Epidemiological situation and treatment of patients with thalassemia major in Germany: results of the German multicenter beta-thalassemia study

Clinical Complications and Healthcare Resource Utilization Associated with Conventional Management of Sickle Cell Disease with Recurrent Vaso-occlusive Crises and Transfusion-Dependent β-Thalassemia in Germany

OBJECTIVE

The purpose of this study was to describe clinical complications and healthcare resource utilization (HCRU) among patients with sickle cell disease (SCD) with recurrent vaso-occlusive crises (VOCs) and patients with transfusion-dependent β-thalassemia (TDT) in Germany.

METHODS

The Betriebskrankenkasse (BKKs) Database was used to identify patients with SCD or TDT. To be eligible for inclusion, patients with SCD were required to have ≥ 2 VOCs/year in any two consecutive years and ≥ 12 months of available data before and after the index date (second VOC in the second consecutive year). Patients with TDT were required to have ≥ 8 red blood cell transfusions (RBCTs) in any 12-month period and ≥ 12 months of available data after the index date (first RBCT). Clinical and HCRU outcomes were analyzed during follow-up.

RESULTS

Overall, 84 patients with SCD with recurrent VOCs and 68 patients with TDT were identified in the BKKs database. Among patients with SCD with recurrent VOCs, the most prevalent complications were retinopathy (45.2%), multisystem organ disease/failure (40.5%), and mental health complications (31.0%); among patients with TDT, they were endocrine (69.1%) and cardiopulmonary (55.9%) complications and malignancies (44.1%). Patients with SCD experienced a mean of 4.0 (standard deviation [SD] 3.9) VOCs and 1.9 (SD 2.5) hospitalizations per patient per year (PPPY) during follow-up. Patients with TDT had a mean (SD) of 16.4 (11.2) RBCTs and 59.4 (40.8) outpatient visits PPPY.

CONCLUSIONS

Patients with SCD with recurrent VOCs or TDT in Germany experience significant clinical complications and HCRU.

A Systematic Review and Meta-Analysis of Stature Growth Complications in β-thalassemia Major Patients

Background

Blood transfusion is a traditional treatment for β-thalassemia (β-thal) that improves the patients' anemia and lifespan, but it may lead to iron overload in parenchymal tissue organs and endocrine glands that cause their dysfunctions as the iron regulatory system can't excrete excess iron from the bloodstream.

Objective

To evaluate the prevalence of iron-related complications (short stature, growth retardation, and growth hormone deficiency) in β-thalassemia major (βTM) patients.

Methods

We performed an electronic search in PubMed, Scopus, and Web of Sciences to evaluate the prevalence of growth hormone impairment in β-thalassemia major (βTM) patients worldwide. Qualities of eligible studies were assessed by the Joanna Briggs Institute checklist for the prevalence study. We used Comprehensive Meta-Analysis (Version 2) to calculate the event rate with 95% CIs, using a random-effects model for all analyses.

Findings

Seventy-four studies were included from five continents between 1978 and 2019; 70.27% (Asia), 16.21% (Europe), 6.75% (Africa), 2.70% (America), 1.35% (Oceania), and 2.70% (Multicenter). The overall mean age of the participants was about 14 years. The pooled prevalence of short stature (ST) was 48.9% (95% CI 35.3-62.6) and in male was higher than female (61.9%, 95% CI 53.4-69.7 vs. 50.9%, CI 41.8-59.9). The pooled prevalence of growth retardation (GR) was 41.1% and in male was higher than in female (51.6%, 95% CI 17.8-84 vs. 33.1%, CI 9.4-70.2). The pooled prevalence of growth hormone deficiency (GHD) was 26.6% (95% CI 16-40.8).

Conclusion

Our study revealed that near half of thalassemia patients suffer from growth impairments. However, regular evaluation of serum ferritin levels, close monitoring in a proper institute, suitable and acceptable treatment methods besides regular chelation therapy could significantly reduce the patients' complications.

