Multicenter COMPACT study of COMplications in patients with sickle cell disease and utilization of iron chelation therapy

BACKGROUND: Over the past few decades, lifespans of sickle cell disease (SCD) patients have increased; hence, they encounter multiple complications. Early detection, appropriate comprehensive care, and treatment may prevent or delay onset of complications. OBJECTIVE: We collected longitudinal data on sickle cell disease (SCD) complication rates and associated resource utilization relative to blood transfusion patterns and iron chelation therapy (ICT) use in patients aged ≥16 years to address a gap in the literature. RESEARCH DESIGN AND METHODS: Medical records of 254 SCD patients ≥16 years were retrospectively reviewed at three US tertiary care centers. MAIN OUTCOME MEASURES: We classified patients into cohorts based on cumulative units of blood transfused and ICT history: RESULTS: Cohorts had 69 (C1), 91 (C2), and 94 (C3) patients. Pain led to most hospitalizations (76%) and emergency department (ED) (82%) visits. Among transfused patients (C2+C3), those receiving ICT were less likely to experience SCD complications than those who did not (RR [95% CI] C2 vs. C3: 1.33 [1.25-1.42]). Similar trends (RR [95% CI]) were observed in ED visits and hospitalizations associated with SCD complications (C2 vs. C3, ED: 1.94 [1.70-2.21]; hospitalizations: 1.61 [1.45-1.78]), but not in outpatient visits. CONCLUSIONS: Although the most commonly reported SCD complication among all patients was pain, patients who received ICT were less likely to experience pain and other complications than those who did not. These results highlight the need for increased patient and provider education on the importance of comprehensive disease management. Abstract source Full text
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Newborn screening and prophylactic interventions for sickle cell disease in 47 countries in sub-Saharan Africa: a cost-effectiveness analysis

BACKGROUND: Sickle cell disease (SCD) constitutes a major public health problem in sub-Saharan Africa (SSA). Newborn screening and early subsequent clinical intervention can reduce early mortality and increase life expectancy, but have not been widely implemented in SSA. This analysis assesses the cost-effectiveness of a newborn screening and prophylactic intervention (NSPI) package for SCD in 47 SSA countries. METHODS: A lifetime Markov model with annual cycles was built with infants either being screened using isoelectric focusing (IEF) or not screened. Confirmed positive cases received interventions including insecticide-treated mosquito bed nets, folic acid supplementation, prophylactic antimalarial and penicillin therapy, and vaccinations against bacterial infections. Estimates for the local incidence of SCD, the life expectancy of untreated children, the SCD disability weight, and the cost of screening laboratory tests were based on published sources. Among treated infants, the annual probability of mortality until 30 years of age was derived from a pediatric hospital-based cohort. The outcome of interest included a country-specific cost per Disability Adjusted Life Year (DALY) averted. RESULTS: Of 47 modeled countries in SSA, NSPI is almost certainly highly cost-effective in 24 countries (average cost per DALY averted: US$184); in 10 countries, it is cost-effective in the base case (average cost per DALY averted: US$285), but the results are subject to uncertainty; in the remaining 13, it is most likely not cost-effective. We observe a strong inverse relationship between the incidence rate of SCD and the cost per DALY averted. Newborn screening is estimated to be cost-effective as long as the incidence rate exceeds 0.2-0.3 %, although in some countries NSPI is cost-effective at incidence rates below this range. In total, NSPI could avert over 2.4 million disability adjusted life years (DALYs) annually across SSA. CONCLUSIONS: Using IEF to screen all newborns for SCD plus administration of prophylactic interventions to affected children is cost-effective in the majority of countries in SSA. Abstract source Full text Full text (PMC)
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Neutrophils, platelets, and inflammatory pathways at the nexus of sickle cell disease pathophysiology

Sickle cell disease (SCD) is a severe genetic blood disorder characterized by hemolytic anemia, episodic vaso-occlusion, and progressive organ damage. Current management of the disease remains symptomatic or preventative. Specific treatment targeting major complications such as vaso-occlusion is still lacking. Recent studies have identified various cellular and molecular factors that contribute to the pathophysiology of SCD. Here, we review the role of these elements and discuss the opportunities for therapeutic intervention. Abstract source Full text Full text (PMC)
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Mistrust of Pediatric Sickle Cell Disease Clinical Trials Research

