obese, respectively. Multivariable analysis of growth was conducted and included variables: age, sex, blood pressure, hemoglobin, reticulocyte count, treatment with chronic red cell transfusion therapy (CRCT), or hydroxyurea therapy. Baseline hemoglobin levels were associated with the lower odds of being underweight (odds ratio [OR]=0.93, 95% confidence interval [CI]: 0.86-0.99), and higher odds of being overweight/obese (OR: 1.26, 95% CI: 1.17-1.36) compared with normal zBMI. CRCT was associated with being overweight/obese at baseline (OR: 1.85, 95% CI: 1.31-2.60). Overall, results showed that children who were underweight improved regardless of therapy over the 2-year time period. However, children on CRCT are at higher risk for being overweight and should be monitored closely.

Association Between Patent Foramen Ovale and Overt Ischemic Stroke in Children With Sickle Cell Disease.

Ischemic stroke is one of the most devastating complications of sickle cell anemia (SCA). Previous studies have shown that intracardiac shunting including patent foramen ovale (PFO) can be a potential risk factor for stroke in children with SCA. This study investigates the association between PFO and overt ischemic stroke in the DISPLACE (Dissemination and Implementation of Stroke Prevention Looking at the Care Environment) study cohort of 5,247 children with SCA of whom 1,414 had at least one clinical non-contrast transthoracic echocardiogram. Presence of PFO was taken from the clinical report. Further, we assessed the association between PFO and other clinical and hemolytic factors in children with SCA such as history of abnormal sickle stroke screen [elevated Transcranial Doppler ultrasound (TCD) velocity] and patient's baseline hemoglobin. In 642 children for whom all data were available, the adjusted odds ratio (OR) for overt stroke was higher in those with PFO but this was not statistically significant (OR: 1.49, 95% CI: 0.20-11.03, p = 0.6994). With an OR of 0.85, the study suggested less PFOs in those with abnormal TCD, but this was not statistically significant (95% CI: 0.17-4.25, p = 0.8463). Overall, the prevalence of PFO in this large sub study of non-contrast echocardiography amongst children with SCA is much lower than previous smaller studies using bubble contrast echocardiography. Overt stroke was non-statistically more common in children with SCA and PFO, but there was no evidence that PFO was more common in those with abnormal TCD, the most important pediatric sickle stroke screen.

High Systolic Blood Pressure, Anterior Segment Changes and Visual Impairment Independently Predict Sickle Cell Retinopathy.

Sickle cell disease is often complicated by retinopathy, which can be proliferative or non proliferative. Proliferative sickle cell retinopathy potentially leads to blindness. There is a paucity of data on sickle cell disease-related retinopathy from Africa, where the disease is most prevalent. We aimed to determine the clinical, ophthalmic, and laboratory predictors of sickle cell retinopathy in an African population. We conducted a cross-sectional study of 262 participants, aged 13 years and above, with sickle cell disease. Demographic and clinical data were collected using a structured questionnaire and standard physical examinations. Vitreo-retinal specialists performed eye examinations on all the participants. Hematological and biochemical assessments were conducted using standard methods. A multivariate stepwise forward logistic regression was performed to determine the predictors of retinopathy. The median age of the participants was 20 years (interquartile range: 17-25 years). Most of the participants had a homozygous Hb S (HBB: c.20A>T) genotype (96.9%), with 3.1% who carried a Hb S/Hb C (HBB: c.19G>A) genotype. The prevalence of non proliferative sickle cell retinopathy was 24.4%. Only 1.9% had proliferative sickle cell retinopathy (PSCR). Elevated systolic blood pressure (BP) [odds ratio (OR): 6.85, 95% confidence interval (95% CI): 1.05-44.45, p = 0.059], moderate visual impairment (OR: 5.2, 95% CI: 1.39-19.63, p = 0.015), and anterior segment changes (OR: 2.21, 95% CI: 1.19-4.13, p = 0.012) were independently predictive of retinopathy. This study provides new insight into predictors of retinopathy in sickle cell disease, with implications on early screening and prevention.

Sickle Cell Disease Genomics of Africa (SickleGenAfrica) Network: ethical framework and initial qualitative findings from community engagement in Ghana, Nigeria and Tanzania.

OBJECTIVES: To provide lay information about genetics and sickle cell disease (SCD) and to identify and address ethical issues concerning the Sickle Cell Disease Genomics of Africa Network covering autonomy and research decision-making, risk of SCD complications and organ damage, returning of genomic findings, biorepository, data sharing, and healthcare provision for patients with SCD. DESIGN: Focus groups using qualitative methods. SETTING: Six cities in Ghana, Nigeria and Tanzania within communities and secondary care. PARTICIPANTS: Patients, parents/caregivers, healthcare professionals, community leaders and government healthcare representatives. RESULTS: Results from 112 participants revealed similar sensitivities and aspirations around genomic research, an inclination towards autonomous decision-making for research, concerns about biobanking, anonymity in data sharing, and a preference for receiving individual genomic results. Furthermore, inadequate healthcare for patients with SCD was emphasised. CONCLUSIONS: Our findings revealed the eagerness of patients and parents/caregivers to participate in genomics research in Africa, with advice from community leaders and reassurance from health professionals and policy-makers, despite their apprehensions regarding healthcare systems.

