Estimated glomerular filtration rate in Brazilian adults with sickle cell disease: results from the REDS-III multicenter cohort study.

Chronic kidney disease (CKD) has a significant impact on sickle cell disease (SCD) morbidity and mortality. Early identification of individuals at highest risk of developing CKD may allow therapeutic intervention to prevent worse outcomes. This study aimed to evaluate the prevalence and risk factors for reduced estimated glomerular filtration rate (eGFR) among adults with SCD in Brazil. Participants in the REDS-III multicenter SCD cohort with more severe genotypes aged ≥ 18 years with at least two serum creatinine values were analyzed. The eGFR was calculated using the Jamaica Sickle Cell Cohort Study GFR equation. The eGFR categories were defined according to the K/DOQI. Participants with eGFR ≥ 90 were compared to those with those with eGFR < 90. Among the 870 participants, 647 (74.4%) had eGFR ≥ 90, 211 (24.3%) had eGFR 60 to 89, six (0.7%) had eGFR 30 to 59, and six (0.7%) had ESRD. Male sex (OR: 37.3; 95%CI: 22.4-65.1), higher age (OR: 1.04; 95%CI: 1.02-1.06), higher diastolic blood pressure (OR: 1.03; 95%CI: 1.009-1.06), lower Hb (OR: 0.80; 95%CI: 0.68-0.93), and lower reticulocytes (OR: 0.94; 95%CI: 0.89-0.99) levels were independently associated with eGFR < 90. There was a trend towards higher odds of death in participants with eGFR < 90 (OR: 1.8; 95%CI: 0.95-3.32; p = 0.065). In turn, participants with eGFR < 60 had a 12.2 (95%CI: 2.1-96.9) times higher odds for death when compared to those with eGFR ≥ 60. In this study, eGFR < 90 was observed in one-quarter of adults. Older age, male sex, higher diastolic blood pressure, lower hemoglobin, and lower reticulocyte levels were associated with occurrence of eGFR < 90. Estimated GFR < 60 increased the risk of mortality.

Blood utilization and characteristics of patients treated with chronic transfusion therapy in a large cohort of Brazilian patients with sickle cell disease.

BACKGROUND: Red blood cell (RBC) transfusions are used in sickle cell disease (SCD) to treat acute complications or as chronic transfusion therapy (CTT) to prevent severe manifestations. The objectives of this study were to describe blood utilization and adverse events (AEs) associated with RBCs in the Brazilian SCD population and compare characteristics of patients treated or not with CTT. STUDY DESIGN AND METHODS: A SCD cohort was established at six Brazilian centers. Medical and blood bank records were abstracted for clinical and transfusion history. Two controls not treated with CTT matched on center, SCD genotype, sex, and age were selected for each CTT case within the cohort to compare characteristics between the two groups. RESULTS: Most of the 2794-member cohort had received a transfusion (75.0% of children and 89.2% of adults) with 29.2% of patients receiving transfusion in the prior year. There were 170 (10.6%) children and 115 (9.2%) adults treated with CTT. Children not treated with CTT were more likely to have pain and acute chest hospitalizations in the prior year (25.3% vs. 11.9%, p = 0.0003; and 22.0% vs. 10.7%, p = 0.002, respectively). Both iron overload and alloimmunization were more common in CTT cases compared to controls (65.6% vs. 17.0% and 36.2% vs. 15.9%, respectively). A higher proportion of adults treated with CTT demonstrated oxygen saturation of greater than 95% compared to controls not treated (51.1% vs. 39.2%), while there was no difference in oxygenation between children treated or not. Of 4501 transfusion episodes, 28 (0.62%) AEs were reported. There was no difference in AEs associated with transfusions for acute indications versus CTT. CONCLUSION: Red blood cell transfusion was common in Brazilian SCD patients, with utilization driven by CTT. Transfusion reactions were not common; however, alloimmunization and iron overload were frequent among those on CTT, highlighting the need for novel clinical strategies to mitigate these risks.

Hb S/ß-Thalassemia in the REDS-III Brazil Sickle Cell Disease Cohort: Clinical, Laboratory and Molecular Characteristics.

We described the clinical, laboratory and molecular characteristics of individuals with Hb S (HBB: c.20A>T)/ß-thalassemia (Hb S/ß-thal) participating in the Recipient Epidemiology and Donor Evaluation Study (REDS-III) Brazil Sickle Cell Disease cohort. HBB gene sequencing was performed to genotype each ß-thal mutation. Patients were classified as Hb S/ß0-thal, Hb S/ß+-thal-severe or Hb S/ß+-thal based on prior literature and databases of hemoglobin (Hb) variants. Characteristics of patients with each ß-thal mutation were described and the clinical profile of patients grouped into Hb S/ß0-thal, Hb S/ß+-thal and Hb S/ß+-thal-severe were compared. Of the 2793 patients enrolled, 84 (3.0%) had Hb S/ß0-thal and 83 (3.0%) had Hb S/ß+-thal; 40/83 (48.2%) patients with Hb S/ß+-thal had mutations defined as severe. We identified 19 different ß-thal mutations, eight Hb S/ß0-thal, three Hb S/ß+-thal-severe and eight Hb S/ß+-thal. The most frequent ß0 and ß+ mutations were codon 39 (HBB: c.118C>T) and IVS-I-6 (T>C) (HBB: c.92+6T>C), respectively. Individuals with Hb S/ß0-thal had a similar clinical and laboratory phenotype when compared to those with Hb S/ß+-thal-severe. Individuals with Hb S/ß+-thal-severe had significantly lower total Hb and Hb A levels and higher Hb S, white blood cell (WBC) count, platelets and hemolysis markers when compared to those with Hb S/ß+-thal. Likewise, individuals with Hb S/ß+-thal-severe showed a significantly higher occurrence of hospitalizations, vaso-occlusive events (VOE), acute chest syndrome (ACS), splenic sequestration, blood utilization, and hydroxyurea (HU) therapy.

