Hydroxyurea effectiveness in children and adolescents with sickle cell anemia: A large retrospective, population-based cohort

Adherence outcomes of a liquid hydroxyurea delivery program in a pediatric population

BACKGROUND

Hydroxyurea remains underutilized in the pediatric sickle cell population despite its well-known efficacy in decreasing sickle cell complications and hospitalizations. Access to refills and liquid formulation remains a critical barrier to adherence to hydroxyurea regimens. This study was undertaken to determine the clinical impact of home-delivering compounded liquid hydroxyurea (LHU) to pediatric patients with sickle cell disease.

PROCEDURE/METHODS

A retrospective cohort study was conducted using electronic health records and pharmacy databases. Pediatric patients younger than 21 years of age at the time of hydroxyurea initiation from March 2016 to July 2020 who received compounded LHU from Boston Medical Center Pharmacy were included. The primary outcomes of the study were drug adherence (assessed by evaluating the proportion of days covered [PDC]), rates of acute care utilization before and after enrolling in the LHU delivery program.

RESULTS

The final cohort included 41 patients, showing a significant decrease in hospitalizations (p = .01) and acute chest syndrome episodes (p = .03) after the initiation of the LHU delivery program. In comparing hydroxyurea-naïve patients with those previously exposed to hydroxyurea, the latter group had lower hospitalization rates (p = .01), fewer vaso-occlusive event (VOE) episodes (p = .02), and fewer emergency department (ED) visits (p = .01). The median PDC value 1 year post initiation of LHU was 95.

CONCLUSIONS

Home delivery of compounded LHU from the pharmacy to pediatric sickle cell disease patients improved access to hydroxyurea, and was linked to reduced hospitalizations and acute chest syndrome episodes. This advancement in cost savings and improved patient outcomes is a significant step forward in pediatric hematology. By overcoming access barriers, home delivery programs can greatly enhance outcomes among pediatric patients with sickle cell disease.

Hydroxyurea reduces infections in children with sickle cell anemia in Uganda

ABSTRACT

After starting hydroxyurea treatment, Ugandan children with sickle cell anemia had 60% fewer severe or invasive infections, including malaria, bacteremia, respiratory tract infections, and gastroenteritis, than before starting hydroxyurea treatment (incidence rate ratio, 0.40 [95% confidence interval, 0.29-0.54]; P < .001).

Evaluation of treatment patterns, healthcare resource utilization and cost of illness for sickle cell disease in Ghana: a private medical insurance claims database study

BACKGROUND

Sickle cell disease (SCD) is a major public health concern in sub-Saharan Africa, accounting for nearly 75% of the global disease burden. The current analysis evaluated patient characteristics, treatment patterns, healthcare resource utilization (HCRU) and associated costs in patients with SCD based on a Private Medical Insurance Database in Ghana.

METHODS

This retrospective longitudinal cohort study was conducted using an e-claims database from Ghana (01 January 2015 to 31 March 2021). Patients were stratified by age (0 month to < 2 years, ≥ 2 years to ˂6 years, ≥ 6 years to < 12 years, ≥ 12 years to < 16 years; ≥16 years), vaso-occlusive crisis (VOC) (< 1, ≥ 1 to < 3, and ≥ 3 per year), and continuous enrolment. Study outcomes related to patient characteristics, comorbidities, treatment pattern, HCRU were evaluated for pre- and post-index period (index period was between July 2015 to March 2020). Descriptive analysis was used to analyse different study variables.

RESULTS

The study included 2,863 patients (mean age: 20.1 years; Min age: 0; Max age: 83; females 56.1%). Overall, 52.2% (n = 1,495) of SCD patients were ≥ 16 years and 17.0% (n = 486) were in the ≥ 2 to ˂6-years age group. The majority of patients aged ≥ 16 years (62.5%) in the database did not have reported VOC episodes, 35.9% of patients had 1 to 3 VOCs per year and 1.5% had ≥ 3 VOCs per year during the follow-up period. Consultation-based prevalence of SCD was 0.5% [95% confidence interval (CI): 0-1.3%] - 1.4% [CI: 0.6-2.2%]. Malaria, upper respiratory tract infection (URTI) and sepsis were the common complications of SCD. Analgesics were the most frequently prescribed medications followed by anti-infectives, hematinics, and antimalarials. Hydroxyurea, a routine standard of care for SCD was under-utilized. SCD patients had median cost incurred for consultation/hospital services of $11.3 (Interquartile range [IQR] $6.2 - $27.2). For patients with VOC, maximum median cost was incurred for medications ($10.9 [IQR $5.0-$32.6]). Overall median healthcare cost was highest for individuals with ≥ 3 VOCs per year during the follow-up period ($166.8 [IQR $70.3-$223.5]).

CONCLUSION

In this retrospective private insurance claims database analysis, SCD imposes a significant healthcare burden, especially in patients with VOC. There is a need for reimbursed treatment options that could reduce the long-term burden associated with SCD and VOC.

Are children with sickle cell disease at particular risk from the harmful effects of air pollution? Evidence from a large, urban/peri-urban cohort

INTRODUCTION

Pathophysiologic pathways of sickle cell disease (SCD) and air pollution involve inflammation, oxidative stress, and endothelial damage. It is therefore plausible that children with SCD are especially prone to air pollution's harmful effects.