HIV-associated nephropathy: Protocol and rationale for an exploratory genotype-phenotype study in a sub-Saharan African population.

BACKGROUND: HIV-positive persons of African descent are disproportionately affected by chronic kidney disease (CKD). Deterioration to end-stage kidney disease (ESKD) also occurs in this population at a higher frequency. There remains a lot to learn about the genetic susceptibility to CKD in HIV positive patients, and the pathophysiology of progression to ESKD. OBJECTIVES: We will conduct an exploratory genotype-phenotype study in HIV-positive persons with CKD in Aminu Kano Teaching Hospital, Nigeria, to determine blood-based differential gene expression biomarkers in different kidney risk groups according to the KDIGO 2012 criteria. METHODS: We will consecutively screen 150 HIV-positive adults (≥18 years of age) attending the HIV clinic of Aminu Kano Teaching Hospital, Kano, Nigeria, for CKD based on proteinuria and elevation of estimated glomerular filtration rate. Among these, two separate groups of 16 eligible participants each (n = 32) will be selected in the four (4) KDIGO 2012 kidney risk categories. The groups will be matched for age, sex, viral suppression level and antiretroviral (ARV) regimen. In the first group (n = 16), we will determine differential gene expression markers in peripheral blood mononuclear cells using mRNA-sequencing (RNA-Seq). We will validate the differential expression markers in the second group (n = 16) using reverse transcription quantitative polymerase chain reaction (RT-qPCR). Using a systems-based approach, we will construct, visualize and analyze gene-gene interaction networks to determine the potential biological roles of identified differential expression markers based on published literature and publicly available databases. RESULTS: Our exploratory study will provide valuable information on the potential roles of differential expression biomarkers in the pathophysiology of HIV-associated kidney disease by identifying novel biomarkers in different risk categories of CKD in a sub-Saharan African population. The results of this study will provide the basis for population-based genome-wide association studies to guide future personalized medicine approaches. CONCLUSION: Validated biomarkers can be potential targets for the development of stage-specific therapeutic interventions, an essential paradigm in precision medicine.

Primary prevention of stroke in children with sickle cell anemia in sub-Saharan Africa: rationale and design of phase III randomized clinical trial.

Strokes in children with sickle cell anemia (SCA) are associated with significant morbidity and premature death. Primary stroke prevention in children with SCA involves screening for abnormal transcranial Doppler (TCD) velocity coupled with regular blood transfusion therapy for children with abnormal velocities, for at least one year. However, in Africa, where the majority of children with SCA live, regular blood transfusions are not feasible due to inadequate supply of safe blood, cost, and the reluctance of caregivers to accept transfusion therapy for their children. We describe the Primary Prevention of Stroke in Children with Sickle Cell Disease in Nigeria Trial [StrokePreventioninNigeria (SPRING) trial, NCT02560935], a three-center double-blinded randomized controlled Phase III clinical trial to 1) determine the efficacy of moderate fixed-dose (20 mg/kg/day) versus low fixed-dose (10 mg/kg/day) hydroxyurea therapy for primary stroke prevention; 2) determine the efficacy of moderate fixed-dose hydroxyurea for decreasing the incidence of all cause-hospitalization (pain, acute chest syndrome, infection, other) compared to low fixed-dose hydroxyurea. We will test the primary hypothesis that there will be a 66% relative risk reduction of strokes in children with SCA and abnormal TCD measurements, randomly allocated, for a minimum of three years to receive moderate fixed-dose versus low fixed-dose hydroxyurea (total n = 220). The results of this trial will advance the care of children with SCA in sub-Saharan Africa, while improving research capacity for future studies to prevent strokes in children with SCA.

Low educational level of head of household, as a proxy for poverty, is associated with severe anaemia among children with sickle cell disease living in a low-resource setting: evidence from the SPRING trial.

Severe anaemia, defined as haemoglobin level < 6·0 g/dl, is an independent risk factor for death in individuals with sickle cell disease living in resource-limited settings. We conducted a cross-sectional study of 941 children with sickle cell anaemia, who had been defined as phenotype HbSS or HbSß0 thalassaemia, aged five to 12 years, and were screened for enrollment into a large primary stroke prevention trial in Nigeria (SPRING; NCT02560935). The main aim of the study was to determine the prevalence and risk factors for severe anaemia. We found severe anaemia to be present in 3·9% (37 of 941) of the SPRING study participants. Severe anaemia was significantly associated with the lower educational level of the head of the household (P = 0·003), as a proxy for poverty, and a greater number of children per room in the household (P = 0·004). Body mass index was not associated with severe anaemia. The etiology of severe anaemia in children living with sickle cell anaemia in Nigeria is likely to be multifactorial with an interplay between an individual's disease severity and other socio-economic factors related to poverty.