Hydroxyurea therapy in children severely affected with sickle cell disease

Epicatechin exerts dual action to shield sickling and hydroxyurea-induced myelosuppression: Implication in sickle cell anemia management

Hydroxyurea (HU) is the key drug to treat Sickle cell anemia (SCA). However, its treatment is associated with the liability of myelosuppression. The present study aimed to investigate the potential of epicatechin as a supplementation therapy for the symptomatic management of SCA under HU therapy. A panel of experiments were performed at first to observe epicatechin's effect on sickling and hemolytic behaviour using SCA patient's blood (ex vivo). Thereafter, the effect of HU in the presence or absence of epicatechin was investigated on cytokine inhibition in rat splenocytes (ex vivo) as well as alterations in hematological parameters and kidney function tests in rats (in vivo). Then, any effect of epicatechin on pharmacokinetic modulation of HU in rats was elucidated along with the underlying mechanism using a battery of in vitro and in vivo models. Epicatechin exhibited potent action on anti-sickling, polymerization inhibition, and erythrocyte membrane stability. It did not show any inherent hemolytic activity and reduced TNF-α level during concomitant administration with HU. Based on hematological changes in rats, epicatechin treatment aided to the beneficial effect of HU and prevented the treatment-linked disadvantageous effects of HU like neutropenia. The plasma exposure of HU was significantly augmented in rats upon simultaneous oral administration of epicatechin with HU. Down-regulation of Oatp1b2 and catalase possibly contributed to the pharmacokinetic interaction of HU. Epicatechin is found to be a promising candidate and should be explored at a reduced dose level of HU towards offsetting the dose-dependent myelosuppressive effect of HU under the frame of supplementation therapy in SCA.

Investigating the Potential Use of Andrographolide as a Coadjuvant in Sickle Cell Anemia Therapy

Andrographolide is one of the main active principles of Andrographolide paniculata and has been extensively explored for its therapeutic use. Current studies focus on phytotherapeutics-based adjuvant therapy to symptomatically treat sickle cell anemia (SCA) as there is no specific drug/gene therapy available to date. The present study aimed to explore the potential of andrographolide as an adjuvant therapy for SCA in the presence or absence of hydroxyurea (HU), a key drug for SCA treatment. A panel of ex vivo and in vivo experimentations was performed to explore the antisickling activity of andrographolide, followed by evaluating pharmacokinetic and pharmacodynamic (PK/PD) activities in the presence of HU. Andrographolide showed significant antisickling activity using blood from SCA patients (ex vivo) and did not show any deleterious effect to cause hemolysis using rat blood (ex vivo). It displayed a substantial decrease in HU-induced decline in splenic lymphocyte proliferation and cytokine level (TNF-α and IFN-γ) using rat splenocytes (ex vivo). Concomitant oral administration of andrographolide with HU in rats for 15 days exhibited a noticeable improvement in the RBC count and hemoglobin levels comparable to the efficacy of l-glutamine (in vivo). Simultaneous administration of andrographolide with HU caused no marked effect on any pharmacokinetic parameters of HU except the highest plasma concentration of HU and its corresponding time point, which significantly dropped and delayed, respectively (in vivo). No considerable effect of andrographolide was observed on urease and horseradish peroxidase activity (in vitro). Overall, results suggest that andrographolide has several beneficial actions to be an adjuvant therapy to symptomatically manage SCA, but it should be avoided during the prescribed therapy of HU.

Hydroxyurea Use Associated with Nonverbal and Executive Skills in Sickle Cell Anemia

OBJECTIVE

Hydroxyurea (HU) is used in children with sickle cell disease (SCD) to increase fetal hemoglobin (HF), contributing to a decrease in physical symptoms and potential protection against cerebral microvasculopathy. There has been minimal investigation into the association between HU use and cognition in this population. This study examined the relationship between HU status and cognition in children with SCD.

METHODS

Thirty-seven children with SCD HbSS or HbS/β0 thalassaemia (sickle cell anemia; SCA) ages 4:0-11 years with no history of overt stroke or chronic transfusion completed a neuropsychological test battery. Other medical, laboratory, and demographic data were obtained. Neuropsychological function across 3 domains (verbal, nonverbal, and attention/executive) was compared for children on HU (n = 9) to those not taking HU (n = 28).

RESULTS

Children on HU performed significantly better than children not taking HU on standardized measures of attention/executive functioning and nonverbal skills. Performance on verbal measures was similar between groups.

CONCLUSIONS

These results suggest that treatment with HU may not only reduce physical symptoms, but may also provide potential benefit to cognition in children with SCA, particularly in regard to attention/executive functioning and nonverbal skills. Replication with larger samples and longitudinal studies are warranted.

Effect of Concomitant Hydroxyurea Therapy with Rutin and Gallic Acid: Integration of Pharmacokinetic and Pharmacodynamic Approaches

Hydroxyurea (HU) is the first-ever approved drug by USFDA for sickle cell anemia (SCA). However, its treatment is associated with severe side effects like myelosuppression. Current studies are focused on the supplementation therapy for symptomatic management of SCA. In the present study, we aimed to explore rutin's and gallic acid's potential individually, for concomitant therapy with HU using pharmacokinetic and pharmacodynamic approaches since there is no such precedent till date. In vivo pharmacokinetic studies of HU in rats showed that rutin could be safely co-administered with HU, while gallic acid significantly raised the plasma concentration of HU. Both the phytochemicals did not have any marked inhibitory effect on urease but have considerable effects on horseradish peroxidase enzyme. The experimental phytoconstituents displayed a very low propensity to cause in vitro hemolysis. Gallic acid markedly enhanced the HU-induced decrease in lymphocyte proliferation. A substantial improvement by rutin or gallic acid was observed in HU-induced reduction of the main hematological parameters in rats. Combined treatment of HU with rutin and gallic acid reduced serum levels of both IL-6 and IL-17A. Overall, both rutin and gallic acid are found to have promising phytotherapy potential with HU. Further exploration needs to be done on both candidates for use as phytotherapeutics for SCA.

