Investigating the Sleep-Pain Relationship in Youth with Sickle Cell Utilizing mHealth Technology.

OBJECTIVES: The current study utilized mHealth technologies that were objective (e.g., sleep actigraphy and pulse oximetry) and time-sensitive (e.g., ecological momentary assessments [EMAs]) to characterize sleep in youth with sickle cell disease (SCD) and investigate the relationships between sleep variables and pain. It also investigated the influence of age on sleep and the sleep-pain relationship. METHODS: Eighty-eight youth with SCD (aged 8-17 years) were recruited from three regional pediatric SCD clinics. Youth completed twice daily EMAs for up to 4 weeks to assess nighttime subjective sleep quality and daily pain. They also wore a sleep actigraph for 2 weeks to assess sleep duration, sleep efficiency, and sleep latency, and a wrist-worn pulse oximeter for two nights to assess whether they had sleep apnea. Multilevel models were calculated predicting daily SCD pain using the sleep variables, age, and the interaction between age and the sleep variables. RESULTS: None of the sleep variables were related to one another. Poor subjective sleep quality during the night was related to high pain severity the next day, and high pain was related to poor subjective sleep quality that night. Older age was associated with poorer subjective sleep quality, shorter duration of nighttime sleep, and high sleep latency. Also, findings indicated that as age increased, the strength of the relationship between poor continuous subjective sleep quality and high pain severity increased. CONCLUSIONS: Future research is needed to examine possible mechanisms connecting subjective sleep quality to high pain.

Controlled trial of transfusions for silent cerebral infarcts in sickle cell anemia.

BACKGROUND: Silent cerebral infarcts are the most common neurologic injury in children with sickle cell anemia and are associated with the recurrence of an infarct (stroke or silent cerebral infarct). We tested the hypothesis that the incidence of the recurrence of an infarct would be lower among children who underwent regular blood-transfusion therapy than among those who received standard care. METHODS: In this randomized, single-blind clinical trial, we randomly assigned children with sickle cell anemia to receive regular blood transfusions (transfusion group) or standard care (observation group). Participants were between 5 and 15 years of age, with no history of stroke and with one or more silent cerebral infarcts on magnetic resonance imaging and a neurologic examination showing no abnormalities corresponding to these lesions. The primary end point was the recurrence of an infarct, defined as a stroke or a new or enlarged silent cerebral infarct. RESULTS: A total of 196 children (mean age, 10 years) were randomly assigned to the observation or transfusion group and were followed for a median of 3 years. In the transfusion group, 6 of 99 children (6%) had an end-point event (1 had a stroke, and 5 had new or enlarged silent cerebral infarcts). In the observation group, 14 of 97 children (14%) had an end-point event (7 had strokes, and 7 had new or enlarged silent cerebral infarcts). The incidence of the primary end point in the transfusion and observation groups was 2.0 and 4.8 events, respectively, per 100 years at risk, corresponding to an incidence rate ratio of 0.41 (95% confidence interval, 0.12 to 0.99; P=0.04). CONCLUSIONS: Regular blood-transfusion therapy significantly reduced the incidence of the recurrence of cerebral infarct in children with sickle cell anemia. (Funded by the National Institute of Neurological Disorders and Stroke and others; Silent Cerebral Infarct Multi-Center Clinical Trial ClinicalTrials.gov number, NCT00072761, and Current Controlled Trials number, ISRCTN52713285.).

Prasugrel in children with sickle cell disease: pharmacokinetic and pharmacodynamic data from an open-label, adaptive-design, dose-ranging study.

INTRODUCTION: This phase 2 study was designed to characterize the relationship among prasugrel dose, prasugrel's active metabolite (Pras-AM), and platelet inhibition while evaluating safety in children with sickle cell disease. It was open-label, multicenter, adaptive design, dose ranging, and conducted in 2 parts. Part A: Patients received escalating single doses leading to corresponding increases in Pras-AM exposure and VerifyNow®P2Y12 (VN) platelet inhibition and decreases in VNP2Y12 reaction units and vasodilator-stimulated phosphoprotein platelet reactivity index. Part B: Patients were assigned daily doses (0.06, 0.08, and 0.12 mg/kg) based on VN pharmacodynamic measurements at the start of 2 dosing periods, each 14±4 days. Platelet inhibition was significantly higher at 0.12 mg/kg (56.3%±7.4%; least squares mean±SE) compared with 0.06 mg/kg (33.8%±7.4%) or 0.08 mg/kg (37.9%±5.6%). Patients receiving 0.12 mg/kg achieved ≥30% platelet inhibition; only 1 patient receiving 0.06 mg/kg exceeded 60% platelet inhibition. High interpatient variability in response to prasugrel and the small range of exposures precluded rigorous characterization of the relationship among dose, Pras-AM, and platelet inhibition. SAFETY: No hemorrhagic events occurred in Part A; 3 occurred in Part B, all mild and self-limited. CONCLUSIONS: Most children with sickle cell disease may achieve clinically relevant platelet inhibition with titration of daily-dose prasugrel.

