A prospective analysis for prevalence of complications in Thai nontransfusion-dependent Hb E/β-thalassemia and α-thalassemia (Hb H disease)

Αlpha-thalassemia: A practical overview

α-Thalassemia is an inherited blood disorder characterized by decreased synthesis of α-globin chains that results in an imbalance of α and β globin and thus varying degrees of ineffective erythropoiesis, decreased red blood cell (RBC) survival, chronic hemolytic anemia, and subsequent comorbidities. Clinical presentation varies depending on the genotype, ranging from a silent or mild carrier state to severe, transfusion-dependent or lethal disease. Management of patients with α-thalassemia is primarily supportive, addressing either symptoms (eg, RBC transfusions for anemia), complications of the disease, or its transfusion-dependence (eg, chelation therapy for iron overload). Several novel therapies are also in development, including curative gene manipulation techniques and disease modifying agents that target ineffective erythropoiesis and chronic hemolytic anemia. This review of α-thalassemia and its various manifestations provides practical information for clinicians who practice beyond those regions where it is found with high frequency.

Distinct lipid profile in haemolytic anaemia-related gallstones compared with the general gallstone

BACKGROUND

Pigment gallstones are not uncommon among patients with chronic haemolytic anaemia. But their clinical characteristics have not been described in detail and not been directly compared with the general gallstone population.

METHODS

Patients at Peking Union Medical College Hospital with haemolytic anaemia and subsequent gallstones from January 2012 to December 2022 were included. Cases were matched (1:2) based on age, sex and location of stones to randomly select non-anaemia patients with gallstones (controls).

RESULTS

Screening 899 cases of gallstones, we finally included 76 cases and 152 controls. Total cholesterol (TC), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) for cases were 3.02 ± 0.98 mmol/L, 0.89 ± 0.30 mmol/L and 1.58 ± 0.70 mmol/L, respectively, significantly lower than those in the control group (all p < 0.001). TC and HDL were both lower than the normal range, but triglyceride and LDL were within the normal range. Multiple stones were significantly more common for cases (n = 59, 78%) than for controls (n = 44, 29%, p < 0.001). The mean diameter of the maximal gallstone was 1.2 ± 0.6 cm and 1.5 ± 1.0 cm for cases and controls (p = 0.120), respectively. Stones in the elderly (p = 0.002 for univariate analysis, and 0.001 for multivariate analysis) and stones in the bile duct (p = 0.005 for univariate analysis, and 0.009 for multivariate analysis) were found to occur in a shorter period after anaemia.

CONCLUSION

The lipid profile of haemolytic anaemia with gallstones was distinct, low TC, low HDL, and increased-to-normal LDL, compared with the general gallstone population. Patients with haemolytic anaemia were recommended an abdominal ultrasound if aged older than 50 years, with more frequent follow-up visits.KEY MESSAGESClinical characteristics of gallstones following chronic haemolytic anaemia were described and compared with the general gallstone population.The lipid profiles were distinctly different between the patients with gallstones following chronic haemolytic anaemia and the general gallstone population.Elder patients were complicated with gallstones in a shorter period after anaemia and thus were recommended an abdominal ultrasound if aged older than 50 years, with more frequent follow-up visits.

Thalassaemia

Thalassaemia is a diverse group of genetic disorders with a worldwide distribution affecting globin chain synthesis. The pathogenesis of thalassaemia lies in the unbalanced globin chain production, leading to ineffective erythropoiesis, increased haemolysis, and deranged iron homoeostasis. The clinical phenotype shows heterogeneity, ranging from close to normal without complications to severe requiring lifelong transfusion support. Conservative treatment with transfusion and iron chelation has transformed the natural history of thalassaemia major into a chronic disease with a prolonged life expectancy, albeit with co-morbidities and substantial disease burden. Curative therapy with allogeneic haematopoietic stem cell transplantation is advocated for suitable patients. The understanding of the pathogenesis of the disease is guiding therapeutic advances. Novel agents have shown efficacy in improving anaemia and transfusion burden, and initial results from gene therapy approaches are promising. Despite scientific developments, worldwide inequality in the access of health resources is a major concern, because most patients live in underserved areas.

