Immunization adherence among children with sickle cell disease and sickle cell trait: Results of a population-based study.

INTRODUCTION: Despite the importance of timely vaccine completion for protection from infectious disease, there is limited knowledge of the immunization adherence rates of children with sickle cell disease (SCD). METHODS: This is a retrospective cohort study comparing the immunization rates of children with SCD to those with sickle cell trait between 2008 and 2019 in Georgia. Completion rates for each vaccine and the proportion of children with up-to-date status at 24 and 35 months were calculated and compared between the cohorts. Chi-square tests with odds ratios (OR) for differences and 95% confidence intervals (CIs) were reported on the overall up-to-date rates and rates for individual vaccines at 24 and 35 months for the two cohorts. RESULTS: Children with SCD had higher up-to-date rates than children with sickle cell trait at 24 and 35 months. At 35 months, the overall up-to-date rates (OR = 1.17; 95% CI, 1.04-1.31; p = .004) and the four-dose pneumococcal conjugate vaccine series (OR = 1.36; 95% CI, 1.18-1.57; p < .001) were significantly different between the groups. Both cohorts had the highest completion rates for the hepatitis B series and the lowest rates for the varicella vaccine. Doses of diphtheria, tetanus, and acellular pertussis vaccine; varicella; and pneumococcal conjugate vaccines were most commonly missed by children in both cohorts. CONCLUSIONS: Children with SCD have better immunization coverage than children with sickle cell trait, but there is an opportunity for improvement. Policymakers and healthcare professionals should focus on increasing access to care coordination services among children with SCD to ensure on-time and preventive healthcare services.

Sickle Cell Trevor Thompson Transition Project (ST3P-UP) protocol for managing care transitions: Methods and rationale.

BACKGROUND: Emerging adults with sickle cell disease (EASCD) experience significant challenges transitioning from pediatric to adult care. Acute care utilization increases, quality of life (QOL) declines, with an increased risk of mortality. Currently, there are no practice standards to guide emerging adults through the transition process. We are creating a structured transition education (STE) based program for EASCD by customizing the Six Core Elements (6 CE) of Health Care Transition model and are evaluating the effectiveness of adding peer mentoring (PM). METHODS: The Sickle Cell Trevor Thompson Transition Project (ST3P-UP) is an ongoing multi-site, cluster randomized clinical trial with a target enrollment of 537 EASCD aged 16 to 25 years in pediatric care. Each site (n = 14) comprises a pediatric clinic, adult clinic, and a sickle cell disease (SCD) community-based organization (CBO). Sites are randomized 1:1 to either STE or STE + PM. EASCDs are followed prospectively for 24 months. Rapid cycle plan-do-study-act quality improvement (QI) methods are used to implement the STE. The primary objective is to compare the effectiveness of STE + PM versus STE only at decreasing the number of acute care visits per year over 24 months. The secondary objectives are to compare overall healthcare utilization and patient-reported QOL outcomes at 24 months. CONCLUSION: We aim to demonstrate the feasibility of using a QI approach to implement 6 CE-based practice standards at 14 disparate SCD clinical programs to guide EASCD through the transition process. We hypothesize that adding PM to the STE program will improve acute care reliance, QOL, and satisfaction with transition outcomes.

Characterizing complication risk from multisite, intermittent transfusions for the treatment of sickle cell disease.

Blood transfusions are indicated for some acute complications of sickle cell disease (SCD). To characterize the SCD population at increased risk of transfusion-associated complications, Georgia hospital discharge data were used to estimate the frequency of intermittent transfusions and the proportion of patients receiving them at multiple institutions. Ten years of data (2007-2016) showed almost 19% of patients with SCD (1585/8529) received transfusions at more than one hospital. The likelihood of multisite transfusions increased from ages 18 through 40 and with the number of transfusions received. The results support the need to track and share transfusion histories in order to reduce complication risks.

Improving an Administrative Case Definition for Longitudinal Surveillance of Sickle Cell Disease.