Associated risk factors for silent cerebral infarcts in sickle cell anemia: low baseline hemoglobin, sex, and relative high systolic blood pressure.

The most common form of neurologic injury in sickle cell anemia (SCA) is silent cerebral infarction (SCI). In the Silent Cerebral Infarct Multi-Center Clinical Trial, we sought to identify risk factors associated with SCI. In this cross-sectional study, we evaluated the clinical history and baseline laboratory values and performed magnetic resonance imaging of the brain in participants with SCA (HbSS or HbSß° thalassemia) between the ages of 5 and 15 years with no history of overt stroke or seizures. Neuroradiology and neurology committees adjudicated the presence of SCI. SCIs were diagnosed in 30.8% (251 of 814) participants who completed all evaluations and had valid data on all prespecified demographic and clinical covariates. The mean age of the participants was 9.1 years, with 413 males (50.7%). In a multivariable logistic regression analysis, lower baseline hemoglobin concentration (P < .001), higher baseline systolic blood pressure (P = .018), and male sex (P = .030) were statistically significantly associated with an increased risk of an SCI. Hemoglobin concentration and systolic blood pressure are risk factors for SCI in children with SCA and may be therapeutic targets for decreasing the risk of SCI. This study is registered at www.clinicaltrials.gov as #NCT00072761.

Silent cerebral infarction, income, and grade retention among students with sickle cell anemia.

Children with sickle cell anemia have a higher-than-expected prevalence of poor educational attainment. We test two key hypotheses about educational attainment among students with sickle cell anemia, as measured by grade retention and use of special education services: (1) lower household per capita income is associated with lower educational attainment; (2) the presence of a silent cerebral infarct is associated with lower educational attainment. We conducted a multicenter, cross-sectional study of cases from 22 U.S. sites included in the Silent Infarct Transfusion Trial. During screening, parents completed a questionnaire that included sociodemographic information and details of their child's academic status. Of 835 students, 670 were evaluable; 536 had data on all covariates and were used for analysis. The students' mean age was 9.4 years (range: 5-15) with 52.2% male; 17.5% of students were retained one grade level and 18.3% received special education services. A multiple variable logistic regression model identified that lower household per capita income (odds ratio [OR] of quartile 1 = 6.36, OR of quartile 2 = 4.7, OR of quartile 3 = 3.87; P = 0.001 for linear trend), age (OR = 1.3; P < 0.001), and male gender (OR, 2.2; P = 0.001) were associated with grade retention; silent cerebral infarct (P = 0.31) and painful episodes (P = 0.60) were not. Among students with sickle cell anemia, household per capita income is associated with grade retention, whereas the presence of a silent cerebral infarct is not. Future educational interventions will need to address both the medical and socioeconomic issues that affect students with sickle cell anemia.

Association of soluble fms-like tyrosine kinase-1 with pulmonary hypertension and haemolysis in sickle cell disease.

The pathophysiology of pulmonary hypertension (PHT) in sickle cell disease (SCD) is probably multifactorial. Soluble fms-like tyrosine kinase-1 (sFLT-1) is a member of the vascular endothelial growth factor receptor (VEGFR) family. By adhering to and inhibiting VEGF and placenta growth factor, it induces endothelial dysfunction. We sought to evaluate the association of sFLT-1 with clinical complications of SCD. We confirmed that sFLT-1 was significantly elevated in SCD patients compared to healthy, race-matched control subjects. The level of sFLT-1 was significantly higher in patients with PHT, but no association was observed between sFLT-1 and the frequency of acute pain episodes or history of acute chest syndrome. sFLT-1 was correlated with various measures of haemolysis, erythropoietin and soluble vascular cell adhesion molecule-1. By inducing endothelial dysfunction, sFLT-1 may contribute to the pathogenesis of SCD-associated PHT, although this effect does not appear to be independent of haemolysis.

