Acute care utilization among individuals with sickle cell disease and related cardiopulmonary and renal complications.

Cardiopulmonary and renal end organ (CPR) complications are associated with early mortality among individuals with sickle cell disease (SCD). However, there is limited knowledge regarding acute care utilization for individuals with SCD and CPR complications. Our objective was to determine the prevalence of CPR complications in a state specific SCD population and compare acute care utilization among individuals with and without CPR complications. We leveraged 2017-2020 data for individuals with SCD identified by the Sickle Cell Data Collection program in Wisconsin. The prevalence of CPR complications is determined for distinct age groups. Generalized linear models adjusted for age compared the rate of acute care visits/person/year among individuals who had cardiopulmonary only, renal only, both cardiopulmonary and renal, or no CPR complications. There were 1378 individuals with SCD, 52% females, mean (SD) age 28.3 (18.5) years; 48% had at least one CPR complication during the study period. The prevalence of CPR complications was higher in adults (69%) compared to pediatric (15%) and transition (51%) groups. Individuals with SCD and cardiopulmonary complications had higher acute visit rates than those without CPR complications (5.4 (IQR 5.0-5.8) vs 2.4 (IQR 2.1-2.5), p <0.001)). Acute care visit rates were similar between individuals with SCD who had renal only complications and no CPR complications (2.7 (IQR 2.5-3.0) vs 2.4 (2.1-2.5), p = 0.24). The high acute care visit rates, especially for those with cardiopulmonary complications, warrant further investigation to understand risk factors for CPR complications, the underlying reasons and identify effective disease management strategies.

Evaluating the Discriminatory Ability of the Sickle Cell Data Collection Program's Administrative Claims Case Definition in Identifying Adults With Sickle Cell Disease: Validation Study.

BACKGROUND: Sickle cell disease (SCD) was first recognized in 1910 and identified as a genetic condition in 1949. However, there is not a universal clinical registry that can be used currently to estimate its prevalence. The Sickle Cell Data Collection (SCDC) program, funded by the Centers for Disease Control and Prevention, funds state-level grantees to compile data within their states from various sources including administrative claims to identify individuals with SCD. The performance of the SCDC administrative claims case definition has been validated in a pediatric population with SCD, but it has not been tested in adults. OBJECTIVE: The objective of our study is to evaluate the discriminatory ability of the SCDC administrative claims case definition to accurately identify adults with SCD using Medicaid insurance claims data. METHODS: Our study used Medicaid claims data in combination with hospital-based medical record data from the Alabama, Georgia, and Wisconsin SCDC programs to identify individuals aged 18 years or older meeting the SCDC administrative claims case definition. In order to validate this definition, our study included only those individuals who were identified in both Medicaid's and the partnering clinical institution's records. We used clinical laboratory tests and diagnostic algorithms to determine the true SCD status of this subset of patients. Positive predictive values (PPV) are reported overall and by state under several scenarios. RESULTS: There were 1219 individuals (354 from Alabama and 865 from Georgia) who were identified through a 5-year time period. The 5-year time period yielded a PPV of 88.4% (91% for data from Alabama and 87% for data from Georgia), when only using data with laboratory-confirmed (gold standard) cases as true positives. With a narrower time period (3-year period) and data from 3 states (Alabama, Georgia, and Wisconsin), a total of 1432 individuals from these states were included in our study. The overall 3-year PPV was 89.4% (92%, 93%, and 81% for data from Alabama, Georgia, and Wisconsin, respectively) when only considering laboratory-confirmed cases as true cases. CONCLUSIONS: Adults identified as having SCD from administrative claims data based on the SCDC case definition have a high probability of truly having the disease, especially if those hospitals have active SCD programs. Administrative claims are thus a valuable data source to identify adults with SCD in a state and understand their epidemiology and health care service usage.

Preliminary construct validity of patient-reported outcomes to assess chronic pain in adults with sickle cell disease.