The worldwide molecular spectrum and distribution of thalassaemia: a systematic review

CONTEXT

Thalassaemia is one of the most common inherited autosomal recessive disorders around the world. A considerable amount of literature has been published about the type of mutations and the prevalence of thalassaemia, but findings are often contradictory.

OBJECTIVE

This systematic review aimed to provide a comprehensive view of the prevalence of thalassaemia-associated mutations in different countries, their effect on haemoglobin (Hb) levels, as well as reporting thalassaemia-associated rare mutations.

METHODS

A systematic search of the literature was carried out through major indexing databases (MEDLINE/PubMed, Scopus, EMBASE, Cochrane central, and ISI web of science) using keywords: "Co-inheritance, αα, β, thalassaemia" and "α-β thalassaemia, Mediterranean anemia, mutations" from 1998-September 2019. Hand-searching was also performed. There was no language restriction.

RESULTS

The initial searches yielded 1059 studies, of which 92 articles were included following inclusion and exclusion criteria. Of these, 3.3% (3) of articles were cohort studies, and 96.7% (89) of the remaining articles were cross-sectional studies. Our findings showed that 45.6% (42) of researchers investigated β-thalassaemia, 22.9% (21) αα-β thalassaemia, and 31.5% (29) α thalassaemia.

CONCLUSION

The present study provides valuable information about the spectrum of thalassaemia-associated mutations, which can be useful for preventing thalassaemia, reducing costs of care, reducing the treatment-related side effects, and showing the most defective mutations.HighlightEvaluating the increase or decrease in the birth prevalence of thalassaemiaIdentifying the most common and rare mutations in various parts of the worldComparing researchers' findings from various parts of the world.

Elevated Prevalence of Abnormal Glucose Metabolism and Other Endocrine Disorders in Patients with β-Thalassemia Major: A Meta-Analysis

Background

Endocrinopathies are common in patients with β-thalassemia major despite parenteral iron chelation therapy with deferoxamine. Prevalence of abnormal glucose metabolism in previous studies was controversial. The aim of this study was to discuss the prevalence of abnormal glucose metabolism in β-thalassemia major based on a meta-analysis.

Methods

PubMed, ScienceDirect, Springerlink, Ovid, Web of Science, MEDLINE, Wanfang database, and Chinese National Knowledge Internet were searched for relevant articles. Two authors selected the articles according to the inclusion criteria and then extracted the data. The prevalence of diabetes mellitus (DM) in β-thalassemia major was defined as the primary outcome. The prevalence with the 95% confidence interval (95%CI) was used to evaluate the proportion of abnormal glucose metabolism and other endocrine disorders in patients with β-thalassemia major. Subgroup analyses were applied to explore the prevalence in different regions. Sensitivity analysis and publication bias assessment were also conducted.

Results

A total of 44 studies with 16605 cases were included in this analysis. Diabetes mellitus was present in 6.54% (95% CI: 5.30%-7.78%). The fixed subgroup study revealed that the region with the highest prevalence was the Middle East (prevalence= 7.90%, 95% CI: 5.75%-10.05%). The accumulated meta-analysis revealed that the prevalence of DM in β-thalassemia major was relatively steady in each year. The prevalence of impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and other endocrine disorders in β-thalassemia major was 17.21% (95% CI: 8.43%-26.00%), 12.46% (95% CI: 5.98%-18.94%), and 43.92% (95% CI: 37.94%-49.89%), respectively. Sensitivity analysis showed that the pooled results were robust; publication bias assessment revealed that there was no significant evidence that the pooled results were influenced by publication bias.

Conclusion

High prevalence of endocrine disorders involving abnormal glucose metabolism was detected in β-thalassemia major. Treatment and prevention measurements may be necessary to prevent growth and endocrine problems.

β-Thalassemia and ocular implications: a systematic review

Background

Beta-thalassemia is a severe genetic blood disorder caused by a mutation in the gene encoding for the beta chains of hemoglobin. Individuals with beta-thalassemia major require regular lifelong Red Blood Cell transfusions to survive. Ocular involvement is quite common and may have serious implications.

