Hydroxyurea in children with sickle cell disease: impact on splenic function and compliance with therapy

Feasibility of Electronic Medication Monitoring Among Adolescents and Emerging Adults with Sickle Cell Disease

Purpose

To examine the feasibility of using MEMS® bottles to assess adherence among adolescents and emerging adults with sickle cell disease.

Patients and Methods

Eighteen non-Hispanic Black participants with HbSS (M = 17.8 years; 61% male) were given a MEMS® bottle to store hydroxyurea (n = 14) or deferasirox (n = 4).

Results

One hundred percent initiated MEMS® use and 61% sustained use through the 18-week study; at follow-up, only 11% returned their bottle on time. Barriers to MEMS® use included medication changes and transition to adult care; facilitators included tip sheets and reminders.

Conclusion

While MEMS® is acceptable to this population, ensuring sustained use and timely provision of bottles will require additional supports.

Clinical and laboratory factors associated with splenic dysfunction among patients with sickle cell disease in a malaria endemic region

BACKGROUND

Although loss of splenic function is the expected natural course for individuals with sickle cell disease (SCD), factors such as high HbF and coexistence of alpha thalassemia may ameliorate this process. We evaluated factors associated with two surrogate markers of spleen dysfunction, namely Howell-Jolly bodies (HJBs) and argyrophilic inclusion (AI) red cell counts, among patients with SCD.

METHODS

Cross-sectional data of 182 patients with SCD (median age 11 y; 1-45 y) and 102 normal controls (median age 12 y; 1-32 y) were evaluated. Blood tests including full blood count, serum chemistry and high-performance liquid chromatography were performed. The HJB and AI red cell counts were performed on peripheral blood smears.

RESULTS

The percentages of HJB and AI red cells rose significantly with increasing age in the SCD group. On regression analysis, the frequency of HJB red cells associated positively with mean corpuscular hemoglobin (MCH) (β=0.289; p=0.001) and negatively with HbF (β=-0.259; p=0.002). The AI red cell counts also associated positively with MCH (β=0.321; P=0.001) and negatively with HbF (β=-0.242; p=0.020).

CONCLUSIONS

Data from this study indicate that the negative association of HbF with both markers of splenic dysfunction among our patients with SCD residing in a malaria endemic region is similar to findings elsewhere of its ameliorating effect on splenic dysfunction.

Pediatric Sickle Cell Disease Patients on Hydroxyurea Have Higher Rates of Surgical Splenectomy

INTRODUCTION

We sought to investigate whether hydroxyurea therapy is associated with the need for surgical splenectomy among patients with sickle cell disease (SCD). We hypothesized that as hydroxyurea gained widespread use, surgical splenectomy among pediatric patients with SCD occurred at a higher rate and older age among those taking hydroxyurea.

METHODS

In this retrospective cross-sectional study, the Pediatric Health Information System was queried for all SCD International Classification of Diseases 9/10 diagnosis codes and splenectomy procedure codes from January 1, 2005, to December 31, 2020. Hydroxyurea use was defined as at least one hospital admission with hydroxyurea listed as a medication. The rates of surgical splenectomy, age at splenectomy, hospital length of stay, and incidence of blood transfusion during the splenectomy admission were compared among patients receiving hydroxyurea versus those not receiving hydroxyurea. Additional subanalysis was performed in the Hemoglobin-SS, Hemoglobin-SC, and Other cohorts separately.

RESULTS

During the study period, 28,520 patients were identified. All patients with SCD receiving hydroxyurea had a significantly higher rate of surgical splenectomy compared with the nontreatment group (7.2% versus 3.2%, P = 0.01). The age at surgical splenectomy was significantly younger among Hemoglobin-SS patients receiving hydroxyurea (5.7 [5.1, 6.4] y versus 6.6 [5.8, 7.4] y; P < 0.01). There were no significant differences in length of stay or incidence of blood transfusion during the surgical splenectomy admission between treatment groups.

CONCLUSIONS

Hydroxyurea use in children is associated with higher rates of surgical splenectomy and occurs at a younger age in the Hemoglobin-SS population. Although these findings warrant further investigation for causality, it provides useful information to clinicians and patients alike, allowing for more informed decision-making.

Development and Validation of the Patient/Caregiver Reported Hydroxyurea Evaluation of Adherence for Life (HEAL) Scale

INTRODUCTION

Hydroxyurea reduces the incidence of vaso-occlusive episodes, stroke, and respiratory, cardiac, and renal damage in sickle cell disease by increasing fetal hemoglobin. However, because suboptimal adherence to hydroxyurea limits its effectiveness, understanding patient-specific barriers to hydroxyurea adherence could help improve adherence and health outcomes in patients with sickle cell disease. The aim of this single-site, prospective, IRB-approved study was to validate a 24-item patient- and caregiver-reported hydroxyurea treatment adherence questionnaire, the Hydroxyurea Evaluation of Adherence for Life (HEAL) scale.

METHODS

A sample of 24 adults with sickle cell disease and 16 caregivers of children with sickle cell disease completed the HEAL scale, and a subset of the original sample provided a second HEAL scale for test-retest reliability. HEAL scale results were validated against global adherence ratings from participants and health-care providers, records of access to pill bottles, and laboratory values for fetal hemoglobin and absolute neutrophil count.

RESULTS AND DISCUSSION

Results demonstrated excellent internal consistency for the HEAL Total score and eight (3-item) subscale scores (Dose, Remember, Plan, Cost, Understand, Effectiveness, Laboratory, and Pharmacy), as well as strong test-retest reliability for all HEAL scores except the Cost subscale. HEAL Total scores correlated significantly with validity measures, including global adherence ratings and lab values. The HEAL scale offers significant clinical potential for understanding adherence in individual sickle cell disease patients and significant research potential for characterizing adherence in persons with sickle cell disease who are treated with hydroxyurea.

