Chronic organ failure in adult sickle cell disease

Two-Dimensional Ultrasound Assessment of Long-Term Intra-Abdominal Organ Changes in Children with Sickle Cell Anemia during Steady State: A Comparative Study

BACKGROUND

Sickle cell anemia (SCA) is a hereditary blood disorder with global prevalence, including in Nigeria. Despite advancements in SCA care management, understanding the long-term impact on organs during steady state has remained inconclusive.

AIM

This study aimed to investigate the long-term changes in intra-abdominal organs of SCA children compared with non-SCA children during steady state using two-dimensional ultrasound assessment.

MATERIALS AND METHODS

A total of 116 children (58 SCA and 58 controls) were enrolled between June 2021 and July 2022. Clinico-demographic data were collected through an interviewer-administered questionnaire. Two-dimensional ultrasound was used to measure the liver, spleen, kidneys, and inferior vena cava in all subjects. Age-matched controls had AA or AS genotypes.

RESULTS

Of the 58 patients with SCA, 65.5% were males with an overall mean age of 8.1 ± 3.4 years, while among the non-SCA cohort (n = 58), 48.3% were males with an overall mean age of 8.7 ± 3.9 years. There was no statistically significant difference in the age and gender distribution between the SCA and non-SCA cohorts (P = 0.390 and P = 0.091, respectively). SCA subjects had a larger mean hepatic size than non-SCA subjects (12.09 cm ± 2.23 vs. 11.67 cm ± 1.96; P = 0.276) but smaller mean splenic size (8.01 cm ± 1.89 vs. 8.19 cm ± 1.61; P = 0.577) and inferior vena cava diameter (1.16 cm ± 0.29 vs. 1.25 cm ± 0.33; P = 0.100). Left kidney length and breadth were significantly greater in SCA patients (8.91 ± 1.16 vs. 8.27 ± 1.30; P = 0.006 and 4.15 ± 0.92 vs. 3.79 ± 0.48; P = 0.008, respectively).

CONCLUSION

This study highlights the utility of two-dimensional ultrasound assessment in monitoring intra-abdominal organ changes in SCA children, suggesting its cost-effective benefits in monitoring health outcomes in SCA patients.

The Resolution of a Cerebrovascular Accident With Phlebotomy in a Hemodialysis Patient With Sickle Cell Disease

Anemia is commonly observed in patients with end-stage renal disease (ESRD) on maintenance hemodialysis (HD) and can be quite severe, particularly when there is an additional comorbidity. With the use of erythropoietin-stimulating agents (ESAs), anemia is effectively treated, but the complete normalization of hemoglobin is not recommended since these agents increase the risk of thrombosis. With improvements in the therapy of sickle cell disease (SCD), patients now survive longer and may more frequently reach end-stage renal disease and require renal replacement therapy. Their anemia can be severe but does respond to ESAs. The goal hemoglobin in these patients is not established and likely should be lower than others on maintenance hemodialysis (HD) since SCD patients already have an increased risk of thrombosis, and the use of ESAs may exacerbate this risk. We present a 57-year-old African-American female with SCD on maintenance HD admitted with an acute cerebrovascular accident (CVA) that occurred in spite of the fact that her hemoglobin was within the accepted range for the general population on maintenance HD. Her neurologic status did not improve with blood pressure control and exchange transfusions, the suggested initial therapy for an acute CVA in a patient with sickle cell disease (SCD). However, with phlebotomy, the patient's symptoms rapidly improved when her hemoglobin was lowered and subsequently maintained with a lower dose of ESAs. Our experience suggests that the hemoglobin goal in SCD patients on maintenance HD should be lower than in other HD patients. The role of phlebotomy during an acute thrombotic event needs to be explored further.

Impact of Genetic Variations on Thromboembolic Risk in Saudis with Sickle Cell Disease

BACKGROUND

Sickle cell disease (SCD) is a Mendelian disease characterized by multigenic phenotypes. Previous reports indicated a higher rate of thromboembolic events (TEEs) in SCD patients. A number of candidate polymorphisms in certain genes (e.g., FVL, PRT, and MTHFR) were previously reported as risk factors for TEEs in different clinical conditions. This study aimed to genotype these genes and other loci predicted to underlie TEEs in SCD patients.

METHODOLOGY

A multi-center genome-wide association study (GWAS) involving Saudi SCD adult patients with a history of TEEs (n = 65) and control patients without TEE history (n = 285) was performed. Genotyping used the 10× Affymetrix Axiom array, which includes 683,030 markers. Fisher's exact test was used to generate p-values of TEE associations with each single-nucleotide polymorphism (SNP). The haplotype analysis software tool version 1.05, designed by the University of Göttingen, Germany, was used to identify the common inherited haplotypes.