INTRODUCTION: Sickle cell disease (SCD) research is hampered by disparities in participation due in part to mistrust of research among racial/ethnic minorities. Beyond the historic context of research misconduct, little is known about the associations of social ecologic factors with mistrust and of mistrust with SCD clinical trials enrollment. This study evaluated proximal (age, gender, disease severity, perceived stress, SES) and distal (religious beliefs, social support, instrumental support) factors related to mistrust of research among caregivers of children with SCD and adolescents and young adults (AYAs) with SCD. METHODS: Over an 18-month period (2009-2010), participants completed questionnaires of perceived barriers and benefits to clinical trials enrollment, perceived stress, and self-reported demographic and disease-related information. Analyses (January-June 2015) used multivariable linear regressions to evaluate predictors of mistrust. RESULTS: Data were analyzed for 154 caregivers (mean age, 38.75 years; SD=9.56 years; 90.30% female) and 88 AYAs (mean age, 24.76 years; SD=7.25 years; 46.40% female). Among caregivers (full model, R(2)=0.14, p≤0.001), greater mistrust was explained by higher perceived stress (β=0.04, p=0.052); religious beliefs (β=0.61, p≤0.001); and greater instrumental support (β=0.07, p=0.044). Among AYAs (full model, R(2)=0.18, p≤0.001), higher mistrust was explained by being male (β=-0.56, p≤0.001) and lower instrumental support (β=-0.11, p=0.016). Mistrust was significantly greater among caregivers that reported no prior involvement in medical research (p=0.003). CONCLUSIONS: By understanding the complexity through which social ecologic factors contribute to mistrust, researchers may create targeted strategies to address mistrust and increase engagement in SCD research for caregivers and AYAs. Abstract source Full text Full text (PMC)
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Microparticles in sickle cell anaemia: promise and pitfalls

Blood from patients with sickle cell disease contains microparticles (MP) derived from multiple cell sources, including red cells, platelets, monocytes and endothelial cells. MPs are of great interest because of their disease associations, their status as promising biomarkers, and the intercellular communications they mediate. To illustrate the likelihood of their relevance in sickle cell disease, we discuss the nature of MP, their profiling in sickle disease, some caveats relevant to their detection, their roles in supporting coagulation and the disparate influences they may exert upon the pathobiology of sickle cell disease. Abstract source Full text
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Magnesium for treating sickle cell disease