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.

Phytomedicines (medicines derived from plants) for sickle cell disease

BACKGROUND

Sickle cell disease, a common recessively inherited haemoglobin disorder, affects people from sub-Saharan Africa, the Middle East, Mediterranean basin, Indian subcontinent, Caribbean and South America. It is associated with complications and a reduced life expectancy. Phytomedicines (medicine derived from plants in their original state) encompass many of the plant remedies from traditional healers which the populations most affected would encounter. Laboratory research and limited clinical trials have suggested positive effects of phytomedicines both in vivo and in vitro. However, there has been little systematic appraisal of their benefits. This is an updated version of a previously published Cochrane Review.

OBJECTIVES

To assess the benefits and risks of phytomedicines in people with sickle cell disease of all types, of any age, in any setting.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register, the International Standard Randomised Controlled Trial Number Register (ISRCTN), the Allied and Complimentary Medicine Database (AMED), ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). Dates of most recent searches: Cochrane Cystic Fibrosis and Genetic Disorders Haemoglobinopathies Trials Register: 17 March 2020; ISRCTN: 19 April 2020; AMED: 18 May 2020; ClinicalTrials.gov: 24 April 2020; and the WHO ICTRP: 27 July 2017.

SELECTION CRITERIA

Randomised or quasi-randomised trials with participants of all ages with sickle cell disease, in all settings, comparing the administration of phytomedicines, by any mode to placebo or conventional treatment, including blood transfusion and hydroxyurea.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed trial quality and extracted data.

MAIN RESULTS

Three trials (212 participants) of three phytomedicines: Niprisan^® (also known as Nicosan^®), Ciklavit^® and a powdered extract of Pfaffia paniculata were included. The Phase IIB (pivotal) trial suggests that Niprisan^® may be effective in reducing episodes of severe painful sickle cell disease crisis over a six-month period (low-quality evidence). It did not appear to affect the risk of severe complications or the level of anaemia (low-quality evidence). The single trial of Cajanus cajan (Ciklavit^®) reported a possible benefit to individuals with painful crises, and a possible adverse effect (non-significant) on the level of anaemia (low-quality evidence). We are uncertain of the effect of Pfaffia paniculata on the laboratory parameters and symptoms of SCD (very low-quality of evidence). No adverse effects were reported with Niprisan^® and Pfaffia paniculata (low- to very low-quality evidence).

AUTHORS' CONCLUSIONS

While Niprisan^® appeared to be safe and effective in reducing severe painful crises over a six-month follow-up period, further trials are required to assess its role in managing people with SCD and the results of its multicentre trials are awaited. Currently, no conclusions can be made regarding the efficacy of Ciklavit^® and the powdered root extract of Pfaffia paniculata in managing SCD. Based on the published results for Niprisan^® and in view of the limitations in data collection and analysis of the three trials, phytomedicines may have a potential beneficial effect in reducing painful crises in SCD. This needs to be further validated in future trials. More trials with improved study design and data collection are required on the safety and efficacy of phytomedicines used in managing SCD.

Hydroxyurea Use for Sickle Cell Disease Among Medicaid-Enrolled Children

BACKGROUND

Recent publications should have resulted in increased hydroxyurea usage in children with sickle cell disease (SCD). We hypothesized that hydroxyurea use in children with SCD increased over time and was associated with decreased acute care visits.

METHODS

This was a secondary analysis of the Truven Health Analytics-IBM Watson Health MarketScan Medicaid database from 2009 to 2015. The multistate, population-based cohort included children 1 to 19 years old with an International Classification of Diseases, Ninth or 10th Revision diagnosis of SCD between 2009 and 2015. Changes in hydroxyurea were measured across study years. The primary outcome was the receipt of hydroxyurea, identified through filled prescription claims. Acute care visits (emergency department visits and hospitalizations) were extracted from billing data.

RESULTS

A mean of 5138 children each year were included. Hydroxyurea use increased from 14.3% in 2009 to 28.2% in 2015 (P < .001). During the study period, the acute-care-visit rate decreased from 1.20 acute care visits per person-year in 2009 to 1.04 acute care visits per person-year in 2015 (P < .001); however, the drop in acute care visits was exclusively in the youngest and oldest age groups and was not seen when only children enrolled continuously from 2009 to 2015 were analyzed.

CONCLUSIONS

There was a significant increase in hydroxyurea use in children with SCD between 2009 and 2015. However, in 2015, only ∼1 in 4 children with SCD received hydroxyurea at least once. Increases in hydroxyurea were not associated with consistently decreased acute care visits in this population-based study of children insured by Medicaid.

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.

Phytomedicines (medicines derived from plants) for sickle cell disease

BACKGROUND

Sickle cell disease, a common recessively inherited haemoglobin disorder, affects people from sub-Saharan Africa, the Middle East, Mediterranean basin, Indian subcontinent, Caribbean and South America. It is associated with complications and a reduced life expectancy. Phytomedicines (medicine derived from plants in their original state) encompass many of the plant remedies from traditional healers which the populations most affected would encounter. Laboratory research and limited clinical trials have suggested positive effects of phytomedicines both in vivo and in vitro. However, there has been little systematic appraisal of their benefits. This is an update of a Cochrane Review first published in 2004, and updated in 2010, 2013, and 2015.

