Madrid Newborn Sickle Cell Disease Cohort: clinical outcomes, stroke prevention and survival

In May 2003, Madrid established the universal newborn screening (NBS) for sickle cell disease (SCD). However, there are no studies resembling the evolution of a SCD neonate cohort followed according to national guidelines in Spain. The aim of this study is to describe the morbimortality and the stroke prevention programme in patients diagnosed by SCD NBS in Madrid. This is a multicentre, observational, prospective cohort study between 2003 and 2018; 187 patients diagnosed with SCD were included (151 HbSS, 6 HbSβ0, 27 HbSC, 3 HbSβ +), and median follow-up was 5.2 years (0.03-14.9). There were 5 deaths: 2 related to SCD in patients with severe genotype (HbSS/HbSβ0). Overall survival reached 95% and SCD-related survival 96.8%. The most frequent events were fever without focus, vaso-occlusive crises and acute chest syndromes. Eight strokes occurred in 5 patients which led to a 90.7% stroke-free survival in severe genotype patients (first stroke rate, 0.54 per 100 patient-years). Transcranial Doppler (TCD) was performed in 95% of eligible patients; 75% of children with pathological TCD remained stroke-free. Regarding HbSS/HbSβ0 patients, 50.1% received hydroxyurea and 9.5% haematopoietic stem cell transplantation. This study reflects the evolution of Madrid SCD cohort and provides morbimortality data similar to other developed countries.

Use of Disease-Modifying Treatments in Patients With Sickle Cell Disease

Importance

Despite hydroxyurea being an established treatment for sickle cell disease (SCD), it remains underused. The recent approval of the disease-modifying treatments (DMTs) l-glutamine, crizanlizumab, and voxelotor underscores the need to understand the uptake of DMTs in the current treatment landscape.

Objective

To explore characteristics that may be associated with DMT use and to describe observed patterns of yearly DMT use from 2014 to 2021.

Design, Setting, and Participants

This cross-sectional study used administrative claims data from Optum's deidentified Clinformatics Data Mart Database from January 1, 2014, to September 30, 2021, to identify adults and children with SCD. Data were analyzed from August 1, 2022, to August 28, 2023.

Exposure

Use of DMTs.

Main Outcomes and Measures

Patient characteristics across groups with varying patterns of DMT use and yearly patterns of prescription fills for hydroxyurea, crizanlizumab, voxelotor, and l-glutamine.

Results

A total of 5022 beneficiaries with SCD (2081 [41.4%] aged 18-45 years; 2929 [58.3%] female) were included in sample A (144 [2.9%] inconsistent users, 274 [5.5%] incident users, 892 [17.8%] consistent users, and 3712 [73.9%] non-DMT users). Inconsistent users had a higher prevalence of vaso-occlusive crises (mean [SD], 3.7 [4.7]), splenic complications (6 of 144 [4.2%]), pulmonary complications (36 of 144 [25.0%]), kidney disease (21 of 144 [14.6%]), acute chest syndrome (18 of 144 [12.5%]), and health care visits (eg, mean [SD] inpatient visits, 7.0 [10.7]) compared with the other use groups. Non-DMT users had the lowest prevalence of vaso-occlusive crises (mean [SD], 0.8 [2.4]), acute chest syndrome (109 of 3712 [2.9%]), and inpatient (mean [SD], 2.0 [6.6]) and emergency department (mean [SD], 0.7 [3.1]) visits and the highest proportion of adults 65 years and older (593 of 3712 [16.0%]). In sample B (6387 beneficiaries with SCD), hydroxyurea use modestly increased from 428 of 2188 participants (19.6%) in 2014 to 701 of 2880 (24.3%) in 2021. Use of l-glutamine increased briefly but gradually decreased throughout the study period. In 2021, out of 2880 participants, 102 (3.5%) had at least 1 fill for crizanlizumab and 131 (4.6%) had at least 1 fill for voxelotor. Overall, total DMT use increased from 428 of 2188 participants (19.6%) in 2014 to 815 of 2880 patients (28.3%) in 2021.

Conclusions and Relevance

In this cross-sectional analysis of adults and children with SCD, uptake of DMTs remained low from 2014 to 2021, despite the approval of newer therapies. Notable differences in patient characteristics across varied DMT exposure types necessitate further exploration into factors that facilitate DMT use and the creation of strategies to enhance DMT uptake.

Evaluation of Intestinal Microbiota in Children With Sickle Cell Disease

BACKGROUND AND AIMS

Sickle cell disease (SCD) is a chronic hemolytic anemia that may be life-threatening due to multisystemic effects. Identification of the factors which affect the pathophysiology of the disease is important in reducing mortality and morbidity. This study aimed to determine gut microbial diversity in children and adolescents with SCA compared with healthy volunteers and to evaluate the clinical impact of microbiota.

MATERIALS AND METHODS

The study included 34 children and young adolescents with SCD and 41 healthy volunteer participants. The microbiome was assessed by 16S rRNA sequencing in stool samples. Laboratory parameters of all participants, such as complete blood count and C-reactive protein values and clinical characteristics of SCD patients, were determined and compared, as well as clinical conditions of the patients, such as vascular occlusive crisis and/or acute chest syndrome, frequency of transfusions, intake of penicillin, hydroxyurea, and chelation therapy were recorded.