Hydroxyurea use in young infants with sickle cell disease

BACKGROUND

Hydroxyurea (HU) reduces complications and improves quality and duration of life in sickle cell disease. Evidence supports the use of HU starting after nine months of age.

PROCEDURES

We performed a retrospective study of patients starting HU at less than five years of age between January 1, 2008, and December 31, 2016. We evaluated clinical events, laboratory data, and toxicity between three different age groups: cohort 1 (0-1 year), cohort 2 (1-2 years), and cohort 3 (2-5 years).

RESULTS

Sixty-five patients were included in the analysis. The mean age was 7.2 months (n = 35), 19.5 months (n = 13), and 35.5 months (n = 17) for cohorts 1, 2, and 3, respectively. Cohort 1 had higher hemoglobin (P = 0.0003) and MCV (P = 0.0199) and lower absolute reticulocyte count (P = 0.0304) at 24 months of age compared with cohort 3. The absolute neutrophil count (ANC) was lower compared with both older cohorts (P = 0.0364, 0.0025). The mean baseline hemoglobin F in cohort 1 was 31.5% compared with 19.7% and 16.5% in cohorts 2 and 3, respectively (P = 0.002, P < 0.0001). The mean duration of therapy was 31.3 months, 57.6 months (P = 0.018), and 29.1 months (P = 0.401), respectively. Mean Hb F levels remained higher in cohort 1 (29.9%) compared with cohorts 2 and 3 (20.4%, P = 0.007; 20.6%, P = 0.003). Cohort 1 experienced fewer hospitalizations (P = 0.0025), pain crises (P = 0.0618), and transfusions (P = 0.0426). There was no difference in toxicity between groups.

CONCLUSION

HU is safe and effective in patients 5 to 12 months of age and generated a more robust response compared with initiation in older patients.

Stroke Recurrence in Nigerian Children With Sickle Cell Disease: Evidence for a Secondary Stroke Prevention Trial

BACKGROUND

To improve the quality of care for children with sickle cell anemia in Kano, Nigeria, we initiated a standard care protocol in 2014 to manage children with strokes at Aminu Kano Teaching Hospital.

METHODS

The standard care protocol requires that children with acute strokes be treated with hydroxyurea at a fixed dose of 20 mg/kg/day within two months of the stroke.

RESULTS

Twenty-nine children with sickle cell anemia and initial stroke were identified based on clinical World Health Organization criteria from 2014 to 2017. Follow-up was a median of 1.04 years (interquartile range 0.43 to 1.83 years) to either July 2017 or a second stroke, corresponding to an initial stroke incidence rate of 0.88 per 100 patient-years. Eight children had a recurrent stroke, six of whom were prescribed hydroxyurea 20 mg/kg/day by two months after initial stroke. Two children died. Six of the recurrent strokes occurred within six months of the initial stroke, two before hydroxyurea prescription. The stroke recurrence rate was 17.4 events per 100 patient-years. Adherence was approximately 60%, partly because families had to pay for hydroxyurea. Stroke incidence is probably underestimated because despite formal training for stroke detection during the quality improvement period, no participant had assessment using a standardized pediatric stroke scale and neuroimaging was not available.

CONCLUSIONS

In children with sickle cell anemia, a high rate of initial and recurrent strokes exists in a low-resource setting. Ongoing needs include training to detect strokes with an objective stroke assessment and government-supported free access to hydroxyurea for stroke prevention.

Intermittent or uneven daily administration of low-dose hydroxyurea is effective in treating children with sickle cell anemia in Angola

BACKGROUND

Although hydroxyurea is proven effective in treatment of sickle cell anemia (SCA) and is widely prescribed in high-income countries, due to questions about feasibility of treating large numbers of patients in resource-limited health systems, its use is limited in sub-Saharan Africa (SSA), where most children with SCA live. We assessed hematological response and toxicity of hydroxyurea treatment for SCA in Angola.

METHODS

Retrospective study of children with SCA (not selected for clinical severity) treated on a fixed dose of hydroxyurea for at least 6 months. Because only the 500 mg capsule was available, dose was averaged weekly. We evaluated toxicity events and magnitude of hydroxyurea-induced changes in blood counts and compared patients who received a uniform daily dose to those prescribed intermittent or uneven daily doses.

RESULTS

Only 13% of 303 patients received a uniform dose of hydroxyurea daily. Dose ranged from 16.5 to 22.8 mg/kg/day. Hydroxyurea increased HGB and mean cell volume values by 0.5 g/dL (P < 0.0001) and 8 fL (P < 0.0001), while ANC, PLT, and ARC decreased 1.1 × 10⁹ /L (P < 0.0001), 34 × 10⁹ /L (P = < 0.0001), and 19 × 10⁹ /L (P = 0.0008), respectively. There were no differences in magnitude of hydroxyurea-induced changes between patients prescribed intermittent or uneven doses and uniform daily doses, or between those treated in the lower and higher dose quartiles. Hematological toxicity events were mild and reversible.

CONCLUSION

Intermittent or uneven daily dosing of hydroxyurea is as effective as fixed daily doses in treating SCA. This strategy may enable treatment of additional children with SCA in SSA.