Methods

Extensive review of observational studies on beta-thalassemia, to determine the prevalence and spectrum of ocular abnormalities, by clinical examination and multimodal imaging, and to investigate risk factors for their development.

Results

Frequency of ocular involvement differs among various studies (41.3–85 %, three studies). Ocular findings in beta-thalassemia may correlate to the disease itself, iron overload or the chelating agents used. Beta-thalassemia ocular manifestations include ocular surface disease, as demonstrated by tear function parameters (two studies). Lens opacities are present in 9.3–44 % (five studies). Lenticular opacities and RPE degeneration correlated positively with use of desferrioxamine and deferriprone respectively (two studies). Ocular fundus abnormalities characteristic of pseudoxanthoma elasticum (PXE), including peau d’orange, angioid streaks, pattern dystrophy-like changes, and optic disc drusen are a consistent finding in seven studies. Patients with PXE-like fundus changes were older than patients without these fundus changes (two studies). Age (two studies) and splenectomy (one study) had the strongest association with presence of PXE-like fundus changes. Increased retinal vascular tortuosity independently of the PXE-like fundus changes was found in 11–17.9 % (three studies), which was associated with aspartate amino transferase, hemoglobin and ferritin levels (two studies). Fundus autofluorescence and electrophysiological testing (ERG and EOG) may indicate initial stages or more widespread injury than is suggested by fundus examination (two studies).

Conclusions

Beta-thalassemia may present with various signs, both structural and functional. Pseudoxanthoma elasticum like fundus changes are a frequent finding in patients with b-thalassemia. These changes increase with duration or severity of the disease. Retinal vascular tortuosity may be an additional disease manifestation related to the severity and duration of anemia and independent of the PXE-like syndrome. Patients with long-standing disease need regular ophthalmic checkups because they are at risk of developing PXE-like fundus changes and potentially of subsequent choroidal neovascularization.

Impact of genotype on endocrinal complications in β-thalassemia patients

In β-thalassemia, certain mutations cause a complete absence of β-globin chain synthesis, termed β⁰-thalassemia, while others may allow certain β-globin production and are termed β⁺- or β⁺⁺-thalassemia. The homozygous state results in severe anemia, which requires regular blood transfusion. By contrast, frequent blood transfusion can in turn lead to iron overload, which may result in several endocrinal complications. The present study aimed to investigate the impact of genotype on the development of endocrine complications in β-thalassemia patients. A cross-sectional study was conducted on 100 thalassemia patients >10 years. A data abstraction form was designed to capture the appropriate information from the individual medical records, including full clinical, laboratory, transfusion and chelation data. The genotype of the patients was identified by the DNA sequencing technique. Growth retardation and hypogonadism were the most prominent endocrinal complications (70 and 67%, respectively) followed by hypothyroidism, diabetes mellitus and hypoparathyrodism (8, 8 and 7%, respectively). The most common mutations identified were IVS-1-110, IVS-1-1 and IVS-1-6 (63, 47 and 41%, respectively). Patients with the β⁰β⁰ genotype had a significantly higher prevalence of growth retardation, hypogonadism, hypothyroidism and hypoparathyrodism compared to those with the β⁰β⁺ and β⁺β⁺ genotypes (P<0.001, P<0.001, P<0.001 and P=0.037, respectively). Patients with the homozygous IVS-11-745 mutation had a significantly higher prevalence of diabetes (P=0.001). The underlying genetic defect in thalassemia patients is a contributing factor for the development of endocrinal complications, as patients with the more severe defects have a greater rate of iron loading through higher red cell consumption.

