Abstract

BACKGROUND Regularly transfused people with sickle cell disease (SCD) and people with thalassaemia are at risk of iron overload. Iron overload can lead to iron toxicity in vulnerable organs such as the heart, liver and endocrine glands, which can be prevented and treated with iron-chelating agents. The intensive demands and uncomfortable side effects of therapy can have a negative impact on daily activities and wellbeing, which may affect adherence. OBJECTIVES To identify and assess the effectiveness of different types of interventions (psychological and psychosocial, educational, medication interventions, or multi-component interventions) and interventions specific to different age groups, to improve adherence to iron chelation therapy compared to another listed intervention, or standard care in people with SCD or thalassaemia. SEARCH METHODS We searched CENTRAL (Cochrane Library), MEDLINE, PubMed, Embase, CINAHL, PsycINFO, ProQuest Dissertations & Global Theses, Web of Science & Social Sciences Conference Proceedings Indexes and ongoing trial databases (13 December 2021). We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register (1 August 2022). SELECTION CRITERIA For trials comparing medications or medication changes, only randomised controlled trials (RCTs) were eligible for inclusion. For studies including psychological and psychosocial interventions, educational interventions, or multi-component interventions, non-randomised studies of interventions (NRSIs), controlled before-after studies, and interrupted time series studies with adherence as a primary outcome were also eligible for inclusion. DATA COLLECTION AND ANALYSIS For this update, two authors independently assessed trial eligibility and risk of bias, and extracted data. We assessed the certainty of the evidence using GRADE. MAIN RESULTS We included 19 RCTs and one NRSI published between 1997 and 2021. One trial assessed medication management, one assessed an education intervention (NRSI) and 18 RCTs were of medication interventions. Medications assessed were subcutaneous deferoxamine, and two oral chelating agents, deferiprone and deferasirox. We rated the certainty of evidence as very low to low across all outcomes identified in this review. Four trials measured quality of life (QoL) with validated instruments, but provided no analysable data and reported no difference in QoL. We identified nine comparisons of interest. 1. Deferiprone versus deferoxamine We are uncertain whether or not deferiprone affects adherence to iron chelation therapy (four RCTs, unpooled, very low-certainty evidence), all-cause mortality (risk ratio (RR) 0.47, 95% confidence interval (CI) 0.18 to 1.21; 3 RCTs, 376 participants; very low-certainty evidence), or serious adverse events (SAEs) (RR 1.43, 95% CI 0.83 to 2.46; 1 RCT, 228 participants; very low-certainty evidence).  Adherence was reported as "good", "high" or "excellent" by all seven trials, though the data could not be analysed formally: adherence ranged from 69% to 95% (deferiprone, mean 86.6%), and 71% to 93% (deferoxamine, mean 78.8%), based on five trials (474 participants) only. 2. Deferasirox versus deferoxamine We are uncertain whether or not deferasirox affects adherence to iron chelation therapy (three RCTs, unpooled, very low-certainty evidence), although medication adherence was high in all trials. We are uncertain whether or not there is any difference between the drug therapies in serious adverse events (SAEs) (SCD or thalassaemia) or all-cause mortality (thalassaemia). 3. Deferiprone versus deferasirox We are uncertain if there is a difference between oral deferiprone and deferasirox based on a single trial in children (average age 9 to 10 years) with any hereditary haemoglobinopathy in adherence, SAEs and all-cause mortality. 4. Deferasirox film-coated tablet (FCT) versus deferasirox dispersible tablet (DT) One RCT compared deferasirox in different tablet forms. There may be a preference for FCTs, shown through a trend for greater adherence (RR 1.10, 95% CI 0.99 to 1.22; 1 RCT, 88 participants), although medication adherence was high in both groups (FCT 92.9%; DT 85.3%). We are uncertain if there is a benefit in chelation-related AEs with FCTs. We are uncertain if there is a difference in the incidence of SAEs, all-cause mortality or sustained adherence. 5. Deferiprone and deferoxamine combined versus deferiprone alone We are uncertain if there is a difference in adherence, though reporting was usually narrative as triallists report it was "excellent" in both groups (three RCTs, unpooled). We are uncertain if there is a difference in the incidence of SAEs and all-cause mortality.  6. Deferiprone and deferoxamine combined versus deferoxamine alone We are uncertain if there is a difference in adherence (four RCTs), SAEs (none reported in the trial period) and all-cause mortality (no deaths reported in the trial period). There was high adherence in all trials. 7. Deferiprone and deferoxamine combined versus deferiprone and deferasirox combined There may be a difference in favour of deferiprone and deferasirox (combined) in rates of adherence (RR 0.84, 95% CI 0.72 to 0.99) (one RCT), although it was high (> 80%) in both groups. We are uncertain if there is a difference in SAEs, and no deaths were reported in the trial, so we cannot draw conclusions based on these data (one RCT). 8. Medication management versus standard care We are uncertain if there is a difference in QoL (one RCT), and we could not assess adherence due to a lack of reporting in the control group. 9. Education versus standard care One quasi-experimental (NRSI) study could not be analysed due to the severe baseline confounding. AUTHORS' CONCLUSIONS The medication comparisons included in this review had higher than average adherence rates not accounted for by differences in medication administration or side effects, though often follow-up was not good (high dropout over longer trials), with adherence based on a per protocol analysis. Participants may have been selected based on higher adherence to trial medications at baseline. Also, within the clinical trial context, there is increased attention and involvement of clinicians, thus high adherence rates may be an artefact of trial participation. Real-world, pragmatic trials in community and clinic settings are needed that examine both confirmed or unconfirmed adherence strategies that may increase adherence to iron chelation therapy. Due to lack of evidence this review cannot comment on intervention strategies for different age groups.