OBJECTIVES

To assess the benefits and risks of phytomedicines in people with sickle cell disease of all types, of any age, in any setting.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register, the International Standard Randomised Controlled Trial Number Register (ISRCTN), the Allied and Complimentary Medicine Database (AMED), ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP).Dates of most recent searches: Cochrane Cystic Fibrosis and Genetic Disorders Haemoglobinopathies Trials Register: 10 April 2017; ISRCTN: 26 July 2017; AMED: 24 August 2017; ClinicalTrials.gov: 02 August 2017; and the WHO ICTRP: 27 July 2017.

SELECTION CRITERIA

Randomised or quasi-randomised trials with participants of all ages with sickle cell disease, in all settings, comparing the administration of phytomedicines, by any mode to placebo or conventional treatment, including blood transfusion and hydroxyurea.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed trial quality and extracted data.

MAIN RESULTS

Two trials (182 participants) and two phytomedicines Niprisan^® (also known as Nicosan^®) and Ciklavit^® were included. The Phase IIB (pivotal) trial suggests that Niprisan^® was effective in reducing episodes of severe painful sickle cell disease crisis over a six-month period (low-quality evidence). It did not affect the risk of severe complications or the level of anaemia (low-quality evidence). No serious adverse effects were reported. The single trial of Cajanus cajan (Ciklavit^®) reported a possible benefit to individuals with painful crises (low-quality evidence), and a possible adverse effect (non-significant) on the level of anaemia (low-quality evidence).

AUTHORS' CONCLUSIONS

While Niprisan^® appeared to be safe and effective in reducing severe painful crises over a six-month follow-up period, further trials are required to assess its role in the management of people with sickle cell disease and the results of its multicentre trials are awaited. Currently no conclusions can be made regarding the efficacy of Ciklavit^®. Based on the published results for Niprisan^® and in view of the limitations in data collection and analysis of both trials, phytomedicines may have a potential beneficial effect in reducing painful crises in sickle cell disease. This needs to be further validated in future trials. More trials are required on the safety and efficacy of phytomedicines used in managing sickle cell disease.

Clinic Attendance of Youth With Sickle Cell Disease on Hydroxyurea Treatment

OBJECTIVE

The objective of this study is to describe rates of clinic attendance of youth with sickle cell disease prescribed hydroxyurea and examine potential demographic and medical factors related to consistent clinic attendance.

METHODS

Participants included 148 youth diagnosed with sickle cell disease and prescribed hydroxyurea during a single calendar year. Clinic attendance and potential demographic and medical factors related to attendance were extracted via systematic retrospective medical chart review.

RESULTS

Youth attended 90.3% of scheduled appointments and 85.1% of youth attended at least 80% of scheduled clinic appointments during the study window. Adjusting for other factors, multivariate analysis revealed families with fewer children in the household, families with private insurance, youth experiencing fever, and youth not experiencing pain during the calendar year were more likely to consistently attend clinic visits.

CONCLUSIONS

Adherence to clinic appointments is critical to optimizing health outcomes for youth with sickle cell disease and integral for adequate monitoring of youth prescribed hydroxyurea, in particular. Findings may aid providers in appropriately identifying possible barriers to clinic attendance to develop attendance promotion interventions.

Hydroxycarbamine: from an Old Drug Used in Malignant Hemopathies to a Current Standard in Sickle Cell Disease

While hydroxycarbamide (hydroxyurea, HU) has less and fewer indications in malignant hemopathies, it represents the only widely used drug which modifies sickle cell disease pathogenesis. Clinical experience with HU for patients with sickle cell disease has been accumulated over the past 25 years in Western countries. The review of the literature provides increasing support for safety and efficacy in both children and adults for reducing acute vaso-occlusive events including pain episodes and acute chest syndrome. No increased incidence of leukemia and teratogenicity was demonstrated. HU has become the standard-of-care for sickle cell anemia but remains underused. Barriers to its use should be identified and overcome.

Adherence to hydroxyurea medication by children with sickle cell disease (SCD) using an electronic device: a feasibility study

Adherence to hydroxyurea (HU) is a significant modifying factor in sickle cell vaso-occlusive pain. We conducted a study using an electronic medication container-monitor-reminder device (GlowCap™) to track adherence and determine whether use of this device affected rates of HU adherence. Subjects were regular attendees to our clinic. They were given a 37-item questionnaire and were asked to use a GlowCap containing HU. When the device cap is opened, it makes a remote "medication taken" record. The device also provides usage reminder in the form of lights and alarm sounds if the cap opening is delayed. Nineteen subjects participated in the survey, and 17 in the intervention phase. Of the 17, 12 had reliable adherence data. Seventeen caregivers of patients and two patients completed the survey. Two most common barriers to adherence identified were lack of reminders and absence of medicine home delivery. The intervention component of this study, which used both the electronic (GlowCap) method and medication possession ratio showed that the median adherence rate for the 12 patients evaluated was 85 %. The GlowCap device accurately kept a record of adherence rates. This device may be an effective tool for increasing HU medication adherence.

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.

