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Efficacy of packed red blood cell transfusions based on weight versus formula in thalassemic children: An open-label randomized control trial
Kaur M, Kaur R, Sood T, Jindal G, Kaur P, Mittal K
Transfusion. 2022
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Editor's Choice
Abstract
BACKGROUND Protocols for transfusion therapy in transfusion-dependent thalassemia (TDT) children differ among various medical centers. In India, most centers consider only the patient's weight while calculating the volume of packed red blood cells (PRBCs) to be transfused. This study aimed to compare the efficacy of PRBC transfusions of different volumes calculated either by weight or by a formula using weight and pretransfusion hemoglobin of patient and hematocrit of PRBC. STUDY DESIGN AND METHODS Sixty TDT patients in the age group of 3-9 years were enrolled and randomly allocated to two groups. Group A received PRBC transfusion volume based on the patient's weight, and Group B received PRBC volume calculated using a formula for 6 months. RESULTS Average pretransfusion hemoglobin in Group A and Group B (9 ± 0.4 vs. 8.9 ± 0.4 g/dl) was not significantly different (p = .353). Although the average number of visits in 6 months was less for Group A compared to Group B (7 ± 1 vs. 8 ± 1; p = .001); the average volume transfused per visit was more (351 ± 78 vs. 287 ± 68 ml; p = .003). The calculated average annual pure red cell requirement of the patients was 178 ml/kg/year for Group A and 154 ml/kg/year for Group B (p = .000). Total donor exposures were significantly lower in Group B than Group A (11 ± 3 vs. 14 ± 3; p = .006). CONCLUSION The number of donor exposures and annual pure red cell requirement was significantly lower in the formula-based group. Transfusions based on formula are recommended in TDT patients.
PICO Summary
Population
Transfusion-dependent thalassemia children (n= 60).
Intervention
Packed red blood cells (PRBC) transfusion volume based on the patient’s weight (Group A, n= 30).
Comparison
PRBC transfusion volume calculated according to a formula based on haematocrit of blood unit, desired rise in patient's haemoglobin, and patient's weight (Group B, n= 30).
Outcome
The average number of visits in 6 months was less for Group A compared to Group B (7 ± 1 vs. 8 ± 1). The average volume transfused per visit was higher for Group A than Group B (351 ± 78 vs. 287 ± 68 ml). The calculated average annual pure red cell requirement of the patients was 178 ml/kg/year for Group A and 154 ml/kg/year for Group B. The total donor exposures were significantly lower in Group B than Group A (11 ± 3 vs. 14 ± 3).
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Overview of current progress and challenges in diagnosis, and management of pediatric sickle cell disease in Democratic Republic of the Congo
Kasai ET, Alworong'a Opara JP, Ntokamunda Kadima J, Kalenga M, Batina Agasa S, Marini Djang'eing'a R, Boemer F
Hematology (Amsterdam, Netherlands). 2022;27(1):132-140
Abstract
OBJECTIVES Sickle cell disease (SCD) encompasses health complications, primarily affecting the hematologic system and leading to high death rates in childhood. As a rule, the World Health Organisation (WHO) stepwise gold-standard about the strategies for prevention, diagnosis, and treatment of SCD must be multidimensional. This overview aimed to highlight current advances and challenges linked to strategic issues, diagnosis, the prevalence, and treatment of pediatric cases in Sub-Saharan Africa, particularly the Democratic Republic of the Congo. METHODS We searched data on Google Scholar, Medline, PubMed, Science Direct, Scopus, and ResearchGate. RESULTS The laboratory diagnosis of SCD has progressed from conventional electrophoresis to rapid point-of-care tests that allows early neonate screening. HemoTypeSC(TM) is an affordable test for neonatal screening in DRC. The pediatric SCD prevalence in Sub-Saharan Africa lay within 1-7.7% of homozygous(SS) and 15-40% of the heterozygous(AS) forms of SCD, depending on the method used and the ethnic population tested. Various supportive management protocols for comorbidities and complications exist, but they are not standardized in the Region. CONCLUSION Notwithstanding some progress accomplished, the disease is still challenging in Sub-Saharan Africa due to limited early diagnostic testing and a lack of specific medications. There is a need for harmonizing therapeutic protocols and conducting controlled valid clinical trials.