METHODS

Patient data were collected from a single-center, urban/peri-urban cohort of children with confirmed SCD. Daily ambient concentrations of particulate matter (PM2.5 ) were collected via satellite-derived remote-sensing technology, and carbon monoxide (CO), nitrogen dioxide (NO2 ), and ozone from local monitoring stations. We used multivariable regression to quantify associations of pollutant levels and daily counts of emergency department (ED) visits, accounting for weather and time trends. For comparison, we quantified the associations of pollutant levels with daily all-patient (non-SCD) ED visits to our center.

RESULTS

From 2010 to 2018, there were 17,731 ED visits by 1740 children with SCD (64.8% HbSS/HbSβ0 ). Vaso-occlusive events (57.8%), respiratory illness (17.1%), and fever (16.1%) were the most common visit diagnoses. Higher 3-day (lags 0-2) rolling mean PM2.5 and CO levels were associated with daily ED visits among those with SCD (PM2.5 incident rate ratio [IRR] 1.051 [95% confidence interval: 1.010-1.094] per 9.4 μg/m3 increase; CO 1.088 [1.045-1.132] per 0.5 ppm). NO2 showed positive associations in secondary analyses; ozone levels were not associated with ED visits. The comparison, all-patient ED visit analyses showed lower IRR for all pollutants.

CONCLUSIONS

Our results suggest short-term air pollution levels as triggers for SCD events and that children with SCD may be more vulnerable to air pollution than those without SCD. Targeted pollution-avoidance strategies could have significant clinical benefits in this population.

Clinical Profiles of Children With Sickle Cell Anaemia Presenting With Acute Clinical Events: A Single-Center Study

BACKGROUND

Sickle cell disease is a common genetic disorder characterised by chronic haemolytic anaemia and vaso-occlusive crisis. Sickle cell anaemia (SCA) has both short-term effects in the form of acute clinical events and long-term repercussions seen with chronic multiorgan involvement. It is associated with significant morbidity and mortality. In India, the disease is largely undocumented. Thus, there is an urgent need to highlight the features of the disease so that locally appropriate models of care may be implemented.

OBJECTIVE

This study aims to evaluate acute clinical events in SCA and to provide data that may help to reduce the rate of morbidity and mortality associated with this disease by early interventions.

MATERIALS AND METHODS

A cross-sectional observational study was conducted between November 2020 and May 2022 at Indira Gandhi Government Medical College and Hospital, Nagpur, Central India. The inclusion criteria included previously diagnosed patients of SCA (homozygous sickle cell disease) on high-performance liquid chromatography (HPLC) between the age groups of six months and 12 years, presenting with acute clinical events. The exclusion criteria included patients younger than six months and older than 12 years of age, and all patients with other haemoglobinopathies and sickle cell trait. The study was approved by the Institutional Ethical Committee. All the data was entered into a well-designed Microsoft Office Excel spreadsheet (v 2019, Microsoft, Washington, USA). All the clinical, biochemical, and haematological data were tabulated and analysed.

RESULTS

A total of 100 children with sickle cell disease diagnosed by HPLC were enrolled during the study period. About 215 acute clinical events among the 100 cases were recorded, for which they were admitted to the paediatric ward or PICU. The majority (35%, n=35) were seen in the age group of six to nine years (school-going age). About 52% were male and 48% were female (male-to-female ratio= 1.08:1). Pain was the most common symptom. The highest incidence of 36.75% (n=79) was seen with acute painful crises and was the most common indication of hospitalisation, followed by acute febrile illness (AFI) (34.42%, n=74), aplastic crisis (10.23%, n=22), splenic sequestration crisis (9.77%, n=21), hepatobiliary involvement (3.72%, n=8), acute chest syndrome and haemolytic crisis (each 1.86%, n=4), and stroke (1.40%, n=3). In cases of having foetal haemoglobin (HbF) ≥20%, the incidence of acute painful crisis (p=0.0001), hand-foot syndrome (p=0.047), aplastic crisis (p=0.033), splenic sequestration crisis (p=0.039), and AFI (p=0.035) was low as compared to cases having HbF ≤20% which was statistically significant. The incidence of acute painful crisis, hand-foot syndrome, and an aplastic crisis was significantly low in patients receiving hydroxyurea therapy as compared to patients who were not on hydroxyurea. Out of 100 cases, four died during the study period, three died because of splenic sequestration crisis with septic shock, and one died due to hepatic encephalopathy due to haemolytic crisis with septic shock.

CONCLUSION

Acute clinical events in sickle cell disease can have significant morbidity and mortality in the paediatric age group. The nutritional status of sickle cell disease children must be given due importance. Early initiation of hydroxyurea must be encouraged to maintain higher HbF levels, which plays a significant role in reducing morbidity.

