Assessment of Liver Fibrosis by Transient Elastography in Children and Young Adults With Sickle Cell Disease With and Without Iron Overload.

Transfusion-associated iron overload may cause liver fibrosis. We compared transient elastography (TE) and aspartate aminotransferase-platelet ratio index (APRI), noninvasive markers for hepatic fibrosis, to liver histology in children and young adults with sickle cell disease (SCD) who were iron overloaded (cohort 1). Age-matched subjects with SCD but without iron overload (cohort 2) were enrolled for APRI and TE assessments. Nineteen subjects ages 10 to 21 years were transfused for a mean of 9.67 years, had a mean serum ferritin of 4899±2849 ng/mL, and a liver iron concentration of 15.56±10.12 mg/g dry liver weight by R2-magnetic resonance imaging. Mean APRI was 0.33±0.13 in cohort 1 and 0.27±0.10 in cohort 2. The mean liver stiffness measures (LSM) in cohort 1, assessed by TE, was 8.46±3.95 kPa, ranging from 3.5 to 14.6 kPa (expected normal <7 kPa). Cohort 2 had a mean LSM of 5.72±1.74 kPa (4.6 to 8.7 kPa). There was a good correlation between LSM and histologic fibrosis (t value 6.94, P<0.0001). There was no significant correlation between APRI and histologic fibrosis and between APRI and LSM. A high LSM suggests liver fibrosis in children and adults with SCD with iron overload and may merit histologic confirmation especially if persistent.

Pediatric to Adult Transition in Sickle Cell Disease: Survey Results from Young Adult Patients.

BACKGROUND/AIMS: We surveyed sickle cell disease (SCD) patients who transitioned from pediatric care at Texas Children's Hematology Center (TCHC) to adult care to determine the characteristics of patients with an adult SCD provider, continuation rates of pre-transition therapies, and patient perceptions of the transition process. METHODS: A cross-sectional study was conducted by telephone survey of 44 young adults with SCD, aged 19-29 years, who transitioned from TCHC to adult care within the last 15 years. RESULTS: Findings of the 23-item questionnaire revealed that transitioned patients with current adult providers (68.2%) were more likely to have seen a provider within 6 months of transition (p = 0.023) and to have been on hydroxyurea and/or monthly blood transfusions pre-transition (p = 0.021) than transitioned patients without a provider; 83% of patients on pre-transition hydroxyurea reported continuing hydroxyurea after transition. Transition challenges included inadequate preparation, difficulty finding knowledgeable adult providers, and lack of healthcare insurance/coverage. CONCLUSION: Transition to adult providers is predicted by establishing care with an adult SCD provider within 6 months of transition and being on pre-transition disease-modifying therapy. Transition may be improved if pediatric hematology centers assist and verify adult provider contact within 6 months of transition and engage patients of all disease severity during transition.

Optimal disease management and health monitoring in adults with sickle cell disease.

In countries with access to organized health care, survival of children with sickle cell disease (SCD) has greatly improved, resulting in a growing population of adults with SCD. Transition from pediatric to adult care presents many challenges for the patient, who now faces the reality of emerging complications in many organs that are cumulative, adding to other age-related nonsickle conditions that interact and add to the disease morbidity. We recommend regular comprehensive annual assessments, monitoring for early signs of organ damage and joint clinics with relevant specialists, if applicable. While maintaining a low threshold for intervention with disease-modifying therapies, we should always keep in mind that there is no single complication that is pathognomonic of SCD, and nonsickle comorbidities should always be excluded and treated if present. We need to reevaluate our approach to managing adults with SCD by putting a greater emphasis on multidisciplinary care while proactively considering curative options (hematopoietic stem cell transplant and gene therapy) and experimental pharmacological agents for adults with SCD of all ages before complications render the patients ineligible for these treatments.

The influence of health literacy on emergency department utilization and hospitalizations in adolescents with sickle cell disease.