Hydroxycarbamide adherence and cumulative dose associated with hospital readmission in sickle cell disease: a 6-year population-based cohort study

Sickle cell disease (SCD) is a congenital haemoglobinopathy that causes frequent acute care/emergency room visits and hospital admissions for affected individuals. Evidence from population-based studies demonstrating the role of hydroxycarbamide (HC, also termed hydroxyurea) in reducing hospital readmission rates is limited. Our objective was to describe the use of HC and its association with acute care utilization and readmission rates using a large, nationally-representative US health insurance claims database over a 6-year period between 2009 and 2014. We identified 20 721 SCD-related inpatient and acute care encounters. Patients had been exposed to HC within 6 months prior to admission in 4263 (21%) of SCD-related admission events. HC use was more common among children aged 10-17 years and young adults aged 18-29 years. HC was associated with lower 30-day all-cause readmission rates in adults treated with average daily doses ≥1 g (odds ratio [OR], 0·72, 95% confidence interval [CI] 0·52-0·99) and doses of 0·5-1 g (OR, 0·73, 95% CI 0·57-0·93), compared to HC treatment with average daily doses of <0·5 g; adherence to HC with proportion of days covered of ≥0·80 was also associated with significantly lower 30-day all-cause readmission risks (OR, 0·59, 95% CI 0·41-0·84). Optimal therapeutic dosing and adherence to HC treatment significantly reduces 30-day readmissions among patients with SCD.

State of the Art Management of Acute Vaso-occlusive Pain in Sickle Cell Disease

Acute vaso-occlusive crisis (VOC) is a hallmark of sickle cell disease (SCD). Multiple complex pathophysiological processes can result in pain during a VOC. Despite significant improvements in the understanding and management of SCD, little progress has been made in the management of pain in SCD, although new treatments are being explored. Opioids and non-steroidal anti-inflammatory drugs (NSAIDs) remain the mainstay of treatment of VOC pain, but new classes of drugs are being tested to prevent and treat acute pain. Advancements in the understanding of the pathophysiology of SCD and pain and the pharmacogenomics of opioids have yet to be effectively utilized in the management of VOC. Opioid tolerance and opioid-induced hyperalgesia are significant problems associated with the long-term use of opioids, and better strategies for chronic pain therapy are needed. This report reviews the mechanisms of pain associated with acute VOC, describes the current management of VOC, and describes some of the new therapies under evaluation for the management of acute VOC in SCD.

Sickle Cell Disease: Advances in Treatment

BACKGROUND

Sickle cell disease causes significant morbidity and mortality and affects the economic and healthcare status of many countries. Yet historically, the disease has not had commensurate outlays of funds that have been aimed at research and development of drugs and treatment procedures for other diseases.

METHODS

This review examines several treatment modalities and new drugs developed since the late 1990s that have been used to improve outcomes for patients with sickle cell disease.

RESULTS

Targeted therapies based upon the pathophysiologic mechanisms of sickle cell disease that result in organ dysfunction and painful episodes include hydroxyurea, L-glutamine, crizanlizumab, and other drugs that are currently on the market or are on the verge of becoming available. These agents have the potential to improve survival and quality of life for individuals with sickle cell disease. Also discussed is stem cell transplantation that, to date, is the only curative approach for this disease, as well as the current status of gene therapy.

CONCLUSION

These examples demonstrate how the current knowledge of sickle cell disease pathophysiology and treatment approaches intersect. Although interest in sickle cell research has blossomed, many more clinical trials need to be initiated and subjected to more strenuous examination and analysis than have been used in the past.

The morbidity pattern of children with sickle cell disorders admitted to the Queen Elizabeth Hospital, Barbados (2009-2013)

A retrospective study was conducted by examining all the medical files of all the children with sickle cell anaemia (Hb SS) admitted from 1 January 2009 to 31 December 2013. A total of 220 admission notes (59 patients aged 5 months-16 years) were analysed. Of these, 53.2% were boys; 85.8% of the patients had Hb SS. The most common reason for admission was vaso-occlusive crisis. Blood transfusions were used in 39.7% of admissions There were no deaths during the study period. We note the number of sickle cell-related admissions and morbidity has increased, along with an increase in the number of blood transfusions. The mortality rate for children with sickle cell in Barbados is low compared to other territories in the Caribbean and worldwide. The need for better comprehensive management protocols and universal screening should decrease the morbidity patterns seen in this study.

Optimizing hydroxyurea therapy for sickle cell anemia

Hydroxyurea has proven efficacy in numerous clinical trials as a disease-modifying treatment for patients with sickle cell anemia (SCA) but is currently under-used in clinical practice. To improve the effectiveness of hydroxyurea therapy, efforts should be directed toward broadening the clinical treatment indications, optimizing the daily dosage, and emphasizing the benefits of early and extended treatment. Here, various issues related to hydroxyurea treatment are discussed, focusing on both published evidence and clinical experience. Specific guidance is provided regarding important but potentially unfamiliar aspects of hydroxyurea treatment for SCA, such as escalating to maximum tolerated dose, treating in the setting of cerebrovascular disease, switching from chronic transfusions to hydroxyurea, and using serial phlebotomy to alleviate iron overload. Future research directions to optimize hydroxyurea therapy are also discussed, including personalized dosing based on pharmacokinetic modeling, prediction of fetal hemoglobin responses based on pharmacogenomics, and the risks and benefits of hydroxyurea for non-SCA genotypes and during pregnancy/lactation. Another critical initiative is the introduction of hydroxyurea safely and effectively into global regions that have a high disease burden of SCA but limited resources, such as sub-Saharan Africa, the Caribbean, and India. Final considerations emphasize the long-term goal of optimizing hydroxyurea therapy, which is to help treatment become accepted as standard of care for all patients with SCA.