Chronic pain affects 30% to 40% of individuals with sickle cell disease (SCD) and impairs patient functioning. Clinically meaningful, practical, and valid assessment tools for investigation, evaluation, and management of chronic pain are limited, representing a barrier for advancing SCD care. We sought to determine whether patient-reported outcomes (PROs) show preliminary construct validity in identifying individuals with SCD who were a priori defined as suggestive of having chronic pain based on previously published criteria. All individuals completed the Patient-Reported Outcomes Measurement Information System (PROMIS) domains: pain interference, pain behavior, pain quality (nociceptive, neuropathic), fatigue, sleep disturbance, depression, and anxiety; the Adult Sickle Cell Quality of Life Measurement Information System (ASCQ-Me) domains: pain impact and emotional impact; and the painDETECT questionnaire. Thirty-three adults living with SCD were enrolled, and 42.4% had chronic pain. Pain-related PROs scores distinctly differentiated individuals with chronic pain from those without. Individuals with chronic pain had significantly worse pain-related PROs scores: PROMIS pain interference (64.2 vs 54.3), PROMIS pain behavior (63.2 vs 50), and ASCQ-Me pain impact (42.9 vs 53.2). According to published PROMIS clinical cut scores for the pain-related domains, individuals with chronic pain were categorized as having moderate impairment, whereas those without chronic pain had mild or no impairment. Individuals with chronic pain had PRO pain features consistent with neuropathic pain and worse scores in fatigue, depression, sleep disturbance, and emotional impact. Pain-related PROs show preliminary construct validity in differentiating individuals with and without chronic SCD pain and could be used as valuable tools for research and clinical monitoring of chronic pain.

Embryo Cryopreservation in a Patient with Sickle Cell Disease Utilizing Letrozole and Enoxaparin: A Case Report.

PURPOSE: To describe a patient with sickle cell disease, a prothrombotic disorder, who underwent successful embryo cryopreservation for the purposes of fertility preservation prior to hematopoietic stem cell transplant. METHODS: To report a successful case of gonadotropin stimulation and embryo cryopreservation using the aromatase inhibitor letrozole to maintain low serum estradiol to minimize thrombotic risk in a patient with sickle cell disease (SCD) and history of retinal artery thrombosis planning hematopoietic stem cell transplant (HSCT). The patient was given letrozole (5 mg daily) as well as prophylactic enoxaparin while undergoing gonadotropin stimulation with an antagonist protocol to preserve fertility prior to HSCT. After the oocyte retrieval, letrozole was continued for one additional week. RESULTS: The patient's peak serum estradiol concentration was 172 pg/mL during gonadotropin stimulation. Ten mature oocytes were retrieved and a total of 10 blastocysts were cryopreserved. The patient required pain medication and intravenous fluids after oocyte retrieval due to pain but had significant improvement at the scheduled post-operative day one follow-up. No embolic events occurred during stimulation or 6 months thereafter. CONCLUSION: The utilization of definitive treatment for SCD with stem cell transplant is increasing. We successfully used letrozole to maintain low serum estradiol during gonadotropin stimulation along with prophylactic enoxaparin in a patient with SCD to minimize her risk of thrombosis. This approach will allow patients planning definitive treatment with stem cell transplant the opportunity to preserve their fertility safely.

Secondary Neoplasms After Hematopoietic Cell Transplant for Sickle Cell Disease.

PURPOSE: To report the incidence and risk factors for secondary neoplasm after transplantation for sickle cell disease. METHODS: Included are 1,096 transplants for sickle cell disease between 1991 and 2016. There were 22 secondary neoplasms. Types included leukemia/myelodysplastic syndrome (MDS; n = 15) and solid tumor (n = 7). Fine-Gray regression models examined for risk factors for leukemia/MDS and any secondary neoplasm. RESULTS: The 10-year incidence of leukemia/MDS was 1.7% (95% CI, 0.90 to 2.9) and of any secondary neoplasm was 2.4% (95% CI, 1.4 to 3.8). After adjusting for other risk factors, risks for leukemia/MDS (hazard ratio, 22.69; 95% CI, 4.34 to 118.66; P = .0002) or any secondary neoplasm (hazard ratio, 7.78; 95% CI, 2.20 to 27.53; P = .0015) were higher with low-intensity (nonmyeloablative) regimens compared with more intense regimens. All low-intensity regimens included total-body irradiation (TBI 300 or 400 cGy with alemtuzumab, TBI 300 or 400 cGy with cyclophosphamide, TBI 200, 300, or 400 cGy with cyclophosphamide and fludarabine, or TBI 200 cGy with fludarabine). None of the patients receiving myeloablative and only 23% of those receiving reduced-intensity regimens received TBI. CONCLUSION: Low-intensity regimens rely on tolerance induction and establishment of mixed-donor chimerism. Persistence of host cells exposed to low-dose radiation triggering myeloid malignancy is one plausible etiology. Pre-existing myeloid mutations and prior inflammation may also contribute but could not be studied using our data source. Choosing conditioning regimens likely to result in full-donor chimerism may in part mitigate the higher risk for leukemia/MDS.

