Working memory and school readiness in preschool children with sickle cell disease compared to demographically matched controls.

Children diagnosed with sickle cell disease (SCD) are at risk of the development of neurobehavioural problems early in life. Specific impairments in executive function skills, including working memory, have been documented in school-aged children with SCD. These executive skills are known to strongly contribute to early academic skills and preparedness for entering kindergarten. This study examined working memory and school readiness in preschool children with SCD compared to a healthy control group matched for race, sex and parent education. A total of 84 patients diagnosed with SCD (61.9% haemoglobin [Hb]SS/HbSß0 -thalassaemia) and 168 controls completed testing. The mean (SD) ages of patients and controls at testing were 4.53 (0.38) and 4.44 (0.65) years respectively. The SCD group performed worse than controls on measures of executive function, working memory and school readiness (p < 0.01; Cohen's D range: 0.32-0.39). Measures of working memory were associated with school readiness after accounting for early adaptive development. Multiple linear regression models among patients diagnosed with SCD revealed that college education of the primary caregiver was positively associated with school readiness (p < 0.001) after controlling for sex, genotype, age and early adaptive development. These results highlight the need to implement school readiness interventions in young children diagnosed with SCD emphasising executive function skills.

Provider prescription of hydroxyurea in youth and adults with sickle cell disease: A review of prescription barriers and facilitators.

Sickle cell disease (SCD) is an inherited red blood cell disorder associated with frequent painful events and organ damage. Hydroxyurea (HU) is the recommended evidence-based treatment of SCD. However, among patients eligible for HU, prescription rates are low. Utilizing a scoping review approach, we summarized and synthesized relevant findings regarding provider barriers and facilitators to the prescription of HU in youth and adults with SCD and provided suggestions for future implementation strategies to improve prescription rates. Relevant databases were searched using specified search terms. Articles reporting provider barriers and/or facilitators to prescribing HU were included. A total of 10 studies met the inclusion criteria. Common barriers to the prescription of HU identified by providers included: doubts around patients' adherence to HU and their engaging in required testing, concerns about side effects, lack of knowledge, cost and patient concerns about side effects. Facilitators to the prescription of HU included beliefs in the effectiveness of HU, provider demographics and knowledge. Findings suggest significant provider biases exist, particularly in the form of negative perceptions towards patients' ability to adhere to taking HU and engaging in the required follow-up. Improving provider knowledge and attitudes towards HU and SCD may help improve low prescription rates.

Sickle cell disease and social determinants of health: A scoping review.

Social determinants of health (SDoH) may impact outcomes in sickle cell disease (SCD). We conducted a comprehensive literature review of five electronic databases to elucidate the relationship between SDoH and SCD, and identify gaps in the literature. Our search yielded 59 articles, which we organized into five SDoH areas: Neighborhood and Built Environment, Health and Healthcare, Social and Community Context, Education, and Economic Stability. We found that social determinants, such as access to healthcare, were inconsistently evaluated. Improved recognition and understanding of SDoH should enhance the development of programs that directly address its detrimental effects on patients with SCD.

Examining the influence of pain and fatigue on neurocognitive functioning in adolescents and young adults with sickle cell disease.

Pain and fatigue are among the most common and impactful complications of sickle cell disease (SCD). Individuals with SCD are also more likely to have neurocognitive deficits. Previous studies have suggested that pain and fatigue might influence neurocognitive functioning in patients with SCD. However, these studies are limited by small sample sizes and inadequate measurement of cognitive performance. The present study aimed to investigate the relationship between pain and fatigue with neurocognitive functioning using performance-based measures of neurocognition. Pain and fatigue were not associated with neurocognitive performance. Implications and directions for future research are discussed.

Social determinants of neurocognitive and academic performance in sickle cell disease.