OBJECTIVE: Healthcare spending in the US is $3.2 trillion. $1.1 trillion is attributed to hospital care, including emergency department (ED) visits and hospitalizations. There is a relationship between ED utilization, hospitalizations, and health literacy in the general population. Health literacy may play a role in frequent ED visits and hospitalizations in patients with sickle cell disease (SCD). The purpose of this paper is to describe the relationship among health literacy levels, annual hospital encounters, annual clinic visits, annual ED visits, and annual hospitalizations in 134 Black, non-Hispanic adolescents aged 10-19 years with SCD. DESIGN: This is a cross-sectional, descriptive correlational study evaluating facilitators and barriers to health literacy and clinical outcomes in adolescents with SCD. SAMPLE: Data were collected from 134 Black, non-Hispanic adolescents with SCD at a large, tertiary care center in Texas. MEASUREMENTS: The Newest Vital Sign and REALM-Teen health literacy instruments were used to evaluate health literacy. RESULTS: Contrasting previous studies evaluating the influence of health literacy on ED visits and hospitalizations in the general population, there were no significant relationships within this sample. CONCLUSIONS: This study gives insight into future research to evaluate other potential influences on ED utilization and hospitalizations in pediatric patients with SCD.

A method for age-matched OCT angiography deviation mapping in the assessment of disease- related changes to the radial peripapillary capillaries.

PURPOSE: To present a method for age-matched deviation mapping in the assessment of disease-related changes to the radial peripapillary capillaries (RPCs). METHODS: We reviewed 4.5x4.5mm en face peripapillary OCT-A scans of 133 healthy control eyes (133 subjects, mean 41.5 yrs, range 11-82 yrs) and 4 eyes with distinct retinal pathologies, obtained using spectral-domain optical coherence tomography angiography. Statistical analysis was performed to evaluate the impact of age on RPC perfusion densities. RPC density group mean and standard deviation maps were generated for each decade of life. Deviation maps were created for the diseased eyes based on these maps. Large peripapillary vessel (LPV; noncapillary vessel) perfusion density was also studied for impact of age. RESULTS: Average healthy RPC density was 42.5±1.47%. ANOVA and pairwise Tukey-Kramer tests showed that RPC density in the ≥60yr group was significantly lower compared to RPC density in all younger decades of life (p<0.01). Average healthy LPV density was 21.5±3.07%. Linear regression models indicated that LPV density decreased with age, however ANOVA and pairwise Tukey-Kramer tests did not reach statistical significance. Deviation mapping enabled us to quantitatively and visually elucidate the significance of RPC density changes in disease. CONCLUSIONS: It is important to consider changes that occur with aging when analyzing RPC and LPV density changes in disease. RPC density, coupled with age-matched deviation mapping techniques, represents a potentially clinically useful method in detecting changes to peripapillary perfusion in disease.

Rapid and Sensitive Assessment of Globin Chains for Gene and Cell Therapy of Hemoglobinopathies.

The ß-hemoglobinopathies sickle cell anemia and ß-thalassemia are the focus of many gene-therapy studies. A key disease parameter is the abundance of globin chains because it indicates the level of anemia, likely toxicity of excess or aberrant globins, and therapeutic potential of induced or exogenous ß-like globins. Reversed-phase high-performance liquid chromatography (HPLC) allows versatile and inexpensive globin quantification, but commonly applied protocols suffer from long run times, high sample requirements, or inability to separate murine from human ß-globin chains. The latter point is problematic for in vivo studies with gene-addition vectors in murine disease models and mouse/human chimeras. This study demonstrates HPLC-based measurements of globin expression (1) after differentiation of the commonly applied human umbilical cord blood-derived erythroid progenitor-2 cell line, (2) in erythroid progeny of CD34+ cells for the analysis of clustered regularly interspaced short palindromic repeats/Cas9-mediated disruption of the globin regulator BCL11A, and (3) of transgenic mice holding the human ß-globin locus. At run times of 8 min for separation of murine and human ß-globin chains as well as of human γ-globin chains, and with routine measurement of globin-chain ratios for 12 nL of blood (tested for down to 0.75 nL) or of 300,000 in vitro differentiated cells, the methods presented here and any variant-specific adaptations thereof will greatly facilitate evaluation of novel therapy applications for ß-hemoglobinopathies.