Clinical pharmacology of deferasirox

Iron accumulation is a consequence of regular red cell transfusions, and can occur as a result of ineffective erythropoiesis secondary to increased intestinal iron absorption, in patients with various anemias. Without appropriate treatment, iron overload can lead to increased morbidity and mortality. Deferasirox is an oral iron chelator effective for reduction of body iron in iron-overloaded patients with transfusion-dependent anemias and non-transfusion-dependent thalassemia, with a well-established safety profile. This review summarizes the clinical pharmacokinetics, pharmacodynamics, and drug-drug interaction profile of deferasirox, and the claims supporting once-daily dosing for effective chelation. Sustained labile plasma iron suppression is observed with no rebound between doses, protecting organs from potential tissue damage. Increased iron excretion positively correlates with increased deferasirox exposure; to optimize iron removal transfusional iron intake, body iron burden and safety parameters should also be considered. Deferasirox dispersible tablets should be taken ≥30 min before food due to an effect of food on bioavailability. Dosing is consistent across pediatric and adult patients and there is no ethnic sensitivity. Dose adjustment is required for patients with hepatic impairment and may be considered upon coadministration with strong uridine diphosphate glucuronosyltransferase inducers or bile acid sequestrants (coadministration should be avoided where possible), and patients should be monitored upon coadministration with cytochrome P450 (CYP) 3A4/5, CYP2C8, or CYP1A2 substrates. Coadministration with hydroxyurea, a fetal hemoglobin modulator, does not appear to impact deferasirox pharmacokinetics. In summary, a substantial body of clinical and pharmacokinetic data are available for deferasirox to guide its optimal use in multiple patient populations and clinical circumstances.

Does hydroxyurea prevent pulmonary complications of sickle cell disease?

A 27-year-old man with sickle cell disease (HbSS) presents to the sickle cell clinic for follow-up after a screening echocardiogram revealed an increased tricuspid regurgitant velocity of 2.7 m/s. He has a history of 2 painful crises per year and has been hospitalized 3 times over the past 10 years for management of painful crises. He had one episode of acute chest syndrome at age 15 that was treated with an RBC exchange transfusion, supplemental oxygen, and intravenous antibiotics; he did not require mechanical ventilation. He has not had additional episodes of acute chest syndrome and does not have a history of stroke, retinopathy, or leg ulcers. The patient has never been treated with hydroxyurea. He wants to know whether hydroxyurea will prevent future pulmonary complications related to sickle cell disease.

Medication adherence among pediatric patients with sickle cell disease: a systematic review

OBJECTIVES

Describe rates of adherence for sickle cell disease (SCD) medications, identify patient and medication characteristics associated with nonadherence, and determine the effect of nonadherence and moderate adherence (defined as taking 60%-80% of doses) on clinical outcomes.

METHODS

In February 2012 we systematically searched 6 databases for peer-reviewed articles published after 1940. We identified articles evaluating medication adherence among patients <25 years old with SCD. Two authors reviewed each article to determine whether it should be included. Two authors extracted data, including medication studied, adherence measures used, rates of adherence, and barriers to adherence.

RESULTS

Of 24 articles in the final review, 23 focused on 1 medication type: antibiotic prophylaxis (13 articles), iron chelation (5 articles), or hydroxyurea (5 articles). Adherence rates ranged from 16% to 89%; most reported moderate adherence. Medication factors contributed to adherence. For example, prophylactic antibiotic adherence was better with intramuscular than oral administration. Barriers included fear of side effects, incorrect dosing, and forgetting. Nonadherence was associated with more vaso-occlusive crises and hospitalizations. The limited data available on moderate adherence to iron chelation and hydroxyurea indicates some clinical benefit.

CONCLUSIONS

Moderate adherence is typical among pediatric patients with SCD. Multicomponent interventions are needed to optimally deliver life-changing medications to these children and should include routine monitoring of adherence, support to prevent mistakes, and education to improve understanding of medication risks and benefits.

Predictors of splenic function preservation in children with sickle cell anemia treated with hydroxyurea

BACKGROUND

More than 90% of children with sickle cell anemia (SCA) lose splenic function by the age of 2 yrs. Splenic function may improve with hydroxyurea, but previous studies are conflicting. We prospectively evaluated the effect of hydroxyurea on splenic filtrative function.

METHODS

Children with SCA enrolled in the Hydroxyurea Study of Long-Term Effects (HUSTLE-NCT00305175) underwent clinical evaluations including Tc(99) m liver-spleen (LS) scans before hydroxyurea initiation and after 3 yrs of treatment to maximum tolerated dose (MTD). LS scans were classified as follows: no uptake, <10% uptake, decreased but ≥10% uptake, and normal.

RESULTS

Mean age (N = 40) was 9.1 yrs, range 2.3-17.0. After 3 yrs of treatment, 13 (33%) had uptake on LS scan. These 13 children were younger (median age 6.0 vs. 10.6 yrs, P = 0.008), had a higher HbF at baseline (mean 10.2% vs. 5.8%, P = 0.004) and after 3 yrs (22.9% vs. 13.9%, P < 0.001), achieved MTD more rapidly (median 288 vs. 358 d, P = 0.021), and were more likely to have baseline splenic uptake (P < 0.001).

CONCLUSIONS

Hydroxyurea at MTD is associated with preserved or improved splenic filtrative function, with 33% demonstrating LS scan uptake after 3 yrs. Younger age, higher %HbF, and baseline splenic function are associated with a favorable outcome.

Efficacy and safety of deferasirox compared with deferoxamine in sickle cell disease: two-year results including pharmacokinetics and concomitant hydroxyurea

We report a prospective, randomized, Phase II study of deferasirox and deferoxamine (DFO) in sickle cell disease patients with transfusional iron overload, with all patients continuing on deferasirox after 24 weeks, for up to 2 years. The primary objective was to evaluate deferasirox safety compared with DFO; long-term efficacy and safety of deferasirox was also assessed. We also report, for the first time, the safety and pharmacokinetics of deferasirox in patients concomitantly receiving hydroxyurea. Deferasirox (n = 135) and DFO (n = 68) had comparable safety profiles over 24 weeks. Adverse events (AEs) secondary to drug administration were reported in 26.7% of patients in the deferasirox cohort and 28.6% in the DFO cohort. Gastrointestinal disorders were more common with deferasirox, including diarrhea (10.4% versus 3.6%) and nausea (5.2% versus 3.6%). The most common AE in the DFO group was injection-site pain irritation, which occurred in 7% of patients. Acute renal failure occurred in one patient on deferasirox who was continued on medication despite progressive impairment of renal function parameters. Serum ferritin levels were reduced in both treatment groups. Patients continuing on deferasirox for up to 2 years demonstrated an absolute median serum ferritin decrease of -614 ng/mL (n = 96). Increasing deferasirox dose was associated with improved response and a continued manageable safety profile. Concomitant hydroxyurea administration (n = 28) did not appear to influence the efficacy, safety (including liver and kidney function), and pharmacokinetic parameters of deferasirox.