Abstract

Children with transfusion-dependent thalassemia (TDT) require regular blood transfusions that, without iron-chelation therapy, lead to iron-overload toxicities. Current practice delays chelation therapy (late-start) until reaching iron overload (serum ferritin ≥1000 μg/L) to minimize risks of iron-depletion. Deferiprone's distinct pharmacological properties, including iron-shuttling to transferrin, may reduce risks of iron depletion during mild-to-moderate iron loads and iron overload/toxicity in children with TDT. The early-start deferiprone (START) study evaluated the efficacy/safety of early-start deferiprone in infants/young children with TDT. Sixty-four infants/children recently diagnosed with beta-thalassemia and serum ferritin (SF) between 200 and 600 μg/L were randomly assigned 1:1 to receive deferiprone or placebo for 12 months or until reaching SF-threshold (≥1000 μg/L at two consecutive visits). Deferiprone was initiated at 25 mg/kg/day and increased to 50 mg/kg/day; some recipients' dosages increased to 75 mg/kg/day based on iron levels. The primary endpoint was the proportion of patients ≥SF-threshold by month 12. Monthly transferrin saturation (TSAT) assessment evaluated iron-shuttling. At baseline, there was no significant difference in mean age (deferiprone: 3.03 years, placebo: 2.63 years), SF (deferiprone: 513.8 μg/L, placebo: 451.7 μg/L), or TSAT (deferiprone: 47.98%, placebo: 43.43%) between groups. At month 12, there was no significant difference in growth or adverse event (AE) rates between groups. No deferiprone-treated patients were iron-depleted. At month 12, 66% of patients receiving deferiprone remained below SF threshold versus 39% of placebo (p = .045). Deferiprone-treated patients showed higher TSAT levels and reached ≥60% TSAT threshold faster. Early-start deferiprone was well-tolerated, not associated with iron depletion, and efficacious in reducing iron overload in infants/children with TDT. TSAT results provide the first clinical evidence of deferiprone shuttling iron to transferrin.