Hypoxic storage of donor red cells preserves deformability after exposure to plasma from adults with sickle cell disease.

BACKGROUND: Red cell (RBC) transfusions are beneficial for patients with sickle cell disease (SCD), but ex vivo studies suggest that inflamed plasma from patients with SCD during crises may damage these RBCs, diminishing their potential efficacy. The hypoxic storage of RBCs may improve transfusion efficacy by minimizing the storage lesion. We tested the hypotheses that (1) The donor RBCs exposed to the plasma of patients in crisis would have lower deformability and higher hemolysis than those exposed to non-crisis plasma, and (2) hypoxic storage, compared to standard storage, of donor RBCs could preserve deformability and reduce hemolysis. STUDY DESIGN AND METHODS: 18 SCD plasma samples from patients who had severe acute-phase symptoms (A-plasma; n = 9) or were at a steady-state (S = plasma; n = 9) were incubated with 16 RBC samples from eight units that were stored either under conventional(CRBC) or hypoxic(HRBC) conditions. Hemolysis and microcapillary deformability assays of these RBCs were analyzed using linear mixed-effect models after each sample was incubated in patient plasma overnight at 37°C RESULTS: Relative deformability was 0.036 higher (p < 0.0001) in HRBC pairs compared to CRBC pairs regardless of plasma type. Mean donor RBC hemolysis was 0.33% higher after incubation with A-plasma compared to S-plasma either with HRBC or CRBC (p = 0.04). HRBCs incubated with steady-state patient plasma demonstrated the highest deformability and lowest hemolysis. CONCLUSION: Hypoxic storage significantly influenced RBC deformability. Patient condition significantly influenced post-incubation hemolysis. Together, HRBCs in steady-state plasma maximized donor red cell ex vivo function and survival.

Fostamatinib for the treatment of warm antibody autoimmune hemolytic anemia: Phase 2, multicenter, open-label study.

Patients with relapsed warm antibody autoimmune hemolytic anemia (wAIHA) have limited treatment options. Fostamatinib is a potent, orally administered spleen tyrosine kinase inhibitor approved in the United States and Europe for the treatment of adults with chronic immune thrombocytopenia (ITP). This phase 2 study evaluated the response to fostamatinib, administered at 150 mg BID orally with or without food in adults with wAIHA and active hemolysis with hemoglobin (Hgb) <10 g/dL who had failed at least one prior treatment. Hemoglobin levels and safety assessments were performed at visits every 2 weeks. The primary endpoint was Hgb >10 g/dL with an increase of ≥2 g/dL from baseline by week 24 without rescue therapy or red blood cell transfusion. Eleven of 24 (46%) patients achieved the primary endpoint. Increases in median Hgb were detected at week 2 and sustained over time. Median lactate dehydrogenase levels and reticulocyte counts generally declined over time with little change in median haptoglobin levels. The most common adverse events (AEs) were diarrhea (42%), fatigue (42%), hypertension (27%), dizziness (27%), and insomnia (23%). AEs were manageable and consistent with the fostamatinib safety database of over 3900 patients across multiple diseases (rheumatoid arthritis, B-cell lymphoma, COVID-19, and ITP). No new safety signals were detected. Fostamatinib may be a promising therapeutic option for wAIHA. A randomized, double-blind, phase 3 study is nearing completion.