Interim assessment of liver damage in patients with sickle cell disease using new non-invasive techniques.

We explored transient elastography (TE) and enhanced liver fibrosis (ELF™ ) score with standard markers of liver function to assess liver damage in 193 well patients with sickle cell disease (SCD). Patients with HbSS or HbSß0 thalassaemia (sickle cell anaemia, SCA; N = 134), had significantly higher TE results and ELF scores than those with HbSC (N = 49) disease (TE, 6·8 vs. 5·3, P < 0·0001 and ELF, 9·2 vs. 8·6 P < 0·0001). In SCA patients, TE and ELF correlated significantly with age and all serum liver function tests (LFTs). Additionally, (weak) positive correlation was found with lactate dehydrogenase (TE: r = 0·24, P = 0·004; ELF: r = 0·26 P = 0·002), and (weak) negative correlation with haemoglobin (TE: r = -0·25, P = 0·002; ELF: r = -0·25 P = 0·004). In HbSC patients, correlations were weaker or not significant between TE or ELF, and serum LFTs. All markers of iron loading correlated with TE values when corrected for sickle genotype (serum ferritin, ß = 0·25, P < 0·0001, total blood transfusion units, ß = 0·25, P < 0·0001 and LIC ß = 0·32, P = 0·046). The exploratory study suggests that, while TE could have a role, the utility of ELF score in monitoring liver damage in SCD, needs further longitudinal studies.

A Comparison of Pain Assessment Measures in Pediatric Sickle Cell Disease: Visual Analog Scale Versus Numeric Rating Scale.

Given the availability of various pain severity scales, greater understanding of the agreement between pain scales is warranted. We compared Visual Analog Scale (VAS) and Numeric Rating Scale (NRS) pain severity ratings in children with sickle cell disease (SCD) to identify the relationship and agreement between pain scale ratings. Twenty-eight patients (mean ± SD age, 14.65 ± 3.12 y, 50% female) receiving pain interventions within the emergency department completed serial VAS and NRS pain severity ratings every 30 minutes. Data were used to calculate the relationship (Spearman correlation) and agreement (Bland-Altman approach) between the VAS and NRS. One hundred twenty-eight paired VAS-NRS measurements were obtained. VAS and NRS ratings were significantly correlated for the initial assessment (rs = 0.88, P < 0.001) and all assessments (rs = 0.87, P < 0.001). Differences between VAS and NRS means were -0.52 (P = 0.006) for the initial assessment and -0.86 (P < 0.001) across all assessments. The difference between VAS and NRS ratings decreased as pain severity increased across all assessments (P = 0.027), but not the initial assessment. Within pediatric patients with SCD, VAS and NRS ratings were found to trend together; however, VAS scores were found to be significantly lower than NRS scores across assessments. The agreement between the 2 measures improved at increasing levels of pain severity. These findings demonstrate that the VAS and NRS are similar, but cannot be used interchangeably when assessing self-reported pain in SCD.

Allogeneic Hematopoietic Cell Transplantation for Children with Sickle Cell Disease Is Beneficial and Cost-Effective: A Single-Center Analysis.