Impact of Hydroxyurea Starting Dose on Pain Outcomes in Patients with Sickle Cell Disease

In patients with sickle cell disease, hydroxyurea decreases the number of pain crises experienced. This study aimed to evaluate the difference in pain outcomes between patients started on a guideline concordant, weight-based starting dose of at least 15 mg/kg/day of hydroxyurea and those not. The first prescription of hydroxyurea was the baseline date, follow-up was a visit 60-120 days after baseline. The primary outcome was the change in opioid prescribing between baseline and follow-up. 138 patients met inclusion criteria; of these, 55 were started on a guideline concordant dose of hydroxyurea. Greater white blood cell count (9.5 vs 12.0; p < 0.01) was statistically associated with subtherapeutic dosing. Greater actual body weight (68.0 vs 72.1 kg; p = 0.16) also appeared higher in the non-guideline concordant group. No statistically significant difference in opioid prescribing was observed between those started on a guideline concordant dose of hydroxyurea and those who were not. In the guideline concordant starting dose group, 42% had a reduction in pain scores at first follow up, compared to 35% with a non-guideline recommended starting dose. (p = 0.41). While this difference is in the direction that would be expected based on the guidelines, the difference does not appear to be clinically meaningful.

Ten-year Longitudinal Analysis of Hydroxyurea Implementation in a Pediatric Sickle Cell Program

Hydroxyurea (HU) has proven benefit in sickle cell anemia (SCA), but HU is still underutilized. The Pediatric Sickle Cell Program of Northern Virginia prescribes HU regardless of symptoms to all SCA patients age ≥ 9 months and prospectively tracks outcomes. HU is dosed to maximum tolerated dosing (MTD), targeting 30% Hgb F. Longitudinal data from 2009-2019 encompassing 1222 HU-eligible and 950 HU-exposure patient-years were analyzed in 2-year intervals for hemoglobin (Hgb), fetal hemoglobin (Hgb F), hospitalizations, transfusions, and treat-and-release ED visits. Comparing HU-eligible patients in the interval prior to HU implementation (2009-2011) to the last interval analyzed after HU implementation (2017-2019), HU usage increased from 33% to 93%, average Hgb increased from 8.3±0.98 to 9.8±1.3 g/dL (p<0.0001), average Hgb F rose from 13±8.7% to 26±9.9% (p<0.0001), hospitalizations decreased from 0.71 (95% CI 0.54-0.91) to 0.2 (95% CI 0.13-0.28) admissions/person-year, sporadic transfusions decreased from 0.4 (95% CI 0.27-0.55) to 0.05 (95% CI 0.02-0.12) transfusions/person-year. Treat-and-release ED visit rates remained unchanged, varying between 0.49 (95% CI 0.36-0.64) and 0.64 (95% CI 0.48-0.83) visits/person-year. By the last interval, 72% of patients had Hgb ≥ 9g/dL, 42% had Hgb F ≥ 30%, 79% experienced no hospitalizations, and 94% received no transfusions. Uniform HU prescription for SCA patients with close monitoring to achieve high Hgb F resulted in significant improvements in laboratory and clinical outcomes within 2 years, which continued to improve over the next 6 years. Rigorous HU implementation in a pediatric sickle cell population is feasible, effective, and sustainable. This article is protected by copyright. All rights reserved.

Impact of hydroxyurea on hospital stay & analgesic utilization in sickle cell anaemia with vaso-occlusive crises

Background & objectives

Hydroxyurea (HU) has been useful in preventing sickle cell vaso-occlusive crises (VOC). A few studies also suggest utility of HU, during acute VOC. Sickle cell anaemia (SCA) is of high prevalence in western districts of Odisha State, India, and VOC is a common presentation, despite being mostly of Arab-Indian haplotype. This study was undertaken to evaluate the impact of HU on hospital stay and analgesic utilization in acute painful VOC of SCA.

Methods

Homozygous sickle cell disease (HbSS) patients were categorized as cases who were receiving low-dose HU (10 mg/kg/day) and patients who were not on HU were considered as control. Days of hospital stay, analgesic utilization and visual analogue scale (VAS) score in patients were compared with that of control. Analgesics used to control pain were tramadol hydrochloride, ketorolac and diclofenac.

Results

A total of 359 homozygous sickle cell disease (SCD) patients with VOC were studied (187 patients and 172 controls). The patient group had lesser mean days of hospital stay (1.4 days less than controls, P<0.001) and required lesser days of analgesic utilization than controls (1.18 days less than controls, P<0.001). Significant differences were observed between patients and controls concerning VAS score and amount of tramadol hydrochloride, ketorolac and diclofenac utilization (P<0.05).

Interpretation & conclusions

In this study, HU was found to have beneficial effects in acute VOC of homozygous SCD, which includes shortening the duration of hospital stay and reducing the net amount of analgesic utilization during hospitalization.

Point-of-care microchip electrophoresis for integrated anemia and hemoglobin variant testing

Anemia affects over 25% of the world's population with the heaviest burden borne by women and children. Genetic hemoglobin (Hb) variants, such as sickle cell disease, are among the major causes of anemia. Anemia and Hb variant are pathologically interrelated and have an overlapping geographical distribution. We present the first point-of-care (POC) platform to perform both anemia detection and Hb variant identification, using a single paper-based electrophoresis test. Feasibility of this new integrated diagnostic approach is demonstrated via testing individuals with anemia and/or sickle cell disease. Hemoglobin level determination is performed by an artificial neural network (ANN) based machine learning algorithm, which achieves a mean absolute error of 0.55 g dL^-1 and a bias of -0.10 g dL^-1 against the gold standard (95% limits of agreement: 1.5 g dL^-1) from Bland-Altman analysis on the test set. Resultant anemia detection is achieved with 100% sensitivity and 92.3% specificity. With the same tests, subjects with sickle cell disease were identified with 100% sensitivity and specificity. Overall, the presented platform enabled, for the first time, integrated anemia detection and hemoglobin variant identification using a single point-of-care test.