BACKGROUND: Sickle cell disease is an autosomal recessive inherited haemoglobinopathy which causes painful vaso-occlusive crises due to sickle red blood cell dehydration. Vaso-occlusive crises are common painful events responsible for a variety of clinical complications; overall mortality is increased and life expectancy decreased compared to the general population. Experimental studies suggest that intravenous magnesium has proven to be well-tolerated in individuals hospitalised for the immediate relief of acute (sudden onset) painful crisis and has the potential to decrease the length of hospital stay. Some in vitro studies and open studies of long-term oral magnesium showed promising effect on pain relief but failed to show its efficacy. The studies show that oral magnesium therapy may prevent sickle red blood cell dehydration and prevent recurrent painful episodes. There is a need to access evidence for the impact of oral and intravenous magnesium effect on frequency of pain, length of hospital stay and quality of life. OBJECTIVES: To evaluate the effects of short-term intravenous magnesium on the length of hospital stay and quality of life in children and adults with sickle cell disease. To determine the effects of long-term oral magnesium therapy on the frequency of painful crises and the quality of life in children and adults with sickle cell disease. SEARCH METHODS: We searched the Cochrane Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books.Date of last search of the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register: 01 December 2016.Date of last search of other resources (clinical trials registries): 29 March 2017. SELECTION CRITERIA: We searched for published and unpublished randomized controlled studies of oral or intravenous magnesium compared to placebo or no magnesium. DATA COLLECTION AND ANALYSIS: Authors independently assessed the study quality and extracted the data using standard Cochrane methodologies. MAIN RESULTS: We included five randomized placebo-controlled studies with a total of 386 participants (aged three to 53 years). Two shorter parallel studies (n = 306) compared intravenous magnesium sulphate to placebo (normal saline) for admission to hospital due to a vaso-occlusive crisis, for which we were able to analyse data. The quality of evidence was moderate for studies presenting this comparison mainly due to limitations due to risk of bias and imprecision. Two of the three longer-term studies comparing oral magnesium pidolate to placebo had a cross-over design. The third was a parallel factorial study which compared hydroxyurea and oral magnesium to each other and to placebo over a longer period of time; we only present the comparison of oral magnesium to placebo from this study. The quality of evidence was very low with uncertainty of the estimation.The eight-hourly dose levels in the two studies of intravenous magnesium were different; one used 100 mg/kg while the second used 40 mg/kg. Only one of these studies (n = 104) reported the mean daily pain score while hospitalised (a non-significant difference between groups, moderate quality evidence). The second study (n = 202) reported a number of child- and parent-reported quality of life scores. None of the scores showed any difference between treatment groups (low quality evidence). Data from one study (n = 106) showed no difference in length of stay in hospital between groups (low quality evidence). Both studies reported on adverse events, but not defined by severity as we had planned. One study showed significantly more participants receiving intravenous magnesium experienced warmth at infusion site compared to placebo; there were no differences between groups for other adverse events (low quality evidence).Three studies (n = 80) compared oral magnesium pidolate to placebo. None of them reported data which we were able to analyse. One study (n = 24) reported on the number of painful days and stated there was no difference between two groups (low quality evidence). None of the studies reported on quality of life or length of hospital stay. Two studies (n = 68) reported there were no differences in levels of magnesium in either plasma or red blood cells (moderate quality evidence). Two studies (n = 56) reported adverse events. One reported episodes of mild diarrhoea and headache, all of which resolved without stopping treatment. The second study reported adverse events as gastrointestinal disorders, headache or migraine, upper respiratory infections and rash; which were all evenly distributed across treatment groups (moderate quality evidence). AUTHORS' CONCLUSIONS: Moderate to low quality evidence showed neither intravenous magnesium and oral magnesium therapy has an effect on reducing painful crisis, length of hospital stay and changing quality of life in treating sickle cell disease. Therefore, no definitive conclusions can be made regarding its clinical benefit. Further randomized controlled studies, perhaps multicentre, are necessary to establish whether intravenous and oral magnesium therapies have any effect on improving the health of people with sickle cell disease. Abstract source Full text
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Macular and peripapillary spectral domain optical coherence tomography changes in sickle cell retinopathy

PURPOSE: To assess peripapillary retinal nerve fiber layer, macular ganglion cell complex, and total macular thicknesses using spectral domain optical coherence tomography on sickle cell disease patients with and without sickle retinopathy. METHOD: Nineteen eyes of 11 patients with hemoglobin sickle cell disease, 65 eyes of 36 patients with hemoglobin SS disease, and 48 eyes of 24 healthy subjects underwent spectral domain optical coherence tomography scanning (RTVue). Eyes of patients with sickle cell disease were classified into 3 groups according to posterior segment changes: no retinopathy (n = 64), nonproliferative retinopathy (n = 12), and proliferative retinopathy (n = 8). RESULTS: The central fovea in eyes with proliferative retinopathy was thickened compared with control group, sickle cell disease without retinopathy, and nonproliferative retinopathy (P = 0.004); a difference between proliferative retinopathy and sickle cell disease without retinopathy groups was still present after age adjustment (P = 0.014). Eyes with proliferative changes showed higher ganglion cell complex focal loss of volume compared with control group (P = 0.002), even after age adjustment (P = 0.004). Thinning of the nasal retinal nerve fiber layer quadrant was observed in eyes with proliferative retinopathy (P < 0.001); however, no retinal nerve fiber layer thickness difference was observed after age correction (P > 0.05). CONCLUSION: Peripheral changes secondary to proliferative sickle retinopathy were associated with thinning of macular inner retinal layers and thickening of central fovea. Abstract source
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Low-molecular-weight heparins for managing vaso-occlusive crises in people with sickle cell disease