Low fixed-dose hydroxyurea in severely affected Indian children with sickle cell disease

There is limited data on the efficacy of hydroxyurea (HU) in Indian sickle cell anemia patients who have severe manifestations despite high fetal hemoglobin (Hb F). Sixty sickle cell anemia children (5-18 years) with more than three episodes of vasoocclusive crises or blood transfusions per year were randomized to receive HU (n = 30) or placebo (n = 30) therapy. Fixed dose (10 mg/kg/day) of HU was administered for 18 months and the patients were followed-up monthly with clinical assessment and laboratory monitoring. In the HU group, hemoglobin (Hb) and Hb F levels increased significantly along with a significant decrease in the number of painful crises, blood transfusion requirements and hospitalizations compared to the placebo group. No major adverse events were observed in this study. In conclusion, low-fixed dose HU therapy was effective for the treatment of Indian sickle cell anemia children. However, there is a need for long-term studies to evaluate the efficacy and toxicity in a larger number of Indian sickle cell anemia patients.

Integrating interactive web-based technology to assess adherence and clinical outcomes in pediatric sickle cell disease

Research indicates that the quality of the adherence assessment is one of the best predictors for improving clinical outcomes. Newer technologies represent an opportunity for developing high quality standardized assessments to assess clinical outcomes such as patient experience of care but have not been tested systematically in pediatric sickle cell disease (SCD). The goal of the current study was to pilot an interactive web-based tool, the Take-Charge Program, to assess adherence to clinic visits and hydroxyurea (HU), barriers to adherence, solutions to overcome these barriers, and clinical outcomes in 43 patients with SCD age 6–21 years. Results indicate that the web-based tool was successfully integrated into the clinical setting while maintaining high patient satisfaction (>90%). The tool provided data consistent with the medical record, staff report, and/or clinical lab data. Participants reported that forgetting and transportation were major barriers for adherence to both clinic attendance and HU. A greater number of self-reported barriers (P < .01) and older age (P < .05) were associated with poorer clinic attendance and HU adherence. In summary, the tool represents an innovative approach to integrate newer technology to assess adherence and clinical outcomes for pediatric patients with SCD.

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.

Hydroxycarbamide in very young children with sickle-cell anaemia: a multicentre, randomised, controlled trial (BABY HUG)

BACKGROUND

Sickle-cell anaemia is associated with substantial morbidity from acute complications and organ dysfunction beginning in the first year of life. Hydroxycarbamide substantially reduces episodes of pain and acute chest syndrome, admissions to hospital, and transfusions in adults with sickle-cell anaemia. We assessed the effect of hydroxycarbamide therapy on organ dysfunction and clinical complications, and examined laboratory findings and toxic effects.

METHODS

This randomised trial was undertaken in 13 centres in the USA between October, 2003, and September, 2009. Eligible participants had haemoglobin SS (HbSS) or haemoglobin Sβ(0)thalassaemia, were aged 9-18 months at randomisation, and were not selected for clinical severity. Participants received liquid hydroxycarbamide, 20 mg/kg per day, or placebo for 2 years. Randomisation assignments were generated by the medical coordinating centre by a pre-decided schedule. Identical appearing and tasting formulations were used for hydroxycarbamide and placebo. Patients, caregivers, and coordinating centre staff were masked to treatment allocation. Primary study endpoints were splenic function (qualitative uptake on (99)Tc spleen scan) and renal function (glomerular filtration rate by (99m)Tc-DTPA clearance). Additional assessments included blood counts, fetal haemoglobin concentration, chemistry profiles, spleen function biomarkers, urine osmolality, neurodevelopment, transcranial Doppler ultrasonography, growth, and mutagenicity. Study visits occurred every 2-4 weeks. Analysis was by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00006400.

FINDINGS

96 patients received hydroxycarbamide and 97 placebo, of whom 83 patients in the hydroxycarbamide group and 84 in the placebo group completed the study. Significant differences were not seen between groups for the primary endpoints (19 of 70 patients with decreased spleen function at exit in the hydroxycarbamide group vs 28 of 74 patients in the placebo group, p=0·21; and a difference in the mean increase in DTPA glomerular filtration rate in the hydroxycarbamide group versus the placebo group of 2 mL/min per 1·73 m(2), p=0·84). Hydroxycarbamide significantly decreased pain (177 events in 62 patients vs 375 events in 75 patients in the placebo group, p=0·002) and dactylitis (24 events in 14 patients vs 123 events in 42 patients in the placebo group, p<0·0001), with some evidence for decreased acute chest syndrome, hospitalisation rates, and transfusion. Hydroxyurea increased haemoglobin and fetal haemoglobin, and decreased white blood-cell count. Toxicity was limited to mild-to-moderate neutropenia.

INTERPRETATION

On the basis of the safety and efficacy data from this trial, hydroxycarbamide can now be considered for all very young children with sickle-cell anaemia.