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Extramedullary haematopoiesis in patients with transfusion dependent β-thalassaemia (TDT): a systematic review
A Subahi E, Ata F, Choudry H, Iqbal P, A AlHiyari M, T Soliman A, De Sanctis V, A Yassin M
Annals of medicine. 2022;54(1):764-774
Abstract
INTRODUCTION Around 5% of the world's population is expected to have some degree and type of thalassaemia. Beta thalassaemia (BT) occurs due to a deficient production of the beta-globin chain of haemoglobin. Extramedullary haematopoiesis (EMH) is one of the complications of BT, mainly observed in minor/intermedia subtypes. EMH is the production of blood cells outside the marrow as a compensatory response to longstanding hypoxia. Due to chronic transfusions, it is not expected in patients with beta-thalassaemia major (BTM). However, there are increasingly reported cases of EMH in BTM. The incidence of EMH in BTM is thought to be <1%. We aim to pool the available data and provide cumulative evidence on the occurrence of EMH in BTM patients. METHODS This is a systematic review of case reports, series, and retrospective studies that presented data on the occurrence of EMH in BTM patients. Data were recorded and analyzed in Microsoft Excel 2016 and SPSS 26. The protocol has been registered in PROSPERO CRD42021242943. RESULTS Data from 253 cases of EMH in BTM patients were extracted with a mean age of 35.3 years. Mean haemoglobin at presentation with EMH was 8.2 mg/dL. Lower limb weakness was the most common presenting feature (N = 23) (paraspinal EMH). Magnetic resonance imaging (MRI) was the most widely used diagnostic modality (226). Overall, blood transfusion was the commonest reported treatment (30), followed by radiotherapy (20), surgery (15), hydroxyurea (12), steroids (6), and exchange transfusion (2). An outcome was reported in 20% of patients, all recovered, except one who died as a result of nosocomial infection. CONCLUSION EMH is rare in BTM and can occur in any organ system with varied clinical features. MRI can effectively diagnose EMH, and conservative management has similar results compared to invasive treatments. Larger studies, focussing on outcomes may enhance guidelines on preventive and therapeutic strategies for managing EMH in BTM.KEY MESSAGESExtramedullary haematopoiesis is a rare complication in beta thalassaemia. Although it is more common in non-transfusion dependent thalassaemia, increasingly reported cases suggest a higher prevalence of EMH in TDT than what is known before.There are no clear guidelines on the management of EMH in TDT, with reported patients showing similar outcomes with conservative invasive treatment modalities.More extensive and preferably prospectively designed studies are required focussing on the management of EMH and its outcomes in patients with TDT to formulate evidence-based guidelines.
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Health related quality of life in children with sickle cell disease: A systematic review and meta-analysis
Stokoe M, Zwicker HM, Forbes C, Abu-Saris Nelh, Fay-McClymont TB, Désiré N, Guilcher GMT, Singh G, Leaker M, Yeates KO, et al
Blood reviews. 2022;:100982
Abstract
This review had three aims: 1) describe the measures used to assess health-related quality of life (HRQL) in pediatric patients diagnosed with sickle cell disease (SCD); 2) document the biopsychosocial factors related to HRQL in pediatric patients diagnosed with SCD; and 3) complete a meta-analysis comparing HRQL in pediatric patients diagnosed with SCD to healthy controls. Included studies were published in English, quantitatively assessed HRQL as a primary aim, in both SCD and controls, and included participants between 0 and 21 years of age. The final review included 66 articles, with a total of 8642 participants with SCD, 4 months-21 years of age, and 62,458 controls, 5-27 years of age. HRQL was predominately measured using the Pediatric Quality of Life Inventory Generic Core and Sickle Cell Disease Module. Meta-analyses revealed children with SCD had significantly worse HRQL compared to healthy controls (standardized mean difference = -0.93, 95% CI = -1.25, -0.61, p < 0.00001). Worse HRQL was associated with more severe SCD, female sex, and pain. The findings indicate that children with SCD are at risk for worse HRQL compared to their healthy peers and their HRQL may be impacted by several biopsychosocial factors. Future research is needed to examine how sociocultural factors uniquely impact this population and their overall quality of life.