BACKGROUND: Sickle cell disease is one of the most common and severe genetic disorders in the world. It can be broadly divided into two distinct clinical phenotypes characterized by either haemolysis or vaso-occlusion. Pain is the most prominent symptom of vaso-occlusion, and hypercoagulability is a well-established pathogenic phenomenon in people with sickle cell disease. Low-molecular-weight heparins might control this hypercoagulable state through their anticoagulant effect. This is an update of a previously published version of this review. OBJECTIVES: To assess the effects of low-molecular-weight heparins for managing vaso-occlusive crises in people with sickle cell disease. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register comprising references identified from comprehensive electronic database searches. We also searched abstract books of conference proceedings and several online trials registries for ongoing trials.Date of the last search of the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register: 28 September 2015. SELECTION CRITERIA: Randomised controlled clinical trials and controlled clinical trials that assessed the effects of low-molecular-weight heparins in the management of vaso-occlusive crises in people with sickle cell disease. DATA COLLECTION AND ANALYSIS: Study selection, data extraction, assessment of risk of bias and analyses were carried out independently by the two review authors. MAIN RESULTS: Two studies comprising 287 participants were included. One study (with an overall unclear to high risk of bias) involved 253 participants and the quality of the evidence for most outcomes was very low. This study, reported that pain severity at day two and day three was lower in the tinzaparin group than in the placebo group (P < 0.01, analysis of variance (ANOVA)) and additionally at day 4 (P < 0.05 (ANOVA)). Thus tinzaparin resulted in more rapid resolution of pain, as measured with a numerical pain scale. The mean difference in duration of painful crises was statistically significant at -1.78 days in favour of the tinzaparin group (95% confidence interval -1.94 to -1.62). Participants treated with tinzaparin had statistically significantly fewer hospitalisation days than participants in the group treated with placebo, with a mean difference of -4.98 days (95% confidence interval -5.48 to -4.48). Two minor bleeding events were reported as adverse events in the tinzaparin group, and none were reported in the placebo group. The second study (unclear risk of bias) including 34 participants and was a conference abstract with limited data and only addressed one of the predefined outcomes of the review; i.e. pain intensity. After one day pain intensity reduced more, as reported on a visual analogue scale, in the dalteparin group than in the placebo group, mean difference -1.30 (95% confidence interval -1.60 to -1.00), with the quality of evidence rated very low. The most important reasons for downgrading the quality of evidence were serious risk of bias and imprecision (due to low sample size or low occurrence of events). AUTHORS' CONCLUSIONS: Based on the results of two studies, evidence is incomplete to support or refute the effectiveness of low-molecular-weight heparins in people with sickle cell disease. Vaso-occlusive crises are extremely debilitating for sufferers of sickle cell disease; therefore well-designed placebo-controlled studies with other types of low-molecular-weight heparins, and in participants with different genotypes of sickle cell disease, still need to be carried out to confirm or dismiss the results of this single study. Abstract source Full text
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Laser therapy for retinopathy in sickle cell disease