BACKGROUND: Sickle cell disease (SCD) is associated with poor neurocognitive outcomes due to biomedical and psychosocial factors. The aims of this study were to investigate associations between household and neighborhood socioeconomic status (SES) with cognitive and academic outcomes in SCD and to determine if these relationships were modified by sickle genotype, fetal hemoglobin, or age. PROCEDURE: We prospectively recruited patients to complete a battery of neurocognitive and academic measures. Household SES was measured using the Barratt Simplified Measure of Social Status, a composite index of parent education and occupation. The Social Vulnerability Index was used to classify individuals based on social vulnerabilities at the neighborhood level. RESULTS: Overall, 299 patients between the ages of 4 and 18 (mean = 11.4, standard deviation = 4.3) years diagnosed with SCD (57% SS/SB0 -thalassemia) completed testing. Stepwise multivariate models demonstrated that patients with low social vulnerability (i.e., high SES) at the neighborhood level displayed intelligence and math scores that were 4.70 and 7.64 points higher than those living in areas with moderate social vulnerability, respectively (p < .05). Reading performance did not differ based on neighborhood SES; however, the effect of neighborhood SES was dependent on age, such that older participants living in neighborhoods with moderate or high levels of social vulnerability displayed poorer reading scores than those with low social vulnerability (p < .05). CONCLUSIONS: This study identified patients with SCD at higher risk of poor academic performance based on SES. Interventions addressing academic difficulties should be offered to all children with SCD, but should be emergently offered to this subpopulation.

Internalizing Symptoms in Adolescents With Sickle Cell Disease.

OBJECTIVE: Sickle cell disease (SCD) is a genetic blood disorder that may affect patients' mood and behavior. However, measuring the prevalence of internalizing symptoms (anxiety and depression) in patients with SCD has been elusive. We assessed internalizing symptoms in adolescents with SCD to evaluate prevalence and to test whether neurocognitive performance and frequency of pain-related episodes were associated with internalizing concerns. METHODS: One hundred eighty-five patients (57% HbSS/HbSß0-thalassemia, 43% HbSC/HbSß+-thalassemia), ages 12-18 years, received a neuropsychological evaluation as a part of a larger cohort study. Internalizing symptoms were measured using the Behavior Assessment System for Children, Second or Third Edition. Scores on the depression and anxiety scales were compared to normative values using Wilcoxon signed rank test. Spearman correlations examined associations between neurocognitive performances and internalizing symptoms. Robust multivariable regression models measured associations between internalizing symptoms and age, sex, sickle genotype, total hemoglobin, fetal hemoglobin, socioeconomic status, and frequency of pain episodes. RESULTS: Parent- and self-reported ratings of internalizing symptoms were not elevated compared to normative expectations. Overall, 1.8% and 6.3% of the sample displayed clinically elevated symptoms of anxiety and depression based on self-report, respectively. There were no associations between internalizing symptoms and neurocognitive performance (all p > .05). In multivariable analyses, the frequency of pain episodes was positively associated with self-reported anxiety (p = .006) and parent-reported depressive symptoms (p = .017). CONCLUSIONS: Adolescents with SCD do not report elevated internalizing symptoms compared to normative expectations. Further research is needed to examine the trajectory of internalizing symptoms and the bidirectional relationship between pain and psychosocial functioning in SCD.

Stakeholders' perspectives on caregiver outcomes for health care transition for adolescents and young adults with special health care needs: A qualitative study.

BACKGROUND: Previous literature has explored parent/caregiver perspectives and satisfaction with the health care transition (HCT) process for their adolescents and young adults with special health care needs (AYASHCN). Limited research has explored the opinion of health care providers and researchers on parent/caregiver outcomes associated with a successful HCT for AYASHCN. METHODS: A web-based survey was distributed through the international and interdisciplinary Health Care Transition Research Consortium listserv, which at the time of the survey was composed of 148 providers dedicated to optimizing the HCT of AYAHSCN. Participants responded to the open-ended question, 'What parent/caregiver-related outcome(s) would represent a successful healthcare transition?' Respondents included 109 providers (52 health care professionals, 38 social service professionals and 19 other). Responses were coded for emergent themes, and research suggestions were identified. RESULTS: Qualitative analyses identified two major themes: emotion- and behaviour-based outcomes. Emotion-based subthemes included relinquishing control of child's health management (n = 50, 45.9%) as well as parental satisfaction and confidence in their child's care and HCT (n = 42, 38.5%). Respondents also noted that parents/caregivers should experience an improved sense of well-being and decreased stress (n = 9, 8.2%) due to a successful HCT. Behaviour-based outcomes included early preparation and planning for HCT (n = 12, 11.0%) and parental instruction on the knowledge and skills necessary for their adolescent to independently manage their health (n = 10, 9.1%). CONCLUSIONS: Health care providers can assist parents/caregivers in learning strategies for instructing their AYASHCN about condition-related knowledge and skills as well as provide support for 'letting go' of the caregiver role during the HCT to adult-focused health services and adulthood. Communication between the AYASCH, their parents/caregivers and paediatric- and adult-focused providers needs to be consistent and comprehensive to ensure continuity of care and a successful HCT. We also offered strategies to address the outcomes suggested by the participants of this study.