Optimizing hydroxyurea therapy for sickle cell anemia

Hydroxyurea has proven efficacy in numerous clinical trials as a disease-modifying treatment for patients with sickle cell anemia (SCA) but is currently under-used in clinical practice. To improve the effectiveness of hydroxyurea therapy, efforts should be directed toward broadening the clinical treatment indications, optimizing the daily dosage, and emphasizing the benefits of early and extended treatment. Here, various issues related to hydroxyurea treatment are discussed, focusing on both published evidence and clinical experience. Specific guidance is provided regarding important but potentially unfamiliar aspects of hydroxyurea treatment for SCA, such as escalating to maximum tolerated dose, treating in the setting of cerebrovascular disease, switching from chronic transfusions to hydroxyurea, and using serial phlebotomy to alleviate iron overload. Future research directions to optimize hydroxyurea therapy are also discussed, including personalized dosing based on pharmacokinetic modeling, prediction of fetal hemoglobin responses based on pharmacogenomics, and the risks and benefits of hydroxyurea for non-SCA genotypes and during pregnancy/lactation. Another critical initiative is the introduction of hydroxyurea safely and effectively into global regions that have a high disease burden of SCA but limited resources, such as sub-Saharan Africa, the Caribbean, and India. Final considerations emphasize the long-term goal of optimizing hydroxyurea therapy, which is to help treatment become accepted as standard of care for all patients with SCA.

Prevention of conversion to abnormal transcranial Doppler with hydroxyurea in sickle cell anemia: A Phase III international randomized clinical trial

Children with sickle cell anemia (SCA) and conditional transcranial Doppler (TCD) ultrasound velocities (170-199 cm/sec) may develop stroke. However, with limited available clinical data, the current standard of care for conditional TCD velocities is observation. The efficacy of hydroxyurea in preventing conversion from conditional to abnormal TCD (≥200 cm/sec), which confers a higher stroke risk, has not been studied prospectively in a randomized trial. Sparing Conversion to Abnormal TCD Elevation (SCATE #NCT01531387) was a National Heart, Lung, and Blood Institute-funded Phase III multicenter international clinical trial comparing alternative therapy (hydroxyurea) to standard care (observation) to prevent conversion from conditional to abnormal TCD velocity in children with SCA. SCATE enrolled 38 children from the United States, Jamaica, and Brazil [HbSS (36), HbSβ(0) -thalassemia (1), and HbSD (1), median age = 5.4 years (range, 2.7-9.8)]. Because of the slow patient accrual and administrative delays, SCATE was terminated early. In an intention-to-treat analysis, the cumulative incidence of abnormal conversion was 9% (95% CI = 0-35%) in the hydroxyurea arm and 47% (95% CI = 6-81%) in observation arm at 15 months (P = 0.16). In post hoc analysis according to treatment received, significantly fewer children on hydroxyurea converted to abnormal TCD velocities when compared with observation (0% vs. 50%, P = 0.02). After a mean of 10.1 months, a significant change in mean TCD velocity was observed with hydroxyurea treatment (-15.5 vs. +10.2 cm/sec, P = 0.02). No stroke events occurred in either arm. Hydroxyurea reduces TCD velocities in children with SCA and conditional velocities.

Health-related Quality of Life in Infants With Sickle Cell Disease

Using historical cohorts of healthy, acutely ill, and chronically ill infants for comparison, we sought to determine whether infants with sickle cell disease (SCD) have impaired health-related quality of life (HRQL). We conducted a cross-sectional study at 2 sites: the Medical College of Wisconsin/Children's of Wisconsin and the University of Alabama School of Medicine/Children's of Alabama. Parents of 90 infants with SCD completed the PedsQL Infant Module corresponding to their infant's age (1 to 12 mo or 13 to 24 mo) during a regular clinic visit. At 1 to 12 months, infants with SCD displayed lower Physical HRQL than healthy infants, but better HRQL than chronically ill infants. By 13 to 24 months, infants with SCD had worse HRQL in all areas than healthy infants and worse Physical and Total HRQL than acutely ill infants. Compared with chronically ill infants in this age group, infants with SCD had similar Physical HRQL and better Psychosocial and Total HRQL. By 13 to 24 months, a greater proportion of infants with SCD had impaired Physical and Total HRQL compared with infants aged 1 to 12 months. All differences were significant at the (P<0.05) level. Impaired HRQL can be detected in infants with SCD.

Systematic and Meta-Analytic Review: Medication Adherence Among Pediatric Patients With Sickle Cell Disease

OBJECTIVE

To provide a comprehensive summary (systematic review) of medication adherence rates by assessment method and medication type for pediatric patients with sickle cell disease (SCD), as well as identify important correlates for future research.

METHODS

Articles assessing medication adherence and published between 1982 and February 2015 (n = 49) were identified using electronic databases. A meta-analysis of 14 studies examining demographic, medical, and psychosocial factors and medication adherence was conducted.

RESULTS

Adherence rates ranged from 12% to 100% across all medications. Approximately 30% of studies reported associations between adherence and key demographic, medical, and psychosocial correlates. Mean effect sizes were small to moderate (r = .02-.53).

CONCLUSIONS

The wide range of adherence rates reported in the literature may be because of, in part, the use of variable assessment strategies. Future studies examining pediatric SCD adherence should incorporate key correlates with the goal of replication.

Genetic education and sickle cell disease: feasibility and efficacy of a program tailored to adolescents

Sickle cell disease (SCD) genetic knowledge is important when individuals make reproductive decisions. This study assessed feasibility and efficacy of delivering basic genetic information to 101 adolescents with SCD. Participants completed a questionnaire to test SCD genetic knowledge at 3 timepoints: before genetic education session (pretest), after the session (posttest), and 6 months later (follow-up). Scores at 3 timepoints were compared by Wilcoxon signed-rank tests, and group differences were compared by Wilcoxon-Mann-Whitney and Kruskal-Wallis tests. Participants' median scores significantly increased from pretest to posttest and from pretest to follow-up. Males had a greater change in scores than females. Scores decreased slightly from posttest to follow-up. Participants with HbSS/HbSβ⁰-thal genotype and participants with more prior pain episodes exhibited a smaller increase in median scores than those with HbSC/HbSβ⁺-thal genotype and no prior pain history; however, all groups had substantial gains from pretest to posttest and follow-up tests demonstrating that adolescents with SCD can learn basic genetics. This study established that genetic education can successfully be incorporated in transition to adult care programs for adolescents with SCD. Genetic education should be included in the standard plan of care for adolescents with SCD to assist them in making informed reproductive choices.