Real-Life experience with hydroxyurea in patients with sickle cell disease: Results from the prospective ESCORT-HU cohort study

Several controlled studies have evidenced good efficacy and short-term and mid-term safety profiles for hydroxyurea (HU), which has become the cornerstone for prevention of sickle-cell disease (SCD)-related vaso-occlusive crises. However, there are few large-scale reports on its long-term use and certain caregivers and patients have concerns about its safety. Following the licensing of HU in Europe for children and adults with severe forms of SCD, ESCORT-HU was designed as a Phase IV observational cohort study. It included 1906 participants, of whom 55% were adults. The most common hemoglobin (Hb) genotypes were HbSS (84.7%) and HbSβ+ (7.0%). The median duration of follow-up was 45 months, for a total of 7309 patient-years of observation. The dose of HU after 1 year was 20.6 mg/kg/d for children and 16.3 mg/kg/d for adults. There was a statistically significant decrease in the number of vaso-occlusive episodes lasting >48 h, acute chest syndrome episodes, hospitalizations, and the percentage of patients requiring blood transfusions within the first 12 months relative to the year before enrolment. Neutropenia and thrombocytopenia were the most commonly reported adverse effects. No new HU toxicity was identified. Overall, 125 pregnancies were reported in 101 women and no malformations were observed in the neonates. There were 12 pregnancies for partners of male patients treated with HU. One case of fatal myelodysplastic syndrome was reported, for which a causal association with HU could not be excluded. This cohort study of patients with SCD highlights the positive benefit-to-risk ratio of HU in children and adults.

Hydroxyurea Use Among Children With Sickle Cell Disease at King Abdulaziz University Hospital in Jeddah City

Background

Sickle cell disease (SCD) is an autosomal recessive hemoglobinopathy that is very common and causes a great burden in Saudi Arabia and worldwide. This study aims to determine the frequency and benefits of using hydroxyurea in treating children with SCD in King Abdulaziz University Hospital (KAUH) in Saudi Arabia.

Method

This retrospective observational study included all SCD patients, males and females, who were following up in KAUH and were less than 18 years old. Patients on chronic transfusion therapy or who had previous stem cell transplantation were excluded from the study. The study was approved by the unit of biomedical ethics in KAUH, Jeddah.

Result

The study included 102 SCD patients; the median age of the sample was 7.5±4.2, with the majority being female (58 patients; 56.9%). Hydroxyurea users among participants in the study were 62 patients (60.8%). Thirty-seven (37) of the patients using hydroxyurea had an increase in the mean corpuscular volume (MCV). There was a decrease in the level of white blood cells (WBCs) and neutrophil count from 15.81±10.24 and 48.31±23.23% to 12.48±5.48 and 40.81±15.78%, respectively. Platelet count showed an increase from 345.4±2.1096 to 359.162±199.87 after starting hydroxyurea. The incidence of vaso-occlusive crisis (VOC) increased after hydroxyurea initiation from 4.555±4.08 to 6.288±9.80. Moreover, the frequency of blood transfusion in patients using hydroxyurea was statistically significant as p-value = 0.048.

Conclusion

In conclusion, our results showed significant clinical and laboratory benefits of hydroxyurea in children with SCD. Hydroxyurea has been shown to reduce the frequency of VOC and blood transfusion in patients with SCD.

Efficacy and safety of recently approved drugs for sickle cell disease: a review of clinical trials

Sickle cell disease is prevalent in several parts of the world. Most hospitalizations of these patients are related to pain crisis episodes. Moreover, levels of hemoglobin are lower in sickle cell disease patients as compared with the general population. Complications related to sickle cell disease are managed with blood transfusions, hydroxyurea, and opioids. Despite these therapies, patients with sickle cell disease experience multiple pain crisis episodes leading to hospitalizations and end-organ damage. The US Food and Drug Administration has approved three new drugs-L-glutamine, voxelotor, and crizanlizumab-for the prophylaxis and treatment of complications related to sickle cell disease. This review was aimed at assessing the efficacy and safety of recently approved drugs for the treatment of sickle cell disease. A comprehensive search was made on PubMed and clinicaltrials.gov to look for clinical trials reporting the efficacy and safety of recently approved drugs for sickle cell disease. Based on the results of clinical trials, L-glutamine, voxelotor, and crizanlizumab were well tolerated by sickle cell disease patients. L-Glutamine and crizanlizumab reduced the number of sickle cell crisis episodes, while voxelotor improved the level of hemoglobin in sickle cell disease patients. These drugs were effective alone and in combination with hydroxyurea.

Sickle Cell Anemia: Variants in the CYP2D6, CAT, and SLC14A1 Genes Are Associated With Improved Hydroxyurea Response

Differences in hydroxyurea response in sickle cell anemia may arise due to a series of factors with genetic factors appearing to be predominant. This study aims to investigate the effects of single nucleotide polymorphisms in genes encoding drug-metabolizing enzymes and solute carriers on hydroxyurea response, in patients with sickle cell anemia. For that purpose, a total number of 90 patients with sickle cell anemia were recruited, 45 were undergoing hydroxyurea treatment, while 45 were not under the treatment. Association analyses were performed between CYP3A4 (rs2740574), CYP2D6 (rs3892097), CAT (rs7943316 and rs1001179), and SLC14A1 (rs2298720) variants and laboratory parameters. According to our findings, patients with hydroxyurea treatment demonstrated higher HbF levels and a significant improvement in hemolytic, hepatic, inflammatory, and lipid parameters in comparison to those without the treatment. We also found significant associations between the CYP2D6 (rs3892097), CAT (rs7943316 and rs1001179), and SLC14A1 (rs2298720) variants and an improvement of the therapeutic effects, specifically the hemolytic, hepatic, inflammatory, lipid, and renal parameters. In conclusion, our results highlight the importance of the investigated variants, and their strong association with hydroxyurea efficacy in patients with sickle cell anemia, which may be considered in the future as genetic markers.