OBJECTIVE: Several states are building infrastructure and data collection methods for longitudinal, population-based surveillance systems for selected hemoglobinopathies. The objective of our study was to improve an administrative case definition for sickle cell disease (SCD) to aid in longitudinal surveillance. METHODS: We collected data from 3 administrative data sets (2004-2008) on 1998 patients aged 0-21 in Georgia who had ≥1 encounter in which an SCD International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code was recorded, and we compared these data with data from a laboratory and medical record review. We assessed performance (sensitivity, specificity, positive predictive value [PPV], and negative predictive value [NPV]) of case definitions that differed by number and type of SCD-coded encounters; addition of SCD-associated treatments, procedures, and complications; and length of surveillance (1 vs 5 years). We identified correct diagnoses for patients who were incorrectly coded as having SCD. RESULTS: The SCD case definition of ≥3 SCD-coded encounters in 5 years simplified and substantially improved the sensitivity (96.0% vs 85.8%) and NPV (68.2% vs 38.2%) of the original administrative case definition developed for 5-year, state-based surveillance (≥2 encounters in 5 years and ≥1 encounter for an SCD-related treatment, procedure, or complication), while maintaining a similar PPV (97.4% vs 97.4%) and specificity (76.5% vs 79.0%). CONCLUSIONS: This study supports an administrative case definition that specifies ≥3 ICD-9-CM-coded encounters to identify SCD with a high degree of accuracy in pediatric patients. This case definition can be used to help establish longitudinal SCD surveillance systems.

Impact of Red Blood Cell Antigen Matching on Alloimmunization and Transfusion Complications in Patients with Sickle Cell Disease: A Systematic Review.

Red blood cells (RBC) transfusion is critical in managing acute and chronic complications in sickle cell disease (SCD); however, it is complicated by RBC alloimmunization, iron overload, transfusion reactions and infection. Several reports documented an increased incidence of alloantibodies in transfused individuals with SCD, especially for Rh and Kell antigens. As a result, the National Institutes of Health Expert Panel and British Society for Haematology guidelines recommend primary matching for C/c, E/e and K antigens in addition to ABO/RhD for RBC transfusions. However, the evidence supporting these recommendations was cited as limited and understanding of alloimmunization in SCD is evolving. To examine the limitations of the evidence, we undertook a systematic review of evidence behind recommendations for limited and extended serologic and genotypic RBC antigen matching to reduce alloimmunization, autoimmunization and transfusion reactions. Searches of PubMed, Embase, Cochrane, and Web of Science databases using MeSH index and free text terms between 1976 through October 2015 and papers and captured through July 2016 through review references in papers, word of mouth, and ongoing Google Scholar and Medline Alerts identified 303 unique articles. Nineteen articles met inclusion criteria and were classified by the Oxford Centre Evidence Based levels of evidence. Strengthening the Reporting of Observational Studies in Epidemiology checklists were completed for 18 of the 19 studies. There were no prospective randomized controlled trials. Sixteen of the articles were cohort studies, two were cross-sectional studies, and one decision tree model examining costs. Low-quality evidence from observational cohort studies supports that alloimmunization prevalence can be decreased by extending serological RBC antigen matching. Transfusion reactions are generally poorly and inconsistently reported. There was no evidence reporting the effect prophylactic genotypic matching has on alloimmunization, autoimmunization or transfusion reactions. There were no studies comparing prophylactic genotypic matching to serologic matching. High-quality evidence was lacking to support clinical decision making regarding best transfusion practices. Multicenter prospective randomized clinical trials are needed to determine best strategies for reducing the rate of alloimmunization using serologic and genotypic matching.

Losartan therapy decreases albuminuria with stable glomerular filtration and permselectivity in sickle cell anemia.

Sickle cell nephropathy begins with hyperfiltration and microalbuminuria and may progress to renal failure. The aim of this study was to determine the effects of losartan on glomerular function and albumin excretion in sickle cell anemia (SCA). Individuals with SCA on hydroxyurea with persistent albuminuria were enrolled in a 1-year study of losartan. Glomerular filtration rate (GFR) measured by iohexol clearance, albumin excretion rate (AER), and fractional clearance of dextran were assessed at baseline, short-term (1-2month), and long-term (≥12month) intervals. Twelve subjects (6 microalbuminuria, 6 macroalbuminuria) completed short-term studies; 8 completed long-term studies. Baseline GFR was 112ml/min/1.73m2 (71-147ml/min/1.73m2). AER decreased significantly at the short-term (median decrease -134 mcg/min, p=0.0063). GFR was not significantly-different at short-term or long-term intervals. Dextran clearance improved for diameters smaller than albumin (<36Å) but not larger sizes. Losartan therapy for ≥1year in sickle nephropathy results in lower albumin excretion with stable GFR. Filtration of neutral molecules ≥36Å was not changed by losartan, suggesting that the effect of losartan is a mechanism other than alteration of glomerular filtration size-selectivity.