Assessment and management of iron overload in β-thalassaemia major patients during the 21st century: a real-life experience from the Italian WEBTHAL project

We conducted a cross-sectional study on 924 β-thalassaemia major patients (mean age 30·1 years) treated at nine Italian centres using the WEBTHAL software, to evaluate real-life application of iron overload assessment and management standards. Serum ferritin <2500 ng/ml was a risk factor for never having liver iron concentration (LIC) measurement, while absence of cardiac disease and siderosis were risk factors for a delay in LIC measurement >2 years. Patients who never had a cardiac MRI (CMR) T2* measurement were <18 years, had iron intake ≤0·4 mg/kg per day, or a serum ferritin <2500 ng/ml. A history of normal CMR T2* was the main risk factor for a delay in subsequent assessment of >2 years. Deferoxamine (22·8%) was more commonly used in patients with Hepatitis C Virus or high serum creatinine. Deferiprone (20·6%) was less commonly prescribed in patients with elevated alanine aminotransferase; while a deferoxamine + deferiprone combination (17·9%) was more commonly used in patients with serum ferritin >2500 ng/ml or CMR T2* <20 ms. Deferasirox (38·3%) was more commonly prescribed in patients <18 years, but less commonly used in those with heart disease or high iron intake. These observations largely echoed guidelines at the time, although some practices are expected to change in light of evolving evidence.

Cross-talk between available guidelines for the management of patients with beta-thalassemia major

Efforts to optimize the management of patients with β-thalassemia major (TM) continue to expand. Evidence from biomedical research evaluating safe and careful processing measures of blood products, the efficacy and safety of oral iron chelators, and noninvasive techniques for the assessment of iron overload are translated into better patient outcomes. The construction of TM management guidelines facilitated the incorporation of such evidence into practice. However, as several aspects of the management of TM remain controversial or governed by resource availability, a concern regarding potential variations in recommendations made by the different guidelines becomes rational, especially for physicians treating TM patients outside countries where the guidelines were constructed. In this work, we overview currently available guidelines for the management of TM and explore apparent similarities and differences between them. The evaluated guidelines included the Thalassaemia International Federation, US, Canadian, UK, Italian and Australian guidelines. We noted a general consensus for most aspects of management, although some guidelines provided more comprehensive and contemporary recommendations than others. We did not identify differences warranting concern, although minor differences in iron overload assessment strategy and more notable variations in the recommendations for iron chelation therapy were observed.

Nineteen years study of beta-thalassaemia in Slovakia

BACKGROUND

Beta-thalassaemia is a congenital disorder caused by point mutations in a haemoglobin beta-globin chain. The heterozygous form produces microcytosis and normal iron levels, however, haemoglobin electrophoresis shows elevated amounts of haemoglobin A2 and eventually foetal haemoglobin F as well.

METHODS

Between 2005-2011, in three centres in Slovakia, carriers of beta-thalassaemic genes or other haemoglobinopathies were searched for. Diagnosis was performed by haematologists whereby the family history was evaluated, together with the overall clinical condition, blood count and blood smear, iron parameters, haemolysis and haemoglobin electrophoresis testing. A proportion of patients was examined by molecular genetic methods.

RESULTS

A clinical suspicion of the heterozygous form of beta-thalassaemia was documented in 402 patients (21.9%) out of a total of 1,834 examinations. From these patients, 87 underwent molecular genetic testing and mutations of beta globin genes were identified in 70 of them, where the most frequent mutations were IVS 2.1 (28.5%), IVS 1.110 (25.6%) and IVS 1.1 (11.3%). Evidence of haemoglobin S (sickle cell anaemia) was also notable in one case (patient of African origin). Unusually high levels of haemoglobin F (6-21%) were found in 23 adult subjects.

CONCLUSION

The study showed that there is a higher number of heterozygotes for beta-thalassaemia and rarely haemoglobinopathies. It is necessary to continue in search of pathological gene carriers in Slovakia.

Thyroid function status and echocardiographic abnormalities in patients with Beta thalassemia major in bahrain

Background:

Thyroid gland dysfunction and echocardiographic cardiac abnormalities are well-documented in patients with transfusion dependent beta-thalassemia major (β-TM).