Treatment of Acute Pain in Adults With Sickle Cell Disease in an Infusion Center Versus the Emergency Department : A Multicenter Prospective Cohort Study.

BACKGROUND: Patients with sickle cell disease (SCD) have vaso-occlusive crises (VOCs). Infusion centers (ICs) are alternatives to emergency department (ED) care and may improve patient outcomes. OBJECTIVE: To assess whether care in ICs or EDs leads to better outcomes for the treatment of uncomplicated VOCs. DESIGN: Prospective cohort. (ClinicalTrials.gov: NCT02411396). SETTING: 4 U.S. sites, with recruitment between April 2015 and December 2016. PARTICIPANTS: Adults with SCD living within 60 miles of a study site. MEASUREMENTS: Participants were followed for 18 months after enrollment. Outcomes of interest were time to first dose of parenteral pain medication, whether pain reassessment was completed within 30 minutes after the first dose, and patient disposition on discharge from the acute care visit. Treatment effects for ICs versus EDs were estimated using a time-varying propensity score adjustment. RESULTS: Researchers enrolled 483 participants; the 269 who had acute care visits on weekdays are included in this report. With inverse probability of treatment-weighted adjustment, the mean time to first dose was 62 minutes in ICs and 132 minutes in EDs; the difference was 70 minutes (95% CI, 54 to 98 minutes; E-value, 2.8). The probability of pain reassessment within 30 minutes of the first dose of parenteral pain medication was 3.8 times greater (CI, 2.63 to 5.64 times greater; E-value, 4.7) in the IC than the ED. The probability that a participant's visit would end in admission to the hospital was smaller by a factor of 4 (0.25 [CI, 0.18 to 0.33]) with treatment in an IC versus an ED. LIMITATION: The study was restricted to participants with uncomplicated VOCs. CONCLUSION: In adults with SCD having a VOC, treatment in an IC is associated with substantially better outcomes than treatment in an ED. PRIMARY FUNDING SOURCE: Patient-Centered Outcomes Research Institute.

Social and Psychological Factors Associated With Health Care Transition for Young Adults Living With Sickle Cell Disease.

Introduction: Due to advances in disease management, mortality rates in children with sickle cell disease (SCD) have decreased. However, mortality rates for young adults (YA) increased, and understanding of social and psychological factors is critical. The aim of this study was to explore factors associated with health care transition experiences for YA with SCD. Method: This was a qualitative descriptive study. A 45-minute semistructured interview was conducted with 13 YA (M = 21.5 years, SD = 1.73). Results: Results suggest that social and psychological factors and self-management experiences influence health care transition. Eight themes emerged: "need for accessible support"; "early assistance with goal setting"; "incongruence among expectations, experiences, and preparation"; "spiritual distress"; "stigma"; "need for collaboration"; "appreciation for caring providers"; and "feeling isolated." Discussion: Consideration of cultural contexts will guide nurses in supporting health care transition. Designing culturally relevant interventions that address unique needs for YA living with SCD is warranted.

Chronic Pain Does Not Impact Baseline Circulating Cytokine Levels in Adults with Sickle Cell Disease.

Chronic pain affects 50% of adults with sickle cell disease (SCD). Although inflammation is thought to contribute to the pathogenesis of chronic pain, no studies have examined the differences in circulating cytokines between patients with SCD with and without chronic pain. We performed an observational cohort study using blood and urine samples from adults with SCD with and without chronic pain at their usual state of health. We tested the hypothesis that, compared to those without chronic pain, those with chronic pain would have significantly higher baseline circulating proinflammatory cytokines. A total of 61 adults with SCD, 40 with chronic pain and 21 without chronic pain were tested. When SCD patients with chronic pain were compared to those without chronic pain, no significant differences in cytokine levels were noted. The variables most associated with the diagnosis of chronic pain in this population were opioid dose and subject age.

Circulating fibrocytes as prognostic biomarkers of autoimmune interstitial lung disease.