Iron overload status in patients with non-transfusion-dependent thalassemia in China

Background:

Iron overload is one of the main factors that increase morbidity and mortality in patients with non-transfusion dependent thalassemia (NTDT).

Aim:

This study aimed at investigating the prevalence and severity of iron overload in Chinese NTDT patients.

Methods:

we analyzed serum ferritin (SF), liver iron concentration (LIC) and cardiac T2* in 178 Chinese NTDT in this cross-sectional study.

Results:

The median SF level was 996.00(27.15–19704.00) ng/ml and the median LIC value was 8.90(0.60–43.00) mg Fe/g dry weight (dw). The youngest patient with liver iron overload was 5 years old with 5.6 mg Fe/g dw in LIC. The median cardiac T2* was 33.06(7.46–75.08) ms. 6 patients had cardiac T2*⩽20ms. The patients with β thalassemia intermedia and HbE/β thalassemia showed a statistically significant lower Hb and higher values of SF and LIC than those of hemoglobin H disease patients. On multivariate logistic regression analysis, patients in ⩾ age 30-year old had a significant higher risk for iron overload (OR: 77.75, 95% CI: 8.76–690.49) in the age group. The detailed analysis of proportions of different LIC indicate in  > 30-year old group, 76.8% patients suffered from moderate and severe LIC.

Conclusion:

Our study provides a strong support for the novel findings that Chinese NTDT patients have a high prevalence of iron overload. The first assessment of MRI LIC should be performed as early as 5 years old. Then, NTDT patients  > 30 years old may suffer with a high burden of iron overload.

Survival and complications in patients with haemoglobin E thalassaemia in Sri Lanka: a prospective, longitudinal cohort study

BACKGROUND

Worldwide, haemoglobin E β-thalassaemia is the most common genotype of severe β-thalassaemia. The paucity of long-term data for this form of thalassaemia makes evidence-based management challenging. We did a long-term observational study to define factors associated with survival and complications in patients with haemoglobin E thalassaemia.

METHODS

In this prospective, longitudinal cohort study, we included all patients with haemoglobin E thalassaemia who attended the National Thalassaemia Centre in Kurunegala, Sri Lanka, between Jan 1, 1997, and Dec 31, 2001. Patients were assessed up to three times a year. Approaches to blood transfusions, splenectomy, and chelation therapy shifted during this period. Survival rates between groups were evaluated using Kaplan-Meier survival function estimate curves and Cox proportional hazards models were used to identify risk factors for mortality.

FINDINGS

109 patients (54 [50%] male; 55 [50%] female) were recruited and followed up for a median of 18 years (IQR 14-20). Median age at recruitment was 13 years (range 8-21). 32 (29%) patients died during follow-up. Median survival in all patients was 49 years (95% CI 45-not reached). Median survival was worse among male patients (hazard ratio [HR] 2·51, 95% CI 1·16-5·43), patients with a history of serious infections (adjusted HR 8·49, 2·90-24·84), and those with higher estimated body iron burdens as estimated by serum ferritin concentration (adjusted HR 1·03, 1·01-1·06 per 100 units). Splenectomy, while not associated with statistically significant increases in the risks of death or serious infections, ultimately did not eliminate a requirement for scheduled transfusions in 42 (58%) of 73 patients. Haemoglobin concentration less than or equal to 4·5 g/dL (vs concentration >4·5 g/dL), serum ferritin concentration more than 1300 μg/L (vs concentration ≤1300 μg/L), and liver iron concentration more than 5 mg/g dry weight of liver (vs concentration ≤5 mg/g) were associated with poorer survival.

INTERPRETATION

Patients with haemoglobin E thalassaemia often had complications and shortened survival compared with that reported in high-resource countries for thalassaemia major and for thalassaemia intermedia not involving an allele for haemoglobin E. Approaches to management in this disorder remain uncertain and prospective studies should evaluate if altered transfusion regimens, with improved control of body iron, can improve survival.

FUNDING

Wellcome Trust, Medical Research Council, US March of Dimes, Anthony Cerami and Ann Dunne Foundation for World Health, and Hemoglobal.