Aim:

This cross-sectional analytic study was conducted to investigate left ventricle (LV) diastolic and systolic function using pulsed Doppler (PD) and tissue Doppler (TD) echocardiography and correlate that with serum level thyroid stimulating hormone in patients with β-TM.

Methods:

The study was conducted on patients with β-TM (n = 110, age 15.9 ± 8.9 years) and compared with a control group (n = 109, age 15.8 ± 8.9 years). In all participants, echocardiographic indices of PD and TD were performed and blood samples were withdrawn for measuring the serum level of TSH, free T4, and ferritin. A linear regression analysis was performed on TSH level as the dependent variable and serum ferritin as independent. Stepwise multiple regression analysis was used to determine the odds ratio of different biochemical and echo variables on the risk of developing hypothyroidism.

Results:

Patients with β-TM compared with controls had thicker LV septal wall index (0.65 ± 0.26 vs. 0.44 ± 0.21 cm/M², P < 0.001), posterior wall index (0.65 ± 0.23 vs. 0.43 ± 0.21 cm/m², P < 0.01) and larger LVEDD index (4.35 ± 0.69 vs.3.88 ± 0.153 mm/m², P < 0.001). In addition, β-TM patients had higher transmitral E wave velocity (E) (70.81 ± 10.13 vs. 57.53 ± 10.13 cm/s, P = 0.02) and E/A ratio (1.54 ± 0.18 vs. 1.23 ± 0.17, P < 0.01) and shorter deceleration time (DT) (170.53 ± 13.3 vs. 210.50 ± 19.20 m sec, P < 0.01). Furthermore, the ratio of transmitral E wave velocity to the tissue Doppler E wave at the basal septal mitral annulus (E/Em) was significantly higher in the β-TM group (19.68 ± 2.81 vs. 13.86 ± 1.41, P < 0.05). The tissue Doppler systolic wave (Sm) velocity and the early diastolic wave (Em) were significantly lower in the β-TM group compared with controls with Sm, 4.82 ± 1.2 vs. 6.22 ± 2.1 mm/sec, P < 0.05 and (Em), 3.51 ± 2.7 vs. 4.12 ± 2.5 mm/sec. P < 0.05, respectively). The tricuspid valve velocity was significantly higher in β-TM patients compared with controls 2.85 ± 0.56 vs. 1.743 ± 0.47 m sec, respectively, P < 0.01). The prevalence of subclinical hypothyroidism in patients with β-TM was 15.4%, with significantly higher mean serum TSH compared with controls (6.78 ± 1.5 vs. 3.10 ± 1.02 μIU/mL, P < 0.01) and positively correlated with the serum ferritin level (r = 0.34, P = 0.014). On multiple regression analysis, the LV mass, LVEF%, and E/A ratio were not positive predictors of hypothyroidism in patients with β-TM.

Conclusion:

We conclude that patients with β-TM had a high prevalence of subclinical hypothyroidism of 15.4%. Thyroid stimulating hormone was significantly high and positively correlated with the serum ferritin level. Echo cardiographic pulsed Doppler showed a restrictive LV diastolic pattern suggestive of severe diastolic dysfunction with preserved left ventricle systolic function.

Compliance of deferoxamine injection in beta-thalassaemia major patients in Iran

AIM/OBJECTIVE

Iran is located on the Mediterranean belt and has high prevalence of thalassaemia. Deferoxamine therapy requires burdensome hours of daily infusion several times a week.

METHODS

We studied 510 thalassaemia major patients referring to thalassaemia tertiary care centre for compliance of deferoxamine and also assessed various reasons for non-compliance. A questionnaire was developed.

RESULTS

Our study showed that 418 (82%) subjects were adherent to deferoxamine therapy. Females were more adherent to the chelation therapy. Among patients whose age was ≤ 12 years, 90.4% showed drug compliance compared with 80.3% in patients aged >12 years (P = 0.03). The most frequently reported reason for poor compliance was pain (38%).