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The Pancreatic changes affecting glucose homeostasis in transfusion dependent β- thalassemia (TDT): a short review
De Sanctis V, Soliman A, Tzoulis P, Daar S, Fiscina B, Kattamis C
Acta bio-medica : Atenei Parmensis. 2021;92(3):e2021232
Abstract
BACKGROUND The natural history of the glycometabolic state in transfusion-dependent β-thalassemia (TDT) patients is characterized by a deterioration of glucose tolerance over time. AIMS This review depicts our current knowledges on the complex and multifacet pathophysiologic mechanisms implicated in the development of alteration of glucose homeostasis in patients with TDT. SEARCH STRATEGY A systematic search was done on December 2020 including Web of Science (ISI), Scopus, PubMed, Embase, and Scholar for papers published in the last 20 years. Moreover, we checked the reference lists of the relevant articles and previously performed reviews for additional pertinent studies. The personal experience on the care of patients with thalassemias is also reported. CONCLUSION A regular packed red blood cells (PRBCs) transfusion program, optimization of chelation therapy, and prevention and treatment of liver infections are critical to achieve adequate glucometabolic control in TDT patients. Many exciting opportunities remain for further research and therapeutic development.
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Red blood cell transfusion in myelodysplastic syndromes: A systematic review
Kaka S, Jahangirnia A, Beauregard N, Davis A, Tinmouth A, Chin-Yee N
Transfusion medicine (Oxford, England). 2021
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Editor's Choice
Abstract
Patients with myelodysplastic syndrome (MDS) frequently receive red blood cell (RBC) transfusions for anaemia resulting from ineffective erythropoiesis. While RBC transfusions may rapidly increase haemoglobin values, their impact on clinical and health services outcomes in MDS patients has not previously been summarized. We conducted a systematic review of the literature to evaluate risks and benefits of RBC transfusions in MDS patients. We searched electronic databases (MEDLINE, Embase, CENTRAL, CINAHL) from inception through June 4, 2021 to identify studies reporting data on RBC transfusions in MDS patients. Full text publications that assessed RBC transfusions as an intervention and reported at least one clinical, laboratory, or healthcare outcome associated with transfusion were included. Study characteristics, transfusion information and transfusion-related outcomes were extracted and reported. We identified 1243 original studies, of which 38 met eligibility requirements and were included. Fourteen reported on survival following diagnosis of MDS, with the majority reporting poorer survival among patients receiving or requiring more frequent transfusions. Nine reported on transfusion-related iron overload and its complications. Other outcomes included rates of allo/autoimmunization and adverse transfusion reactions, and healthcare costs incurred by patients with a greater transfusion burden. Only two studies reported on symptom relief following transfusion. This review underscores transfusion dependence as a negative prognostic factor for MDS patients and highlights the paucity of evidence surrounding quality of life and symptom-related outcomes following RBC transfusions in this population. Further study of patient-important outcomes associated with transfusion in MDS patients is warranted to improve therapeutic recommendations and inform resource allocation.
PICO Summary
Population
Patients with myelodysplastic syndromes (MDS), (38 studies, n= 11,101).
Intervention
Red blood cell (RBC) transfusions.
Comparison
Various comparators including not receiving RBC transfusions, transfusion thresholds, and RBC transfusion prophylactically matched/not matched.