Improving outcomes in children with sickle cell disease: treatment considerations and strategies

Over the past decades there has been a significant improvement in the care of patients with sickle cell disease (SCD) in high-income countries. However, more needs to be learned about the complex pathophysiology and the factors that contribute to the development of end organ damage from the disease. While antibiotic prophylaxis and appropriate treatment of infections have resulted in a significant reduction of early mortality, management of the painful episodes and prevention of organ damage remain a challenge. Hydroxyurea is the only medication approved as disease-modifying therapy, and bone marrow transplant as curative treatment is not available to most patients. In low-income countries with the highest disease burden, early mortality is high due to limited resources for systematic screening, early diagnosis, and disease management. In order to improve outcomes in patients with SCD in high-income countries, better and widespread implementation of known disease-modifying therapies and the development of newer therapies targeting key pathophysiologic pathways are required. In low-income countries with high disease burden, innovative approaches to develop low-cost diagnostic devices and treatments that can be implemented to scale are needed to combat early mortality from the disease. Sustainable solutions in low-resource settings require evidence-based affordable interventions that can be integrated into primary and secondary healthcare systems.

PedsQL™ Multidimensional Fatigue Scale in sickle cell disease: feasibility, reliability, and validity

BACKGROUND

Sickle cell disease (SCD) is an inherited blood disorder characterized by a chronic hemolytic anemia that can contribute to fatigue and global cognitive impairment in patients. The study objective was to report on the feasibility, reliability, and validity of the PedsQL™ Multidimensional Fatigue Scale in SCD for pediatric patient self-report ages 5-18 years and parent proxy-report for ages 2-18 years.

PROCEDURE

This was a cross-sectional multi-site study whereby 240 pediatric patients with SCD and 303 parents completed the 18-item PedsQL™ Multidimensional Fatigue Scale. Participants also completed the PedsQL™ 4.0 Generic Core Scales.

RESULTS

The PedsQL™ Multidimensional Fatigue Scale evidenced excellent feasibility, excellent reliability for the Total Scale Scores (patient self-report α = 0.90; parent proxy-report α = 0.95), and acceptable reliability for the three individual scales (patient self-report α = 0.77-0.84; parent proxy-report α = 0.90-0.97). Intercorrelations of the PedsQL™ Multidimensional Fatigue Scale with the PedsQL™ Generic Core Scales were predominantly in the large (≥0.50) range, supporting construct validity. PedsQL™ Multidimensional Fatigue Scale Scores were significantly worse with large effects sizes (≥0.80) for patients with SCD than for a comparison sample of healthy children, supporting known-groups discriminant validity. Confirmatory factor analysis demonstrated an acceptable to excellent model fit in SCD.

CONCLUSIONS

The PedsQL™ Multidimensional Fatigue Scale demonstrated acceptable to excellent measurement properties in SCD. The results demonstrate the relative severity of fatigue symptoms in pediatric patients with SCD, indicating the potential clinical utility of multidimensional assessment of fatigue in patients with SCD in clinical research and practice.

PedsQL™ sickle cell disease module: feasibility, reliability, and validity

BACKGROUND

Sickle cell disease (SCD) is an inherited chronic disease that is characterized by complications such as recurrent painful vaso-occlusive events that require frequent hospitalizations and contribute to early mortality. The objective of the study was to report on the initial measurement properties of the new PedsQL™ SCD Module for pediatric patient self-report ages 5-18 years and parent proxy-report for ages 2-18 years.

PROCEDURE

The 43-item PedsQL™ SCD Module was completed in a multisite study by 243 pediatric patients with SCD and 313 parents. Participants also completed the PedsQL™ 4.0 Generic Core Scales and PedsQL™ Multidimensional Fatigue Scale.

RESULTS

The PedsQL™ SCD Module Scales evidenced excellent feasibility, excellent reliability for the Total Scale Scores (patient self-report α = 0.95; parent proxy-report α = 0.97), and good reliability for the nine individual scales (patient self-report α = 0.69-0.90; parent proxy-report α = 0.83-0.97). Intercorrelations with the PedsQL™ Generic Core Scales and PedsQL™ Multidimensional Fatigue Scales were medium (0.30) to large (0.50) range, supporting construct validity. PedsQL™ SCD Module Scale Scores were generally worse for patients with severe versus mild disease. Confirmatory factor analysis demonstrated an acceptable to excellent model fit.

CONCLUSIONS

The PedsQL™ SCD Module demonstrated acceptable measurement properties. The PedsQL™ SCD Module may be utilized in the evaluation of SCD-specific health-related quality of life in clinical research and practice. In conjunction with the PedsQL™ Generic Core Scales and the PedsQL™ Multidimensional Fatigue Scale, the PedsQL™ SCD Module will facilitate the understanding of the health and well-being of children with SCD.

National trends in incidence rates of hospitalization for stroke in children with sickle cell disease

BACKGROUND

The success of primary stroke prevention for children with sickle cell disease (SCD) throughout the United States is unknown. Therefore, we aimed to generate national incidence rates of hospitalization for stroke in children with sickle cell disease (SCD) before and after publication of the Stroke Prevention Trial in Sickle Cell Anemia (STOP trial) in 1998.

PROCEDURE

We performed a retrospective trend analysis of the 1993-2009 Nationwide Inpatient Sample and Kids' Inpatient Databases. Hospitalizations for SCD patients 0-18 years old with stroke were identified by ICD-9CM code. The primary outcome, the trend in annual incidence rate of hospitalization for stroke in children with SCD, was analyzed by linear regression. Incidence rates of hospitalization for stroke before and after 1998 were compared by the Wilcoxon rank-sum test.