CONCLUSION

High percentage of patients had adherence to iron chelation, which is in contrast to previous studies. This may be attributed to the vigorous efforts of governmental and non-governmental organisations in educating patients and provision of free drug and equipment in the past few years. The results were satisfying but still more is to be done to increase drug adherence and to minimise reasons causing poor compliance.

Hemoglobinopathies: clinical manifestations, diagnosis, and treatment

BACKGROUND

Hemoglobinopathies are among the most common inherited diseases around the world. They have become much more common recently in northern and central Europe, including Germany, due to immigration.

METHOD

Selective review of the literature with consideration of national guidelines.

RESULTS

The hemoglobinopathies encompass all genetic diseases of hemoglobin. They fall into two main groups: thalassemia syndromes and structural hemoglobin variants (abnormal hemoglobins). α- and β-thalassemia are the main types of thalassemia; the main structural hemoglobin variants are HbS, HbE and HbC. There are many subtypes and combined types in each group. The highly variable clinical manifestations of the hemoglobinopathies range from mild hypochromic anemia to moderate hematological disease to severe, lifelong, transfusion-dependent anemia with multiorgan involvement. Stem-cell transplantation is the preferred treatment for the severe forms of thalassemia. Supportive, rather than curative, treatment consists of periodic blood transfusions for life, combined with iron chelation. Drugs to treat the symptoms of sickle-cell disease include analgesics, antibiotics, ACE inhibitors and hydroxyurea. Blood transfusions should be given only when strictly indicated. More than 90% of patients currently survive into adulthood. Optimally treated patients have a projected life span of 50 to 60 years.

CONCLUSION

Hemoglobinopathies are a public health issue in today's multiethnic German population. Adequate care of the affected patients requires a wide variety of diagnostic and therapeutic measures.

Hemoglobinopathies: a longitudinal study over four decades

BACKGROUND

Hemoglobinopathies are among the most common hereditary diseases worldwide, with high prevalence in the Mediterranean basin, Africa, and Asia. Although they are rare in the indigenous central European population, they have become much more common in Germany recently through the immigration of millions of people from endemic regions.

METHODS

In a long-term study (1971-2007), 100,621 hemoglobin analyses were performed and retrospectively evaluated. Basic clinical and hematological information were provided by the participating physicians. The hemoglobin defects were characterized with hematological and biochemical methods, as well as by DNA analysis in selected cases (from the mid-1980's onward). 73% of the analyses were performed in patients with an immigration background, 27% in patients of German ethnic origin.

RESULTS

34,228 persons, or 34% of those studied, were found to have a hemoglobinopathy. Most cases involved thalassemia syndromes (25,798 cases, 25.6%); the second most common type was a structural abnormality of hemoglobin (8,430 cases, 8.4%). This study provides the first broad overview of the occurrence, spectrum, and geographical distribution of hemoglobinopathies in Germany.

CONCLUSIONS

These data show that hemoglobinopathies are a relevant health problem in the population of Germany today. This is not an epidemiological study, and thus it is unknown to what extent these data are representative. Because hemoglobin defects are of widely diverse genetic and clinical types, specialized laboratory analysis is needed to diagnose them correctly and provide a basis for proper therapeutic decisions.

Complications and treatment of patients with β-thalassemia in France: results of the National Registry

BACKGROUND

beta-thalassemia is a rare disease in France, encountered mainly in patients originating from Italy and North Africa. In the setting of the recent French plan for rare diseases, a National Registry for thalassemia has been developed since 2005. Epidemiological and clinical data have been collected on living patients with beta-thalassemia major or intermedia, including those who underwent hematopoietic stem cell transplantation.

DESIGN AND METHODS

A standardized questionnaire was sent to clinicians throughout the national professional networks involved in the management of thalassemic patients and data were updated every 18 months. A cross-sectional study was performed in February 2009.

