Sickle Cell Trait and the Risk of ESRD in Blacks

Blacks, compared with whites, have an increased risk of progression to end-stage renal disease (ESRD). Emerging evidence suggests that, in addition to APOL1 high-risk genotypes, hemoglobin variants, including sickle cell trait (SCT) and hemoglobin C trait, have a role in kidney disease in blacks. However, the association between these hemoglobin traits and ESRD remains unknown. In a large population-based cohort, the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, we evaluated 9909 self-reported blacks (739 with SCT and 243 with hemoglobin C trait). Incident ESRD occurred in 40 of 739 (5.4%) individuals with SCT, six of 243 (2.5%) individuals with hemoglobin C trait, and 234 of 8927 (2.6%) noncarriers. The incidence rate for ESRD was 8.5 per 1000 person-years for participants with SCT and 4.0 per 1000 person-years for noncarriers. Compared with individuals without SCT, individuals with SCT had a hazard ratio for ESRD of 2.03 (95% confidence interval, 1.44 to 2.84). Hemoglobin C trait did not associate with prevalent CKD or ESRD. The incidence rate for ESRD among participants with APOL1 high-risk genotypes was 6.6 per 1000 person-years, with a hazard ratio for ESRD of 1.77 (95% confidence interval, 1.31 to 2.38) for participants with, compared with those without, APOL1 high-risk genotypes. In this cohort, SCT strongly associated with risk of progression to ESRD in blacks, and this degree of risk for ESRD was similar to that conferred by APOL1 high-risk genotypes. These results may have important public policy implications for genetic counseling of SCT carriers. Abstract source Full text
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Spinal versus general anesthesia for Cesarean section in patients with sickle cell anemia

BACKGROUND: Sickle cell anemia (SCA) increases the rate of maternal and fetal complications. This pilot study was designed to compare the maternal and fetal outcomes of spinal versus general anesthesia (GA) for parturients with SCA undergoing cesarean delivery. METHODS: Forty parturients with known SCA scheduled for elective Cesarean delivery were randomized into spinal anesthesia (n = 20) and GA groups (n = 20). Perioperative hemodynamic parameters were recorded. Postpartum complications were followed up. Opioid consumption was calculated. Blood loss during surgery and the number of patients who received intraoperative or postpartum blood transfusion were recorded. Patient satisfaction with the type of anesthesia was assessed. The Apgar score at 1 and 5 min, neonatal admission to the intensive care unit, and mortality were also recorded. RESULTS: Blood loss was significantly higher in the GA than spinal group (P = 0.01). However, the number of patients who received an intraoperative or postpartum blood transfusion was statistically insignificant. Significantly more patients developed intraoperative hypotension and bradycardia in the spinal than GA group. Opioid use during the first 24 h was significantly higher in the GA than spinal group (P < 0.0001). More patients had vaso-occlusive crisis in the GA than spinal group without statistical significance (P = 0.4). There was one case of acute chest syndrome in the GA group. No significant differences were observed in postoperative nausea and/or vomiting, patient satisfaction, or hospital length of stay. Neonatal Apgar scores were significantly better in the spinal than GA group at 1 and 5 min (P = 0.006 and P = 0.009, respectively). Neonatal intensive care admission was not significantly different between the two groups, and there was no neonatal mortality. CONCLUSIONS: Spinal anesthesia may have advantages over GA in parturients with SCA undergoing Cesarean delivery. Abstract source Full text Full text (PMC)
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Systematic and Meta-Analytic Review: Medication Adherence Among Pediatric Patients With Sickle Cell Disease

OBJECTIVE: To provide a comprehensive summary (systematic review) of medication adherence rates by assessment method and medication type for pediatric patients with sickle cell disease (SCD), as well as identify important correlates for future research. METHODS: Articles assessing medication adherence and published between 1982 and February 2015 (n = 49) were identified using electronic databases. A meta-analysis of 14 studies examining demographic, medical, and psychosocial factors and medication adherence was conducted. RESULTS: Adherence rates ranged from 12% to 100% across all medications. Approximately 30% of studies reported associations between adherence and key demographic, medical, and psychosocial correlates. Mean effect sizes were small to moderate (r = .02-.53). CONCLUSIONS: The wide range of adherence rates reported in the literature may be because of, in part, the use of variable assessment strategies. Future studies examining pediatric SCD adherence should incorporate key correlates with the goal of replication. Abstract source Full text
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Spectral domain optical coherence tomography in patients with sickle cell disease