Pulmonary, gonadal, and central nervous system status after bone marrow transplantation for sickle cell disease.

We conducted a prospective, multicenter investigation of human-leukocyte antigen (HLA) identical sibling bone marrow transplantation (BMT) in children with severe sickle cell disease (SCD) between 1991 and 2000. To determine if children were protected from complications of SCD after successful BMT, we extended our initial study of BMT for SCD to conduct assessments of the central nervous system (CNS) and of pulmonary function 2 or more years after transplantation. In addition, the impact on gonadal function was studied. After BMT, patients with stroke who had stable engraftment of donor cells experienced no subsequent stroke events after BMT, and brain magnetic resonance imaging (MRI) exams demonstrated stable or improved appearance. However, 2 patients with graft rejection had a second stroke after BMT. After transplantation, most patients also had unchanged or improved pulmonary function. Among the 11 patients who had restrictive lung changes at baseline, 5 were improved and 6 had persistent restrictive disease after BMT. Of the 2 patients who had obstructive changes at baseline, 1 improved and 1 had worsened obstructive disease after BMT. There was, however, significant gonadal toxicity after BMT, particularly among female recipients. In summary, individuals who had stable donor engraftment did not experience sickle-related complications after BMT, and were protected from progressive CNS and pulmonary disease.

Urinary albumin excretion is associated with pulmonary hypertension in sickle cell disease: potential role of soluble fms-like tyrosine kinase-1.

BACKGROUND: Pulmonary hypertension (PHT) is reported to be associated with measures of renal function in patients with sickle cell disease (SCD). The purpose of this exploratory study was to determine the relationship between albuminuria and both clinical and laboratory variables in SCD. DESIGN AND METHODS: This cross-sectional study was performed using a cohort of adult patients with SCD and control subjects without SCD. Spot urine for microalbumin/creatinine ratio, measures of hemolysis, inflammation and other laboratory studies were obtained. Pulmonary artery systolic pressure was determined by Doppler echocardiography, and the diagnosis of PHT was defined using age-, sex- and body mass index-adjusted reference ranges. RESULTS: Seventy-three patients with SCD and 21 healthy, race-matched control subjects were evaluated. In patients with SCD, normoalbuminuria was observed in 34 patients (46.6%), microalbuminuria in 24 patients (32.9%) and macroalbuminuria in 15 patients (20.5%). There was a significant correlation between urine albumin excretion and age. In patients with HbSS and Sbeta(0) thalassemia, the levels of sFLT-1, soluble VCAM and NT pro-BNP were significantly higher in those with macroalbuminuria, compared to patients with microalbuminuria and normoalbuminura, but no significant differences were observed in the levels of laboratory measures of hemolysis. Urine albumin excretion was associated with PHT and a history of stroke. CONCLUSIONS: Our study confirms the high prevalence of albuminuria in SCD. The association of urine albumin excretion with sFLT-1 suggests that this vascular endothelial growth factor receptor family member may contribute to the development of albuminuria in SCD. By inducing endothelial activation and endothelial dysfunction, sFLT-1 appears to be a link between glomerulopathy and PHT in SCD.

Depression and Anxiety as Moderators of the Pain-Social Functioning Relationship in Youth with Sickle Cell Disease.

PURPOSE: Youth with sickle cell disease (SCD), a genetic disorder of red blood cells, may experience acute pain episodes lasting 2 to 3 days on average. While existing research has demonstrated associations between SCD pain and poor social functioning in youth with SCD, there are no data on whether symptoms of depression and anxiety modify the relationship between pain and functional outcomes in pediatric pain populations. It was hypothesized that more symptoms of depression and anxiety would exacerbate the relationship between high pain and poor social functioning in youth with SCD. PATIENTS AND METHODS: We conducted a cross-sectional study of 114 youth with SCD and their guardians assessing the youth's pain, social functioning, and symptoms of depression and anxiety. RESULTS: Analyses indicated that elevated levels of depressive symptoms were related to poorer self-reported interpersonal skills. More anxiety symptoms were related to better guardian-reported social skills and weakened the relationship between high pain frequency and poor self-reported interpersonal skills. CONCLUSION: Findings build on previous work supporting the need for multidisciplinary approaches to care for youth with SCD who experience pain, and provide rationale for future studies to investigate the direct and possible moderating effects of depression and anxiety symptoms on other functional outcomes in youth with SCD and other pediatric pain populations.