An urgent need for improving thalassemia care due to the wide gap in current real-life practice and clinical practice guidelines

Based on Thalassemia International Federation clinical practice guidelines (CPG) for non-transfusion dependent and transfusion dependent thalassemia, several measures should be routinely implemented such as monitoring and surveillance of thalassemia related complications for early detection and proper clinical management. To evaluate the prevalence and the performance of routine surveillance for thalassemia related complications during 2 periods; before and after published CPGs (2012-2014 vs 2015-2017), data from 524 adult thalassemia patients attended at Siriraj hospital were compared among different treating physician groups; thalassemia, private hematology, and internal medicine clinics. Three most common complications were osteopenia/osteoporosis (69.8%), gallstones (67.6%) and abnormal vitamin D level (67.6%). Iron overload has been widely evaluated (93.1%) followed by liver function test (82.3%). However, the rate of evaluation for other complications were significantly reduced and < 25% of patients were evaluated in several complications. Comparing among clinics, the surveillance rate has increased significantly for several endocrine complications only in patients treated at thalassemia clinic but not in others. This study was the first study that evaluated real-world practical management of thalassemia patient in terms of complication surveillance. This different clinical practice has called for an immediate policy change to improve and standardize a care for thalassemia patients in Thailand.

Epidemiology of thalassemia among the hill tribe population in Thailand

BACKGROUND

Thalassemia is a severe disease that occurs due to abnormalities in hemoglobin genes. Various genetic factors in different populations lead to different clinical manifestations of thalassemia disease, particularly among people who have a long history of migration and who have married among tribes, such as the hill tribe people in Thailand. This genetic epidemiological study aimed to estimate the prevalence of various forms of thalassemia among the six main hill tribe populations in Thailand.

METHODS

A cross-sectional study was conducted to obtain information and blood specimens from school children belonging to one of the six main hill tribes in Thailand: Akha, Lau, Hmong, Yao, Karen, and Lisu. Hill tribe children who were attending grades 4-6 in 13 selected schools in Chiang Rai Province, Thailand, were invited to participate in the study. A validated questionnaire and 3 mL blood specimens were collected after obtaining information consent forms from both the children and their parents on a voluntary basis. A complete blood count (CBC) was performed, followed by osmotic fragility (OF) and dichlorophenol indophenol precipitation (DCIP) tests to screen for thalassemia. High-performance liquid chromatography (HPLC) and real-time quantitative polymerase chain reaction (qPCR) were used to identify hemoglobin type and α-thalassemia, respectively. A t-test, chi-square and logistic regression were used to detect the associations between variables at the significance level of α = 0.05.

RESULTS

A total of 1,200 participants from 6 different tribes were recruited for the study; 50.0% were males, and 67.3% were aged 11-12 years. The overall prevalence of thalassemia carriers according to the screening tests was 9.8% (117 of 1,200). Among the cases, 83 were A2A (59 cases were α-thalassemia 1 carrier or α-thalassemia 2 carrier or homozygous α-thalassemia 2, and 24 cases were β-thalassemia trait with or without α-thalassemia); 1 case was EE (homozygous Hb E with or without α-thalassemia); 31 cases were EA (30 cases were the Hb E trait, and 1 case was Hb E trait with or without α-thalassemia); 1 case was A2A Bart's H (Hb H disease α-thalassemia 1/α-thalassemia 2); and 1 case was A2A with abnormal Hb. The prevalence of the α-thalassemia 1 trait among the hill tribe population was 2.5%. The greatest prevalence of the α-thalassemia 1 trait was found in the Karen (3.0%) and Hmong (3.0%) tribes.

CONCLUSIONS

The prevalence of some forms of thalassemia in the hill tribe population is higher than that in the Thai and other populations. Effective and available thalassemia screening tests, including essential information to protect the next generation through the specific counseling clinic, are crucial, particularly due to increasing marriages within these populations.