RESULTS

No association was identified between the targeted single-nucleotide polymorphism rs1801133 in MTHFR and TEEs in SCD (p = 0.79). The allele frequency of rs6025 in FVL and rs1799963 in PRT in our cohort was extremely low (<0.01); thus, both variants were excluded from the analysis as no meaningful comparison was possible. In contrast, the GWAS analysis showed novel genome-wide associations (p < 5 × 10-8) with seven signals; five of them were located on Chr 11 (rs35390334, rs331532, rs317777, rs147062602, and rs372091), one SNP on Chr 20 (rs139341092), and another on Chr 9 (rs76076035). The other 34 SNPs located on known genes were also detected at a signal threshold of p < 5 × 10-6. Seven of the identified variants are located in olfactory receptor family 51 genes (OR51B5, OR51V1, OR51A1P, and OR51E2), and five variants were related to family 52 genes (OR52A5, OR52K1, OR52K2, and OR52T1P). The previously reported association between rs5006884-A in OR51B5 and fetal hemoglobin (HbF) levels was confirmed in our study, which showed significantly lower levels of HbF (p = 0.002) and less allele frequency (p = 0.003) in the TEE cases than in the controls. The assessment of the haplotype inheritance pattern involved the top ten significant markers with no LD (rs353988334, rs317777, rs14788626882, rs49188823, rs139349992, rs76076035, rs73395847, rs1368823, rs8888834548, and rs1455957). A haplotype analysis revealed significant associations between two haplotypes (a risk, TT-AA-del-AA-ins-CT-TT-CC-CC-AA, and a reverse protective, CC-GG-ins-GG-del-TT-CC-TT-GG-GG) and TEEs in SCD (p = 0.024, OR = 6.16, CI = 1.34-28.24, and p = 0.019, OR = 0.33, CI = 0.13-0.85, respectively).

CONCLUSIONS

Seven markers showed novel genome-wide associations; two of them were exonic variants (rs317777 in OLFM5P and rs147062602 in OR51B5), and less significant associations (p < 5 × 10-6) were identified for 34 other variants in known genes with TEEs in SCD. Moreover, two 10-SNP common haplotypes were determined with contradictory effects. Further replication of these findings is needed.

Relationship between paramacular thinning, cerebral vasculopathy, and hematological risk factors in sickle cell disease

Purpose

To identify risk factors for sickle cell maculopathy due to hematological parameters (especially anemia and hemolysis) or cerebral vasculopathy.

Methods

This retrospective study was conducted at a Referral Center. The follow-up included optical coherent tomography/optical coherent tomography angiography, neuro-radiological imaging, and a hematological assessment (hemoglobin, hemoglobin S level, reticulocytes, mean corpuscular volume, bilirubin, and lactate dehydrogenase).

Results

Hundred and thirty-two sickle cell patients were included. Maculopathy was observed in 127 eyes of SS patients and 10 eyes of SC patients (p < 0.001), unrelated to peripheral retinopathy. Cerebral vasculopathy was more frequent in SS patients (p < 0.001) and was also associated with the presence of maculopathy (p = 0.049), and it was related to peripheral retinopathy (p < 0.001). All biological parameters significantly differed according to the genotype (p < 0.001) but not according to the presence of cerebral vasculopathy or maculopathy. In the multivariate analysis, reticulocytes and bilirubin were associated with the presence of cerebral vasculopathy and maculopathy.

Conclusion

The data obtained were consistent with the role of anemia or hemolysis markers in cerebral vasculopathy and macular involvement. As a trend of hemolysis appears to be a risk factor for these complications, this validates the use of preventive plasmapheresis in these patients.

An open-label, multicenter, phase 2 study of a food enriched with docosahexaenoic acid in adults with sickle cell disease

Sickle cell disease (SCD) induces red blood cell sickling, which causes debilitating symptoms including vaso-occlusion and inflammation. We investigated a food enriched with omega-3 fatty acids to determine its effect on certain factors: blood cell membrane fatty acid composition (including anti-inflammatory elements-docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)-and the pro-inflammatory, arachidonic acid (AA)); the inflammation biomarker, C-reactive protein (CRP); and vaso-occlusive crisis (VOC) pain. Ten adults with SCD ingested the food, daily, for 28 days. Evaluated measures included blood cell membrane fatty acid ratios (AA vs omega-3 (DHA+EPA)), CRP (mg/L) levels, and Visual Analogue Scale (VAS) scores (a VOC assessment). The food was well tolerated and led to a statistically significant CRP reduction (39%). However, changes in omega-3 fatty acid ratios and VAS scores were not significant. Overall, while the omega-3-enriched food reduced inflammation, larger, blinded studies are needed to assess its effectiveness on other measures.

Prevalence and predictors of non-rheumatic valvular heart disease in patients with sickle cell disease: insights from the National In-Patient Database in 2016 and 2017

Sickle cell disease (SCD) life expectancy has increased in high-income countries, approaching the fifth decade in the United States. Aging in SCD has raised concerns about chronic organ damage due to adaptative and maladaptive cardiac remodeling. This study aims to assess the prevalence and predictors of non-rheumatic valvular heart disease (NRVHD) in SCD patients using the United States National Inpatient Sample database from 2016 and 2017. We conducted a weighted analysis on SCD patients during their index hospitalization. We obtained the prevalence of NRVHD and calculated adjusted odds ratios to identify the associated demographic, social, and clinical characteristics using multivariable logistic regression. We identified 192,460 SCD admissions during 2016 and 2017. Of them, 2450 (1.3%) had NRVHD. Mitral insufficiency (MI) was the most common NRVHD present in 52% of the cases. Mitral valve prolapse represented 12.4%, while aortic stenosis and aortic insufficiency in 10.8% and 12.7%, respectively. Right-sided NRVHD had a lower prevalence, with 17.1% of patients having tricuspid insufficiency (TI) and 6.3% pulmonary insufficiency. There were no cases of mitral, tricuspid, or pulmonary stenosis. Characteristics associated with the presence of NRVHD in SCD were secondary pulmonary hypertension, congestive heart failure, chronic kidney disease, and female sex. NRVHDs, especially MI and TI, are comorbidities in SCD. Literature is scarce on this topic. The predictors found for its occurrence could help address modifiable factors that can positively affect patients with SCD who, due to the natural history of the disease, are at risk of developing NRVHD.