Abstract

OBJECTIVES To examine the efficacy of deferasirox (DFX) by comparison with deferoxamine (DFO) in managing iron overload in patients with sickle cell anaemia (SCA). METHODS Online databases were systematically searched for studies published from January 2007 to July 2022 that had investigated the efficacy of DFX compared with DFO in managing iron overload in patients with SCA. RESULTS Of the 316 articles identified, three randomized clinical trials met the inclusion criteria. Meta-analysis of liver tissue iron concentration (LIC) showed that iron overload was not significantly higher in the DFX group compared with DFO group (WMD, -1.61 mg Fe/g dw (95% CI -4.42 to 1.21). However, iron overload as measured by serum ferritin was significantly lower in DFO compared with DFX group (WMD, 278.13 µg/l (95% CI 36.69 to 519.57). Although meta-analysis was not performed on myocardial iron concentration due to incomplete data, the original report found no significant difference between DFX and DFO. CONCLUSION While limited by the number of studies included in this meta-analysis, overall, the results tend to show that DFX was as effective as DFO in managing iron overload in patients with SCA.

Abstract

BACKGROUND Deferasirox has proved good efficacy and acceptable safety for the management of thalassaemia patients. However, some patients are unresponsive or intolerant to once-daily administration of deferasirox even at a high dose. The current study evaluated the effectiveness and tolerability of twice-daily dosing of deferasirox among transfusion-dependent paediatric beta-thalassaemia patients. METHODS This prospective randomized single-blinded parallel study included all transfusion-dependent paediatric beta-thalassaemia patients prescribed with deferasirox, who visit the study site for their regular blood transfusions and follow-up. The enrolled patients were randomized into intervention and control groups by using a simple block randomization method. In the intervention group, the once-daily dosing of deferasirox was changed to twice-daily dosing with the same total daily dose. Whereas, in the control group, the patients continued with the once-daily deferasirox dosing. The serum ferritin levels of both groups were determined on the enrolment day and after 6 months of follow-up. RESULTS Forty-one patients were included for analysis. A statistically significant mean decrease in serum ferritin levels was detected in the intervention group, while the serum ferritin levels of the control group significantly increased from baseline. The twice-daily dosing of deferasirox was better tolerated by the thalassaemia patients when compared to once-daily dosing. CONCLUSION This study concludes that twice-daily dosing of deferasirox with the same total daily dose significantly enhances the iron chelation efficacy and tolerability among transfusion-dependent paediatric beta-thalassaemia patients when compared to once-daily regimen.

Abstract

BACKGROUND Although cardiac magnetic resonance (CMR) is the most reliable tool for assessment of CIO in patients with thalassemia, it is not always readily available. Recent studies have explored the potential of GLS as an alternative for diagnosis of CIO. We aimed to investigate the efficacy of global longitudinal strain (GLS) for detection of cardiac iron level (CIO). METHODS We searched SCOPUS, MEDLINE, and Embase to identify the studies which used GLS for assessment of CIO. We searched for individual participant data (IPD) in eligible studies to perform ROC curve analysis. CMR with a T2* cut-off value of 20 ms was considered as the gold standard. A meta-analysis was performed and the risk of bias was assessed using the JBI Checklist. RESULTS A total of 14 studies with 789 thalassemia patients (310 and 430 with and without CIO respectively and 49 with undetermined condition) were considered eligible for meta-analysis. IPDs of 405 participants were available. GLS was significantly lower in patients with CIO (-17.5 ± 2.7%) compared to those without CIO (-19.9 ± 2.3%; WMD = 1.6%, 95% CI = [0.76-2.4], p = 0.001, I(2) = 77.1%) and to normal population (-20.61 ± 2.26%; WMD = 2.2%, 95% CI = [0.91-3.5], p = 0.001, I(2) = 83.9%). A GLS < -19.5% could predict CIO with 92.8% sensitivity and 34.63% specificity (AUC = 0.659, 95% CI = [0.6-0.72], p-value < 0.0001). A GLS value < -6% has 100% positive predictive and ≥ -24.5% has 100% negative predictive values for detection of CIO. CONCLUSIONS According to our study, GLS is a strong predictor of CIO and when CMR is not available, it may be a useful screening method for identification of CIO in thalassemia patients.