A complication risk score to evaluate clinical severity of thalassaemia syndromes

The thalassaemia syndromes (TS) show different phenotype severity. Developing a reliable, practical and global tool to determine disease severity and tailor treatment would be of great value. Overall, 7910 patients were analysed with the aim of constructing a complication risk score (CoRS) to evaluate the probability of developing one or more complications. Nine independent variables were included in the investigation as predictors. Logistic regression models were used for Group A [transfusion-dependent thalassaemia (TDT)], Group B [transfused non-TDT (NTDT)] and Group C (non-transfused NTDT). Statistically significant predictors included age (years), haemoglobin levels, hepatic transaminases [alanine aminotransferase (ALT) and aspartate aminotransferase] and left-ventricular ejection fraction (LVEF) for Group A; age (years), age at first chelation (months), ALT and LVEF for Group B; and age (years), mean serum ferritin (SF) levels and LVEF for Group C. The area under the receiver operating characteristic curve was 84·5%, 82·1% and 80·0% for Groups A, Group B and Group C respectively, suggesting the models had good discrimination. Finally, the CoRS for each group was categorised into four risk classes (low, intermediate, high, and very high) using the centiles of its distribution. In conclusion, we have developed a CoRS for TS that can assist physicians in prospectively tailoring patients' treatment.

Moderate to severe liver siderosis and raised AST are independent risk factors for vitamin D insufficiency in β-thalassemia patients

Numerous problematic disorders such as vitamin D (Vit-D) deficiency subsequent to large iron loading can be developed in patients with β-thalassemia. The study aimed to estimate Vit-D insufficiency and its risk factors in patients with β-thalassemia. In this multicenter and observational study, all β-thalassemia patients, who referred to 14 hospital-based thalassemia divisions or clinics in Mazandaran province, Iran were included in the study. The data belong to December 2015 until December 2019. The study population was made of transfusion dependent thalassemia (TDT) and non-transfusion-dependent thalassemia (NTDT) patients. Serum levels of 25-OHD3 have been measured by high performance liquid chromatography (HPLC) method as ng/mL. Demographic and clinical information along with some biological tests, as well as the results of T2*-weighted magnetic resonance imaging were analyzed. Of 1959 registered patients, 487 (24.9%) patients had Vit-D-related data. The prevalence of Vit-D insufficiency (< 30 ng/mL) was 41.9, 95% CI 37.5–46.3. The adjusted risks of moderate to severe liver siderosis and raised AST (aspartate aminotransferase) for Vit-D insufficiency (< 30 ng/mL) were 2.31, 95% CI 1.38–3.89 and 2.62, 95% CI 1.43–4.79, respectively. The receiver operating characteristic (ROC) curve analysis showed that the predictive accuracy of ferritin for Vit-D insufficiency status was 0.61, 95% CI 0.54–0.68 with a cutoff point of 1,078 ng/mL (P = 0.03, sensitivity 67%, specificity 49%, positive predictive value [PPV] 47% and negative predictive value [NPV] 68%). In spite of the national programs for treating Vit-D deficiency and our previous efforts for giving supplements to all patients, Vit-D insufficiency/deficiency is still common in our patients. Also, moderate to severe liver siderosis and raised AST were the independent risk factors for the Vit-D insufficiency.

The relationships between pancreatic T2* values and pancreatic iron loading with cardiac dysfunctions, hepatic and cardiac iron siderosis among Egyptian children and young adults with β-thalassaemia major and sickle cell disease: a cross-sectional study

Background: Cardiac, hepatic and pancreatic T2* measured by magnetic resonance imaging (MRI) has been proven to be an accurate and non-invasive method for measuring iron overload in iron overload conditions. There is accumulating evidence that pancreatic iron can predict cardiac iron in young children because the pancreas loads earlier than the heart. The aim of our study was to assess the relationships between pancreatic T2* values and pancreatic iron loading with cardiac dysfunctions and liver and cardiac iron among patients with β-thalassaemia major (βTM) and sickle cell disease (SCD).

Methods: 40 βTM and 20 transfusion-dependant SCD patients were included along with 60 healthy age and sex-matched controls. Echocardiography and Tissue Doppler Imaging were performed for all subjects as well as the control group.  Hepatic, cardiac and pancreatic iron overload in cases were assessed by MRI T2*.

Results:  The mean age of our patients was 13.7 years with mean frequency of transfusion/year 12. Mean cardiac T2* was 32.9 ms and mean myocardial iron concentration was 0.7 mg/g; One patient had cardiac iron overload of moderate severity. Mean pancreatic T2* was 22.3 ms with 20 patients having mild pancreatic iron overload.