RESULTS

From 1993 to 2009, 2,024 hospitalizations were identified for stroke. Using the mean annual incidence rate of hospitalization for stroke from 1993 to 1998 as the baseline, the rate decreased from 1993 to 2009 (point estimate = -0.022/100 patient years [95% CI, -0.039, -0.005], P = 0.027). The mean annual incidence rate of hospitalization stroke decreased by 45% from 0.51 per 100 patient years in 1993-1998 to 0.28 per 100 patient years in 1999-2009 (P = 0.008). Total hospital days and charges attributed to stroke also decreased by 45% and 24%, respectively.

CONCLUSIONS

After publication of the STOP trial and hydroxyurea licensure in 1998, the incidence of hospitalization for stroke in children with SCD decreased across the United States, suggesting that primary stroke prevention has been effective nationwide, but opportunity for improvement remains.

What is the evidence that hydroxyurea improves health-related quality of life in patients with sickle cell disease?

A 10-year-old male patient with homozygous sickle cell disease presents for a follow-up clinic visit after a recent hospitalization for a painful vasoocclusive event. His parents mention that in the past year he has had 4 hospitalizations for vasoocclusive events, 2 of which were complicated by the development of acute chest syndrome that resulted in transfer to the intensive care unit. He has missed many school days and may be retained a grade this year. He feels particularly sad about missing the school field trip that occurred during his last hospitalization. He also reports that he is not able to keep up with his friends when participating in physical activities at school. The child's parents are worried that he may be depressed. You as the provider discuss the option of hydroxyurea therapy. His parents ask if hydroxyurea would improve his overall well-being and functioning.

Primary Prophylaxis in Sickle Cell Disease: Is It Feasible? Is It Effective?

Consideration of primary prophylaxis to prevent complications of sickle cell disease (SCD) requires a clear understanding of the earliest manifestations of SCD-related organ injury, a reliable clinical or laboratory tool to detect organ dysfunction, and evidence that an intervention instituted in the presymptomatic state can mitigate disease progression. This review examines the pathophysiology of SCD in organs that may be potential targets for intervention, our current capacity to evaluate early SCD manifestations, results of clinical trials, and opportunities for future interventions.

"Sickle Cell Disease in the Emergency Department: Atypical Complications and Management"

Sickle cell disease is the most common inherited blood disorder in the United States. This disorder of hemoglobin structure leads to a chronic hemolytic anemia and complex chronic disease manifested by sudden, severe, and life-threatening complications. These acute complications can occur in any organ system beginning in early childhood and lasting throughout life. The intermittent nature and acuity of these complications lend the emergency department to be an important site of care. The hallmark of sickle cell disease is the vasoocclusive painful event. Other more "typical" complications include fever, acute chest syndrome, priapism, and ischemic stroke. Children with sickle cell disease can also present with other "atypical" complications that can have devastating consequences if they are unrecognized. Detailed discussion of these "atypical" sickle cell disease complications, organized by organ system involved, will be the focus of this article.

Differences in health-related quality of life in children with sickle cell disease receiving hydroxyurea

Hydroxyurea is a safe and efficacious medication for children with sickle cell disease (SCD). Our objective was to compare health-related quality of life (HRQL) between children taking hydroxyurea and those not taking hydroxyurea. We conducted a retrospective cohort study of children with SCD who had completed the PedsQL 4.0 at Duke University Medical Center or the Midwest Sickle Cell Center. Our primary outcome was HRQL in children receiving hydroxyurea therapy compared with those not receiving hydroxyurea. One hundred and ninety-one children with SCD were included in the study. Children in the hydroxyurea group had higher self-reported Total PedsQL median scores than children in the no hydroxyurea group (P=0.04). Child self-reported physical functioning scores were significantly higher for children in the hydroxyurea group (P=0.01). In conclusion, children with SCD who received hydroxyurea therapy reported better overall HRQL and better physical HRQL than children who did not receive this therapy despite disease severity. Further research assessing the impact of hydroxyurea therapy on HRQL, such as prospective assessment over time, would aid in our understanding of the effectiveness of hydroxyurea for individual children. Ultimately, this may aid in decreasing the barriers to the use of hydroxyurea.

Current strategies for the management of children with sickle cell disease

Children with sickle cell disease may present to doctors anywhere in the world. In developed countries, neonatal screening allows early identification and management of the disease, mostly through daily antibioprophylaxis, immunizations and education of the parents. Stroke prevention relies on the detection of high-risk patients by annual transcranial Doppler ultrasonography from 2 to 16 years of age. Annual check-ups aim to detect early organ deficiencies. The most frequent complications are pain, infections and acute anemia; they may occur in combination. Approximately 10% of children have severe sickle cell disease that may require chronic blood transfusion, hydroxyurea or hematopoietic stem cell transplantation. Comprehensive management programs have dramatically increased survival, and most patients now reach adulthood.

The effect of parental mental health on proxy reports of health-related quality of life in children with sickle cell disease

BACKGROUND

The objectives of this study were to evaluate factors that influence agreement between parent-proxy and child self-report of health-related quality of life (HRQL) in sickle cell disease. We hypothesized that the mental health of the parent, parental HRQL and child characteristics would affect agreement.

PROCEDURE

In a cross-sectional study of children with sickle cell disease, HRQL of the child and the parent's HRQL and mental health were assessed. The effect of parent and child characteristics on agreement between parent-proxy and child self-report of HRQL were determined.

RESULTS

Rates of agreement between parent-proxy and child self-report of HRQL ranged between 42% and 49%. Parents with increased symptoms of distress had an increased odds of reporting a worse physical (Odds Ratio (OR) 1.12) and psychosocial HRQL (OR 1.10) compared to the child's self-report. Severe sickle cell disease was associated with an increased odds of the parent reporting the child's physical HRQL was worse, (OR 4.68) compared to the child's self-report.

CONCLUSIONS

Greater symptoms of distress in the parent are associated with worse parent-proxy report of the child's HRQL. Severe sickle cell disease is associated with greater disagreement between parent-proxy and child self-report of HRQL. These findings broaden our understanding of factors that influence proxy-reporting of a child's HRQL.