BACKGROUND: Autoimmunity is a common cause of pulmonary fibrosis and can present either as a manifestation of an established connective tissue disease or as the recently described entity of interstitial pneumonia with autoimmune features. The rate of progression and responsiveness to immunosuppression in these illnesses are difficult to predict. Circulating fibrocytes are bone marrow-derived progenitor cells that home to injured tissues and contribute to lung fibrogenesis. We sought to test the hypothesis that the blood fibrocyte concentration predicts outcome and treatment responsiveness in autoimmune interstitial lung diseases. METHODS: We compared the concentration of circulating fibrocytes in 50 subjects with autoimmune interstitial lung disease and 26 matched healthy controls and assessed the relationship between serial peripheral blood fibrocyte concentrations and clinical outcomes over a median of 6.25 years. RESULTS: As compared to controls, subjects with autoimmune interstitial lung disease had higher circulating concentrations of total fibrocytes, the subset of activated fibrocytes, and fibrocytes with activation of PI3K/AKT/mTOR, transforming growth factor-ß (TGF-ß) receptor and interleukin (IL)-4/IL-13 receptor signalling pathways. Over the follow-up period, there were episodes of marked elevation in the concentration of circulating fibrocytes in subjects with autoimmune interstitial lung disease but not controls. Initiation of immunosuppressive therapy was associated with a decline in the concentration of circulating fibrocytes. For each 100 000 cells·mL-1 increase in peak concentration of circulating fibrocytes, we found a 5% increase in odds of death or lung function decline. CONCLUSION: In patients with autoimmune interstitial lung disease, circulating fibrocytes may represent a biomarker of outcome and treatment response.

Phase 2 trial of montelukast for prevention of pain in sickle cell disease.

Cysteinyl leukotrienes (CysLTs) are lipid mediators of inflammation. In patients with sickle cell disease (SCD), levels of CysLTs are increased compared with controls and associated with a higher rate of hospitalization for pain. We tested the hypothesis that administration of the CysLT receptor antagonist montelukast would improve SCD-related comorbidities, including pain, in adolescents and adults with SCD. In a phase 2 randomized trial, we administered montelukast or placebo for 8 weeks. The primary outcome measure was a >30% reduction in soluble vascular cell adhesion molecule 1 (sVCAM), a marker of vascular injury. Secondary outcome measures were reduction in daily pain, improvement in pulmonary function, and improvement in microvascular blood flow, as measured by laser Doppler velocimetry. Forty-two participants with SCD were randomized to receive montelukast or placebo for 8 weeks. We found no difference between the montelukast and placebo groups with regard to the levels of sVCAM, reported pain, pulmonary function, or microvascular blood flow. Although montelukast is an effective treatment for asthma, we did not find benefit for SCD-related outcomes. This clinical trial was registered at www.clinicaltrials.gov as #NCT01960413.

American Society of Hematology 2020 guidelines for sickle cell disease: transfusion support.

BACKGROUND: Red cell transfusions remain a mainstay of therapy for patients with sickle cell disease (SCD), but pose significant clinical challenges. Guidance for specific indications and administration of transfusion, as well as screening, prevention, and management of alloimmunization, delayed hemolytic transfusion reactions (DHTRs), and iron overload may improve outcomes. OBJECTIVE: Our objective was to develop evidence-based guidelines to support patients, clinicians, and other healthcare professionals in their decisions about transfusion support for SCD and the management of transfusion-related complications. METHODS: The American Society of Hematology formed a multidisciplinary panel that was balanced to minimize bias from conflicts of interest and that included a patient representative. The panel prioritized clinical questions and outcomes. The Mayo Clinic Evidence-Based Practice Research Program supported the guideline development process. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to form recommendations, which were subject to public comment. RESULTS: The panel developed 10 recommendations focused on red cell antigen typing and matching, indications, and mode of administration (simple vs red cell exchange), as well as screening, prevention, and management of alloimmunization, DHTRs, and iron overload. CONCLUSIONS: The majority of panel recommendations were conditional due to the paucity of direct, high-certainty evidence for outcomes of interest. Research priorities were identified, including prospective studies to understand the role of serologic vs genotypic red cell matching, the mechanism of HTRs resulting from specific alloantigens to inform therapy, the role and timing of regular transfusions during pregnancy for women, and the optimal treatment of transfusional iron overload in SCD.