Managing patients with sickle cell disease in primary care

Sickle cell disease (SCD) is a group of disorders affecting the hemoglobin in erythrocytes. SCD is associated with significant morbidity and mortality and occurs most commonly among people of African ancestry. In 2014, the National Heart, Lung, and Blood Institute updated its guidelines for the management of SCD. These guidelines were implemented to provide evidence-based recommendations to assist primary care clinicians in the proper management of patients with SCD. This article reviews the current practice guidelines for SCD, with attention to health maintenance and hydroxyurea.

Association between clinical outcomes and metformin use in adults with sickle cell disease and diabetes mellitus

Metformin was recently found to increase fetal hemoglobin, which is protective in sickle cell disease (SCD). We tested the hypothesis that, among adults with SCD and diabetes mellitus (DM), metformin use is associated with fewer adverse SCD clinical outcomes and lower health care utilization. This is a retrospective cohort study using the MarketScan Medicaid claims database for 2006 to 2016, comparing metformin users and nonusers. Patients on hydroxyurea, insulin, or iron chelation were excluded. Main outcomes included annual rates of all-cause inpatient encounters, all-cause emergency department (ED) encounters, inpatient and ED encounters with SCD codes, vaso-occlusive episodes (VOEs), strokes, acute chest syndrome (ACS), avascular necrosis (AVN), and gallstones. Of 457 adults (median age [interquartile range], 43 years [33-52 years]; 72% female), 142 (31%) were treated with metformin. Adjusted for age, sex, and Charlson Comorbidity Index, metformin users had significantly lower rate ratios of all-cause inpatient encounters (0.68; 95% confidence interval [CI], 0.52-0.88; P < .01), inpatient encounters with SCD codes (0.45; 95% CI, 0.30-0.66; P < .01), ED encounters with SCD codes (0.34; 95% CI, 0.21-0.54; P < .01), VOE (0.22; 95% CI, 0.12-0.41; P < .01), ACS (0.17; 95% CI, 0.05-0.60; P = .01), and AVN (0.30; 95% CI, 0.11-0.87; P = .03). A subgroup analysis of 54 enrollees preinitiation and postinitiation of metformin did not indicate significant changes in rates of clinical events. Metformin was associated with significantly fewer inpatient and ED SCD encounters in adults with SCD and DM; however, confounding of underlying SCD severity cannot be excluded.

Impact of Medicaid expansion on access and healthcare among individuals with sickle cell disease

PURPOSE

Sickle cell disease (SCD) is associated with high acute healthcare utilization. The purpose of this study was to examine whether Medicaid expansion in California increased Medicaid enrollment, increased hydroxyurea prescriptions filled, and decreased acute healthcare utilization in SCD.

METHODS

Individuals with SCD (≤65 years and enrolled in Medicaid for ≥6 total calendar months any year between 2011 and 2016) were identified in a multisource database maintained by the California Sickle Cell Data Collection Program. We describe trends and changes in Medicaid enrollment, hydroxyurea prescriptions filled, and emergency department (ED) visits and hospital admissions before (2011-2013) and after (2014-2016) Medicaid expansion in California.

RESULTS

The cohort included 3635 individuals. Enrollment was highest in 2014 and lowest in 2016 with a 2.8% annual decease postexpansion. Although <20% of the cohort had a hydroxyurea prescription filled, the percentage increased by 5.2% annually after 2014. The ED visit rate was highest in 2014 and decreased slightly in 2016, decreasing by 1.1% annually postexpansion. Hospital admission rates were similar during the pre- and postexpansion periods. Young adults and adults had higher ED and hospital admission rates than children and adolescents.

CONCLUSIONS

Medicaid expansion does not appear to have improved enrollment or acute healthcare utilization among individuals with SCD in California. Future studies should explore whether individuals with SCD transitioned to other insurance plans or became uninsured postexpansion, the underlying reasons for low hydroxyurea utilization, and the lack of effect on hospital admissions despite a modest effect on ED visits.

Inpatient Ordering of Home Hydroxyurea by Residents for Hospitalized Patients With Sickle Cell Disease

BACKGROUND

Hydroxyurea is a well-established disease-modifying medication for sickle cell disease (SCD). At some institutions, hydroxyurea can only be ordered by "chemotherapy-certified" providers which may not include pediatric resident physicians.

METHODS

We conducted a survey of 39 American pediatric hospitals regarding their policy on resident hydroxyurea ordering for SCD. Our institution changed its policy in June 2016 to allow residents to order hydroxyurea for hospitalized patients with SCD who were already on hydroxyurea at home. We conducted a retrospective review of the medical records of a random sample of patients with SCD on hydroxyurea admitted the year before and the year after this policy change.