How I use hydroxyurea to treat young patients with sickle cell anemia

Hydroxyurea has many characteristics of an ideal drug for sickle cell anemia (SCA) and provides therapeutic benefit through multiple mechanisms of action. Over the past 25 years, substantial experience has accumulated regarding its safety and efficacy for patients with SCA. Early proof-of-principle studies were followed by prospective phase 1/2 trials demonstrating efficacy in affected adults, then adolescents and children, and more recently infants and toddlers. The phase 3 National Heart, Lung and Blood Institute-sponsored Multicenter Study of Hydroxyurea trial proved clinical efficacy for preventing acute vaso-occlusive events in severely affected adults. Based on this cumulative experience, hydroxyurea has emerged as an important therapeutic option for children and adolescents with recurrent vaso-occlusive events; recent evidence documents sustained long-term benefits with prevention or reversal of chronic organ damage. Despite abundant evidence for its efficacy, however, hydroxyurea has not yet translated into effective therapy for SCA. Because many healthcare providers have inadequate knowledge about hydroxyurea, patients and families are not offered treatment or decline because of unrealistic fears. Limited support for hydroxyurea by lay organizations and inconsistent medical delivery systems also contribute to underuse. Although questions remain regarding its long-term risks and benefits, current evidence suggests that many young patients with SCA should receive hydroxyurea treatment.

Hydroxyurea for children with sickle cell disease

Hydroxyurea therapy offers promise for ameliorating the clinical course of children with sickle cell disease (SCD). Hydroxyurea is a prototypic therapeutic option; it can be administered with minimal side effects, has a relatively wide therapeutic window, and has mechanisms of action that address pathophysiologic pathways of sickling, vaso-occlusion, hemolysis, and organ damage. There are limited data regarding hydroxyurea's ability to prevent or diminish organ dysfunction, and the long-term risks of hydroxyurea therapy remain incompletely defined. Although clinical trials are underway to address long-term issues, hydroxyurea remains an effective but underutilized therapy for SCD.

The pediatric hydroxyurea phase III clinical trial (BABY HUG): challenges of study design

Evidence of the laboratory benefits of hydroxyurea and its clinical efficacy in reducing acute vaso-occlusive events in adults and children with sickle cell anemia has accumulated for more than 15 years. A definitive clinical trial showing that hydroxyurea can also prevent organ damage might support widespread use of the drug at an early age. BABY HUG is a randomized, double-blind placebo-controlled trial to test whether treating young children ages 9-17 months at entry with a liquid preparation of hydroxyurea (20 mg/kg/day for 2 years) can decrease organ damage in the kidneys and spleen by at least 50%. Creation of BABY HUG entailed unique challenges and opportunities. Although protection of brain function might be considered a more compelling endpoint, preservation of spleen and renal function has clinical relevance, and significant treatment effects might be discernable within the mandated sample size of 200. Concerns about unanticipated severe toxicity and burdensome testing and monitoring requirements were addressed in part by an internal Feasibility and Safety Pilot Study, the successful completion of which was required prior to enrolling a larger number of children on the protocol. Concerns over recruitment of potentially vulnerable subjects were allayed by inclusion of a research subject advocate, or ombudsman. Finally, maintenance of blinding of research personnel was aided by inclusion of an unblinded primary endpoint person, charged with transmitting endpoint data and monitoring blood work locally for toxicity (ClinicalTrials.gov number, NCT00006400).

Decision analysis of treatment strategies in children with severe sickle cell disease

We designed a decision analysis model comparing 4 treatment strategies for severe sickle cell disease: no intervention, hydroxyurea (HU), chronic transfusion, or stem cell transplant (SCT). The treatment strategy associated with the highest average utility (quality of life) was SCT (0.85). Average utilities for no treatment, chronic transfusion, and HU were 0.68, 0.71, and 0.80, respectively. Our model was quite sensitive to quality-of-life estimates, indicating that a true comparison of HU and transplantation cannot occur until investigators directly measure the health-related quality of life in children with sickle cell disease during HU therapy and after SCT.

Growth patterns in children with sickle cell anemia during puberty

BACKGROUND

Previous studies of children with homozygous sickle cell anemia (SCA) show impaired growth and maturation. The correlation of this suboptimal growth with metabolic and hematological factors during puberty is poorly understood.

PROCEDURE

We studied a group of pre-adolescent children with SCA (19 males, 14 females) and healthy controls (16 males, 15 females) matched for race, sex, body size, and pubertal development. Height, weight, body mass index (BMI), and body composition changes were longitudinally assessed over a 2-year period and compared between the groups and with Z scores based on US growth charts. These changes were correlated with hemoglobin (Hgb) concentration and with energy expenditure (EE) measured using indirect whole-room calorimetry.

RESULTS

Children with SCA progressed through puberty slower than control children. While, after 2 years, pubertal males with SCA were shorter, their annual increases in weight were not different from controls. The mean fat free mass (FFM) increments were significantly less in males and females with SCA than in control children. In males with SCA, growth in height declined over time and was significantly slower than in matched controls (P < 0.05).

CONCLUSION

Growth delays were present during puberty in children with SCA. Decreased growth velocity in children with SCA was independently associated with decreased Hgb concentration and increased total EE.