Neurocognitive risk in sickle cell disease: Utilizing neuropsychology services to manage cognitive symptoms and functional limitations.

Sickle cell disease (SCD) is an inherited blood disorder that is associated with developmental delays and neurocognitive deficits. This review details key findings related to neurocognitive outcomes for children and adults with emphasis on the impact of neurological correlates and disease severity. Associations between neurocognition, demographic factors and social determinants of health are also reviewed. Emerging literature has reported on the neurocognitive impact of SCD in children and adolescents in Africa and Europe, including children from immigrant communities. Neurocognitive deficits are linked to poor functional outcomes, including transition from paediatric to adult care, medication adherence and unemployment. Integrating neuropsychology into multidisciplinary care for individuals with SCD can assist with identification and management of neurocognitive concerns, intervention development, individualized care plan development and continued multidisciplinary research.

Neurocognitive functioning in preschool children with sickle cell disease.

BACKGROUND: Children with sickle cell disease (SCD) experience neurodevelopmental delays; however, there is limited research with preschool-age children. This study examined neurocognitive risk and protective factors in preschoolers with SCD. PROCEDURE: Sixty-two patients with SCD (60% HbSS/HbSß0 -thalassemia; 40% HbSC/HbSß+ -thalassemia) between the ages of 3 and 6 years (mean = 4.77 years) received a neuropsychological evaluation as routine systematic surveillance. Patients were not selected for disease severity, prior central nervous system findings, or existing cognitive concerns. Thirty-four patients (82% HbSS/HbSß0 -thalassemia) were prescribed hydroxyurea (HU) at the time of their neuropsychological evaluation. On average, these patients had been prescribed HU at 2.15 (standard deviation = 1.45) years of age. The average dose was 28.8 mg/kg/day. Besides genotype, there were no group differences in medical or demographic factors based on HU treatment status. RESULTS: Patients with HbSS/HbSß0 -thalassemia scored below normative expectations on measures of intelligence, verbal comprehension, and school readiness (false discovery rate-adjusted p-value [pFDR ] < .05). Age, sickle genotype, and HU treatment exposure were not associated with measured neurocognitive outcomes (pFDR  > .05). Greater social vulnerability at the community level was associated with poorer performance on measures of intellectual functioning, verbal comprehension, visuomotor control, and school readiness, as well as parent report of executive dysfunction (pFDR  < .05). Greater household socioeconomic status was positively associated with academic readiness. CONCLUSIONS: Preschoolers with severe SCD (HbSS/HbSß0 -thalassemia) perform below age expectations on measures of intelligence and academic readiness. Sociodemographic factors were stronger drivers of neurocognitive performance than disease severity or disease-modifying treatment. Neurodevelopmental interventions targeting the home and broader community environment are needed.

Enuresis and Hyperfiltration in Children With Sickle Cell Disease.