Abstract

OBJECTIVES Iron overload is a common complication experienced by transfusion-dependent children with hemoglobin disorders. Chelators such as deferasirox (DFX) and deferiprone (DFP) are effective in overcoming this problem. We conducted this systematic review and meta-analysis to evaluate the effectiveness of DFX compared to DFP in treating iron overload amongst pediatric patients with hemoglobin disorders. MATERIAL AND METHODS PubMed and Cochrane Central were searched from their inception until Dec 21 2021, for randomized clinical trials (RCTs) and observational studies, which assessed the efficacy of DFX compared to DFP in the treatment of inherited hemoglobin disorders. The outcomes of interest included myocardial iron concentration (MRI T2*) at the end of the trial and change in mean serum ferritin (SF) levels at the 6 and 12 months mark. Weighted mean differences (WMDs) with their corresponding 95% confidence intervals (CIs) were calculated for continuous outcomes using random effects model. RESULTS A total of 5 studies comprising 607 children were included. The results of our analysis revealed no significant difference between DFX and DFP in MRI T2* at the end of treatment (WMD: -0.92;95% CI[-3.35,1.52]; p=0.46; I(2)=0). Moreover, there has been no significant difference noted in SF levels at both 6 months (WMD: 97.31; 95% CI[-236.16,430.77]; p=0.57; I(2)=0) and 12 months (WMD: 46.99; 95% CI[-191.42,285.40]; p=0.70; I(2)=0) respectively. CONCLUSION Our analysis shows no significant difference between the efficacy of DFX and DFP in the management of iron overload in children with inherited blood disorders. Future large-scale clinical trials are required to further validate our results.

Abstract

INTRODUCTION Iron chelation therapy (ICT) is essential to prevent complications of iron overload in patients with transfusion-dependent thalassaemia. However, there is currently no standard for how to best measure adherence to ICT, nor what level of adherence necessitates concern for poor outcomes, especially in paediatric patients. The objectives of this review are to identify rates of adherence to ICT, predictors of adherence, methods of measurement, and adherence-related health outcomes in children and adolescents. METHODS This review covers the literature published between 1980 and 2020 on ICT in thalassaemia that assessed adherence or compliance. Included studies reflect original research. The preferred reporting items of systematic reviews and meta-analyses (PRISMA) guidelines were followed for reporting results, and the findings were critically appraised with the Oxford Centre for Evidence-based Medicine criteria. RESULTS Of the 543 articles, 37 met the inclusion criteria. The most common methods of assessing adherence included patient self-report (n = 15/36, 41.7%), and pill count (n = 15/36, 41.7%), followed by subcutaneous medication monitoring (5/36, 13.8%) and prescription refills (n = 4/36, 11.1%). Study sizes ranged from 7 to 1115 participants. Studies reported adherence either in "categories" with different levels of adherence (n = 29) or "quantitatively" as a percentage of medication taken out of those prescribed (n = 7). Quantitatively, the percentage of adherence varied from 57% to 98.4% with a median of 89.5%. Five studies focussed on interventions, four of which were designed to improve adherence. Studies varied in sample size and methods of assessment, which prohibited performing a meta-analysis. CONCLUSIONS Due to a lack of clinical consensus on how adherence is defined, it is difficult to compare adherence to ICT in different studies. Future studies should be aimed at creating guidelines for assessing adherence and identifying suboptimal adherence. These future efforts will be crucial in informing evidence-based interventions to improve adherence and health outcomes in thalassaemia patients.Key messagesPredictive factors associated with ICT adherence in the paediatric population include age, social perception of ICT, social support, and side effects/discomfort.Increased adherence in the paediatric population is associated with decreased serum ferritin and improved cardiac, hepatic, and endocrine outcomes.Inadequate adherence to ICT is associated with increased lifetime health costs.There are few studies that focussed on interventions to increase adherence in the paediatric population, and the studies that do exist all focussed on different types of interventions; successful interventions focussed on consistent, long-term engagement with patients.