Hemoglobin and End-Organ Damage in Individuals with Sickle Cell Disease

Background

Sickle cell disease (SCD) is an inherited, chronic, multifaceted blood disorder. Patients with SCD develop anemia, which has been associated with end-organ damage (EOD).

Objectives

This retrospective, observational, repeated-measures study systematically characterizes the relationship between hemoglobin (Hb) level and EOD in adolescent and adult patients with SCD.

Methods

The study population comprised patients with SCD aged ≥12 years with available Hb data from a US provider-centric health care database. For each patient, each Hb value over time was included as a separate observation. Study outcomes-the onset of any new EOD, including chronic kidney disease, pulmonary hypertension, stroke, and leg ulcer-were ascertained during the 1-year period after each Hb assessment. The association between Hb levels and risk of new EOD was estimated using multivariable generalized estimating equations.

Results

A total of 16,043 unique patients with SCD contributed 44,913 observations. Adjusted odds of any EOD during the 1-year follow-up were significantly lower with higher Hb level. Risk reductions with higher Hb levels for chronic kidney disease, pulmonary hypertension, and leg ulcer were comparable. The risk of new EOD was significantly lower among adolescent and adult patients with higher Hb levels.

Conclusions

In patients with SCD, higher Hb levels are associated with a reduced risk of developing EOD. Therapeutic strategies that result in higher Hb levels may offer clinical and economic value for patients with SCD. (Curr Ther Res Clin Exp. 2023; 84:XXX-XXX).

Surveillance for Sickle Cell Disease - Sickle Cell Data Collection Program, Two States, 2004-2018

PROBLEM/CONDITION

Sickle cell disease (SCD), an inherited blood disorder affecting an estimated 100,000 persons in the United States, is associated with multiple complications and reduced life expectancy. Complications of SCD can include anemia, debilitating acute and chronic pain, infection, acute chest syndrome, stroke, and progressive organ damage, including decreased cognitive function and renal failure. Early diagnosis, screenings and preventive interventions, and access to specialist health care can decrease illness and death. Population-based public health surveillance is critical to understanding the course and outcomes of SCD as well as the health care use, unmet health care needs, and gaps in essential services of the population affected by SCD.

PERIOD COVERED

2004-2018.

DESCRIPTION OF THE PROGRAM

In 2015, CDC established the Sickle Cell Data Collection (SCDC) program to characterize the epidemiology of SCD in two states (California and Georgia). Previously, surveillance for SCD was conducted by two short-term projects: Registry and Surveillance System for Hemoglobinopathies (RuSH), which was conducted during 2010-2012 and included 2004-2008 data, and Public Health Research, Epidemiology, and Surveillance for Hemoglobinopathies (PHRESH), which was conducted during 2012-2014 and included 2004-2008 data. Both California and Georgia participated in RuSH and PHRESH, which guided the development of the SCDC methods and case definitions. SCDC is a population-based tracking system that uses comprehensive data linkages in state health systems. These linkages serve to synthesize and disseminate population-based, longitudinal data for persons identified with SCD from multiple sources using selected International Classification of Diseases, Ninth Revision, Clinical Modification, and Tenth Revision codes and laboratory results confirmed through state newborn screening (NBS) programs or clinic case reporting. Administrative and clinical data sources include state Medicaid and Children's Health Insurance Program databases, death certificates, NBS programs, hospital discharge and emergency department records, and clinical records or case reports. Data from multiple sources and years are linked and deduplicated so that states can analyze and report on SCD population prevalence, demographic characteristics, health care access and use, and health outcomes. The SCD case definition is based on an algorithm that classifies cases with laboratory confirmation as confirmed cases and those with a reported clinical diagnosis or three or more diagnostic codes over a 5-year period from an administrative data source as probable cases. In 2019, nine states (Alabama, California, Georgia, Indiana, Michigan, Minnesota, North Carolina, Tennessee, and Virginia) were funded as part of an SCDC capacity-building initiative. The newly funded states developed strategies for SCD case identification and data linkage similar to those used by California and Georgia. As of 2021, the SCDC program had expanded to 11 states with the addition of Colorado and Wisconsin.

RESULTS

During 2004-2018, the cumulative prevalence of confirmed and probable SCD cases identified in California and Georgia was 9,875 and 14,777 cases, respectively. The 2018 annual prevalence count was 6,027 cases for California and 9,141 for Georgia. Examination of prevalence counts by contributing data source during 2014-2018 revealed that each data source captured 16%-71% of cases in California and 17%-87% in Georgia; therefore, no individual source is sufficient to estimate statewide population prevalence. The proportion of pediatric SCD patients (children aged 0-18 years) was 27% in California and 40% in Georgia. The percentage of females with SCD in California and Georgia was 58% and 57%, respectively. Of the cases with SCD genotyping data available (n = 5,856), 63% of patients had sickle cell anemia. SCDC data have been used to directly apprise health care providers and policymakers about health care needs and gaps for patients with SCD. For example, an SCDC Georgia assessment indicated that 10% of babies born during 2004-2016 with SCD lived more than a 1-hour drive from any SCD specialty care option, and another 14% lived within a 1-hour drive of a periodic SCD specialty clinic only. Likewise, an SCDC California assessment indicated that during 2016-2018, most patients with SCD in Los Angeles County lived approximately 15-60 miles from hematologists experienced in SCD care. A surveillance capacity and performance assessment of all 11 SCDC states during 2020-2021 indicated that states differed in the availability of data sources used for SCD surveillance and the time frames for accessing each state data source. Nonetheless, methods for standardizing reporting were developed across all participating states.