Nocturnal enuresis is a common symptom in children with sickle cell disease (SCD). Risk factors for development of enuresis are currently unknown. An early manifestation of SCD-associated kidney damage is glomerular hyperfiltration. We test the hypothesis that in a pediatric SCD cohort, individuals with hyperfiltration are more likely to have nocturnal enuresis when compared to children without hyperfiltration. To assess the relationship between nocturnal enuresis and hyperfiltration, we retrospectively evaluated children with SCD enrolled in the Evaluation of Nocturnal Enuresis and Barriers to Treatment among Pediatric Patients with SCD study and prospectively identified children who reported nocturnal enuresis and were enrolled in the longitudinal cohort study Sickle Cell Clinical Research and Intervention Program. Nocturnal enuresis occurred in 46.5% of Pediatric Patients with Sickle Cell Disease participants and was more frequent in participants with HbSS/HbSß 0 thalassemia and in male participants. We did not identify an association between hyperfiltration from 3 to 5 years of age with the later development of enuresis. Severe SCD genotypes and male sex were associated with nocturnal enuresis after age 5 years. We could not identify additional renal or hematologic predictors associated with the diagnosis of nocturnal enuresis. Future studies should incorporate nonrenal risk factors into studies that predict development of enuresis.

Nocturnal Enuresis in Sickle Cell: Sociodemographic, Medical, and Quality of Life Factors.

OBJECTIVE: Nocturnal enuresis is more prevalent in youth with sickle cell disease (SCD) compared to the general population. The purpose of this study is to estimate prevalence of nocturnal enuresis using diagnostic criteria and identify associated sociodemographic, medical, and health-related quality of life (HRQOL) factors. METHODS: Youth with SCD (N = 248; ages 6.00-17.99 years) and their caregivers completed semi-structured interviews and questionnaires. HRQOL was measured using the Pediatric Quality of Life (PedsQL) Inventory. Medical information was abstracted from medical record. We generated multivariable logistic regression models to examine associations between factors and current nocturnal enuresis and nocturnal enuresis occurring any time in the past (lifetime). RESULTS: Among participants (mean age, 11.3 ± 3.6 years; 50.8% male), 21.4% reported current nocturnal enuresis and 46% reported lifetime nocturnal enuresis. Male sex [odds ratio (OR), 2.57; p = .001], difficulty arousing from sleep (OR, 3.57; p < .001), higher school functioning HRQOL (OR, 1.02; p = .014), and higher fetal hemoglobin levels (OR, 1.03; p = .048) were associated with lifetime nocturnal enuresis. Younger age (OR, 1.16; p = .005), higher youth-reported fatigue (OR, 1.01; p = .045), difficulty arousing from sleep (OR, 4.92; p < .001), and higher lactate dehydrogenase levels (OR, 1.00; p = .042) were associated with current nocturnal enuresis. CONCLUSIONS: Nocturnal enuresis is prevalent in youth with SCD and is associated with HRQOL, diminished sleep, greater fatigue, and disease severity markers. Routine assessment of sleep behaviors and fatigue are necessary when treating patients with SCD to understand the impact of nocturnal enuresis on HRQOL.

Hydroxyurea treatment and neurocognitive functioning in sickle cell disease from school age to young adulthood.

Neurocognitive impairment is common in sickle cell disease (SCD) and is associated with significant functional limitations. In a cross-sectional analysis, we examined the association between hydroxyurea (HU) treatment and neurocognitive functioning from school-age to young adulthood in individuals with SCD. A total of 215 patients with HbSS/HbSß0 -thalassaemia (71% HU treated) and 149 patients with HbSC/HbSß+ -thalassaemia (20% HU treated) completed neurocognitive measures at one of four developmental stages: school-age (age 8-9 years), early adolescence (age 12-13 years), late adolescence (age 16-17 years) and young adulthood (ages 19-24 years). For participants with multiple assessments, only the most recent evaluation was included. In multivariable analysis adjusted for social vulnerability, HU treatment and sex, older age was associated with a reduction in overall intelligence quotient (IQ) of 0·55 points per year of life [standard error (SE) = 0·18, false discovery rate adjusted P value (PFDR) = 0.01] for patients with HbSS/HbSß0 -thalassaemia. Earlier initiation of HU (n = 152) in HbSS/HbSß0 -thalassaemia was associated with higher scores on neurocognitive measures across most domains, including IQ [estimate (SE) 0·77 (0·25)/year, PFDR = 0·01], after adjusting for social vulnerability, sex and treatment duration. These results support the early use of HU to limit the detrimental neurocognitive effects of SCD, while highlighting the need for additional measures to further mitigate neurocognitive deterioration.