Pancreatic T2* correlated positively peak late diastolic velocity at septal mitral annulus (r=0.269, p=0.038), peak early diastolic velocity at tricuspid annulus (r=0.430, p=0.001) and mitral annular plane systolic excursion (r=0.326, p=0.01); and negatively with end systolic pulmonary artery pressure (r=-0.343, p=0.007) and main pulmonary artery diameter (MPA) (r=-0.259, p=0.046). We couldn’t test the predictability of pancreatic T2* in relation to cardiac T2* as only one patient had cardiac T2*<20 ms.

Conclusion: There was a relationship between pancreatic iron siderosis with cardiac dysfunction in multi-transfused patients with βTM and SCD. No direct relation between pancreatic iron and cardiac siderosis was detected.

Long non-coding RNAs MALAT1, MIAT and ANRIL gene expression profiles in beta-thalassemia patients: a cross-sectional analysis

OBJECTIVES

Beta-thalassemia (β-thal) is one of the most common genetic disorders worldwide. Multiple genetic and epigenetic mechanisms could be implicated in the pathogenesis and/or phenotype variations. We sought to explore the serum expression profile of three disease-related long non-coding RNAs (lncRNAs) in a sample of Egyptian β-thal patients with correlation to the patients' clinicolaboratory data.

METHODS

Fifty consecutive β-thal patients and 50 unrelated controls were enrolled in the study. Quantification of circulating lncRNAs; MALAT1 (metastasis-associated lung adenocarcinoma transcript 1), MIAT (myocardial infarction associated transcript), and ANRIL (antisense non-coding RNA in the INK4 locus) was done by Real-time qRT-PCR.

RESULTS

Significant higher expression levels of the studied lncRNAs in β-thal patients compared to the controls (all P values < 0.001) were identified. There was no significant difference between β-thal-major and intermedia patients at the level of any of the studied lncRNAs. Higher MALAT1 expression profile was associated with early age at onset, early age at first blood transfusion, and a higher frequency of splenomegaly. Whereas, up-regulated MIAT levels were associated with early age at first blood transfusion.

CONCLUSIONS

Taken together, the studied lncRNAs MALAT1, MIAT, and ANRIL might be implicated in β-thal pathogenesis and could provide new molecular biomarkers for β-thalassemia after validation in large-scale future studies.

Vascular and hemostatic alterations associated with pulmonary hypertension in β-thalassemia hemoglobin E patients receiving regular transfusion and iron chelation

INTRODUCTION

Pulmonary hypertension (PH) is the commonest cardiac complication in β-thalassemia intermedia, including β-thalassemia/hemoglobin E (β-thal/HbE), and is strongly associated with splenectomy. We aimed to define the prevalence and comprehensively explore mechanisms of PH in β-thal/HbE patients receiving regular transfusion and iron chelation, which were reported to alleviate PH.

MATERIALS AND METHODS

β-Thal/HbE patients receiving regular transfusion and iron chelation over one year were enrolled. Patients at risk for PH were defined by tricuspid-regurgitant-jet-velocity (TRV) ≥ 2.5 m/s. Laboratory and echocardiographic variables were compared with healthy controls.

RESULTS

There were 68 β-thal/HbE, including 31 (45.6%) splenectomized patients, and 38 controls included for analysis. PH was detected in 29 β-thal/HbE (42.6%). β-Thal/HbE with PH had a significant reduction in nitric oxide metabolites (NOx) but elevations in thrombin-antithrombin (TAT) complex, soluble thrombomodulin (sTM), endothelin-1 (ET-1) and flow-mediated dilation (FMD) values compared to those without PH (all, p < 0.05). TRV was significantly correlated with NOx, TAT, sTM, ET-1 and FMD values (r = -0.514, r = 0.281, r = 0.313, r = 0.245 and r = -0.474; all p < 0.05). Erythropoietic activity, serum ferritin, circulating total tissue factor (TF) antigen, microparticle-associated TF activity, microparticle's procoagulant activity and soluble p-selectin levels were not different between PH and non-PH subgroups. Notably, there were no significant associations between splenectomy and PH.

CONCLUSIONS

PH remains prevalent in β-thal/HbE patients receiving long-term transfusion and iron chelation. PH is not associated with splenectomy status but correlated with NO depletion, TF-independent hypercoagulability and endothelial perturbation.