Limited data exist regarding health care utilization (HCU) in patients receiving allogeneic hematopoietic cell transplantation (alloHCT) for sickle cell disease. Financial data from 2002 to 2011 were analyzed for 26 alloHCT patients and 48 control subjects (referred but without alloHCT). HCU of alloHCT was determined over 3 time periods: pre-alloHCT, during alloHCT (day 0 to day +365), and post-alloHCT. The median total cost per patient during the alloHCT year was $413,000 inpatient and $18,000 outpatient. Post-alloHCT HCU decreased when compared with pre-alloHCT and control subjects. The median cost of post-alloHCT outpatient visits per patient was significantly less when compared with pre-alloHCT (P = .044). The median cost of post-alloHCT inpatient visits per patient approached significance when compared with those pre-alloHCT (P = .079). Sixteen post-alloHCT patients, 19 control subjects, and 14 unaffected siblings were surveyed using Pediatric Quality of Life Inventory and EuroQOL questionnaires; however, the questionnaire scores across all 3 patient groups were not statistically significant (P = .2638). When adjusted for health-related quality of life, the analysis suggested alloHCT has a positive impact on health-related quality of life over control subjects. These pilot data support our hypothesis that alloHCT in children with sickle cell disease reduces HCU compared with control subjects without alloHCT.

Wide-field computational imaging of pathology slides using lens-free on-chip microscopy.

Optical examination of microscale features in pathology slides is one of the gold standards to diagnose disease. However, the use of conventional light microscopes is partially limited owing to their relatively high cost, bulkiness of lens-based optics, small field of view (FOV), and requirements for lateral scanning and three-dimensional (3D) focus adjustment. We illustrate the performance of a computational lens-free, holographic on-chip microscope that uses the transport-of-intensity equation, multi-height iterative phase retrieval, and rotational field transformations to perform wide-FOV imaging of pathology samples with comparable image quality to a traditional transmission lens-based microscope. The holographically reconstructed image can be digitally focused at any depth within the object FOV (after image capture) without the need for mechanical focus adjustment and is also digitally corrected for artifacts arising from uncontrolled tilting and height variations between the sample and sensor planes. Using this lens-free on-chip microscope, we successfully imaged invasive carcinoma cells within human breast sections, Papanicolaou smears revealing a high-grade squamous intraepithelial lesion, and sickle cell anemia blood smears over a FOV of 20.5 mm(2). The resulting wide-field lens-free images had sufficient image resolution and contrast for clinical evaluation, as demonstrated by a pathologist's blinded diagnosis of breast cancer tissue samples, achieving an overall accuracy of ~99%. By providing high-resolution images of large-area pathology samples with 3D digital focus adjustment, lens-free on-chip microscopy can be useful in resource-limited and point-of-care settings.

The clinical effectiveness and cost-effectiveness of primary stroke prevention in children with sickle cell disease: a systematic review and economic evaluation.