RESULTS

In our national survey, 51% of surveyed hospitals allowed residents to order hydroxyurea, 19% required a second signature, and 30% did not allow residents to order hydroxyurea. In our institutional study, patients after the policy change were significantly more likely to have received their home hydroxyurea by hospital day 1: before 62/90 (69%) versus after 105/119 (88%), P=0.0005. The proportion of patients who inappropriately received hydroxyurea was very low in both groups: before 1/91 (1%) versus after 3/126 (2%), P=0.64, with no serious adverse clinical events due to inappropriate hydroxyurea administration.

CONCLUSIONS

Considerable national variation in practice currently exists in regards to resident hydroxyurea ordering hospital policies. A policy allowing residents to order hydroxyurea significantly increased the likelihood of a patient receiving hydroxyurea while hospitalized with no significant increase in inappropriate hydroxyurea administration. Resident hydroxyurea ordering seems safe and beneficial.

The role of hydroxyurea in decreasing the occurrence of vasso-occulusive crisis in pediatric patients with sickle cell disease at King Saud Medical City in Riyadh, Saudi Arabia

OBJECTIVES

To measure the incidence of vaso-occlusive crises (VOC) and the role of hydroxyurea (HU) in reducing VOC in sickle cell anemia  patients being treated at a large tertiary care setting in Kingdom of Saudi Arabia (KSA). The secondary objective of this study is to observe the gradual improvement in laboratory data (white blood cell [WBC], platelets, mean corpuscular volume [MCV], hemoglobin [Hgb], HgbF) following regular use of HU. Methods: Clinical effectiveness of HU was evaluated in a large pediatric population using a retrospective cohort, non-interventional, pre-post treatment study designed to control disease severity selection bias. The cohort included children with SCA (sickle cell (SS), sickle-beta thalassemia) at King Saud Medical City, Riyadh, KSA, who initiated HU between January 2012 and June 2017. For each patient healthcare utilization, laboratory values, and clinical outcomes were observed for an equal duration of time pre and post hydroxyurea. Results: Out of 416 SCD patients, 128 children with SCD who initiated HU, of them 82 met the eligibility criteria. After initiation of HU, there was significant reduction in both VOC (80%) and length of stay (LOS) (73%). Significant increase in Hgb (13%), MCV (10%), and HgbF (28%) and significant decrease in WBC (28%) was observed. Only the mean platelet count decreased by 3% with a p greater than 0.05. Conclusion: Hydroxyurea treatment significantly decreased episodes of VOC and LOS, it also led to reductions in hospitalizations and significant improvement in complete blood count indices.

Optimizing Hydroxyurea Treatment for Sickle Cell Disease Patients: The Pharmacokinetic Approach

Background: Hydroxyurea (HU) is a FDA- and EMA-approved drug that earned an important place in the treatment of patients with severe sickle cell anemia (SCA) by showing its efficacy in many studies. This medication is still underused due to fears of physicians and families and must be optimized. Methods: We analyzed our population and identified HU pharmacokinetic (PK) parameters in order to adapt treatment in the future. Working with a pediatric population, we searched for the most indicative sampling time to reduce the number of samples needed. Results: Nine children treated by HU for severe SCA were included for this PK study. HU quantification was made using a validated gas chromatography/mass spectrometry (GC/MS) method. Biological parameters (of effectiveness and compliance) and clinical data were collected. None of the nine children reached the therapeutic target defined by Dong et al. as an area under the curve (AUC) = 115 h.mg/L; four patients were suspected to be non-compliant. Only two patients had an HbF over 20%. The 2 h sample was predictive of the medication exposure (r² = 0.887). Conclusions: It is urgent to be more efficient in the treatment of SCA, and pharmacokinetics can be an important asset in SCA patients.

Robust clinical and laboratory response to hydroxyurea using pharmacokinetically guided dosing for young children with sickle cell anemia

Hydroxyurea is FDA-approved and now increasingly used for children with sickle cell anemia (SCA), but dosing strategies, pharmacokinetic (PK) profiles, and treatment responses for individual patients are highly variable. Typical weight-based dosing with step-wise escalation to maximum tolerated dose (MTD) leads to predictable laboratory and clinical benefits, but often takes 6 to 12 months to achieve. The Therapeutic Response Evaluation and Adherence Trial (TREAT, NCT02286154) was a single-center study designed to prospectively validate a novel personalized PK-guided hydroxyurea dosing strategy with a primary endpoint of time to MTD. Enrolled participants received a single oral 20 mg/kg dose of hydroxyurea, followed by a sparse PK sampling approach with three samples collected over three hours. Analysis of individual PK data into a population PK model generated a starting dose that targets the MTD. The TREAT cohort (n = 50) was young, starting hydroxyurea at a median age of 11 months (IQR 9-26 months), and PK-guided starting doses were high (27.7 ± 4.9 mg/kg/d). Time to MTD was 4.8 months (IQR 3.3-9.3), significantly shorter than comparison studies (p < 0.0001), thus meeting the primary endpoint. More remarkably, the laboratory response for participants starting with a PK-guided dose was quite robust, achieving higher hemoglobin (10.1 ± 1.3 g/dL) and HbF (33.3 ± 9.1%) levels than traditional dosing. Though higher than traditional dosing, PK-guided doses were safe without excess hematologic toxicities. Our data suggest early initiation of hydroxyurea, using a personalized dosing strategy for children with SCA, provides laboratory and clinical response beyond what has been seen historically, with traditional weight-based dosing.