Outcome
Fourteen studies reported data on survival following diagnosis of MDS, and the majority reported an inverse relationship between RBC transfusion and survival. Three studies found no significant differences in overall survival in MDS patients who received a greater number of RBC transfusions. From the 9 studies reporting on transfusion-related iron overload and its complications, 3 studies found an increased risk including presentations of cardiomyopathy/heart failure, conduction disorders, diabetes and liver disease. Five studies measuring health care utilization related to transfusion found a higher healthcare utilization, including emergency visits and hospitalizations in MDS patients.
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Impact of the preparation method of red cell concentrates on transfusion indices in thalassemia patients: A randomized crossover clinical trial
Gamberini MR, Fortini M, Stievano A, Calori E, Riontino MV, Ceccherelli G, Venturelli D, Chicchi R, Biguzzi R, Fagnoni F, et al
Transfusion. 2021
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Editor's Choice
Abstract
BACKGROUND The average hemoglobin content of red cell concentrates (RCC) varies depending on the method of preparation. Surprisingly less data are available concerning the clinical impact of those differences. STUDY DESIGN AND METHODS The effects of two types of RCC (RCC-A, RCC-B) on transfusion regime were compared in a non-blinded, prospective, randomized, two-period, and crossover clinical trial. RCC-A was obtained by whole blood leukoreduction and subsequent plasma removal, RCC-B removing plasma and buffy coat first, followed by leukoreduction. Eligible patients were adult, with transfusion-dependent thalassemia (TDT). RESULTS RCC-A contained 63.9 (60.3-67.8) grams of hemoglobin per unit (median with 1(st) and 3(rd) quartile), RCC-B 54.5 (51.0-58.2) g/unit. Fifty-one patients completed the study. With RCC-B, the average pre-transfusion hemoglobin concentration was 9.3 ± 0.5 g/dl (mean ± SD), the average transfusion interval 14.2 (13.7-16.3) days, the number of RCC units transfused per year 39.3 (35.4-47.3), and the transfusion power index (a composite index) 258 ± 49. With RCC-A, the average pre-transfusion hemoglobin concentration was 9.6 ± 0.5 g/dl (+2.7%, effect size 0.792), the average transfusion interval 14.8 (14.0-18.5) days (+4.1%, effect size 0.800), the number of RCC units transfused per year 34.8 (32.1-42.5) (-11.4%, effect size -1.609), and the transfusion power index 272 ± 61 (+14.1%, effect size 0.997). All differences were statistically highly significant (p < .00001). The frequency of transfusion reactions was 0.59% with RCC-A and 0.56% with RCC-B (p = 1.000). CONCLUSION To reduce the number of RCC units consumed per year and the number of transfusion episodes, TDT patients should receive RCC with the highest average hemoglobin content.
PICO Summary
Population
Adult patients with transfusion-dependent thalassemia (n= 51).
Intervention
Red cell concentrates obtained by whole blood leukoreduction and subsequent plasma removal (RCC-A).
Comparison
Red cell concentrates obtained by removing plasma and buffy coat first, followed by leukoreduction (RCC-B).
Outcome
With RCC-B, the average pre-transfusion haemoglobin concentration was 9.3 ± 0.5 g/dl (mean ± SD), the average transfusion interval 14.2 (13.7-16.3) days, the number of RCC units transfused per year 39.3 (35.4-47.3), and the transfusion power index (a composite index) 258 ± 49. With RCC-A, the average pre-transfusion haemoglobin concentration was 9.6 ± 0.5 g/dl (+2.7%, effect size 0.792), the average transfusion interval 14.8 (14.0-18.5) days (+4.1%, effect size 0.800), the number of RCC units transfused per year 34.8 (32.1-42.5) (-11.4%, effect size -1.609), and the transfusion power index 272 ± 61 (+14.1%, effect size 0.997). All differences were statistically highly significant. The frequency of transfusion reactions was 0.59% with RCC-A and 0.56% with RCC-B.