Standard measures for sickle cell disease research: the PhenX Toolkit sickle cell disease collections.

Standard measures and common data elements for sickle cell disease (SCD) will improve the data quality and comparability necessary for cross-study analyses and the development of guidelines that support effective treatments and interventions. In 2014, the National Institutes of Health, National Heart, Lung, and Blood Institute (NHLBI) funded an Administrative Supplement to the PhenX Toolkit (consensus measures for Phenotypes and eXposures; https://www.phenxtoolkit.org/) to identify common measures to promote data comparability across SCD research. An 11-member Sickle Cell Disease Research and Scientific Panel provided guidance to the project, establishing a core collection of SCD-related measures and defining the scope of 2 specialty collections: (1) cardiovascular, pulmonary, and renal complications, and (2) neurology, quality-of-life, and health services. For each specialty collection, a working group of SCD experts selected high-priority measures using a consensus process that included scientific community input. The SCD measures were released into the Toolkit in August 2015. The 25 measures included in the core collection are recommended for use by all NHLBI-funded investigators performing human-subject SCD research. The 10 neurology, quality-of-life, and health services measures and 14 cardiovascular, pulmonary, and renal measures are recommended for use within these specialized research areas. For SCD and other researchers, PhenX measures will promote collaborations with clinicians and patients, facilitate cross-study analysis, accelerate translational research, and lead to greater understanding of SCD phenotypes and epigenetics. For clinicians, using PhenX measures will help elucidate the etiology, progression, and treatment of SCD, leading to improved patient care and quality of life.

Defining Sickle Cell Disease Mortality Using a Population-Based Surveillance System, 2004 through 2008.

OBJECTIVE: Population-based surveillance data from California and Georgia for years 2004 through 2008 were linked to state death record files to determine the all-cause death rate among 12,143 patients identified with sickle cell disease (SCD). METHODS: All-cause death rates, by age, among these SCD patients were compared with all-cause death rates among both African Americans and the total population in the two states. All-cause death rates were also compared with death rates for SCD derived from publicly available death records: the compressed mortality files and multiple cause of death files. RESULTS: Of 12,143 patients identified with SCD, 615 patients died. The all-cause mortality rate for the SCD population was lower than the all-cause mortality rate among African Americans and similar to the total population all-cause mortality rates from birth through age 4 years, but the rate was higher among those with SCD than both the African American and total population rates from ages 5 through 74 years. The count of deceased patients identified by using population-based surveillance data (n=615) was more than twice as high as the count identified in compressed mortality files using SCD as the underlying cause of death alone (n=297). CONCLUSION: Accurate assessment of all-cause mortality and age at death requires long-term surveillance via population-based registries of patients with accurately diagnosed SCD.

Newborn screening for sickle cell diseases in the United States: A review of data spanning 2 decades.

UNLABELLED: Sickle cell disease is a group of disorders, the majority of which are detected through state newborn screening programs. There is limited knowledge of disease prevalence in the U.S. POPULATION: We report 20 years of case finding and laboratory data for sickle cell disease and trait to assist in: planning for health services delivery; providing data for researchers; aiding in tracking health outcome trends; and assessing sickle gene prevalence in the newborn population. During the 20-year period, there were 39,422 confirmed cases of sickle cell disease among 76,527,627 newborn births screened (1:1941) and 1,107,875 laboratory reports of probable sickle trait among 73,951,175 newborn births screened (1:67). The highest sickle cell disease incidence during the 20 years was in the District of Columbia (1:437) followed by Mississippi (1:683) and South Carolina (1:771). For sickle cell trait, the highest incidences were in the District of Columbia (1:22), Mississippi (1:26), and South Carolina (1:31).

Factors associated with survival in a contemporary adult sickle cell disease cohort.