Hydroxyurea alters hematological, biochemical and inflammatory biomarkers in Brazilian children with SCA: Investigating associations with βS haplotype and α-thalassemia

This study investigated the effects of hydroxyurea (HU) on hematological, biochemical and inflammatory parameters in children with sickle cell anemia (SCA) in association with βS haplotype and α-thalassemia. We included 22 children with SCA who were followed for an average of 14.5 months. Laboratory parameters were assessed by electronic methods, and molecular analysis was investigated by PCR-RFLP and allele-specific PCR. Results showed significant increases in hemoglobin, HbF, hematocrit, MCV, MCH, glucose, HDL-C and albumin levels, as well as significant decreases in MCHC and AST levels, WBC, neutrophils, eosinophils, lymphocytes and reticulocytes, in children during HU therapy. HbF levels were positively correlated with hemoglobin, hematocrit, MCV and total protein, yet negatively correlated with MCHC, RDW, AAT and AST during HU therapy (p<0.05). Children who carried the Central African Republic haplotype, in response to HU therapy, presented significant increases in hemoglobin, hematocrit, triglycerides and uric acid levels, as well as significant decreases in MCHC, AST and direct bilirubin levels, WBC, neutrophils, eosinophils, lymphocytes and reticulocytes. Those with the Benin haplotype presented increases in HbF and albumin levels, and a reduction in platelet counts (p<0.05). Children with α-thalassemia presented decreased ALT during HU use, while those without this deletion presented increases in hemoglobin, hematocrit, MCV, MCH, HDL-C and albumin, as well as decreases in MCHC, neutrophils, lymphocytes, reticulocytes and AST (p<0.05). Hence, regardless of its use in association with βS haplotypes or α-thalassemia, HU seems to be linked to alterations in hemolytic, inflammatory, hepatic, lipid and glycemic profiles.

Hydroxyurea: Pattern of Use, Patient Adherence, and Safety Profile in Patients with Sickle Cell Disease in Oman

OBJECTIVES

Many barriers contribute to the underutilization of hydroxyurea (HU) in the treatment of sickle cell disease (SCD), and adherence to its use is often reported to be suboptimal. It is important to have information on the safety of HU in patients with SCD. Our study assessed the pattern of use, patients' adherence to medication, discontinuation of use, and safety of HU in patients with SCD.

METHODS

This cross-sectional study was conducted in the department of medicine of a referral hospital in Oman over five months and included a review of patient files and patient interview. Approval was obtained from the Regional Research and Ethics Committee of the A'Dakhiliyah Governorate and the hospital administration. The parameters were compared between groups using the chi-square test.

RESULTS

Of 298 patients studied, 128 (43.0%) had used HU at some points. The difference in the prevalence of HU use was statistically significant based only on age (p = 0.014), with younger patients more likely to be currently using HU or used HU in the past. The majority of patients were adherent (82.5%) based on self-reported adherence. The prevalence of discontinuation (temporary or permanent) of HU use was high (57.0%), and suspected adverse drug reaction (ADR) was the most common reason. Among those who had never used HU, 33.7% of patients had an indication for the initiation of HU. A quarter of patients who used HU developed a suspected ADR, with blood abnormalities being the commonest. The duration of HU use influenced ADR prevalence (p = 0.015).

CONCLUSIONS

Among the current users of HU, the majority of the patients were adherent based on self-reported medication adherence. The prevalence of discontinuation of HU use and instances of non-initiation of HU among those indicated were high. A larger study, ideally of a prospective nature, in various governorates of Oman, would provide a wider picture at the national level.

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.

Targeted Hydroxyurea Education after an Emergency Department Visit Increases Hydroxyurea Use in Children with Sickle Cell Anemia

OBJECTIVE

To evaluate the impact of an initiative to increase hydroxyurea use among children with sickle cell anemia (SCA) who presented to the emergency department (ED).

STUDY DESIGN

This observational cohort study included children with SCA not taking hydroxyurea who presented to the ED with pain or acute chest syndrome and then attended a Quick-Start Hydroxyurea Initiation Project (Q-SHIP) session. A Q-SHIP session includes a hematologist-led discussion on hydroxyurea, a video of patients talking about hydroxyurea, and a direct offer to start hydroxyurea.

RESULTS

Over 64 weeks, 112 eligible patients presented to the ED and 59% (n = 66) participated in a Q-SHIP session a median of 6 days (IQR 2, 20 days) after ED or hospital discharge; 55% of participants (n = 36) started hydroxyurea. After a median follow-up of 49 weeks, 83% (n = 30) of these participants continued hydroxyurea. Laboratory markers of hydroxyurea adherence were significantly increased from baseline: median mean corpuscular volume +8.6 fL (IQR 5.0, 17.7, P < .0001) and median hemoglobin F +5.7% (IQR 2.5, 9.8, P = .0001). Comparing Q-SHIP participants to nonparticipants, 12 weeks after ED visit, participants were more likely to have started hydroxyurea than nonparticipants (53% vs 20%, P = .0004) and to be taking hydroxyurea at last follow-up (50% vs 20%, P = .001). Two years after the implementation of Q-SHIP the overall proportion of eligible patients on hydroxyurea presenting to our ED increased from 56% to 80%, P = .0069.