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Comparison of efficacy of packed red blood cell transfusion based on its hemoglobin content versus the standard transfusion practice in thalassemia major patients (HEMOCON study)
Raja A, Jain A, Marwaha N, Trehan A
Transfusion and apheresis science : official journal of the World Apheresis Association : official journal of the European Society for Haemapheresis. 2020;:102736
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Editor's Choice
Abstract
The hemoglobin (Hb) content of packed red blood cell (PRBC) units is heterogenous. The efficacy of a transfusion episode can be assessed if the Hb content of the PRBC is known and the patient's post-transfusion Hb increment is also determined. This prospective study compared the efficacy of PRBC transfusion based on its Hb content versus the standard transfusion practice. A total of 160 thalassemia major patients were enrolled and randomly divided into two equal groups: Group I (n = 80) - they received ABO/RhD identical PRBCs after determining its Hb content (≥50 g); and Group II (n = 80) - they received randomly selected ABO/RhD identical PRBCs. Hb estimation and a direct antiglobulin test were performed on the post-transfusion sample (1 h). The mean Hb content of the PRBC units was significantly higher (p = 0.000) in group I (67.86 +/- 8.07 g; range: 50.80-92.13 g) than group II (60.92 +/- 8.29 g; range: 40.86-86.76 g). The mean Hb increment was also significantly higher in group I patients (p = 0.04). In both the groups, there was a significant negative correlation between Hb increment and weight, age, body surface area and blood volume (p < 0.05). There was a significant positive correlation between Hb increment and Hb dose adjusted for body surface area as well as blood volume (p < 0.05). PRBC transfusion was more efficacious in patients who were transfused with PRBCs having a Hb content ≥50 g as compared to those who received randomly selected PRBCs.
PICO Summary
Population
Thalassemia major patients (n=160).
Intervention
ABO/RhD identical packed red blood cell (PRBCs) after determining its Hb content (>/=50 g) group I, (n = 80).
Comparison
Randomly selected ABO/RhD identical PRBCs group II ,(n = 80).
Outcome
The mean Hb content of the PRBC units was significantly higher in group I (67.86 +/- 8.07 g; range: 50.80-92.13 g) than group II (60.92 +/- 8.29 g; range: 40.86-86.76 g). The mean Hb increment was also significantly higher in group I patients. In both the groups, there was a significant negative correlation between Hb increment and weight, age, body surface area and blood volume. There was a significant positive correlation between Hb increment and Hb dose adjusted for body surface area as well as blood volume. PRBC transfusion was more efficacious in patients who were transfused with PRBCs having a Hb content >/=50 g as compared to those who received randomly selected PRBCs.
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Preoperative blood transfusions for sickle cell disease
Estcourt LJ, Kimber C, Trivella M, Doree C, Hopewell S
Cochrane Database Syst Rev. 2020;7:Cd003149
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Editor's Choice
Abstract
BACKGROUND Sickle cell disease (SCD) is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta globin) genes. SCD can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Surgical interventions are more common in people with SCD, and occur at much younger ages than in the general population. Blood transfusions are frequently used prior to surgery and several regimens are used but there is no consensus over the best method or the necessity of transfusion in specific surgical cases. This is an update of a Cochrane Review. OBJECTIVES To determine whether there is evidence that preoperative blood transfusion in people with SCD undergoing elective or emergency surgery reduces mortality and perioperative or sickle cell-related serious adverse events. To compare the effectiveness of different transfusion regimens (aggressive or conservative) if preoperative transfusions are indicated in people with SCD. SEARCH METHODS We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 28 January 2020 We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register: 19 September 2019. SELECTION CRITERIA All randomised controlled trials and quasi-randomised controlled trials comparing preoperative blood transfusion regimens to different regimens or no transfusion in people with SCD undergoing elective or emergency surgery. There was no restriction by outcomes examined, language or publication status. DATA COLLECTION AND ANALYSIS Two authors independently assessed trial eligibility and the risk of bias and extracted data. MAIN RESULTS Three trials with 990 participants were eligible for inclusion