Sleep Moderating the Relationship Between Pain and Health Care Use in Youth With Sickle Cell Disease.

OBJECTIVES: The purpose of the current study was to investigate the influence of sleep on the relationship between pain and health care use (HCU) in youth with sickle cell disease (SCD). It was hypothesized that poor sleep would be related to higher HCU and would strengthen the relationship between high pain frequency and more HCU among youth with SCD. MATERIALS AND METHODS: Ninety-six youth with SCD (aged 8 to 17 y) and their guardians were recruited from 3 regional pediatric SCD clinics. Guardians reported on the youth's pain frequency and HCU using the Structured Pain Interview for parents, and youth wore a sleep actigraph for up to 2 weeks to assess sleep duration and sleep efficiency. A series of regression models were calculated with the following outcomes: emergency department visits, hospitalizations, and health care provider contacts. RESULTS: Inconsistent with hypotheses, poor sleep was not directly related to HCU. Also, higher sleep duration appeared to strengthen the relationship between high pain frequency and more emergency department visits. CONCLUSIONS: Findings suggest that good sleep may serve as a protective factor for better matching pain to HCU. Results should be interpreted in the context of study limitations. Research is needed to investigate possible mechanisms linking sleep duration to HCU in response to pain and to ascertain if sleep patterns influence the relationship between pain and other functional outcomes in youth with SCD. Clinically, these findings support the need to acknowledge and address the role that sleep plays in responding to SCD pain in pediatric populations.

Optimism predicting daily pain medication use in adolescents with sickle cell disease.

This study examined the influence of optimism on pain medication use in adolescents with sickle cell disease (n=27; 18 females, 9 males). Participants completed a baseline measure of optimism and an average of 100 daily-diary assessments of pain severity and medication use. Results indicated that adolescents who experienced more severe pain used more analgesic and opioid medications. Optimism was a significant moderator of the relation between pain and opioid-medication use. At medium and high levels of optimism, pain was positively related to opioid use, but at low levels of optimism, the same relation was not present, suggesting that more optimistic adolescents are better able to match their medication use to their pain severity. Future research should examine how other psychosocial factors might influence pain medication use in adolescents and adults who experience pain, and clinicians should take into account psychosocial factors when working with pain populations.

Immunogenicity of pneumococcal vaccination in a patient with sickle hemoglobinopathy: a case report.

Despite decrease in morbidity and mortality from invasive pneumococcal disease (IPD), individuals with asplenia remain at risk for IPD compared to the general population. This report describes a young adult with hemoglobin SD and documented splenic autoinfarction with pneumococcal sepsis, meningitis, and pneumonia within seven months of immunization with PPSV-23.

A 19-year-old man with sickle cell disease presenting with spinal infarction: a case report.

INTRODUCTION: Vasculopathy of the large vessels commonly occurs in sickle cell disease, and as a result cerebral infarction is a well characterized complication of this condition. However, spinal infarction appears to be rare. Spinal infarct is infrequent in the non-sickle cell population as well, and accounts for only about 1 percent of all central nervous system infarcts. CASE PRESENTATION: In the present work, we report the case of a 19-year-old African-American man with sickle cell disease who experienced an anterior spinal infarct and subsequent quadriplegia. He was incidentally noted to be a heterozygote for factor V Leiden. We also reviewed the literature and found two previous cases of spinal cord infarction and sickle hemoglobin. Our literature search did not demonstrate that heterozygocity for factor V Leiden plays an important role in spinal cord infarction. CONCLUSIONS: The paucity of cases associated with sickle hemoglobin does not allow us to postulate any particular risk factors with sickle cell disease that might predispose patients to spinal cord infarction. Our patient's case raises the question as to whether spinal cord infarction is being missed in individuals with sickle cell disease and neurologic symptoms.

Daily mood as a mediator or moderator of the pain-sleep relationship in children with sickle cell disease.

OBJECTIVE: To investigate mood as a mediator or moderator of the pain-sleep relationship in children with sickle cell disease (SCD). METHOD: Children with SCD (n = 20; aged 8-12 years) completed daily diaries assessing mood, sleep, and pain for up to 2 months. Data was analyzed using multilevel modeling. Results Results indicate that negative mood partially mediates the relationship between high daily pain and poor sleep that night as well the relationship between poor sleep and high daily pain the following day. The impact of poor sleep on high pain the following day was weakened at increasing levels of positive mood. CONCLUSION: Research is needed to fully explore the ways positive and negative mood may relate to pain and sleep characteristics. This information may be beneficial for developing more effective pain management and sleep interventions.