INTERPRETATION

This report is the first comprehensive description of CDC's efforts in collaboration with participating states to establish, maintain, and expand SCD surveillance through the SCDC program to improve health outcomes for persons living with SCD. Findings from California and Georgia analyses highlighted a need for additional SCD specialty clinics. Despite different approaches, expansion of SCDC to multiple states was possible using standardized, rigorous methods developed across all participating states for reporting on disease prevalence, health care needs and use, and deaths.

PUBLIC HEALTH ACTION

Findings from surveillance can be used to improve and monitor care and outcomes for persons with SCD. These and other SCDC analyses have had a role in opening new SCD clinics, educating health care providers, developing state health care policies, and guiding new research initiatives. Public health officials can use this report as a guiding framework to plan or implement surveillance programs for persons with SCD. Both data-related activities (data sources; patient identifiers; and obtaining, transferring, and linking data) and the administrative considerations (stakeholder engagement, costs and resources, and long-term sustainability) are crucial to the success of these programs.

The Montreal cognitive assessment as a cognitive screening tool in sickle cell disease: Associations with clinically significant cognitive domains

Adults with sickle cell disease (SCD) are at risk for cognitive impairment, which causes significant morbidity. Guidelines support routine cognitive screening, but no screening test is validated in this population. We explored the Montreal Cognitive Assessment (MoCA) as a possible screening test in SCD. We administered the MoCA; a literacy test, the Wide Range Achievement Test, fourth edition (WRAT-4); and a health literacy test, the Shortened Test of Functional Health Literacy in Adults (S-TOFHLA) to adults with SCD and gathered clinical variables through chart review. Spearman's rho, Mann-Whitney, and Kruskal-Wallis tests and quantile regression models were used. Among our sample of 49 adults with SCD, the median MoCA score was 25.0 [interquartile range (IQR) 22.0-28.0]. Higher educational attainment was associated with MoCA scores (p = 0.001). In multivariable models, MoCA scores were associated with S-TOFHLA (p = 0.001) and WRAT-4 Reading (p = 0.002) scores, and overt stroke (p = 0.03) at the median. This pilot study adds to the limited literature of cognitive screening tests in adults with SCD and demonstrates a relationship between MoCA scores and measures of literacy and health literacy. The MoCA is a promising option for briefly screening for cognitive impairment in adults with SCD, though further study is needed to confirm its validity.

Sickle cell nephropathy: insights into the pediatric population

The life expectancy of individuals with sickle cell disease has increased over the years, majorly due to an overall improvement in diagnosis and medical care. Nevertheless, this improved longevity has resulted in an increased prevalence of chronic complications such as sickle cell nephropathy (SCN), which poses a challenge to the medical care of the patient, shortening the lifespan of patients by 20-30 years. Clinical presentation of SCN is age-dependent, with kidney dysfunction slowly beginning to develop from childhood, progressing to chronic kidney disease and kidney failure during the third and fourth decades of life. This review explores the epidemiology, pathology, pathophysiology, clinical presentation, and management of SCN by focusing on the pediatric population. It also discusses the factors that can modify SCN susceptibility.

Incorporation of novel therapies for the management of sickle cell disease: A pharmacist's perspective

Patients with sickle cell disease (SCD) experience significant disease-related morbidity including multiorgan damage, chronic anemia, and debilitating pain crises. While hydroxyurea has been the primary disease modifying modality in SCD, novel therapies with unique mechanism of action have recently been approved. This review article examines the evidence surrounding the available SCD therapies to guide pharmacists on potential treatment selection and management strategies for patients with SCD. A systematic search of online databases was performed to identify literature on the management of SCD. While the newly approved novel agents have demonstrated clinical benefit it remains unclear how these agents fit into the treatment paradigm. Pharmacists should be aware of the data supporting the use of these novel agents to optimize use on a patient-specific basis.

Safety, Pharmacokinetics, and Pharmacodynamics of Etavopivat (FT-4202), an Allosteric Activator of Pyruvate Kinase-R, in Healthy Adults: A Randomized, Placebo-Controlled, Double-Blind, First-in-Human Phase 1 Trial

Etavopivat (FT‐4202) is an orally administered, small‐molecule allosteric activator of erythrocyte pyruvate kinase‐R (PKR) in clinical development for the treatment of sickle cell disease and other hemoglobin disorders. This randomized, placebo‐controlled, double‐blind, first‐in‐human combination single‐ascending dose and multiple‐ascending dose phase 1 trial (NCT03815695) evaluated the safety and pharmacokinetics/pharmacodynamics of etavopivat in 90 healthy adult subjects. In 4 single‐ascending dose cohorts, 8 participants were randomized 3:1 to a single oral dose of either etavopivat (n = 6) or placebo (n = 2). In four 14‐day multiple‐ascending dose cohorts, 12 participants were randomized 3:1 to 14 days of etavopivat (n = 9) or placebo (n = 3). In these studies, most treatment‐emergent adverse events were of mild severity (grade 1) and none led to study discontinuation. Etavopivat exhibited a linear and time‐independent pharmacokinetic profile (at doses ≤400 mg) and elicited the expected pharmacodynamic effects of PKR activation (decreased 2,3‐diphosphoglycerate and increased adenosine triphosphate) and evidence of improved hemoglobin‐oxygen affinity. In addition, pharmacodynamic responses were durable with effects continuing for 48 to 72 hours after the last dose, thereby supporting once‐daily dosing. Food appeared to have no clinically meaningful effects on etavopivat exposure, thus facilitating administration with or without food. In conclusion, the evaluation of etavopivat in healthy subjects demonstrated proof of mechanism (PKR activation) without significant adverse events. This study also allowed for the selection of dose levels, projected to have an acceptable safety profile and provide therapeutic benefit, for evaluation in future trials in patients with sickle cell disease.