In this study, the relationship of clinical differences among patients with sickle cell disease (SCD) was examined to understand the major contributors to early mortality in a contemporary cohort. Survival data were obtained for 542 adult subjects who were enrolled since 2002 at three university hospitals in the southeast United States. Subjects were followed up for a median of 9.3 years. At enrollment, clinical parameters were collected, including hemoglobin (Hb) genotype, baseline laboratory values, comorbidities, and medication usage. Levels of soluble adhesion molecules were measured for a subset of 87 subjects. The relationship of clinical characteristics to survival was determined using regression analysis. Median age at enrollment was 32 years. Median survival was 61 years for all subjects. Median survival for Hb SS and Sß(0) was 58 years and for Hb SC and Sß(+) was 66 years. Elevated white blood count, lower estimated glomerular filtration rate, proteinuria, frequency of pain crises, pulmonary hypertension, cerebrovascular events, seizures, stroke, sVCAM-1, and short-acting narcotics use were significantly associated with decreased survival. Forty-two percent of subjects were on hydroxyurea therapy, which was not associated with survival. SCD continues to reduce life expectancy for affected individuals, particularly those with Hb Sß(0) and SS. Not only were comorbidities individually associated with decreased survival but also an additive effect was observed, thus, those with a greater number of negative endpoints had worse survival (P < 0.0001). The association of higher sVCAM-1 levels with decreased survival suggests that targeted therapies to reduce endothelial damage and inflammation may also be beneficial.

IMPROVE trial: a randomized controlled trial of patient-controlled analgesia for sickle cell painful episodes: rationale, design challenges, initial experience, and recommendations for future studies.

BACKGROUND: The hallmark of sickle cell disease (SCD) is pain from a vaso-occlusive crisis. Although ambulatory pain accounts for most days in pain, pain is also the most common cause of hospitalization and is typically treated with parenteral opioids. The evidence base is lacking for most analgesic practice in SCD, particularly for the optimal opioid dosing for patient-controlled analgesia (PCA), in part because of the challenges of the trial design and conduct for this rare disease. PURPOSE: The purpose of this report is to describe our Network's experiences with protocol development, implementation, and analysis, including overall study design, the value of pain assessments rather than 'crisis' resolution as trial endpoints, and alternative statistical analysis strategies. METHODS: The Improving Pain Management and Outcomes with Various Strategies (IMPROVE) PCA trial was a multisite inpatient randomized controlled trial comparing two PCA-dosing strategies in adults and children with SCD and acute pain conducted by the SCD Clinical Research Network. The specified primary endpoint was a 25-mm change in a daily average pain intensity using a Visual Analogue Scale, and a number of related pain intensity and pain interference measures were selected as secondary efficacy outcomes. A time-to-event analysis strategy was planned for the primary endpoint. RESULTS: Of 1116 individuals admitted for pain at 31 participating sites over a 6-month period, 38 were randomized and 4 withdrawn. The trial was closed early due to poor accrual, reflecting a substantial number of challenges encountered during trial implementation. LIMITATIONS: While some of the design issues were unique to SCD or analgesic studies, many of the trial implementation challenges reflected the increasing complexity of conducting clinical trials in the inpatient setting with multiple care providers and evolving electronic medical record systems, particularly in the context of large urban academic medical centers. LESSONS LEARNED: Complicated clinical organization of many sites likely slowed study initiation. More extensive involvement of research staff and site principal investigator in the clinical care operations improved site performance. During the subsequent data analysis, alternative statistical approaches were considered, the results of which should inform future efficacy assessments and increase future trial recruitment success by allowing substantial reductions in target sample size. CONCLUSIONS: A complex randomized analgesic trial was initiated within a multisite disease network seeking to provide an evidence base for clinical care. A number of design considerations were shown to be feasible in this setting, and several pain intensity and pain interference measures were shown to be sensitive to time- and treatment-related improvements. While the premature closure and small sample size precluded definitive conclusions regarding treatment efficacy, this trial furnishes a template for design and implementation considerations that should improve future SCD analgesic trials.

High dose vitamin D therapy for chronic pain in children and adolescents with sickle cell disease: results of a randomized double blind pilot study.

We report results of a pilot study of high-dose vitamin D in sickle cell disease (SCD). Subjects were given a 6-week course of oral high-dose cholecalciferol (4000-100 000 IU per week) or placebo and monitored prospectively for a period of six months. Vitamin D insufficiency and deficiency was present at baseline in 82·5% and 52·5% of subjects, respectively. Subjects who received high-dose vitamin D achieved higher serum 25-hydroxyvitamin D, experienced fewer pain days per week, and had higher physical activity quality-of-life scores. These findings suggest a potential benefit of vitamin D in reducing the number of pain days in SCD. Larger prospective studies with longer duration are needed to confirm these effects.