Cognitive performance as a predictor of healthcare transition in sickle cell disease.

Neurocognitive deficits in sickle cell disease (SCD) may impair adult care engagement. We investigated the relationship between neurocognitive functioning and socio-environmental factors with healthcare transition outcomes. Adolescents aged 15-18 years who had neurocognitive testing and completed a visit with an adult provider were included. Transition outcomes included transfer interval from paediatric to adult care and retention in adult care at 12 and 24 months. Eighty adolescents (59% male, 64% HbSS/HbSß0 -thalassaemia) were included. Mean age at adult care transfer was 18·0 (±0·3) years and transfer interval was 2·0 (±2·3) months. Higher IQ (P = 0·02; PFDR  = 0·05) and higher verbal comprehension (P = 0·008; PFDR  = 0·024) were associated with <2 and <6 month transfer intervals respectively. Better performance on measures of attention was associated with higher adult care retention at 12 and 24 months (P = 0·009; PFDR  = 0·05 and P = 0·04; PFDR  = 0·12 respectively). Transfer intervals <6 months were associated with smaller households (P = 0·02; PFDR  = 0·06) and households with fewer children (P = 0·02; PFDR  = 0·06). Having a working parent was associated with less retention in adult care at 12 and 24 months (P = 0·01; P = 0·02 respectively). Lower IQ, verbal comprehension, attention difficulties and environmental factors may negatively impact transition outcomes. Neurocognitive function should be considered in transition planning for youth with SCD.

Patient-reported neurocognitive symptoms influence instrumental activities of daily living in sickle cell disease.

Individuals with sickle cell disease (SCD) experience neurocognitive decline, low medication adherence, increased unemployment, and difficulty with instrumental activities of daily living (IADL). The relationship between self-perceived cognitive difficulties and IADLs, including employment, school enrollment, independence, engagement in leisure activities, and medication adherence is unknown. We hypothesized that self-reported difficulties across neurocognitive areas would predict lower IADL skills. Adolescent and adult participants of the multi-site Sickle Cell Disease Implementation Consortium (SCDIC) (n = 2436) completed patient-reported outcome (PRO) measures of attention, executive functioning, processing speed, learning, and comprehension. Cognitive symptoms were analyzed as predictors in multivariable modeling. Outcome variables included 1) an IADL composite that consisted of employment, participation in school, reliance on others, and leisure pursuits, and 2) hydroxyurea adherence. Participants reported cognitive difficulty across areas of attention (55%), executive functioning (51%), processing speed (57%), and reading comprehension (65%). Executive dysfunction (p < 0.001) and sometimes or often experiencing learning difficulties (p < 0.001 and p = 0.04) and poor comprehension (p = 0.000 and p = 0.001), controlled for age (p < 0.001), pain (p < 0.001), and hydroxyurea use (p = 0.001), were associated with poor IADL skills. Executive functioning difficulties (p = 0.021), controlled for age (p = 0.013 for ages 25-34), genotype (p = 0.001), and hemoglobin (p = 0.004), predicted hydroxyurea non-adherence. Analysis of PRO measures indicated that cognitive dysfunction is prevalent in adolescents and adults with SCD. Cognitive dysfunction translated into clinically meaningful outcomes. PRO of cognitive symptoms can be used as an important adjunct clinical tool to monitor symptoms that impact functional skills, including engagement in societal activities and medication adherence.

A scoping review of transition interventions for young adults with sickle cell disease.

Standardized programming for individuals with sickle cell disease (SCD) transitioning from pediatric to adult-centered care does not currently exist, resulting in high rates of mortality and morbidity. This scoping review examines and evaluates the current literature on SCD transition programs and interventions. Eligible studies described an existing program for individuals with SCD aged 12-29 years preparing to transition. The Evidence Project risk-of-bias tool was used to assess article quality. We identified 30 eligible articles, of which, only two were randomized controlled trials. Many studies have incomplete reports of feasibility information, such as completion rates, patient characteristics, and attrition; all studies were limited to a single institution; and most studies were rated high for risk of bias. Progress has been made in designing and gathering initial evaluation data for SCD transition programs; however, there is a need for higher quality studies, consistent assessment, and better dissemination of programs.