Indirect Economic Burden of Sickle Cell Disease

OBJECTIVE

This study aimed to quantify the indirect costs of sickle cell disease in the United States.

METHODS

Adult patients from a sickle cell disease clinic at an urban academic healthcare system completed an adapted Institute for Medical Technology Assessment Productivity Cost Questionnaire related to the impact of their disorder on absenteeism, presenteeism, ability to contribute through unpaid work outside of employment, and other aspects of life. Additional data were collected from patient records about each participant's genotype, total hemoglobin level, and pain level.

RESULTS

Of the 192 individuals, 187 who completed the survey reported experiencing vaso-occlusive crisis pain events during the last year that negatively affected their productivity at work and in daily roles. Three-fourths of respondents reported impairment in their ability to complete everyday tasks, such as caring for children, running errands, doing housework, shopping for groceries, and volunteer (unpaid) work. Only 30% of respondents reported being employed or self-employed. Of those employed, estimated costs of absenteeism and presenteeism attributable to pain events averaged $15 103 per person annually. Estimated total annual losses in unpaid work productivity averaged $3 145 862 for the study respondents and another $2 870 652 for their caregivers.

CONCLUSIONS

Sickle cell disease affected the work productivity, nonwork productivity, and the daily lives of adults seen with the disorder in an academic medical center.

Bibliometric analysis of global sickle cell disease research from 1997 to 2017

Introduction

Sickle cell disease is an autosomal recessive genetic disease caused by a single point mutation in the β-globin chain of the hemoglobin. It has been recognized by the World Health Organization as a public health priority since 2006.

Methods

The Scopus database was used in this study with the search descriptors: “sickle cell” and “sickle cell disease”. We applied common bibliometric indicators to evaluate the trend in scientific literature in sickle cell disease research.

Results

We retrieved a total of 19,921 pieces of scientific literature in the repertoire from 1997 to 2017. The Price law was fulfilled in the trend of production of scientific literature on SCD as the growth of scientific literature was more exponential (r = 0.9751; r² = 0.9509) than linear (r = 0.9721; r² = 0.9449). We observed a duplication time of 4.52 years. The Bradford core was made up of 69 journals with Blood at the top, publishing the greatest number of articles. The most productive institutions were mostly United States agencies and hospitals. The United States was the most productive country. The National Institute of Health was the most productive institution and also had the highest number of citations. Vichinsky E was the most productive author, while the most cited article was published by Circulation.

Conclusion

The growth of scientific literature in Sickle cell disease was found to be high. However, the exponential growth trend shows a “yet-to-be-explored” area of research. This study will be useful for physicians, researchers, research funders and policy-cum-decision makers.

Hyponatremia in Patients with Hematologic Diseases

Hyponatremia is the most common electrolyte disorder in clinical practice and is associated with increased morbidity and mortality. It is frequently encountered in hematologic patients with either benign or malignant diseases. Several underlying mechanisms, such as hypovolemia, infections, toxins, renal, endocrine, cardiac, and liver disorders, as well as the use of certain drugs appear to be involved in the development or the persistence of hyponatremia. This review describes the pathophysiology of hyponatremia and discusses thoroughly the contributing factors and mechanisms that may be encountered specifically in patients with hematologic disorders. The involvement of the syndrome of inappropriate antidiuretic hormone (SIADH) secretion and renal salt wasting syndrome (RSWS) in the development of hyponatremia in such patients, as well as their differential diagnosis and management, are also presented. Furthermore, the distinction between true hyponatremia and pseudohyponatremia is explained. Finally, a practical algorithm for the evaluation of hyponatremia in hematologic patients, as well as the principles of hyponatremia management, are included in this review.

Mortality trends in sickle cell patients

BACKGROUND

Sickle cell disease affects a significant portion of US patients with African descent. It continues to be one of the leading causes of frequent hospitalizations and high in-hospital morality risk. Until the approval of disease-modifying therapies in last two years, medical therapy has relied mostly on management of pain episodes and the use of hydroxyurea. We discuss the nationwide analysis of trends in in-hospital mortality in patients with Sickle Cell Disease from 2000 to 2014.

METHODS

Trends of in-hospital mortality in sickle cell patients were analyzed from a database provided by the Agency of Healthcare Research and Quality. From the data hospitalization rates and in-hospital mortality in categories by region in the US, hospital size, health insurance status, comorbidities and gender were examined. Patterns of in-hospital mortality were analyzed by logistic regression.