BACKGROUND: Sickle cell disease includes a group of inherited haemoglobinopathies affecting multiple organs including the eyes. Some people with the disease develop ocular manifestations due to vaso-occlusion. Vision-threatening complications of sickle cell disease are mainly due to proliferative sickle retinopathy which is characterized by proliferation of new blood vessels. Laser photocoagulation is widely applicable in proliferative retinopathies such as proliferative sickle retinopathy and proliferative diabetic retinopathy. It is important to evaluate the efficacy and safety of laser photocoagulation in the treatment of proliferative sickle retinopathy to prevent sight-threatening complications. OBJECTIVES: To evaluate the effectiveness of various techniques of laser photocoagulation therapy in sickle cell disease-related retinopathy. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Date of last search: 21 September 2015.We also searched the following resources (24 March 2015): Latin American and Carribean Health Science Literature Database (LILACS); WHO International Clinical Trials Registry Platforms (ICTRP); and ClinicalTrials.gov. SELECTION CRITERIA: Randomised controlled trials comparing laser photocoagulation to no treatment in children and adults. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial eligibility, the risk of bias of the included trials and extracted and analysed data. We contacted the trial authors for additional information. MAIN RESULTS: Two trials (341 eyes of 238 children and adults) were included comparing efficacy and safety of laser photocoagulation to no therapy in people with proliferative sickle retinopathy. There were 121 males and 117 females with an age range from 13 to 67 years. The laser photocoagulation technique used was different in the two trials; one single-centre trial employed sectoral scatter laser photocoagulation using an argon laser; and the second, two-centre trial, employed feeder vessel coagulation using argon laser in one centre and xenon arc in the second centre. The follow-up period ranged from a mean of 21 to 32 months in one trial and 42 to 47 months in the second. Both trials were at risk of selection bias (random sequence generation) because of the randomisation method employed for participants with bilateral disease. One study was considered to be at risk of reporting bias.Using sectoral scatter laser photocoagulation, one trial (174 eyes) reported that complete regression of proliferative sickle retinopathy was seen in 30.2% in the laser group and 22.4% in the control group (no difference between groups). The same trial reported the development of new proliferative sickle retinopathy in 34.3% of laser-treated eyes and in 41.3% of eyes given no treatment; again, there was no difference between treatment groups. The second trial, using feeder vessel coagulation, did not present full data for either treatment group for these outcomes.There was evidence from both trials (341 eyes) that laser photocoagulation using scatter laser or feeder vessel coagulation may prevent the loss of vision in eyes with proliferative sickle retinopathy (at median follow up of 21 to 47 months). Data from both trials indicated that laser treatment prevented the occurrence of vitreous haemorrhage with both argon and xenon laser; with the protective effect being greater with feeder vessel laser treatment compared to scatter photocoagulation.Regarding adverse effects, the incidence of retinal tear was minimal, with only one event reported. Combined data from both trials were available for 341 eyes; there was no difference between the laser and control arms for retinal detachment. In relation to choroidal neovascularization, treatment with xenon arc was found to be associated with a significantly higher risk, but visual loss related to this complication is uncommon with long-term follow up of three years or more.Data regarding quality of life and other adverse effects were not reported in the included trials. AUTHORS' CONCLUSIONS: Our conclusions are based on the data from two trials conducted over 20 years ago. In the absence of further evidence, laser treatment for sickle cell disease-related retinopathy should be considered as a one of therapeutic options for preventing visual loss and vitreous haemorrhage. However, it does not appear to have a significant different effect on other clinical outcomes such as regression of proliferative sickle retinopathy and development of new ones. No evidence is available assessing efficacy in relation to patient-important outcomes (such as quality of life or the loss of a driving licence). There is limited evidence on safety, overall, scatter argon laser photocoagulation is superior in terms of adverse effects, although feeder vessel coagulation has a better effect in preventing vitreous haemorrhage. Further research is needed to examine the safety of laser treatment compared to other interventions such as intravitreal injection of anti-vascular endothelial growth factors. In addition, patient-important outcomes as well as cost-effectiveness should be addressed. Abstract source Full text
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Ketamine Infusion for Pain Control in Acute Pediatric Sickle Cell Painful Crises

OBJECTIVES: Sickle cell disease is the most common hemoglobin variant in the world and can present with recurrent vaso-occlusive painful crises. Pain control in these patients is often difficult and requires a multimodal approach. In patients with uncontrolled pain after traditional pain control methods, ketamine infusions have proven beneficial. Unfortunately, no source alone had described ketamine infusions for pediatric sickle cell patients. Our objective was to provide a thorough definitive reference for health care providers regarding the use of ketamine infusion for pain control in pediatric sickle cell painful crises. METHODS: Literature review. RESULTS: Low-dose ketamine infusions for pediatric patients with sickle cell disease painful crises resulted in improved pain scores and reduced opioid usage. CONCLUSIONS: Ketamine infusions have shown promise in assisting physicians in appropriately treating pediatric sickle cell painful crises. Abstract source Full text
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