Transition care continuity promotes long-term retention in adult care among young adults with sickle cell disease.

BACKGROUND/OBJECTIVES: Care continuity prevents increased health care utilization and mortality during transition from pediatric to adult care. Our program employs a co-located care delivery model, in which pediatric provider involvement continues during young adulthood. We tested the hypothesis that individuals who participated in the co-located model have greater retention in adult care compared to those who only received pediatric transition services. METHODS: This study consisted of 311 youth with SCD (51.4% male; 63.0% HbSS/HbSß0 -thalassemia) who transferred to adult care from 2007 to 2017. Retention was defined as continuation with an adult provider for ≥12 or ≥24 months post-pediatric care. Logistic regression estimated the association between co-location status and retention at 12 and 24 months. Logistic regression and t-tests were used to evaluate potential predictors of retention in adult care. RESULTS: Individuals who participated in the co-location model were 1.9 times more likely to remain in adult care 12 (95% CI: 1.01, 3.47) and 24 (95% CI: 1.01, 3.70) months post-pediatric care compared to those who did not participate. Individuals with HbSS/HbSß0 -thalassemia were 1.9 times more likely to be retained at 12 months compared to those with HbSC/HbSß+ -thalassemia/HbS/HPFH (95% CI: 1.12, 3.09). For every clinic encounter in the last 2 years of pediatric care, the odds of being retained at least 24 months after initiating adult care increased 1.1 times (95% CI: 1.02, 1.13). CONCLUSIONS: Continuity of providers from pediatric to adult care may increase long-term retention in adult care. Longitudinal monitoring of adult outcomes is critical to identifying the efficacy of transition services.

Use of Wise Device Technology to Measure Adherence to Hydroxyurea Therapy in Youth With Sickle Cell Disease.

Despite broad support for hydroxyurea (HU) therapy, suboptimal adherence is reported for youth with sickle cell disease. Valid adherence measurement is crucial to understanding the relationship between medication behavior, disease response, and patient-centered health outcomes. The current pilot study examined the feasibility of the Wise electronic device for longitudinal HU adherence measurement in a sample of 36 youths prescribed HU. The study also explored the association between HU adherence, as measured by the Wise device, with other adherence measures (ie, family report, lab values, pill count, and medication possession ratio). A measure of family-reported acceptability was also completed. Overall, results supported the feasibility of the Wise device (rate of consent=82%, device use=75%, device failure=3%) for HU adherence measurement and most families rated their experience using their device positively (favorable responses ranged from 67% to 100%). Associations between HU adherence, as measured by the Wise device, and other adherence measures were not significant. Overall, the feasibility was supported. The Wise device allows longitudinal measurement of adherence with HU from initiation as a young child (ie, with liquid formulations) through adolescence and provides a novel means of adherence measurement for both clinical and research use.

Empirically Derived Profiles of Health-Related Quality of Life in Youth and Young Adults with Sickle Cell Disease.

OBJECTIVE: Determining how the health-related quality of life (HRQOL) is impacted by living with Sickle Cell Disease (SCD) can inform psychosocial interventions. The purpose of the present study is to determine if demographic and treatment variables predict membership into empirically derived subgroups of HRQOL among youth and young adults with SCD. METHODS: Three hundred and seven youth and young adults with SCD (mean 17.63 years ± 3.74 years, 50.5% female) completed the Pediatric Quality of Life InventoryTM Sickle Cell Disease Module. Latent profile analysis examined subgroups/classes of HRQOL and relationships with demographic and treatment variables. RESULTS: Three distinct classes emerged: High HRQOL (34% of the sample), Moderate HRQOL (44% of the sample), and Low HRQOL (22% of the sample). Being female was associated with increased odds of being in the moderate or low groups. Living with more severe SCD (genotypes HbSS and HbSß0 thalassemia) was associated with increased odds of being in the Low HRQOL group. Treatment with chronic red blood cell transfusion therapy was associated with increased odds of being in the High HRQOL group. Older age predicted a small increase in the odds of being in the Low versus High HRQOL group. CONCLUSIONS: The present study adds to the literature on HRQOL in SCD by exploring person-centered, empirically derived groups of HRQOL. Identification of demographic and treatment factors that predict membership into those groups within a large sample assists in tailoring needed psychosocial interventions for youth with SCD.