RESULTS

Data on 378 patients (267 with thalassemia major) with a median age of 20 were recorded. Hematopoietic stem cell transplantation was performed in 52 patients. Stature, rates of parenthood, splenectomy, and cholecystectomy were no different between non-transplanted thalassemia major and thalassemia intermedia patients, after adjustment for age. Among the 215 non-transplanted thalassemia major patients, the median serum ferritin level was 1240 ng/mL and the rates of iron-related complications were 10%, 6%, 10% and 48% for cardiac failure, diabetes, hypothyroidism, and hypogonadism, respectively. From 2005 to 2008, a dramatic switch in chelation treatment, from deferoxamine to deferasirox, was observed.

CONCLUSIONS

The rates of complications of iron overload in French thalassemia major patients appeared similar to those reported in other developed countries in which this condition is not endemic. There were no significant differences in height and parenthood rates between patients with the major and the intermedia forms of the disease, underlining the progress in clinical care. Future developments will focus on mortality and morbidity under oral chelation treatment.

Prevalence of impaired glucose metabolism in beta-thalassemic children receiving hypertransfusions with a suboptimal dosage of iron-chelating therapy

A cross-sectional study of impaired glucose metabolism was carried out in 48 beta-thalassemic patients receiving hypertransfusions. An oral glucose tolerance test (OGTT) was performed using the method and criteria of the American Diabetes Association (ADA). Diabetes mellitus was diagnosed in two patients, and impaired glucose tolerance was found in four patients, giving a prevalence of impaired glucose metabolism of 12.5% in our patient population. The significant clinical characteristics associated with the diagnosis of impaired glucose metabolism were wasting (-2.15/-0.86 SDS, p = 0.025), stunting (-2.69/-1.22 SDS, p = 0.03), higher ferritin levels (8679/4710 microg/L, p = 0.005), splenectomy (50/9.5%, p = 0.012), and lower area under curve (AUC) of insulin secretion after OGTT (40.0/77.7, p = 0.002). The significant decrease of AUC insulin in thalassemic patients with an impaired glucose tolerance test suggests that the pathogenesis may originate from pancreatic beta-cell damage rather than from insulin resistance. In conclusion, the prevalence of impaired glucose tolerance in our population of thalassemic patients receiving hypertransfusions with suboptimal iron chelating therapy was 12.5%. The clinical characteristics of thalassemic patients who developed impaired glucose tolerance were wasting, stunting, higher ferritin levels, splenectomy, and lower AUC insulin.

Epidemiology of haemoglobin disorders in Europe: an overview

OBJECTIVE

As a result of global population movements, haemoglobin disorders (thalassaemias and sickle cell disorders) are increasingly common in the formerly non-indigenous countries of Northern and Western Europe and in the indigenous countries of Southern Europe. This article presents an overview of the changing picture and a method for assessing service needs.

METHOD

Data on country of birth or ethnic origin of residents are adjusted to obtain the estimated proportions of residents and births in non-indigenous groups at risk for haemoglobin disorders in European countries. The results are combined with prevalence data in each country of origin to obtain country prevalence estimates. Service indicators (annual tests or other interventions required to ensure equitable delivery of treatment and prevention) are then derived by country.

RESULTS

Haemoglobin disorders now occur at comparable frequency throughout Northern, Western and Southern Europe. Annually, there are more affected conceptions in Northern and Western than in Southern Europe, and sickle cell disorders are more common than thalassaemias. There is growing need for health policy-makers to support motivated professionals working to develop optimal patient care, carrier diagnosis, genetic counselling and access to prenatal diagnosis throughout the Region.

CONCLUSION

There is a strong case for pan-European collaboration on haemoglobin disorders to share policies, standards and the instruments required to support them. These include methods for needs assessment, service standards, education and information strategies and materials, and methods for evaluating service delivery.

Disproportionately elevated fasting proinsulin levels in normoglycemic patients with thalassemia major are correlated to the degree of iron overload

OBJECTIVE

To analyze the secretion of the insulin precursor proinsulin in patients with beta-thalassemia and its possible relation to iron overload.