American Society of Hematology 2020 guidelines for sickle cell disease: transfusion support

Red cell transfusions remain a mainstay of therapy for patients with sickle cell disease (SCD), but pose significant clinical challenges. Guidance for specific indications and administration of transfusion, as well as screening, prevention, and management of alloimmunization, delayed hemolytic transfusion reactions (DHTRs), and iron overload may improve outcomes. Our objective was to develop evidence-based guidelines to support patients, clinicians, and other healthcare professionals in their decisions about transfusion support for SCD and the management of transfusion-related complications. The American Society of Hematology formed a multidisciplinary panel that was balanced to minimize bias from conflicts of interest and that included a patient representative. The panel prioritized clinical questions and outcomes. The Mayo Clinic Evidence-Based Practice Research Program supported the guideline development process. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to form recommendations, which were subject to public comment. The panel developed 10 recommendations focused on red cell antigen typing and matching, indications, and mode of administration (simple vs red cell exchange), as well as screening, prevention, and management of alloimmunization, DHTRs, and iron overload. The majority of panel recommendations were conditional due to the paucity of direct, high-certainty evidence for outcomes of interest. Research priorities were identified, including prospective studies to understand the role of serologic vs genotypic red cell matching, the mechanism of HTRs resulting from specific alloantigens to inform therapy, the role and timing of regular transfusions during pregnancy for women, and the optimal treatment of transfusional iron overload in SCD.

The controversial role of red cell transfusions for sickle cell pain.

PURPOSE OF REVIEW: Red cell transfusions are one of the most common and important therapies used for patients with sickle cell disease (SCD). For prevention of strokes, there is abundant evidence that transfusions are efficacious, whereas for other indications, such as prevention of pain, there are less data. Nonetheless, with few therapeutic options, the use of transfusion for prevention of acute pain has increased in children and adults with SCD without a clear understanding of its benefits. RECENT FINDINGS: Although it makes conceptual sense that red cell transfusions would prevent pain that arises from vaso-occlusion, we now know that the mechanism of pain is more complex than vaso-occlusion alone. Recent taxonomies recognize a chronic pain syndrome that is both common in adults with SCD and affects the presentation of acute pain. It is not known if acute pain on the background of chronic pain responds differently to sickle cell therapies, such as hydroxyurea and blood transfusion. SUMMARY: In this review, we will examine the studies that have investigated whether red cell transfusions are efficacious for preventing pain. In the absence of high-quality data that specifically addresses this question, we will outline our approach, which might soon change with new drugs and curative therapies on the horizon.

Identifying Clinical and Research Priorities in Sickle Cell Lung Disease. An Official American Thoracic Society Workshop Report.

Background: Pulmonary complications of sickle cell disease (SCD) are diverse and encompass acute and chronic disease. The understanding of the natural history of pulmonary complications of SCD is limited, no specific therapies exist, and these complications are a primary cause of morbidity and mortality.Methods: We gathered a multidisciplinary group of pediatric and adult hematologists, pulmonologists, and emergency medicine physicians with expertise in SCD-related lung disease along with an SCD patient advocate for an American Thoracic Society-sponsored workshop to review the literature and identify key unanswered clinical and research questions. Participants were divided into four subcommittees on the basis of expertise: 1) acute chest syndrome, 2) lower airways disease and pulmonary function, 3) sleep-disordered breathing and hypoxia, and 4) pulmonary vascular complications of SCD. Before the workshop, a comprehensive literature review of each subtopic was conducted. Clinically important questions were developed after literature review and were finalized by group discussion and consensus.Results: Current knowledge is based on small, predominantly observational studies, few multicenter longitudinal studies, and even fewer high-quality interventional trials specifically targeting the pulmonary complications of SCD. Each subcommittee identified the three or four most important unanswered questions in their topic area for researchers to direct the next steps of clinical investigation.Conclusions: Important and clinically relevant questions regarding sickle cell lung disease remain unanswered. High-quality, multicenter, longitudinal studies and randomized clinical trials designed and implemented by teams of multidisciplinary clinician-investigators are needed to improve the care of individuals with SCD.