Abstract

BACKGROUND Myocardial iron deposition is a significant cause of morbidity and mortality in patients with transfusion-dependent thalassemia (TDT). Amlodipine, L-type calcium channel blocker with regular chelation therapy may reduce myocardial iron overload. Lack of randomized trials prompted this study to assess the effect of calcium channel blocker (amlodipine) in combination with iron chelation therapy on iron overload in patients with TDT. METHODS Sixty-four eligible patients were randomized to receive either amlodipine and chelation (group A) or chelation alone (group B) in double-blind placebo-controlled trial. Myocardial iron concentration (MIC) using T2* magnetic resonance imaging (MRI), liver iron concentration (LIC), left ventricular ejection fraction (LVEF), and serum ferritin were measured at baseline and 12 months. RESULTS In the amlodipine group, mean cardiac T2* value significantly increased from 18.11 ± 8.47 to 22.15 ± 7.61 (p = .002) at 12 months, whereas in control group, there was a nonsignificant increase (p = .62) in cardiac T2* value from 19.50 ± 8.84 to 20.03 ± 9.07. There was a significant decrease in MRI-derived MIC in the amlodipine group compared to control group (1.93 ± 1.61 to 1.29 ± 0.90, p = .01). Changes in the LVEF (p = .45), MRI-derived LIC (p = .09), and serum ferritin (p = .81) were not significant between the two groups. CONCLUSION Amlodipine is safe and when combined with chelation therapy appears to be more effective in reducing cardiac iron overload than chelation only in children and young adults with TDT.

Abstract

BACKGROUND AND AIM This study aimed to assess the antioxidant effects of amlodipine in transfusion-dependent β-thalassemia (TDT) patients. METHODS This crossover trial consisted of two sequences (AP and PA). In the AP sequence, nine cases received amlodipine 5 mg daily (phase I) and then were switched to placebo (phase II). In PA sequence, 10 patients took the placebo (phase I) and were shifted to amlodipine (phase II). The washout period was 2 weeks. The length of each phase was 6 months. Serum malondialdehyde (MDA, μmol/L), carbonyl (protein CO, μM/L), glutathione (GSH, nM/L), and total antioxidant capacity (TAC, μmol FeSO4/L) were measured in the beginning and at the end of phases I and II. The clinical significance was viewed as a minimum change difference of 5% for each outcome between amlodipine and placebo. RESULTS Seventeen cases completed the study. According to the baseline MDA values, the adjusted Hedges's g for MDA was -0.59, 95% confidence interval [CI] -1.26 to 0.08. After controlling the baseline protein CO values, Hedges's g computed for protein CO was -0.11, 95% CI -0.76 to 0.55. The estimated values of the adjusted Hedges's g for GSH and TAC were also 0.26, 95% CI -0.40 to 0.91, and 0.42, 95% CI -0.24 to 1.09, respectively. The change difference for MDA was 8.3% (protein CO 2.2%, GSH 3.1%, and TAC 12.9%). CONCLUSION Clinically, amlodipine therapy is an efficacious adjuvant treatment with conventional iron chelators for improving the levels of MDA and TAC in patients with TDT.

Abstract

Iron chelation therapy (ICT) is essential to prevent complications of iron overload in patients with transfusion-dependent thalassemia. However, the role that adherence to ICT plays in health-related outcomes is less well known. Our objectives were to identify adherence rates of ICT, and to assess methods of measurement, predictors of adherence, and adherence-related health outcomes in the literature published between 1980 and 2020. Of 543 articles, 43 met the inclusion criteria. Studies measured ICT adherence, predictors, and/or outcomes associated with adherence. Most studies were across multiple countries in Europe and North America (n = 8/43, 18.6%), recruited in clinics (n = 39/43, 90.7%), and focused on β-thalassemia (β-thal) (n = 25/43, 58.1%). Common methods of assessing ICT adherence included patient self-report (n = 24/43, 55.8%), pill count (n = 9/43, 20.9%), prescription refill history (n = 3/43, 7.0%), provider scoring (n = 3/43, 7.0%), and combinations of methods (n = 4/43, 9.3%). Studies reported adherence either in 'categories' with different levels of adherence (n = 24) or 'quantitatively' as a percentage of doses of medication taken out of those prescribed (n = 17). Adherence levels varied (median 91.7%, range 42.0-99.97%). Studies varied in sample size and methods of adherence assessment and reporting, which prohibited meta-analysis. Due to a lack of consensus on how adherence is defined, it is difficult to compare ICT adherence reporting. Further research is needed to establish guidelines for assessing adherence and identifying suboptimal adherence. Behavioral digital interventions have the potential to optimize ICT adherence and health outcomes.