AIM:To evaluate spectral domain optical coherence tomography (SD-OCT) changes in central retina and choroid in patients with sickle cell disease (SCD). METHODS:Data on visual acuity, severity of sickle cell retinopathy, macular volume scans and choroidal thickness on SD-OCT were analysed from 208 eyes of 107 consecutive patients referred for screening for SCD. The retinal and choroidal thickness of eyes with SCD were also compared with age and ethnicity matched controls. RESULTS:44% of the eyes of patients with SCD showed discrete areas of retinal thinning in the temporal macular area. Proliferative sickle cell retinopathy was more prevalent in these eyes compared with SCD eyes with normal macular morphology (67% vs. 48%; p=0.0017). The temporal total and inner retinal thickness, macular volume and choroidal thickness were significantly lower in patients with SCD compared with age, gender and ethnicity matched controls. Macular splaying (widening of the macular contour) was noted in 30% of eyes in both groups. The choroidal and retinal thickness values showed good intergrader reliability using weighted κ statistics (0.550-0.9). CONCLUSIONS:Quantitative and qualitative changes on SD-OCT are present in asymptomatic SCD eyes. Proliferative retinopathy is more prevalent in eyes with discrete areas of macular thinning. Abstract source Full text
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Single Nucleotide Polymorphisms at +191 and +292 of Galectin-3 Gene (LGALS3) Related to Lower GAL-3 Serum Levels Are Associated with Frequent Respiratory Tract Infection and Vaso-Occlusive Crisis in Children with Sickle Cell Anemia

INTRODUCTION: Patients with sickle cell anemia (SCA) may present chronic hemolytic anemia, vaso-occlusion and respiratory tract infection (RTI) episodes. Galectin-3 (GAL-3) is a multifunctional protein involved in inflammation, apoptosis, adhesion and resistance to reactive oxygen species. Studies point to a dual role for GAL-3 as both a circulation damage-associated molecular pattern and a cell membrane associated pattern recognition receptor. OBJECTIVE: To investigate associations between the SNPs of GAL-3 gene (LGALS3) and serum levels with RTI and vaso-occlusive crisis (VOC) in children with SCA. MATERIALS AND METHODS: SNPs +191 and +292 in LGALS3 were studied using the TaqMan real-time PCR system; GAL-3 serum levels were measured by ELISA. The study included 79 children with SCA ranging from 2 to 12 years old. RESULTS: GAL-3 serum levels were associated with LGALS3 +191 and +292 genotypes (p <0.0001; p = 0.0169, respectively). LGALS3 +191, AA genotype was associated with low and CC with higher levels of GAL-3. For LGALS3 +292, the CC genotype was associated with lower GAL-3 and AA with higher levels. Patients with Frequency of RTI (FRTI) >=1 presented higher frequency of +191AA (p = 0.0263) and +292AC/CC genotypes (p = 0.0320). SNP +292 was associated with Frequency of VOC (FVOC) (p = 0.0347), whereas no association was shown with SNP +191 and FVOC. However, CA/AC and AA/CC genotypes with lower GAL-3 levels showed a higher frequency in patients with FRTI >=1 (p = 0.0170; p = 0.0138, respectively). Also, patients with FVOC >=1 presented association with CA/AC (p = 0.0228). LGALS3 +191 and +292 combined genotypes related to low (p = 0.0263) and intermediate expression (p = 0.0245) were associated with FRTI >=1. Lower GAL-3 serum levels were associated with FRTI >=1 (p = 0.0426) and FVOC >=1 (p = 0.0012). CONCLUSION: Variation of GAL-3 serum levels related to SNPs at +191 and +292 may constitute a susceptibility factor for RTI and VOC frequency. Abstract source Full text Full text (PMC)
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Sickle Cell Trait, Rhabdomyolysis, and Mortality among U.S. Army Soldiers

BACKGROUND: Studies have suggested that sickle cell trait elevates the risks of exertional rhabdomyolysis and death. We conducted a study of sickle cell trait in relation to these outcomes, controlling for known risk factors for exertional rhabdomyolysis, in a large population of active persons who had undergone laboratory tests for hemoglobin AS (HbAS) and who were subject to exertional-injury precautions. METHODS: We used Cox proportional-hazards models to test whether the risks of exertional rhabdomyolysis and death varied according to sickle cell trait status among 47,944 black soldiers who had undergone testing for HbAS and who were on active duty in the U.S. Army between January 2011 and December 2014. We used the Stanford Military Data Repository, which contains comprehensive medical and administrative data on all active-duty soldiers. RESULTS: There was no significant difference in the risk of death among soldiers with sickle cell trait, as compared with those without the trait (hazard ratio, 0.99; 95% confidence interval [CI], 0.46 to 2.13; P=0.97), but the trait was associated with a significantly higher adjusted risk of exertional rhabdomyolysis (hazard ratio, 1.54; 95% CI, 1.12 to 2.12; P=0.008). This effect was similar in magnitude to that associated with tobacco use, as compared with no use (hazard ratio, 1.54; 95% CI, 1.23 to 1.94; P<0.001), and to that associated with having a body-mass index (BMI; the weight in kilograms divided by the square of the height in meters) of 30.0 or more, as compared with a BMI of less than 25.0 (hazard ratio, 1.39; 95% CI, 1.04 to 1.86; P=0.03). The effect was less than that associated with recent use of a statin, as compared with no use (hazard ratio, 2.89; 95% CI, 1.51 to 5.55; P=0.001), or an antipsychotic agent (hazard ratio, 3.02; 95% CI, 1.34 to 6.82; P=0.008). CONCLUSIONS: Sickle cell trait was not associated with a higher risk of death than absence of the trait, but it was associated with a significantly higher risk of exertional rhabdomyolysis. (Funded by the National Heart, Lung, and Blood Institute and the Uniformed Services University of the Health Sciences.). Abstract source Full text Full text (PMC)
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Silent cerebral infarcts in very young children with sickle cell anaemia are associated with a higher risk of stroke