CONCLUSIONS

Participation in a clinic to specifically address starting hydroxyurea after a SCA complication increases hydroxyurea use.

Lower than expected elevated tricuspid regurgitant jet velocity in adults with sickle cell disease in Nigeria

Background

Cardiopulmonary disease is a major cause of morbidity and mortality in persons with sickle cell disease (SCD). Tricuspid regurgitant jet velocity (TRJV) and predicted forced expiratory volume in 1 s (FEV1%) predicted are independently associated with death in SCD. The goal of this study was to determine the prevalence of elevated TRJV and the association, if any, between TRJV and FEV1% predicted among persons with sickle cell anaemia (SCA) in Nigeria.

Methods

Using a cross-sectional design, we enrolled 100 adult Nigerians (≥15 y) with SCA. We screened participants using Doppler echocardiogram to determine their TRJV and assessed their lung function with spirometry.

Results

The prevalence of elevated TRJV was 6%, with 74% of participants having low FEV1% predicted (<70%). TRJV was negatively correlated with FEV1%, but this finding was not statistically significant (Spearman's ρ=-0.0263, p=0.8058).

Conclusions

We found a low prevalence of elevated TRJV and a trend in association between TRJV and FEV1% predicted in Nigerian adults with SCA. Our findings underscore the need to explore further the relationship between SCD and cardiopulmonary disease in adults.

Healthcare utilization and hydroxyurea adherence in youth with sickle cell disease

BACKGROUND

Sickle cell disease (SCD) complications lead to poor health-related quality of life (HRQOL) and increased healthcare utilization in this population, which could be mitigated with hydroxyurea therapy; however, adherence is suboptimal. We assessed the relationship of healthcare utilization to hydroxyurea adherence and HRQOL amongst youth with SCD.

METHODS

Thirty-four patients with SCD (median age 14 years, IQR 12-18) on hydroxyurea participated in this cross-sectional study and completed Morisky Adherence Scale 8-items and Patient Reported Outcomes Measurement Information System (PROMIS®) HRQOL measures. A medical chart review was conducted to assess healthcare utilization.

RESULTS

Participants with more frequent hospitalizations and emergency room (ER) visits and longer length of stay (LOS) had significantly lower fetal hemoglobin (r_s=-0.44; r_s=-0.45; r_s=-0.46, p < 0.05) and mean corpuscular volume (r_s=-0.47; r_s=-0.42; r_s=-0.48, p < 0.05), respectively. More frequent hospitalizations and ER visits and longer LOS correlated significantly with worse fatigue (r_s=0.51; r_s=0.41; r_s=0.53, p < 0.05), pain (r_s=0.41; r_s=0.38; r_s=0.47, p < 0.05), physical function mobility (r_s=-0.67; r_s=-0.59; r_s=-0.67, p < 0.05), depression (r_s=0.38; r_s=0.31; r_s=0.42, p < 0.05), and social isolation (r_s=0.76; r_s=0.76; r_s=-0.84, p < 0.05), respectively.

CONCLUSIONS

We conclude that increased healthcare utilization in youth with SCD is associated with low adherence to hydroxyurea and worse HRQOL domain scores. It is important emphasize the clinical benefits of high adherence to hydroxyurea, particularly among youth with SCD. Future longitudinal studies are warranted to assess the directionality of these relationships, and may reveal modifiable behavioral factors associated with early changes in hydroxyurea adherence levels.

Hydroxyurea prescription, availability and use for children with sickle cell disease in Italy: Results of a National Multicenter survey

BACKGROUND

The number of patients with sickle cell disease (SCD) has increased in Italy in the past decade due to immigration. In spite of the established efficacy of hydroxyurea (HU) in childhood, population-based data regarding its prescription and effectiveness come mainly from studies performed in adults or outside Europe.

POPULATION AND METHODS

The Hydroxyurea in SCD: A Large Nation-wide Cohort Study from Italy was a retrospective cohort study of adult and pediatric patients with SCD attending 32 centers. Pediatric data are analyzed separately.

RESULTS

Out of 504 children followed in 11 centers, 206 (40%) were on HU (194 SS/Sβ°, 12 SC/Sß+); 74% came from Sub-Saharian Africa and 18% from Europe. HU therapy indications for SS/Sβ° patients were as follows: 57% painful vaso-occlusive crisis, acute chest syndrome or both, 24% anemia, 8% anemia, and other reasons (the majority had Hb ≤ 8-8.5 g/dl, revealing scarce acceptance of low Hb values by pediatric hematologist). Mean starting dose was 15.5 mg/kg, and dose at full regimen was 17.1 mg/kg. Mean age at HU therapy was 7.68 years, although it was lower for SS/Sβ° patients. Only 10% started HU before 3 years. In 92%, 500 mg capsule was used; in 6%, the galenic was used; and in 2%, 100 mg tablet was used. Significant reduction of clinical events and inpatients admissions, with improvement in hematological parameters, was observed for SS/Sβ° patients and a trend toward improvement for SC/Sß+ patients was also observed.

CONCLUSIONS

HU effectiveness is demonstrated in a national cohort of children with SCD living in Italy, even at a lower dose than recommended, revealing good adherence to a treatment program by a socially vulnerable group of patients such as immigrants.