FUNDING

The US National Heart, Lung, and Blood Institute; and the National Institute of Child Health and Human Development.

Adherence to hydroxyurea therapy in children with sickle cell anemia

OBJECTIVES

To assess adherence to hydroxyurea therapy in children with sickle cell anemia (SCA), evaluate the association between adherence and hematologic profile, and identify barriers and facilitators of adherence.

STUDY DESIGN

Children with SCA (n=75) receiving hydroxyurea were recruited for a single-institution cross-sectional study. The primary outcome was association between treatment adherence and percent fetal hemoglobin (HbF).

RESULTS

Good adherence was estimated at 82% with visual analog scale, 84% with Morisky score, 85% with medical provider report, 77% with clinic visits, and 49% on the basis of pharmacy refills. Increase in HbF was moderately associated with good adherence as measured with the parent/proxy Morisky score (r=-0.39; 95% CI, -0.58-0.17; P < .01) and prescription refills (r=0.39; 95% CI, 0.16-0.57; P < .01). The number of pharmacy refills and the Morisky score explained 23% of the variation in HbF response.

CONCLUSIONS

Adherence was > or =75% with 4 of 5 measures. Pharmacy refills and the Modified Morisky Scale may be used to identify children at high risk for poor response because of non-adherence and children with good adherence with poor response because of individual pharmacodynamics. Future research should prospectively compare adherence measures and evaluate methods to improve treatment adherence.

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).

Adherence to study medication and visits: data from the BABY HUG trial

BACKGROUND

Subject retention and adherence are essential to maintain the power and validity of the Pediatric Hydroxyurea Phase III Clinical Trial (BABY HUG). We designed a study to assess adherence with study medication administration and study visits and to evaluate socioeconomic factors (SES) that may influence these measurements of adherence. These data are important for assessing impact of adherence on BABY HUG trial outcome and defining impact of SES on adherence.

METHODS

Each subject's median study medication (MedAd) and mean visit adherence (VAd) were evaluated. We examined associations of adherence with SES of participating families.

RESULTS

MedAd data were available on 153 of the 191 subjects who started randomized study medication. MedAd was 101.7% of volume prescribed, with 88.9% of subjects taking at least 80% of doses. VAd data were available on 185 of the 191 subjects who started randomized study medication. VAd was 97.3%, with 82.2% of subjects having no missed visits. During dose titration, subjects had on average 12.9% higher medication adherence than subjects who were on a stable dose and had less frequent study visits. MedAd and VAd were not significantly associated with SES.

CONCLUSION

Subjects in the BABY HUG trial have had excellent adherence. SES was not associated with adherence, suggesting that SES should not be used as a criterion for enrolment in clinical trials. Additional efforts are needed to maintain medication adherence, particularly when the interval between scheduled visits increases. (ClinicalTrials.gov number, NCT00006400).

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.

The spleen in the sickling disorders: an update

In early life, patients with sickle cell disease (SCD) can have acute, life-threatening emergencies related to splenic hypofunction (overwhelming bacterial sepsis), as well as anemic crises from acute splenic sequestration because of sudden pooling of blood in the spleen. The landmark penicillin prophylaxis study in 1985 showed a remarkable decrease in mortality from sepsis in young children with SCD who were treated with oral penicillin prophylaxis compared to placebo. Since that study, newborns are screened for SCD and placed on oral penicillin prophylaxis in nearly all of the United States, as well as in other countries where the disease is highly prevalent. The previously described permanent, complete and nearly universal "autosplenectomy" emerging by late childhood or early adulthood is now challenged by recent findings of reversibility of splenic dysfunction by the antisickling drug hydroxyurea or by successful allogeneic stem cell transplantation, even in older patients. Imaging techniques for hypofunction of the spleen are the most commonly used modalities to guide the clinician in decisions regarding medical or surgical management.

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.

Systematic review: Hydroxyurea for the treatment of adults with sickle cell disease

BACKGROUND

Hydroxyurea is the only approved drug for treatment of sickle cell disease.

OBJECTIVE

To synthesize the published literature on the efficacy, effectiveness, and toxicity of hydroxyurea when used in adults with sickle cell disease.

DATA SOURCES

MEDLINE, EMBASE, TOXLine, and CINAHL were searched through 30 June 2007.

STUDY SELECTION

Randomized trials, observational studies, and case reports evaluating efficacy and toxicity of hydroxyurea in adults with sickle cell disease, and toxicity studies of hydroxyurea in other conditions that were published in English.

DATA EXTRACTION

Paired reviewers abstracted data on study design, patient characteristics, and outcomes sequentially and did quality assessments independently.

DATA SYNTHESIS

In the single randomized trial, the hemoglobin level was higher in hydroxyurea recipients than placebo recipients after 2 years (difference, 6 g/L), as was fetal hemoglobin (absolute difference, 3.2%). The median number of painful crises was 44% lower than in the placebo group. The 12 observational studies that enrolled adults reported a relative increase in fetal hemoglobin of 4% to 20% and a relative reduction in crisis rates by 68% to 84%. Hospital admissions declined by 18% to 32%. The evidence suggests that hydroxyurea may impair spermatogenesis. Limited evidence indicates that hydroxyurea treatment in adults with sickle cell disease is not associated with leukemia. Likewise, limited evidence suggests that hydroxyurea and leg ulcers are not associated in patients with sickle cell disease, and evidence is insufficient to estimate the risk for skin neoplasms, although these outcomes can be attributed to hydroxyurea in other conditions.

LIMITATION

Only English-language articles were included, and some studies were of lower quality.