RESULTS

White blood cell count, hemoglobin, immature granulocyte and C-reactive protein levels were significantly higher in the patient group ( P <0.05). Microbiota analysis revealed 3 different clusters among subjects; controls and 2 clusters in the SCD patients (patient G1 and G2 groups). Bacteroides spp. were more prevalent, while Dialester spp. and Prevotella spp. were less prevalent in SCD compared with controls ( t =2.142, P <0.05). Patient G2 (n=9) had a higher prevalence of Bacteroides and a lower prevalence of Prevotella than patient G1 (n=25).

CONCLUSION

In our study, there was a difference between SCD patients and the control group, while 2 different microbiota profiles were encountered in SCD patients. This difference between the microbiota of the patients was not found to affect the clinical picture (such as vascular occlusive crisis, acute chest syndrome).

Influenza vaccination rates and hospitalizations among Medicaid enrollees with and without sickle cell disease, 2009-2015

BACKGROUND

Personswith sickle cell disease (SCD) face increased risks for pulmonary and infection-related complications. This study examines influenza vaccination coverage and estimates influenza-related morbidity among Medicaid enrollees with and without SCD.

PROCEDURE

Influenza vaccination coverage and hospitalizations related to influenza and pneumonia/acute chest syndrome (ACS) during each influenza season from 2009-2010 to 2014-2015 were assessed among enrollees in the IBM MarketScan® Multi-State Medicaid Database. Enrollees with SCD were identified as enrollees with greater than or equal to three claims listing SCD within a 5-year period during 2003-2017. Vaccinations were identified in outpatient claims. Hospitalizations associated with influenza or pneumonia/ACS were identified using inpatient claims. This study includes a series of cross-sectional assessments by season.

RESULTS

From 2009-2010 through 2014-2015 seasons, the SCD sample ranged from 5044 to 8651 enrollees; the non-SCD sample ranged from 1,841,756 to 3,796,337 enrollees. Influenza vaccination coverage was higher among enrollees with SCD compared with enrollees without SCD for all seasons (24.5%-33.6% and 18.2%-22.0%, respectively). Age-standardized rates of influenza-related hospitalizations were 20-42 times higher among SCD enrollees compared with non-SCD enrollees, and ACS/pneumonia hospitalizations were 18-29 times higher. Among enrollees with SCD, influenza-related hospitalization rates were highest among children aged 0-9 years. Among enrollees without SCD, influenza-related hospitalization rates were highest among adults aged 40-64 years.

CONCLUSIONS

Although vaccine coverage was higher in persons with versus without SCD, efforts to increase influenza coverage further are warranted for this high-risk group, who experienced markedly higher rates of influenza and ACS/pneumonia hospitalizations during each season.

Chlorine inhalation induces acute chest syndrome in humanized sickle cell mouse model and ameliorated by postexposure hemopexin

Triggering factors of Acute Chest Syndrome (ACS) is a leading cause of death in patients with Sickle Cell Disease (SCD) and targeted therapies are limited. Chlorine (Cl2) inhalation happens frequently, but its role as a potential trigger of ACS has not been determined. In this study, we hypothesized that Cl2 exposure resembling that in the vicinity of industrial accidents induces acute hemolysis with acute lung injury, reminiscent of ACS in humanized SCD mice. When exposed to Cl2 (500 ppm for 30 min), 64% of SCD mice succumbed within 6 h while none of the control mice expressing normal human hemoglobin died (p<0.01). Surviving SCD mice had evidence of acute hemolysis, respiratory acidosis, acute lung injury, and high concentrations of chlorinated palmitic and stearic acids (p<0.05) in their plasmas and RBCs compared to controls. Treatment with a single intraperitoneal dose of human hemopexin 30 min after Cl2 inhalation reduced mortality to around 15% (p<0.01) with reduced hemolysis (decreased RBCs fragility (p<0.001) and returned plasma heme to normal levels (p<0.0001)), improved oxygenation (p<0.0001) and reduced acute lung injury scores (p<0.0001). RBCs from SCD mice had significant levels of carbonylation (which predisposes RBCs to hemolysis) 6 h post-Cl2 exposure which were absent in RBCs of mice treated with hemopexin. To understand the mechanisms leading to carbonylation, we incubated RBCs from SCD mice with chlorinated lipids and identified sickling and increased hemolysis compared to RBCs obtained from control mice and treated similarly. Our study indicates that Cl2 inhalation induces ACS in SCD mice via induction of acute hemolysis, and that post exposure administration of hemopexin reduces mortality and lung injury. Our data suggest that SCD patients are vulnerable in Cl2 exposure incidents and that hemopexin is a potential therapeutic agent.

Multiple sclerosis in a young woman with sickle cell disease

BACKGROUND

Comorbidities can impose diagnostic and treatment challenges in patients with multiple sclerosis (MS). Sickle cell disease (SCD) and MS are both inflammatory diseases featuring immune system dysregulation, and the reciprocal interaction of these diseases deserves investigation.

METHODS/RESULTS

We present the case of a 28-year-old woman with SCD who developed a sickle cell crisis and acute chest syndrome during corticosteroid treatment for a first MS attack. We then provide a review of the literature on co-management of SCD and MS. In patients with SCD experiencing an acute MS exacerbation, pre-treatment with red blood cell exchange transfusion before corticosteroids may reduce adverse vaso-occlusive events. Plasma exchange may also be considered. Finally, we discuss innovative pre-clinical research that suggests that natalizumab or dimethyl fumarate may ameliorate SCD symptoms while preventing MS relapses; human trials, however, are needed.

CONCLUSION

The co-occurrence of inflammatory disorders, in this case MS and SCD, requires providers to appropriately manage each condition with consideration of the other. Future studies may generate shared avenues for treatment.