RESULTS

Ratio for hospitalization and mortality among the four regions described Northeast, Midwest, South, West with respective values of 0.63%, 0.65%, 0.76% and 0.89% with P = 0.008 and OR = 1.07. Odds ratio for sickle cell patients that died during hospitalization and health insurance status was OR = 0.08. Comorbidities considered in sickle cell patients; diabetes mellitus (DM), hypertension (HTN), hyperlipidemia (HLD), chronic kidney disease (CKD), smoking status. The odds ratio for comorbidities show A-fib with a value of OR = 4.47, followed by hypertension OR = 1.92, diabetes mellitus OR = 1.44 and chronic kidney disease OR = 1.29, smoking status OR = 0.60. Mortality-hospitalization ratio by gender was: males 0.77% and females 0.69% with OR = 0.87.

CONCLUSIONS

In-hospital mortality by US regions, as well as health insurance status are important measurable elements that show the impact of the disease from a public health perspective. Further and more specific data of regions by states, comorbidities by states and sex, as well as health insurance status by states will provide further insight in local mortality trends.

Accelerated approval of Oxbryta® (voxelotor): A case study on novel endpoint selection in sickle cell disease

Sickle cell disease (SCD) is an inherited disease characterized by hemolysis, anemia, and vaso-occlusion leading to substantial morbidity and mortality. Development of prior pharmacologic therapies exclusively utilized vaso-occlusive crisis (VOC) as a clinical efficacy endpoint; however, this focus on VOC did not capture the full extent of disease symptomatology and complications and slowed the development of new therapies. Voxelotor, a hemoglobin S polymerization inhibitor, was recently approved in the United States for the treatment of SCD in adults and adolescents 12 years of age and older through an accelerated approval pathway. The rapid approval and availability of voxelotor was facilitated in a collaborative effort with the US Food and Drug Administration (FDA), using hemoglobin, a biologic surrogate endpoint, as reasonably likely to predict clinical benefit. Use of this new endpoint was supported by FDA-led multistakeholder discussions with physician and patient communities to identify unmet needs and potential clinical trial endpoints, as well as by a company-sponsored analysis of external patient-level data to demonstrate a correlation between hemoglobin change and stroke risk. A two-part phase 3 study was used to allow for rank ordering of key secondary endpoints based on a planned interim analysis. Continued open communication with the FDA was essential to gain agreement on hemoglobin as a novel endpoint and to address the unmet and urgent need of new therapies for SCD.

Heme Induces IL-6 and Cardiac Hypertrophy Genes Transcripts in Sickle Cell Mice

Emerging data indicate that free heme promotes inflammation in many different disease settings, including in sickle cell disease (SCD). Although free heme, proinflammatory cytokines, and cardiac hypertrophy are co-existing features of SCD, no mechanistic links between these features have been demonstrated. We now report significantly higher levels of IL-6 mRNA and protein in hearts of the Townes sickle cell disease (SS) mice (2.9-fold, p ≤ 0.05) than control mice expressing normal human hemoglobin (AA). We find that experimental administration of heme 50 μmoles/kg body weight induces IL-6 expression directly in vivo and induces gene expression markers of cardiac hypertrophy in SS mice. We administered heme intravenously and found that within three hours plasma IL-6 protein significantly increased in SS mice compared to AA mice (3248 ± 275 vs. 2384 ± 255 pg/ml, p ≤ 0.05). In the heart, heme induced a 15-fold increase in IL-6 transcript in SS mice heart compared to controls. Heme simultaneously induced other markers of cardiac stress and hypertrophy, including atrial natriuretic factor (Nppa; 14-fold, p ≤ 0.05) and beta myosin heavy chain (Myh7; 8-fold, p ≤ 0.05) in SS mice. Our experiments in Nrf2-deficient mice indicate that the cardiac IL-6 response to heme does not require Nrf2, the usual mediator of transcriptional response to heme for heme detoxification by heme oxygenase-1. These data are the first to show heme-induced IL-6 expression in vivo, suggesting that hemolysis may play a role in the elevated IL-6 and cardiac hypertrophy seen in patients and mice with SCD. Our results align with published evidence from rodents and humans without SCD that suggest a causal relationship between IL-6 and cardiac hypertrophy.

Outcomes following kidney transplantation in patients with sickle cell disease: The impact of automated exchange blood transfusion

There are over 12,000 people with sickle cell disease (SCD) in the UK, and 4-12% of patients who develop Sickle Cell Nephropathy (SCN) progress to End Stage Renal Disease (ESRD). Renal transplantation offers the best outcomes for these patients with but their access to transplantation is often limited. Regular automated exchange blood transfusions (EBT) reduce the complications of SCD and may improve outcomes. However, concerns over alloimmunisation limit its widespread implementation. In this retrospective multicenter study, data were collected on 34 SCD patients who received a kidney transplant across 6 London Hospitals between 1997 and 2017. 20/34 patients were on an EBT program, pre or post renal transplantation. Overall patient and graft survival were inferior to contemporaneous UK data in the ESRD population as a whole, a finding which is well-recognised. However, patient survival (CI 95%, p = 0.0032), graft survival and graft function were superior at all time-points in those who received EBT versus those who did not. 4/20 patients (20%) on EBT developed de novo donor specific antibodies (DSAs). 3/14 patients (21%) not on EBT developed de novo DSAs. The incidence of rejection in those on EBT was 5/18 (28%), as compared with 7/13 (54%) not on EBT. In conclusion, our data, while limited by an inevitably small sample size and differences in the date of transplantation, do suggest that long-term automated EBT post renal transplant is effective and safe, with improvement in graft and patient outcomes and no increase in antibody formation or graft rejection.