Chronic pain persists in adults with sickle cell disease despite regular red cell transfusions.

BACKGROUND: Pain affects over 50% of adults with sickle cell disease (SCD), and this pain is largely managed outside of the hospital. While chronic transfusion therapy is used to decrease the rate of acute pain events in patients with SCD, less is known about its impact on the day-to-day experience of pain. To address this knowledge gap, we provided pain diaries to patients with SCD receiving chronic transfusion. PATIENTS AND METHODS: A convenience sample of chronically-transfused adults with SCD successfully completed a diary over the course of at least 2 transfusion events. Patients receiving simple transfusions and red cell exchanges were included. Pain was rated on a scale of 0 to 10 each day, and patient laboratory values, co-morbidities, and hospital utilization were also obtained using the electronic medical record. The mean pain scores pre- and post-transfusion were evaluated using both a random effects-expectation maximization regression tree analysis and a generalized linear mixed regression model. RESULTS: Ten subjects (63%) in this cohort were defined as having chronic pain, while the remaining four (27%) subjects had episodic pain. Despite chronic transfusion and a suppressed HbS% (22.5% (16.5-25.9)), 10 patients (63%) continued to report nearly daily pain, and on almost 70% of diary days, the pain was significant (≥5/10). When the relationship between HbS% and reported pain intensity was examined, no association was found. DISCUSSION: These results suggest that, even with regular transfusions and a low HbS%, daily pain persists in many adults with SCD.

Contrast-enhanced ultrasound detects changes in microvascular blood flow in adults with sickle cell disease.

In patients with sickle cell disease (SCD), poor outcome measures compromise the potential success of clinical trials. Contrast-enhanced ultrasound (CEUS) is a technique that can non-invasively quantify deep tissue microvascular blood flow. We tested the hypothesis that CEUS of forearm skeletal muscle could be used to: 1) assess microvascular abnormalities that occur during vaso-occlusive crisis; and 2) test new therapies for SCD that are targeted to improving the status of the microcirculation. We performed a prospective study, CEUS perfusion imaging of resting forearm muscle was performed in adults with SCD: 1) during and after a pain episode, and 2) before, during, and after a 24-hour infusion of the investigative agent, regadenoson, an adenosine A2A agonist. CEUS destruction-replenishment time-intensity data were analyzed to measure microvascular blood flow, as well as its components, microvascular blood volume and flux rate. Serial CEUS measurements were obtained in 32 adults with SCD. For the studies during crisis, there was a 30% reduction in microvascular blood flow compared to steady-state (p = 0.031), a reduction that was largely due to microvascular flux rate. For the regadenoson group, a non-significant 25% increase in flux rate and 9% increase in microvascular blood flow compared to baseline were detected during infusion. In a study of adults with SCD, CEUS detected changes in microvascular blood flow associated with vaso-occlusive crises. No changes were found during an infusion of the adenosine A2A agonist, regadenoson. This study provides preliminary evidence that CEUS could detect blood flow changes consistent with SCD physiology.

Chronic pain in adults with sickle cell disease is associated with alterations in functional connectivity of the brain.

Chronic pain affects 50% of adults with sickle cell disease (SCD). Although central sensitization is thought to contribute to the pathogenesis of this chronic pain, no studies have examined differences in functional connectivity of the brain between patients with SCD with and without chronic pain. We performed an observational cohort study using resting-state functional MRI (rsfMRI) of the brain on adults with SCD with and without chronic pain. We tested the hypothesis that, compared to those without chronic pain, those with chronic pain would have differences in functional connectivity between the periaqueductal grey (PAG) and other regions of the brain. Twenty-two adults with SCD, 15 with chronic pain and 7 without chronic pain, as well as 10 African-American controls, underwent rsfMRI of the brain. When SCD patients with chronic pain were compared to those without chronic pain, significant differences in connectivity were noted between the PAG and 9 regions of the brain, including several in the default mode network, a network involved in introspection that has been implicated in other chronic pain syndromes. Changes in functional connectivity between patients with SCD with and without chronic pain suggest a mechanism for chronic pain that involves neuro-plastic changes to the brain.