Feasibility of Medical Student Mentors to Improve Transition in Sickle Cell Disease.

OBJECTIVE: Advances in medical care have resulted in nearly 95% of all children with sickle cell disease (SCD) living to adulthood. There is a lack of effective transition programming, contributing to high rates of mortality and morbidity among adolescents and young adults (AYAs) during the transition from pediatric to adult healthcare. This nonrandomized study evaluated the feasibility, acceptability, and preliminary outcomes of a novel medical student mentor intervention to improve transition outcomes for AYA with SCD. METHODS: Eligible participants were ages 18-25 years, either preparing for transition or had transferred to adult care within the past year. Twenty-four AYA with SCD (Mage = 20.3, SD = 2.6) enrolled in the program and were matched with a medical student mentor. Feasibility and acceptability of the intervention was assessed through enrollment rates, reasons for refusal, retention rates, engagement with the intervention, satisfaction, and reasons for drop-out. Dependent t-tests were used to evaluate the preliminary effects of the intervention on patient transition readiness, health-related quality of life, self-efficacy, SCD knowledge, medication adherence, and health literacy. RESULTS: Participants (N = 24) demonstrated adequate retention (75.0%), adherence to the intervention (M = 5.3 of 6 sessions), and satisfaction with the intervention components. Participants demonstrated significant improvements in transition readiness (p = .001), self-efficacy (p = .002), medication adherence (p = .02), and health literacy (p = .05). CONCLUSIONS: A medical student mentor intervention to facilitate transition from pediatric to adult care for AYA with SCD is both feasible and acceptable to patients and medical students. Preliminary results suggest benefits for patients, warranting a larger efficacy study.

Association between hydroxycarbamide exposure and neurocognitive function in adolescents with sickle cell disease.

Patients with sickle cell disease (SCD) are at increased risk for neurocognitive impairments. While disease-modifying treatment, such as hydroxycarbamide (hydroxyurea), may decrease this risk, it has not been systematically investigated in children with SCD. We screened neurocognitive functioning in 103 adolescents with SCD (16-17 years, 50% female) and compared outcomes between patients with a history of exposure to hydroxycarbamide (n = 12 HbSC/HbSß+ thalassaemia; n = 52 HbSS/HbSß0 thalassaemia) and those never treated with hydroxycarbamide (n = 31 HbSC/HbSß+ thalassaemia; n = 8 HbSS/HbSß0 thalassaemia). Demographic distributions were similar between the groups. After adjusting for socioeconomic status, the hydroxycarbamide group had significantly higher scores on nonverbal IQ (HbSC/HbSß thalassaemia: P = 0·036, effect size [d] = 0·65), reaction speed (HbSS/HbSß0 thalassaemia: P = 0·002, d = 1·70), sustained attention (HbSS/HbSß0 thalassaemia: P = 0·014, d = 1·30), working memory (HbSC/HbSß+ thalassaemia: P = 0·034, d = 0·71) and verbal memory (HbSC/HbSß+ thalassaemia: P = 0·038, d = 0·84) when compared to those who did not receive hydroxycarbamide. In patients with HbSS/HbSß0 thalassaemia, longer treatment duration with hydroxycarbamide was associated with better verbal memory (P = 0·009) and reading (P = 0·002). Markers of hydroxycarbamide effect, including higher fetal haemoglobin (HbF), higher mean corpuscular volume (MCV) and lower white blood cell count (WBC), were associated with better verbal fluency (HbF: P = 0·014, MCV: P = 0·006, WBC: P = 0·047) and reading (MCV: P = 0·021, WBC: P = 0·037). Cognitive impairment may be mitigated by exposure to hydroxycarbamide in adolescents with SCD.