Serum albumin is independently associated with higher mortality in adult sickle cell patients: Results of three independent cohorts

Sickle cell disease (SCD) impacts liver and kidney function as well as skin integrity. These complications, as well as the hyperinflammatory state of SCD, could affect serum albumin. Serum albumin has key roles in antioxidant, anti-inflammatory and antithrombotic pathways and maintains vascular integrity. In SCD, these pathways modulate disease severity and clinical outcomes. We used three independent SCD adult cohorts to assess clinical predictors of serum albumin as well its association with mortality. In 2553 SCD adult participants, the frequency of low (<35 g/L) serum albumin was 5%. Older age and lower hemoglobin (P <0.001) were associated with lower serum albumin in all three cohorts. In age and hemoglobin adjusted analysis, higher liver enzymes (P <0.05) were associated with lower serum albumin. In two of the three cohorts, lower kidney function as measured by Glomerular Filtration Rate (P<0.001) was associated with lower serum albumin. Lower serum albumin predicted higher risk of tricuspid regurgitation velocity ≥ 2.5 m/s (OR = 1.1 per g/L, P ≤0.01). In all three cohorts, patients with low serum albumin had higher mortality (adjusted HR ≥2.9, P ≤0.003). This study confirms the role of serum albumin as a biomarker of disease severity and prognosis in patients with SCD. Albumin as a biomarker and possible mediator of SCD severity should be studied further.

Biochemical and therapeutic effects of Omega-3 fatty acids in sickle cell disease

Sickle cell disease (SCD) is a hematologic disorder with complex pathophysiology that includes chronic hemolysis, vaso-occlusion and inflammation. Increased leukocyte-erythrocyte-endothelial interactions, due to upregulated expression of adhesion molecules and activated endothelium, are thought to play a primary role in initiation and progression of SCD vaso-occlusive crisis and end-organ damage. Several new pathophysiology-based therapeutic options for SCD are being developed, chiefly targeting the inflammatory pathways. Omega-3 fatty acids are polyunsaturated fatty acids that are known to have effects on diverse physiological processes. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the principal biologically active omega-3 fatty acids. The therapeutic effects of DHA and EPA on chronic inflammatory disorders and cardiovascular diseases are well recognized. The therapeutic effects of omega-3 fatty acids are attributed to their anti-inflammatory and anti-thrombotic eicosanoids, and the novel class of EPA and DHA derived lipid mediators: resolvins, protectins and maresins. Blood cell membranes of patients with SCD have abnormal fatty acids composition characterized by high ratio of pro-inflammatory arachidonic acid (AA) to anti-inflammatory DHA and EPA (high omega-6/omega-3 ratio). In addition, experimental and clinical studies provide evidence that treatment with DHA does confer improvement in rheological properties of sickle RBC, inflammation and hemolysis. The clinical studies have shown improvements in VOC rate, markers of inflammation, adhesion, and hemolysis. In toto, the results of studies on the therapeutic effects of omega-3 fatty acids in SCD provide good body of evidence that omega-3 fatty acids could be a safe and effective treatment for SCD.

Haptoglobin Therapeutics and Compartmentalization of Cell-Free Hemoglobin Toxicity

Hemolysis and accumulation of cell-free hemoglobin (Hb) in the circulation or in confined tissue compartments such as the subarachnoid space is an important driver of disease. Haptoglobin is the Hb binding and clearance protein in human plasma and an efficient antagonist of Hb toxicity resulting from physiological red blood cell turnover. However, endogenous concentrations of haptoglobin are insufficient to provide protection against Hb-driven disease processes in conditions such as sickle cell anemia, sepsis, transfusion reactions, medical-device associated hemolysis, or after a subarachnoid hemorrhage. As a result, there is increasing interest in developing haptoglobin therapeutics to target 'toxic' cell-free Hb exposures. Here, we discuss key concepts of Hb toxicity and provide a perspective on the use of haptoglobin as a therapeutic protein.

A Comprehensive Review of the Treatment and Management of Pain in Sickle Cell Disease

PURPOSE OF REVIEW

Sickle cell disease (SCD) is a hematological disorder which leads to serious complications in multiple organ systems. While significant research has addressed many of the effects of acute pain episodes and end-organ damage connected to this disease, little has approached the chronic pain state associated with this condition.

RECENT FINDINGS

Associated chronic pain represents a significant detractor from the quality of life experienced by these patients, affecting over half of those with SCD on more days than not. Current treatment typically is centered upon preventing and responding to acute vasoocclusive crises, presumably because this is the most common reason for hospitalization in these patients. The lack of management of chronic pain symptoms leaves many with SCD in a state of suffering. In this review, the treatment methodologies of SCD patients are examined including alternative treatments, both pharmaceutical and non-pharmaceutical, as well as procedural approaches specifically aimed at reducing chronic pain in these patients.

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.

A Phase 3 Randomized Trial of Voxelotor in Sickle Cell Disease

BACKGROUND

Deoxygenated sickle hemoglobin (HbS) polymerization drives the pathophysiology of sickle cell disease. Therefore, direct inhibition of HbS polymerization has potential to favorably modify disease outcomes. Voxelotor is an HbS polymerization inhibitor.

METHODS

In a multicenter, phase 3, double-blind, randomized, placebo-controlled trial, we compared the efficacy and safety of two dose levels of voxelotor (1500 mg and 900 mg, administered orally once daily) with placebo in persons with sickle cell disease. The primary end point was the percentage of participants who had a hemoglobin response, which was defined as an increase of more than 1.0 g per deciliter from baseline at week 24 in the intention-to-treat analysis.