BACKGROUND: Sickle cell disease (SCD) is a recessive genetic blood disorder, caused by a mutation in the ß-globin gene. For children with SCD, the risk of stroke is estimated to be up to 250 times higher than in the general childhood population. Transcranial Doppler (TCD) ultrasonography is a non-invasive technique which measures local blood velocity in the proximal portions of large intracranial arteries. Screening with TCD ultrasonography identifies individuals with high cerebral blood velocity; these children are at the highest risk of stroke. A number of primary stroke prevention strategies are currently used in clinical practice in the UK including blood transfusion, treatment with hydroxycarbamide and bone marrow transplantation (BMT). No reviews have yet assessed the clinical effectiveness and cost effectiveness of primary stroke prevention strategies in children with SCD identified to be at high risk of stroke using TCD ultrasonography. OBJECTIVE: To assess the clinical effectiveness and cost-effectiveness of primary stroke prevention treatments for children with SCD who are identified (using TCD ultrasonography) to be at high risk of stroke. DATA SOURCES: Electronic databases were searched from inception up to May 2011, including the Cochrane Database of Systematic Reviews (CDSR), the Cochrane Central Register of Controlled Trials (CENTRAL), the Database of Abstracts of Reviews of Effects (DARE), EMBASE, the Health Technology Assessment (HTA) database, ISI Web of Science Proceedings, ISI Web of Science Citation Index, the NHS Economic Evaluation Database (NHS EED) and MEDLINE. REVIEW METHODS: The assessment was conducted according to accepted procedures for conducting and reporting systematic reviews and economic evaluations. A de novo Markov model was developed to determine the cost-effectiveness of TCD ultrasonography and blood transfusion, where clinically appropriate, in patients with SCD. RESULTS: Two randomised controlled trials met the inclusion criteria involving a study population of 209 participants. One compared blood transfusion with standard care for children who are identified as being at high risk of stroke using TCD ultrasonography. In this trial, one patient in the transfusion group had a stroke (1/63) compared with 11 children in the standard care group (11/67). The other trial assessed the impact of halting chronic transfusion in patients with SCD. Sixteen patients in the transfusion-halted group had an event (16/41) (two patients experienced stroke and 14 reverted to abnormal TCD velocity); there were no events in the continued-transfusion group (0/38). No meta-analyses of these trials were undertaken. No relevant economic evaluations were identified for inclusion in the review. The de novo modelling suggests that blood transfusions plus TCD scans (compared with just TCD scans) for patients with SCD at high risk of stroke, aged ≥ 2 years, may be good value for money. The intervention has an incremental cost-effectiveness ratio of £24,075 per quality-adjusted life-year gained, and helps avoid 68 strokes over the lifetime of a population of 1000 patients. The intervention costs an additional £13,751 per patient and generates 0.6 extra years of life in full health per patient. The data available for the economic analysis are limited. Sensitivity analyses and validation against existing data and expert opinion provide some reassurance that the conclusion of the model is reliable but further research is required to validate these findings. LIMITATIONS: The main limitations relate to the availability of published clinical data; no completed randomised controlled trials were identified which evaluated the efficacy of either BMT or hydroxycarbamide for primary stroke prevention. Both the clinical and cost data available for use in the economic analysis are limited. Sensitivity analyses and validation against existing data and expert opinion provide some reassurance that the conclusions of the model are reliable, but further research is required to validate these findings. CONCLUSIONS: The use of TCD ultrasonography to identify children at high risk of stroke, and treating these children with prophylactic blood transfusions, appears to be both clinically effective and cost-effective compared with TCD ultrasonography only. However, given the limitations in the data available, further research is required to verify this conclusion. Several research recommendations can be proposed from this review. Clinically, more research is needed to assess the effects and optimal duration of long-term blood transfusion and the potential role of hydroxycarbamide in primary stroke prevention. From an economics perspective, further research is required to generate more robust data on which to base estimates of cost-effectiveness or against which model outputs can be calibrated. More data are required to explain how utility weights vary with age, transfusions and strokes. Research is also needed around the cost of paediatric stroke in the UK. STUDY REGISTRATION: PROSPERO CRD42011001496. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

A potent oral P-selectin blocking agent improves microcirculatory blood flow and a marker of endothelial cell injury in patients with sickle cell disease.

Abnormal blood flow accounts for most of the clinical morbidity of sickle cell disease (SCD) [1,2]. Most notably, occlusion of flow in the microvasculature causes the acute pain crises [3] that are the commonest cause for patients with SCD to seek medical attention [4] and major determinants of their quality of life [5]. Based on evidence that endothelial P-selectin is central to the abnormal blood flow in SCD we provide results from four of our studies that are germane to microvascular blood flow in SCD. A proof-of-principle study established that doses of heparin lower than what are used for anticoagulation but sufficient to block P-selectin improved microvascular blood flow inpatients with SCD. An in vitro study showed that Pentosan Polysulfate Sodium (PPS) had greater P-selectin blocking activity than heparin. A Phase I clinical study demonstrated that a single oral dose of PPS increased microvascular blood flow in patients with SCD. A Phase II clinical study that was not completed documented that daily oral doses of PPS administered for 8 weeks lowered plasma levels of sVCAM-1 and tended to improve microvascular blood flow in patients with SCD. These data support the concept that P-selectin on the microvascular endothelium is critical to both acute vascular occlusion and chronically impaired microvascular blood flow in SCD. They also demonstrate that oral PPS is beneficial to microvascular sickle cell blood flow and has potential as an efficacious agent for long-term prophylactic therapy of SCD.