in the review. There were no ongoing trials identified. These trials were conducted between 1988 and 2011. The majority of people included had haemoglobin (Hb) SS SCD. The majority of surgical procedures were considered low or intermediate risk for developing sickle cell-related complications. Aggressive versus simple red blood cell transfusions One trial (551 participants) compared an aggressive transfusion regimen (decreasing sickle haemoglobin to less than 30%) to a simple transfusion regimen (increasing haemoglobin to 100 g/L). This trial re-randomised\ participants and therefore quantitative analysis was only possible on two subsets of data: participants undergoing cholecystectomy (230 participants); and participants undergoing tonsillectomy or adenoidectomy surgeries (107 participants). Data were not combined as we do not know if any participant received both surgeries. Overall, the quality of the evidence was very low across different outcomes according to GRADE methodology. This was due to the trial being at high risk of bias primarily due to lack of blinding, indirectness and the outcome estimates being imprecise. Cholecystectomy subgroup results are reported in the abstract. Results for both subgroups were similar. There was no difference in all-cause mortality between people receiving aggressive transfusions and those receiving conservative transfusions. No deaths occurred in either subgroup. There were no differences between the aggressive transfusion group and conservative transfusion group in the number of people developing: * an acute chest syndrome, risk ratio (RR) 0.84 (95% confidence interval (CI) 0.38 to 1.84) (one trial, 230 participants, very low-quality evidence); * vaso-occlusive crisis, risk ratio 0.30 (95% CI 0.09 to 1.04) (one trial, 230 participants, very low quality evidence); * serious infection, risk ratio 1.75 (95% CI 0.59 to 5.18) (one trial, 230 participants, very low-quality evidence); * any perioperative complications, RR 0.75 (95% CI 0.36 to 1.55) (one trial, 230 participants, very low-quality evidence); * a transfusion-related complication, RR 1.85 (95% CI 0.89 to 3.88) (one trial, 230 participants, very low-quality evidence). Preoperative transfusion versus no preoperative transfusion Two trials (434 participants) compared a preoperative transfusion plus standard care to a group receiving standard care. Overall, the quality of the evidence was low to very low across different outcomes according to GRADE methodology. This was due to the trials being at high risk of bias due to lack of blinding, and outcome estimates being imprecise. One trial was stopped early because more people in the no transfusion arm developed an acute chest syndrome. There was no difference in all-cause mortality between people receiving preoperative transfusions and those receiving no preoperative transfusions (two trials, 434 participants, no deaths occurred). There was significant heterogeneity between the two trials in the number of people developing an acute chest syndrome, a meta-analysis was therefore not performed. One trial showed a reduced number of people developing acute chest syndrome between people receiving preoperative transfusions and those receiving no preoperative transfusions, risk ratio 0.11 (95% confidence interval 0.01 to 0.80) (65 participants), whereas the other trial did not, RR 4.81 (95% CI 0.23 to 99.61) (369 participants). There were no differences between the preoperative transfusion groups and the groups without preoperative transfusion in the number of people developing: * a vaso-occlusive crisis, Peto odds ratio (OR) 1.91 (95% confidence interval 0.61 to 6.04) (two trials, 434 participants, very low-quality evidence). * a serious infection, Peto OR 1.29 (95% CI 0.29 to 5.71) (two trials, 434 participants, very low-quality evidence); * any perioperative complications, RR 0.24 (95% CI 0.03 to 2.05) (one trial, 65 participants, low-quality evidence). There was an increase in the number of people developing circulatory overload in those receiving preoperative transfusions compared to those not receiving preoperative transfusions in one of the two trials, and no events were seen in the other trial (no meta-analysis performed). AUTHORS' CONCLUSIONS There is insufficient evidence from randomised trials to determine whether conservative preoperative blood transfusion is as effective as aggressive preoperative blood transfusion in preventing sickle-related or surgery-related complications in people with HbSS disease. There is very low quality evidence that preoperative blood transfusion may prevent development of acute chest syndrome. Due to lack of evidence this review cannot comment on management for people with HbSC or HbSbeta(+) disease or for those with high baseline haemoglobin concentrations.