Clinical and Laboratory Effects of Hydroxyurea in Children and Adolescents with Sickle Cell Anemia: A Portuguese Hospital Study

Our aim was to assess the efficacy and safety of hydroxyurea (HU) in children with severe forms of sickle cell anemia followed in a Portuguese hospital. We carried out an open-label uncontrolled prospective study, which included children with severe forms of sickle cell anemia. Hydroxyurea was started at 15 mg/kg/day and increased to a maximum dose of 25 mg/kg/day. Patients were monitored to assess compliance, clinical and hematological response and toxicity. Nine children and adolescents, five girls and four boys, with a median age of 13 years (range 8 to 16) were enrolled in the study during a period of 24 months. All patients completed at least 15 months of therapy. Hb F was significantly increased, from a mean of 7.0 +/- 3.9% to 13.7 +/- 5.3% (p = 0.028). Clinically, all patients responded significantly with a reduction of 80% in the number of vaso-occlusive crises (VOC), 69% in hospital admissions, 76% in hospitalization days and 67% in transfusion requirements, without significant toxicity. We concluded that, in our population, HU proved to be effective in increasing Hb F levels, and in decreasing hospitalizations for VOC and transfusion requirements with no major side effects. Long-term clinical follow-up is important to certify benefit maintenance.

A pilot study of hydroxyurea to prevent chronic organ damage in young children with sickle cell anemia

BACKGROUND

Hydroxyurea improves laboratory parameters and prevents acute clinical complications of sickle cell anemia (SCA) in children and adults, but its effects on organ function remain incompletely defined.

METHODS

To assess the safety and efficacy of hydroxyurea in young children with SCA and to prospectively assess kidney and brain function, 14 young children (mean age 35 months) received hydroxyurea at a mean maximum tolerated dose (MTD) of 28 mg/kg/day.

RESULTS

After a mean of 25 months, expected laboratory effects included significant increases in hemoglobin, MCV and %HbF along with significant decreases in reticulocytes, absolute neutrophil count, and bilirubin. There was no significant increase in glomerular filtration rate by DTPA clearance or Schwartz estimate. Mean transcranial Doppler (TCD) velocity changes were -25.6 cm/sec (P < 0.01) and -26.8 cm/sec (P < 0.05) in the right and left MCA vessels, respectively. At study exit, no child had conditional or abnormal TCD values, and none developed brain ischemic lesions or vasculopathy progression by MRI/MRA. Growth and neurocognitive scores were preserved and Impact-on-Family scores improved.

CONCLUSIONS

These pilot data indicate hydroxyurea at MTD is well-tolerated by both children and families, and may prevent chronic organ damage in young children with SCA.

A psychometric evaluation of the PedsQL Family Impact Module in parents of children with sickle cell disease

Background

Caring for a child with a chronic condition, such as sickle cell disease, can have a significant impact on parents and families. In order to provide comprehensive care and support to these families, psychometrically sound instruments are needed as an initial step in measuring the impact of chronic diseases on parents and families. We sought to evaluate the psychometric properties of the PedsQL™ Family Impact Module in populations of children with and without sickle cell disease. In addition, we sought to determine the correlation between parent's well being and their proxy report of their child's health-related quality of life (HRQL).

Methods

We conducted a cross-sectional study of parents of children with and without sickle cell disease who presented to an urban hospital-based sickle cell disease clinic and an urban primary care clinic. We assessed the HRQL and family functioning of both groups of parents utilizing the PedsQL™ Family Impact Module. The reliability, validity and factor structure of the instrument were determined and scores from the instrument were correlated with scores from parent-proxy report of their child's HRQL using the PedsQL™ 4.0 Generic Core Scales.

Results

Parents of 170 children completed the module (97 parents of children with sickle cell disease and 73 parents of children without sickle cell disease). The Family Impact Module had high ceiling effects but was reliable (Cronbach's alpha > 0.80 in all scales). The empirical factor structure was generally consistent with the theoretical factor structure and supported construct validity. The Family Impact Module discriminated between parents of children with severe sickle cell disease from parents of children with mild disease or no disease in the areas of communication and worry. There were no significant differences across any of the subscales between parents of children with mild sickle cell disease and those with no disease. Parents with higher scores, representing better HRQL and family functioning, generally reported higher HRQL scores for their children.

Conclusion

The PedsQL™ Family Impact module was reliable, however it displayed large ceiling effects and did not discriminate well between parents of children with and without sickle cell disease. Future research to evaluate the psychometric properties of the Family Impact Module for parents of healthy children may be helpful.

Hydroxyurea for sickle cell disease: a systematic review for efficacy and toxicity in children

CONTEXT

Hydroxyurea is the only approved medication for the treatment of sickle cell disease in adults; there are no approved drugs for children.

OBJECTIVE

Our goal was to synthesize the published literature on the efficacy, effectiveness, and toxicity of hydroxyurea in children with sickle cell disease.

METHODS

Medline, Embase, TOXLine, and the Cumulative Index to Nursing and Allied Health Literature through June 2007 were used as data sources. We selected randomized trials, observational studies, and case reports (English language only) that evaluated the efficacy and toxicity of hydroxyurea in children with sickle cell disease. Two reviewers abstracted data sequentially on study design, patient characteristics, and outcomes and assessed study quality independently.

RESULTS

We included 26 articles describing 1 randomized, controlled trial, 22 observational studies (11 with overlapping participants), and 3 case reports. Almost all study participants had sickle cell anemia. Fetal hemoglobin levels increased from 5%-10% to 15%-20% on hydroxyurea. Hemoglobin concentration increased modestly (approximately 1 g/L) but significantly across studies. The rate of hospitalization decreased in the single randomized, controlled trial and 5 observational studies by 56% to 87%, whereas the frequency of pain crisis decreased in 3 of 4 pediatric studies. New and recurrent neurologic events were decreased in 3 observational studies of hydroxyurea compared with historical controls. Common adverse events were reversible mild-to-moderate neutropenia, mild thrombocytopenia, severe anemia, rash or nail changes (10%), and headache (5%). Severe adverse events were rare and not clearly attributable to hydroxyurea.

CONCLUSIONS

Hydroxyurea reduces hospitalization and increases total and fetal hemoglobin levels in children with severe sickle cell anemia. There was inadequate evidence to assess the efficacy of hydroxyurea in other groups. The small number of children in long-term studies limits conclusions about late toxicities.