Silent cerebral infarctions (SCI) are the most common neurological injury in children with sickle cell anaemia (SCA), but their incidence/prognosis in early childhood has not been well described. We report clinical, neuroradiological, psychometric and academic follow-up over an average period of 14 years in 37 children with SCA who had magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) of the brain between ages 7 and 48 months. Ten patients (27%) younger than age 5 years (Group I) had SCI, as did 12 (32%) older than 5 years (Group II). Fifteen (41%) had no lesions (Group III). Overt stroke or transient ischaemic attack occurred in 5/9 (56%) in Group I. Most Group I patients had progressive MRI abnormalities, concurrent stenosis, decreased cognitive ability, attention/executive function deficits and hindered academic attainment. The proportions of subjects in Group I with subsequent neurological events (P =< 0·006), progressive ischaemia (P =< 0·001) and vascular stenosis (P =< 0·006) were greater than in Groups II and III. Thus, SCI in young children with SCA may predict overt central nervous system events, progressive MRI abnormalities, stenosis, cognitive dysfunction and poor academic performance. Children younger than 5 years may benefit from MRI/MRA testing and should be considered for aggressive intervention when SCI are detected. Abstract source Full text
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Sickle cell disease

Sickle cell disease is a common and life-threatening haematological disorder that affects millions of people worldwide. Abnormal sickle-shaped erythrocytes disrupt blood flow in small vessels, and this vaso-occlusion leads to distal tissue ischaemia and inflammation, with symptoms defining the acute painful sickle-cell crisis. Repeated sickling and ongoing haemolytic anaemia, even when subclinical, lead to parenchymal injury and chronic organ damage, causing substantial morbidity and early mortality. Currently available treatments are limited to transfusions and hydroxycarbamide, although stem cell transplantation might be a potentially curative therapy. Several new therapeutic options are in development, including gene therapy and gene editing. Recent advances include systematic universal screening for stroke risk, improved management of iron overload using oral chelators and non-invasive MRI measurements, and point-of-care diagnostic devices. Controversies include the role of haemolysis in sickle cell disease pathophysiology, optimal management of pregnancy, and strategies to prevent cerebrovascular disease. Abstract source Full text
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Sickle cell disease: a neglected chronic disease of increasing global health importance

Sickle cell disease (SCD) is a single gene disorder causing a debilitating systemic syndrome characterised by chronic anaemia, acute painful episodes, organ infarction and chronic organ damage and by a significant reduction in life expectancy. The origin of SCD lies in the malarial regions of the tropics where carriers are protected against death from malaria and hence enjoy an evolutionary advantage. More recently, population migration has meant that SCD now has a worldwide distribution and that a substantial number of children are born with the condition in higher-income areas, including large parts of Europe and North and South America. Newborn screening, systematic clinical follow-up and prevention of sepsis and organ damage have led to an increased life expectancy among people with SCD in many such countries; however, in resource-limited settings where the majority continue to be born, most affected children continue to die in early childhood, usually undiagnosed, due to the lack of effective programmes for its early detection and treatment. As new therapies emerge, potentially leading to disease amelioration or cure, it is of paramount importance that the significant burden of SCD in resource-poor countries is properly recognised. Abstract source Full text Full text (PMC)
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Safety of deep sedation in young children with sickle cell disease: a retrospective cohort study

OBJECTIVE: To assess the rates and types of complications associated with deep sedation in children with sickle cell disease (SCD) and to explore potential risk factors. STUDY DESIGN: This was a retrospective cohort study of children with SCD and a comparison group of children without SCD who underwent magnetic resonance imaging with deep sedation. The rates of general and SCD-associated sedation complications were calculated, and potential associated clinical and laboratory variables were assessed. RESULTS: A total of 162 sedation records in 94 subjects with SCD and 324 sedation records in 321 subjects without SCD were assessed (mean age, 4.3 years in both groups). Pentobarbital, fentanyl, and midazolam were used in the majority of sedation episodes without routine presedation transfusion. Sedation-related complication rates did not differ significantly between the SCD and comparison groups. Within 1 month after the sedation procedure, 17 children (10%) experienced a vaso-occlusive pain episode (VOE), and 2 children (1.2%) developed acute chest syndrome. Preprocedure and postprocedure rates of these complications did not differ significantly. Subjects who developed VOE after sedation had a significantly higher VOE rate before sedation, but no other significant clinical or laboratory risk factors were identified. CONCLUSION: Deep sedation in young children with SCD using a standard protocol is safe, with a sedation-related complication rate comparable to that of the general pediatric population. The observed rate of VOE, although not significantly higher than expected, warrants further investigation. Abstract source Full text
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