CONCLUSION

Hydroxyurea has demonstrated efficacy in adults with sickle cell disease. The paucity of long-term studies limits conclusions about toxicity.

Systematic review: Hydroxyurea for the treatment of adults with sickle cell disease

BACKGROUND

Hydroxyurea is the only approved drug for treatment of sickle cell disease.

OBJECTIVE

To synthesize the published literature on the efficacy, effectiveness, and toxicity of hydroxyurea when used in adults with sickle cell disease.

DATA SOURCES

MEDLINE, EMBASE, TOXLine, and CINAHL were searched through 30 June 2007.

STUDY SELECTION

Randomized trials, observational studies, and case reports evaluating efficacy and toxicity of hydroxyurea in adults with sickle cell disease, and toxicity studies of hydroxyurea in other conditions that were published in English.

DATA EXTRACTION

Paired reviewers abstracted data on study design, patient characteristics, and outcomes sequentially and did quality assessments independently.

DATA SYNTHESIS

In the single randomized trial, the hemoglobin level was higher in hydroxyurea recipients than placebo recipients after 2 years (difference, 6 g/L), as was fetal hemoglobin (absolute difference, 3.2%). The median number of painful crises was 44% lower than in the placebo group. The 12 observational studies that enrolled adults reported a relative increase in fetal hemoglobin of 4% to 20% and a relative reduction in crisis rates by 68% to 84%. Hospital admissions declined by 18% to 32%. The evidence suggests that hydroxyurea may impair spermatogenesis. Limited evidence indicates that hydroxyurea treatment in adults with sickle cell disease is not associated with leukemia. Likewise, limited evidence suggests that hydroxyurea and leg ulcers are not associated in patients with sickle cell disease, and evidence is insufficient to estimate the risk for skin neoplasms, although these outcomes can be attributed to hydroxyurea in other conditions.

LIMITATION

Only English-language articles were included, and some studies were of lower quality.

CONCLUSION

Hydroxyurea has demonstrated efficacy in adults with sickle cell disease. The paucity of long-term studies limits conclusions about toxicity.

[The use of hydroxyurea in severe forms of sickle cell disease: study of 47 Tunisian paediatric cases]

INTRODUCTION

The Sickle Cell Disease (SCD) is a serious illness considering its complications. For the children seriously affected, three therapeutic options are currently validated: transfusion therapy, hydroxyurea and bone-marrow transplantation.

OBJECTIVES

To see the contribution of hydroxyurea therapy on severe forms of SCD in affected Tunisian children.

MATERIAL AND METHODS

This investigative study lasted over 6 years and 9 months, (September 2000-May 2007), enrolling 47 patients including 27 homozygous SCD and 20 double heterozygote SCD-S/beta thalassemia. The median age was 12 years and a half. The average dosage were 20mg/kg/d (14-30 mg/kg/d). The average duration of treatment was 52 months (18-81 months).

RESULTS

The main indication for hydroxyurea treatment was prevention of recurrence of an acute chest syndrome in seven cases; episodic vaso-occlusive crises exceeding three events per year in 38 cases and prevention of deterioration of cerebral vascular accident in two cases. We observed a fast and sustained improvement of the clinical expression of the disease with a significant decrease of the number of days of hospitalization per patient and per annum from 29.3 d (10-84 d) to 3.2 d/(p<0.01). Treatment was well tolerated. We observed a significant increase of haemoglobin fetus (HbF) rates from 3 to 30% (p<0.01), hemoglobin from 7.8 to 9.6g/dl (p<0.05), average blood cells volume from 79.1 to 100.3 fl (p<0.05) and a significant fall of the white blood cells rates from 14,914 to 8464 per millimetre cube (p<0.05), polynuclear neutrophils from 6799 to 3486 per millimetre cube (p<0.05) and platelets from 508,666 to 293,500 per millimetre cube (p<0.05).

CONCLUSIONS

Hydroxyurea represents a privileged choice of treatment in the severe forms of SCD in children, for homozygous SCD-SS as well as for double heterozygote SCD-S/beta thalassemia. Used carefully, with frequent monitoring, it appeared as a safe treatment in short and medium term, but studies of long-term tolerance should be undertaken.

Assessing associations between medication adherence and potentially modifiable psychosocial variables in pediatric kidney transplant recipients and their families

Post-transplant immunosuppressant (IS) medication adherence is essential for long-term graft survival and relatively little is known about psychosocial barriers that interfere with optimum medication adherence in pediatric kidney transplant patients. The objective of this prospective observational cohort study was to assess the impact of modifiable psychosocial variables on medication adherence. Our hypothesis was that parental stress, dysfunctional parent-child interactions and child behavior problems would be associated with poorer medication adherence. Thirteen pediatric kidney transplant patients and their caregivers were enrolled. Transplant recipients who were able to read and caregivers of all the transplant recipients completed behavioral and attitudinal surveys. A subgroup of seven families dispensed their primary IS medication from an electronic monitoring vial (MEMS Smart Cap). For these patients, medication adherence was calculated by computing a ratio of the medication taken divided by the prescribed dose. In addition, for the entire group, serial IS levels were reviewed by two board certified pediatric nephrologists who categorized all 13 transplant recipient families as either 'probably adherent (PA)' or 'possibly non-adherent (PNA)'. Pearson correlation coefficients and independent samples Student t-tests were used to assess the association between medication adherence and psychosocial variables measured by standardized questionnaires. In this study, elevated parental stress, dysfunctional parent-child interactions, and child behavior problems were associated with poorer medication adherence. In addition, we found evidence to support the relationship between subjective dissatisfaction with appearance and poorer medication adherence. These findings suggest that pre-transplant recipient evaluations of risk factors for poor adherence are warranted.