RESULTS

A total of 274 participants were randomly assigned in a 1:1:1 ratio to receive a once-daily oral dose of 1500 mg of voxelotor, 900 mg of voxelotor, or placebo. Most participants had sickle cell anemia (homozygous hemoglobin S or hemoglobin Sβ⁰-thalassemia), and approximately two thirds were receiving hydroxyurea at baseline. In the intention-to-treat analysis, a significantly higher percentage of participants had a hemoglobin response in the 1500-mg voxelotor group (51%; 95% confidence interval [CI], 41 to 61) than in the placebo group (7%; 95% CI, 1 to 12). Anemia worsened between baseline and week 24 in fewer participants in each voxelotor dose group than in those receiving placebo. At week 24, the 1500-mg voxelotor group had significantly greater reductions from baseline in the indirect bilirubin level and percentage of reticulocytes than the placebo group. The percentage of participants with an adverse event that occurred or worsened during the treatment period was similar across the trial groups. Adverse events of at least grade 3 occurred in 26% of the participants in the 1500-mg voxelotor group, 23% in the 900-mg voxelotor group, and 26% in the placebo group. Most adverse events were not related to the trial drug or placebo, as determined by the investigators.

CONCLUSIONS

In this phase 3 randomized, placebo-controlled trial involving participants with sickle cell disease, voxelotor significantly increased hemoglobin levels and reduced markers of hemolysis. These findings are consistent with inhibition of HbS polymerization and indicate a disease-modifying potential. (Funded by Global Blood Therapeutics; HOPE ClinicalTrials.gov number, NCT03036813.).

Cardiac expression of HMOX1 and PGF in sickle cell mice and haem-treated wild type mice dominates organ expression profiles via Nrf2 (Nfe2l2)

Haemolysis is a major feature of sickle cell disease (SCD) that contributes to organ damage. It is well established that haem, a product of haemolysis, induces expression of the enzyme that degrades it, haem oxygenase-1 (HMOX1). We have also shown that haem induces expression of placental growth factor (PGF), but the organ specificity of these responses has not been well-defined. As expected, we found high level expression of Hmox1 and Pgf transcripts in the reticuloendothelial system organs of transgenic sickle cell mice, but surprisingly strong expression in the heart (P < 0·0001). This pattern was largely replicated in wild type mice by intravenous injection of exogenous haem. In the heart, haem induced unexpectedly strong mRNA responses for Hmox1 (18-fold), Pgf (4-fold), and the haem transporter Slc48a1 (also termed Hrg1; 2·4-fold). This was comparable to the liver, the principal known haem-detoxifying organ. The NFE2L2 (also termed NRF2) transcription factor mediated much of the haem induction of Hmox1 and Hrg1 in all organs, but less so for Pgf. Our results indicate that the heart expresses haem response pathway genes at surprisingly high basal levels and shares with the liver a similar transcriptional response to circulating haem. The role of the heart in haem response should be investigated further.

How I treat the older adult with sickle cell disease

With increasing survival, cumulative complications of sickle cell disease (SCD), which develop insidiously over time, are becoming more apparent and common in older patients, particularly those in their fifth decade and beyond. The older patient is also more likely to develop other age-related nonsickle conditions that interact and add to the disease morbidity. A common misconception is that any symptom in a SCD patient is attributable to their SCD and this may lead to delays in diagnosis and appropriate intervention. We recommend regular comprehensive reviews and monitoring for early signs of organ damage and a low threshold for the use of hydroxyurea and blood transfusions as preventative measures for end-organ disease. Treatable comorbidities and acute deterioration should be managed aggressively. Although the primary goal in management of the older adult with SCD is improving anemia and minimizing organ damage, the time has come for us to be more proactive in considering curative therapies previously offered to the younger patient. Curative or experimental interventions should be discussed early, before complications render the patients ineligible for these treatments.

Curative therapies: Allogeneic hematopoietic cell transplantation from matched related donors using myeloablative, reduced intensity, and nonmyeloablative conditioning in sickle cell disease

Sickle cell disease (SCD) chronically damages multiple organs over the lifetime of affected individuals. Allogeneic hematopoietic cell transplantation (allo-HCT) is the most studied curative intervention. Fully matched related marrow, peripheral blood derived, or cord blood HCT have the best transplant outcome for symptomatic patients with SCD. For patients with asymptomatic or milder disease who have this donor option available, risks and benefits of HCT should be discussed among the patient, family, treating hematologist, and transplant physician, and decision to proceed to HCT should be individualized. Myeloablative conditioning with busulfan, cyclophosphamide, and ATG has been a commonly employed regimen for children and young adults. Recently, low intensity conditioning with low dose total body irradiation and alemtuzumab is emerging as an efficacious and safe regimen for adults, young adults, and possibly children. Mixed donor chimerism (minimum ≥20% myeloid cells), from myeloablative or nonmyeloablative conditioning regimen, produces robust normal donor erythropoiesis and is sufficient to provide a clinical cure. The proportion of patients remaining on immunosuppression beyond 2 years post-HCT is likely <10% with either myeloablative or low intensity regimens. Late effects from myeloablative or reduced intensity conditioning, or from several more months of immunosuppression in low intensity conditioning may be less common than those observed in HCT for malignant indications. Nonmyeloablative approaches with low toxicities should be the focus of future research efforts. Prevention of GVHD is a shared goal in all approaches of allo-HCT in SCD.