PICO Summary
Population
Patients with sickle cell disease (SCD) undergoing elective or emergency surgery (3 studies, n= 990).
Intervention
Aggressive transfusion regime prior to surgery.
Comparison
Conservative transfusion regime or no transfusion prior to surgery.
Outcome
There was no difference between the aggressive and the conservative transfusion regimens before surgery in preventing surgical or sickle‐related complications immediately after surgery. There was no difference in all‐cause mortality between patients receiving preoperative transfusions and those receiving no preoperative transfusions. There was significant heterogeneity between the two trials in the number of people developing an acute chest syndrome, however there was no difference between giving a blood transfusion before surgery compared to not giving a blood transfusion before surgery in preventing any other sickle‐related or surgical complications immediately after surgery.
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Interventions for preventing silent cerebral infarcts in people with sickle cell disease
Estcourt LJ, Kimber C, Hopewell S, Trivella M, Doree C, Abboud MR
Cochrane Database Syst Rev. 2020;4:Cd012389
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Editor's Choice
Abstract
BACKGROUND Sickle cell disease (SCD) is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta globin) genes. SCD can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Silent cerebral infarcts are the commonest neurological complication in children and probably adults with SCD. Silent cerebral infarcts also affect academic performance, increase cognitive deficits and may lower intelligence quotient. OBJECTIVES To assess the effectiveness of interventions to reduce or prevent silent cerebral infarcts in people with SCD. SEARCH METHODS We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 14 November 2019. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register: 07 October 2019. SELECTION CRITERIA Randomised controlled trials comparing interventions to prevent silent cerebral infarcts in people with SCD. There were no restrictions by outcomes examined, language or publication status. DATA COLLECTION AND ANALYSIS We used standard Cochrane methodological procedures. MAIN RESULTS We included five trials (660 children or adolescents) published between 1998 and 2016. Four of the five trials were terminated early. The vast majority of participants had the haemoglobin (Hb)SS form of SCD. One trial focused on preventing silent cerebral infarcts or stroke; three trials were for primary stroke prevention and one trial dealt with secondary stroke prevention. Three trials compared the use of regular long-term red blood cell transfusions to standard care. Two of these trials included children with no previous long-term transfusions: one in children with normal transcranial doppler (TCD) velocities; and one in children with abnormal TCD velocities. The third trial included children and adolescents on long-term transfusion. Two trials compared the drug hydroxyurea and phlebotomy to long-term transfusions and iron chelation therapy: one in primary prevention (children), and one in secondary prevention (children and adolescents). The quality of the evidence was moderate to very low across different outcomes according to GRADE methodology. This was due to trials being at high risk of bias because they were unblinded; indirectness (available evidence was only for children with HbSS); and imprecise outcome estimates. Long-term red blood cell transfusions versus standard care Children with no previous long-term transfusions and higher risk of stroke (abnormal TCD velocities or previous history of silent cerebral infarcts) Long-term red blood cell transfusions may reduce the incidence of silent cerebral infarcts in children with abnormal TCD velocities, risk ratio (RR) 0.11 (95% confidence interval (CI) 0.02 to 0.86) (one trial, 124 participants, low-quality evidence); but make little or no difference to the incidence of silent cerebral infarcts in children with previous silent cerebral infarcts on magnetic resonance imaging and normal or conditional TCDs, RR 0.70 (95% CI 0.23 to 2.13) (one trial, 196 participants, low-quality evidence). No deaths were reported in either trial. Long-term red blood cell transfusions may reduce the incidence of: acute chest syndrome, RR 0.24 (95% CI 0.12 to 0.49) (two trials, 326 participants, low-quality evidence); and painful crisis, RR 0.63 (95% CI 0.42 to 0.95) (two trials, 