METHODS

We assessed fasting proinsulin, insulin, C-peptide and glucose levels from 34 patients with beta-thalassemia and 33 healthy controls. The correlation to age, body mass index, hepatic iron concentration, serum ferritin and serum AST was analyzed.

RESULTS

Fasting proinsulin (p < 0.002) and proinsulin-to-insulin ratio (p < 0.02) were significantly increased in patients with thalassemia irrespective of the degree of glucose tolerance. They correlated positively to serum ferritin, liver iron, patient age and serum AST (all p < 0.05).

CONCLUSIONS

Disproportionately elevated proinsulin levels in thalassemic patients indicate early beta-cell dysfunction due to siderosis. An additional biological significance of hyperproinsulinemia and its possible ability to predict long-term iron toxicity in these patients remain to be clarified.

Insulin sensitivity and beta-cell secretion in thalassaemia major with secondary haemochromatosis: assessment by oral glucose tolerance test

Diabetes mellitus in patients with thalassaemia major is caused by secondary haemochromatosis due to transfusional iron overload. The pathogenetic mechanisms leading from siderosis to diabetes are still poorly understood. This study aimed at assessing the influence of insulin resistance and insulin deficiency on that process. Glucose, insulin and C-peptide levels during oral glucose tolerance tests (OGTT) from 36 thalassaemic patients with normal ( n=23), impaired ( n=6), or diabetic glucose tolerance ( n=7) and 32 control subjects were examined. Insulin secretion and insulin sensitivity were assessed by established calculated indices. Fasting, 2h and integrated glucose concentration were significantly increased in thalassaemic patients with normal glucose tolerance compared to controls (5.01/4.59 mmol/l, 6.33/5.17 mmol/l, and 844.2/739.3 mmol/l per min, respectively; all P<0.03). Patients with impaired glucose tolerance presented hyperinsulinaemia and delayed peak insulin during OGTT. The C-peptide/insulin ratio was decreased in patients with abnormal glucose tolerance compared to controls (5.85/7.33 x 10(3)pmol/l per min, P<0.03). It was negatively correlated with age in patients ( r=-0.45, P<0.01), but positively in controls ( r=0.43, P<0.03). Insulin sensitivity was significantly reduced in patients with impaired glucose tolerance or diabetes compared to controls. In addition, a significant decrease in patients with normal glucose tolerance was shown by two insulin sensitivity indices (all P<0.05). In thalassaemia patients, insulin sensitivity was negatively correlated with age. Insulin secretion capacity according to the homeostasis assessment model was significantly reduced in patient groups compared to controls (Kruskal-Wallis-test, P<0.004).

CONCLUSION

Insulin resistance is of central importance for the development of diabetes mellitus in patients with secondary haemochromatosis. An additional early defect in beta-cell secretion cannot be excluded.

Orally active iron chelators

In patients with transfusion-dependent anemias, iron accumulation is fatal in the absence of chelating therapy. Extended survival, free of most complications of iron overload is observed in patients treated with early, adequate parenteral deferoxamine. Despite its success in prevention and treatment of iron toxicity, the expense and inconvenience of this therapy have stimulated a continued quest for an effective chelating agent that is orally active. Unfortunately, studies emerging over the last five years have confirmed that the most widely administered orally active agent, deferiprone (L1; 1,2-dimethyl-3-hydropyrid-4-one) may be harmfully ineffective in many patients: 18-65% of patients in six studies which obtained hepatic irons after long term deferiprone treatment had body iron exceeding the threshold for cardiac disease and premature death. The impact of deferiprone on cardiac and liver disease must be evaluated further, while the association between deferiprone and accelerated hepatic fibrosis still awaits refutation in large prospective trials. In view of the striking therapeutic successes of deferoxamine over the past 20 years, administration of deferiprone outside the setting of prospective clinical trials may need to be reconsidered. Meanwhile, an orally active iron chelator of demonstrated safety and effectiveness remains an objective for development for transfused patients.