Use of an automated pyrosequencing technique for confirmation of sickle cell disease.

BACKGROUND: The diagnosis of sickle cell disease (SCD) is made by hemoglobin assays such as high-performance liquid chromatography (HPLC), isoelectric focusing and cellulose acetate or citrate agar electrophoresis. These assays are easy to perform and used in large-scale newborn screening in many countries. These tests however may not easily differentiate Sß0 thalassemia from SS or identify other hemoglobin variants, and in this case, hemoglobin (HBB) gene sequencing may be necessary. OBJECTIVES: To develop a high throughput DNA based confirmatory assay for SCD and to detect mutations in the HBB gene. METHODS: We developed an automated pyrosequencing technique (PyS) based on QIAGEN technology (Hilden, Germany) to detect homozygous or heterozygous hemoglobin S mutations as well as hemoglobin C mutations. The technique was tested on 2,748 samples from patients enrolled in a multi-center SCD cohort in Brazil. Patients were previously tested using HPLC to diagnose SCD as part of routine clinical care. Any subjects with discrepant results between HPLC and PyS or with heterozygous hemoglobin S detected had Sanger sequencing of the HBB gene. RESULTS: We identified 168 samples with discrepant results between HPLC and PyS and 100 with concordant PyS = heterozygous S and HPLC, which would suggest SB-thalassemia or other heterozygous S variants. The PyS assay correctly identified 1906 (98.7%) of the 1930 HbSS and 628 (98.7%) of the 636 HbSC samples. Of the 179 remaining samples, PyS correctly indicated S heterozygosis in 165 (92.2%). Of the 165 heterozygous S samples confirmed by Sanger as consistent with Sß thalassemia genotype, 84 samples were classified as Sß0 thalassemia and 81 as Sß+ thalassemia. The most frequent beta thalassemia mutations of Sß0 and Sß+ were HBB: c.118C>T (Gln40Stop) and HBB c.92 + 6T> C, respectively. DISCUSSION: The PyS proved to be satisfactory for large-scale confirmatory testing of hemoglobin mutation. Moreover, with this study we were able to describe the most common ß+ and ß0 mutations in SCD patients with Sß-thalassemia in a large multi-institutional SCD cohort in Brazil.

Clinical and Genetic Predictors of Priapism in Sickle Cell Disease: Results from the Recipient Epidemiology and Donor Evaluation Study III Brazil Cohort Study.

INTRODUCTION: Priapism is the persistent and painful erection of the penis and is a common sickle cell disease (SCD) complication. AIM: The goal of this study was to characterize clinical and genetic factors associated with priapism within a large multi-center SCD cohort in Brazil. METHODS: Cases with priapism were compared to SCD type-matched controls within defined age strata to identify clinical outcomes associated with priapism. Whole blood single nucleotide polymorphism genotyping was performed using a customized array, and a genome-wide association study (GWAS) was conducted to identify single nucleotide polymorphisms associated with priapism. MAIN OUTCOME MEASURE: Of the 1,314 male patients in the cohort, 188 experienced priapism (14.3%). RESULTS: Priapism was more common among older patients (P = .006) and more severe SCD genotypes such as homozygous SS (P < .0001). In the genotype- and age-matched analyses, associations with priapism were found for pulmonary hypertension (P = .05) and avascular necrosis (P = .01). The GWAS suggested replication of a previously reported candidate gene association of priapism for the gene transforming growth factor beta receptor 3 (TGFBR3) (P = 2 × 10-4). CLINICAL IMPLICATIONS: Older patients with more severe genotypes are at higher risk of priapism, and there is a lack of consensus on standard treatment strategies for priapism in SCD. STRENGTHS & LIMITATIONS: This study characterizes SCD patients with any history of priapism from a large multi-center cohort. Replication of the GWAS in an independent cohort is required to validate the results. CONCLUSION: These findings extend the understanding of risk factors associated with priapism in SCD and identify genetic markers to be investigated in future studies to further elucidate priapism pathophysiology. Ozahata M, Page GP, Guo Y, et al. Clinical and Genetic Predictors of Priapism in Sickle Cell Disease: Results from the Recipient Epidemiology and Donor Evaluation Study III Brazil Cohort Study. J Sex Med 2019;16:1988-1999.

Quality of life in pre-adolescent children with sickle cell disease in Brazil.

Sickle cell disease (SCD) affects more than 13 million people and can have a significant impact on the quality of life (QoL) of those persons. We performed a cross-sectional study to evaluate the QoL in SCD children 8-12 years old enrolled from November 2014 to March 2016 in a large multicenter cohort study in Brazil. The PedsQL™ SCD Module was used to evaluate QoL in 412 children from six Brazilian health centers. The mean age of participants was 10.5 years and 193(46.7%) were women. The mean global score was 60.7, with a Cronbach´s alpha of 0.92. There were significant differences in socioeconomic demographics and treatments among participants at the six centers, but age, income, SCD genotype, and use of hydroxyurea did not significantly affect the QoL scores. After adjustment for all of these variables in a linear regression model, a significant difference was observed by site in global QoL score and the dimensions 'worry II'(ß0 = 20.7, p < .00), 'treatment´(ß0 = 66.8, p < .00) and communication II'(ß0 = 45.8, p < .00). These dimensions are affected by the capacity of health professionals to provide clinical and psychological support to patients. Our results suggest that QoL of this patient population varied according the health center even adjusted by sociodemographics characteristics. Additional training of health professionals in psychological and clinical support could directly reduce patient apprehension about the disease its clinical complications.