326 participants, low-quality evidence); and probably reduces the incidence of clinical stroke, RR 0.12 (95% CI 0.03 to 0.49) (two trials, 326 participants, moderate-quality evidence). Long-term red blood cell transfusions may improve quality of life in children with previous silent cerebral infarcts (difference estimate -0.54; 95% confidence interval -0.92 to -0.17; one trial; 166 participants), but may have no effect on cognitive function (least squares means: 1.7, 95% CI -1.1 to 4.4) (one trial, 166 participants, low-quality evidence). Transfusions continued versus transfusions halted: children and adolescents with normalised TCD velocities (79 participants; one trial) Continuing red blood cell transfusions may reduce the incidence of silent cerebral infarcts, RR 0.29 (95% CI 0.09 to 0.97 (low-quality evidence). We are very uncertain whether continuing red blood cell transfusions has any effect on all-cause mortality, Peto odds ratio (OR) 8.00 (95% CI 0.16 to 404.12); or clinical stroke, RR 0.22 (95% CI 0.01 to 4.35) (very low-quality evidence). The trial did not report: comparative numbers for SCD-related adverse events; quality of life; or cognitive function. Hydroxyurea and phlebotomy versus transfusions and chelation Primary prevention, children (121 participants; one trial) We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: silent cerebral infarcts (no infarcts); all-cause mortality (no deaths); risk of stroke (no strokes); or SCD-related complications, RR 1.52 (95% CI 0.58 to 4.02) (very low-quality evidence). Secondary prevention, children and adolescents with a history of stroke (133 participants; one trial) We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: silent cerebral infarcts, Peto OR 7.28 (95% CI 0.14 to 366.91); all-cause mortality, Peto OR 1.02 (95%CI 0.06 to 16.41); or clinical stroke, RR 14.78 (95% CI 0.86 to 253.66) (very low-quality evidence). Switching to hydroxyurea and phlebotomy may increase the risk of SCD-related complications, RR 3.10 (95% CI 1.42 to 6.75) (low-quality evidence). Neither trial reported on quality of life or cognitive function. AUTHORS' CONCLUSIONS We identified no trials for preventing silent cerebral infarcts in adults, or in children who do not have HbSS SCD. Long-term red blood cell transfusions may reduce the incidence of silent cerebral infarcts in children with abnormal TCD velocities, but may have little or no effect on children with normal TCD velocities. In children who are at higher risk of stroke and have not had previous long-term transfusions, long-term red blood cell transfusions probably reduce the risk of stroke, and other SCD-related complications (acute chest syndrome and painful crises). In children and adolescents at high risk of stroke whose TCD velocities have normalised, continuing red blood cell transfusions may reduce the risk of silent cerebral infarcts. No treatment duration threshold has been established for stopping transfusions. Switching to hydroxyurea with phlebotomy may increase the risk of silent cerebral infarcts and SCD-related serious adverse events in secondary stroke prevention. All other evidence in this review is of very low-quality.
PICO Summary
Population
Children or adolescents with sickle cell disease (SCD), five trials (n=660).
Intervention
Long-term red blood cell transfusions.
Comparison
Standard care or halting transfusions, or hydroxyurea and phlebotomy.
Outcome
Long-term red blood cell transfusions may reduce the incidence of silent cerebral infarcts in children with abnormal transcranial doppler (TCD) velocities; but make little or no difference to the incidence of silent cerebral infarcts in children with previous silent cerebral infarcts on magnetic resonance imaging and normal or conditional TCDs. Long-term red blood cell transfusions may improve quality of life in children with previous silent cerebral infarcts, but may have no effect on cognitive function. Continuing red blood cell transfusions may reduce the incidence of silent cerebral infarcts. It is uncertain whether switching to hydroxyurea and phlebotomy has any effect on silent cerebral infarcts (no infarcts); all-cause mortality (no deaths); risk of stroke (no strokes); or SCD-related complications. For children and adolescents with a history of stroke it was uncertain whether switching to hydroxyurea and phlebotomy has any effect on silent cerebral infarcts all-cause mortality or clinical stroke. Switching to hydroxyurea and phlebotomy may increase the risk of SCD-related complications.