MYH9 and APOL1 are both associated with sickle cell disease nephropathy.

Renal failure occurs in 5-18% of sickle cell disease (SCD) patients and is associated with early mortality. At-risk SCD patients cannot be identified prior to the appearance of proteinuria and the pathobiology is not well understood. The myosin, heavy chain 9, non-muscle (MYH9) and apolipoprotein L1 (APOL1) genes have been associated with risk for focal segmental glomerulosclerosis and end-stage renal disease in African Americans. We genotyped 26 single nucleotide polymorphisms (SNPs) in MYH9 and 2 SNPs in APOL1 (representing the G1 and G2 tags) in 521 unrelated adult (18-83 years) SCD patients screened for proteinuria. Using logistic regression, SNPs were evaluated for association with proteinuria. Seven SNPs in MYH9 and one in APOL1 remained significantly associated with proteinuria after multiple testing correction (P < 0·0025). An MYH9 risk haplotype (P = 0·001) and the APOL1 G1/G2 recessive model (P < 0·0001) were strongly associated with proteinuria, even when accounting for the other. Glomerular filtration rate was negatively correlated with proteinuria (P < 0·0001), and was significantly predicted by an interaction between MYH9 and APOL1 in age-adjusted analyses. Our data provide insight into the pathobiology of renal dysfunction in SCD, suggesting that MYH9 and APOL1 are both associated with risk.

Chronic kidney disease and albuminuria in children with sickle cell disease.

BACKGROUND AND OBJECTIVES: Sickle cell nephropathy begins in childhood and may progress to renal failure. Albuminuria is a sensitive marker of glomerular damage that may indicate early chronic kidney disease (CKD). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The aims of this study were to determine the cross-sectional prevalence and clinical correlates of albuminuria and CKD among children with sickle cell disease (SCD). Over a 10-year period (1995 to 2005) 410 pediatric SCD patients ages 2 to 21 years were enrolled: 261 with hemoglobin SS (HbSS) or HbSß(0) thalassemia (HbSß(0)) and 149 with HbSC or HbSß(+) thalassemia (HbSß(+)). The albumin/creatinine ratio (ACR) of spot-urine specimens and serum creatinine were measured; abnormal albuminuria was defined as urinary ACR ≥ 30 mg/g. RESULTS: The prevalence of abnormal albuminuria was 20.7% (23.0% in HbSS/HbSß(0), 16.8% in HbSC/HbSß(+)). Among HbSS/HbSß(0), abnormal albuminuria was associated with increasing age and lower baseline hemoglobin. GFR, estimated in 189 patients using the updated Schwartz formula, correlated negatively with age (r = -0.27, P = 0.0002). CKD defined according to the Kidney Disease: Improving Global Outcomes study was present in 26.5% (50 of 189) of patients: stage 1 in 27 (14.8%) and stage 2 in 22 (11.6%). In multivariate analysis, age and HbSC/HbSß(+) genotype were associated with CKD. CONCLUSIONS: This is the first study to stage CKD in children with SCD and highlights a high prevalence of albuminuria and glomerular injury early in life. Detecting CKD in childhood could allow for earlier intervention and prevention of renal failure in adulthood.

Leg ulcers in sickle cell disease.

Sickle cell disease is a single amino acid molecular disorder of hemoglobin leading to its pathological polymerization, red cell rigidity that causes poor microvascular blood flow, with consequent tissue ischemia and infarction. The manifestations of this disease are protean.Among them, leg ulcers represent a particularly disabling and chronic complication, often associated with a more severe clinical course.Despite the fact that this complication has been recognized since the early times of SCD, there has been little improvement in the efficacy of its management and clinical outcome over the past 100 years. Recently, vasculopathic abnormalities involving abnormal vascular tone and activated, adhesive endothelium have been recognized as another pathway to end organ damage in sickle cell disease. Vasculopathy of sickle cell disease has been implicated in the development of pulmonary hypertension, stroke, leg ulceration and priapism, particularly associated with hemolytic severity, and reported in other severe hemolytic disorders. The authors present the proceedings from the Educational Session on Chronic leg ulcers in Sickle cell disease, held during the 4th Annual Sickle Cell Disease Research and Educational Symposium, on February 17, 2010 in Fort Lauderdale, Fla.