Brief report: sleep in children with sickle cell disease: an analysis of daily diaries utilizing multilevel models.

OBJECTIVE: To investigate the pain-sleep relationship in children with sickle cell disease (SCD) and the influence of stress and pain medication use on this relationship. METHOD: Children with SCD (n = 20; aged 8-12 years) completed daily diaries assessing sleep, pain, stress, and pain medication use for up to 2 months. Data analyzed using multilevel modeling. RESULTS: High daily pain was related to poor sleep quality that night and poor sleep quality was related to high pain the following day. High stress was related to less sleep. High same-day pain and pain medication attenuated the impact of pain on sleep quality. CONCLUSION: Results highlight the importance of sleep in addressing functioning in children with chronic pain, knowledge which may help patients and their families better manage the child's pain. Behavioral pain interventions may be improved by the inclusion of strategies to encourage proper sleep hygiene and address sleep issues.

Molecular characterization of Hb D-Ibadan [beta87(F3)Thr-->Lys] in combination with Hb S [beta6(A3)Glu-->Val] and with beta+-Thalassemia: report of two cases.

Hb D-Ibadan [beta87(F3)Thr-->Lys] is a common variant in the Nigerian population, which has been reported in association with Hb S [beta6(A3)Glu-->Val] and with beta-thalassemia. Unlike the Hb S/Hb D-Los Angeles [beta121(GH4)Glu-->Gln] combination, compound heterozygosity for Hb D-Ibadan and Hb S does not result in a sickling disorder. We report the first case of a combination of Hb D-Ibadan with beta+-thalassemia, and the first observation of Hb S/Hb D-Ibadan in the African-American population. In both cases, the characterization of Hb D-Ibadan was achieved by sequencing of the genomic DNA. Although protein based methods such as isoelec-trofocusing and high performance liquid chromatography may suggest that the "D-like" variant is different from Hb D-Los Angeles, the definitive identification of the variant by structural analysis or molecular genetic methods should be undertaken, particularly in newborn screening programs when the variant is found in combination with Hb S.

Daily stress and mood and their association with pain, health-care use, and school activity in adolescents with sickle cell disease.

OBJECTIVE: To determine the extent to which daily stress and mood are associated with pain, health-care use, and school activity in adolescents with sickle cell disease (SCD). METHOD: Adolescents with SCD (n = 37; aged 13 to 17 years) completed daily diaries assessing pain, stress, mood, activity, and health-care use for up to 6 months. Multilevel modeling was used to analyze the data. RESULTS: Daily increases in stress and negative mood were associated with increases in same-day pain, health-care use, and reductions in school and social activity. Increases in positive mood were associated with decreases in pain, less health-care use, and more activity participation. Notably, pain was predictive of higher stress and lower positive mood on subsequent days. CONCLUSION: Pain in adolescents with SCD is stressful and may lead to alterations in mood states. Understanding the way in which these variables relate to health-care use and activity may lead to improved pain management approaches.

Effect of hydroxyurea on growth in children with sickle cell anemia: results of the HUG-KIDS Study.

OBJECTIVES: Although hydroxyurea is effective in treating adults with sickle-cell anemia (SCA), there is concern that it may adversely affect growth in children. We report the growth characteristics of patients in the Phase I-II pediatric hydroxyurea trial (HUG-KIDS) before and during treatment at the maximum tolerated dose for one year. STUDY DESIGN: Children and adolescents with SCA (n = 68), aged 5 to 16 years at baseline, reached the maximum tolerated dose and had serial height, weight, and Tanner stage measurements. Data from the Cooperative Study of Sickle Cell Disease (CSSCD) were used for comparison. Mixed-effects models were used to compare serial measurements as a function of age and group. RESULTS: In girls, there were no significant differences in height or weight among the pretreatment, on-treatment, and CSSCD groups. Compared with the CSSCD group, HUG-KIDS boys were heavier starting at age 9 years, and pretreatment HUG-KIDS boys were taller starting at age 7 years. The Tanner stage transitions took place at appropriate ages. CONCLUSIONS: Hydroxyurea treatment had no adverse effect on height or weight gain or pubertal development in school-aged children with SCA.