Managing sickle cell disease

Advances are being made in the management of sickle cell disease for all age groups. This review discusses the progress in amelioration of symptoms, problems unique to particular age groups, and the types of drugs and treatments currently under investigation

Pathophysiological-based approaches to treatment of sickle cell disease

Sickle hemoglobin (HbS), as a result of its polymer-related and oxidant effects, damages the sickle erythrocyte, provokes inflammation, and causes endothelial injury. All these elements cause the phenotype of sickle cell disease. Novel treatments inhibit HbS polymerization by inducing fetal hemoglobin expression, prevent or repair erythrocyte dehydration by slowing cellular potassium and water loss, and replace HbS-producing erythroid progenitors by stem cell transplantation. Future treatment prospects include gene therapy, interruption of the interaction of sickle cells with the endothelium, inhibition of oxidative damage, and protection of an injured endothelium.

The role of hydroxyurea in the management of sickle cell disease

Sickle cell disease (SCD) is one of the most common genetic diseases with some 250,000 new births each year. Most patients suffer intermittent pain crises and life-threatening events while life expectancy is considerably reduced. Until the last decade management was purely preventative or supportive aimed at symptom control. Apart from stem cell transplant, there is no cure but the oral chemotherapeutic drug hydroxyurea (HU) has now established a role in ameliorating the disease and improving life expectancy for most patients. There are side effects and risks of HU treatment in SCD but for moderate and severely affected patients, the benefits can be significant.

Drug compliance in adolescents: assessing and managing modifiable risk factors

Many studies have found that adolescence represents a problem in compliance with prescribed drug regimens. Multiple factors contribute to this problem, including the developmental evolution taking place in the adolescent physique and psyche. Health belief and patient demographic factors, inherent disease and regimen factors, as well as the dynamics between patient and provider may also contribute to problems with compliance to treatment. Simple interventions such as working with the teen to construct a tolerable treatment regimen, assessing anticipated compliance, discussing potential adverse effects, and establishing cues from the adolescent's daily routine can positively impact treatment compliance. Healthcare providers should recognize the fact that psychosocial changes in an adolescent's life can impact upon compliance with medications and enlist the help of their patients in constructing treatment regimens taking into account the individual's lifestyle that may impact upon compliance. In particular, the healthcare provider should ask the adolescents what they anticipate their success with compliance to treatment might be, adverse effects they are concerned about and what cues could best aid the treatment plan. The healthcare provider should then synthesize this information to create the best treatment plan for that patient.

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.

Predictors of fetal hemoglobin response in children with sickle cell anemia receiving hydroxyurea therapy

In the phase I/II pediatric hydroxyurea safety trial (HUG-KIDS), school-aged children with sickle cell anemia receiving hydroxyurea at the maximally tolerated dose (MTD) had variable increases in the percentage of fetal hemoglobin (%HbF). To identify predictors of the HbF response to hydroxyurea therapy, baseline clinical and laboratory values (age, sex, hemoglobin concentration, %HbF, reticulocytes, white blood cell [WBC], platelets, and serum chemistries), as well as treatment variables (number of toxicities, noncompliance, MTD dose, and MTD blood counts) were analyzed in 53 HUG-KIDS children who achieved MTD. Baseline %HbF values (P =.001), baseline hemoglobin concentration (P =.01), MTD dose (P =.02), and compliance (P =.02) were significantly associated with a higher %HbF at MTD; in contrast, age, sex, number of toxicities, and other baseline hematologic parameters were not. After adjusting for variations in baseline %HbF, the baseline reticulocyte count (P =.05) and baseline WBC count (P =.05) were also significantly associated with a higher %HbF at MTD. Hydroxyurea-induced increases in the hemoglobin concentration and mean corpuscular volume (both higher absolute values at MTD and larger positive changes from baseline values), as well as hydroxyurea-induced decreases in reticulocytes and WBC count, were significantly associated with a higher %HbF at MTD. These data suggest that selected baseline laboratory parameters, a higher MTD dose with attention to compliance, and greater therapy-related changes in blood counts may predict the HbF response to hydroxyurea therapy for children with sickle cell anemia. The HbF response to hydroxyurea is variable and complex, however, and even children with low baseline %HbF values can develop substantial increases in %HbF at MTD.

Pediatric psychotropic medication compliance: a literature review and research-based suggestions for improving treatment compliance

Without good compliance the best psychiatric treatment is ineffective. This article reviews what is known or can be inferred about compliance with psychiatric medications in the pediatric population. The review includes discussions of assessment techniques, risk and protective factors, the relevant research literature, and research-based practical techniques to improve compliance. A Medline search surveying the years from 1966 to August 2000 yielded only seven peer-reviewed papers reporting on compliance with pediatric psychopharmacology. All seven studies looked at stimulant compliance among children with attention deficit hyperactivity disorder. Reported levels of compliance range from 56% to 75%. These rates, although low, are likely to be overestimates of actual compliance. We review two related areas of research for which there are small but significant bodies of knowledge: pharmacological compliance studies among adult psychiatric populations and pediatric medical populations. This literature supports the idea that medication compliance is a significant obstacle to the effective treatment of patients. Because compliance rates are lower for children as compared to adults and psychiatric patients as compared to medical patients, we suspect that children with psychiatric illness may be at great risk for poor medication compliance. Fortunately, the research literature demonstrates several simple techniques that clinicians can use to improve medication compliance among their patients. The treatment alliance; education; and medication duration, dosing, palatability, and cost can all be tailored to improve medication compliance.