Endocrinopathies in patients with transfusion-dependent beta-thalassemia

β-Thalassemia and Diabetes Mellitus: Current State and Future Directions

β-Thalassemia major is a congenital hemoglobin disorder that requires regular blood transfusion. The disease is often associated with iron overload and diabetes mellitus, among other complications. Pancreatic iron overload in β-thalassemia patients disrupts β-cell function and insulin secretion and induces insulin resistance. Several risk factors, including family history of diabetes, sedentary lifestyle, obesity, gender, and advanced age increase the risk of diabetes in β-thalassemia patients. Precautionary measures such as blood glucose monitoring, anti-diabetic medications, and healthy living in β-thalassemia patients notwithstanding, the prevalence of diabetes in β-thalassemia patients continues to rise. This review aims to address the relationship between β-thalassemia and diabetes in an attempt to understand how the pathology and management of β-thalassemia precipitate diabetes mellitus. The possible employment of surrogate biomarkers for early prediction and intervention is discussed. More work is still needed to better understand the molecular mechanism(s) underlying the link between β-thalassemia and diabetes and to identify novel prognostic and therapeutic targets.

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.

Diabetes Mellitus in Thalassaemia Major Patients: A Report from the Southeast of Iran

INTRODUCTION

Diabetes Mellitus (DM) represents a major concern in Thalassaemia Major (TM) patients.

AIM

The present study was conducted to evaluate the frequency of Impaired Fasting Glucose (IFG) and DM in TM patients in Southeast of Iran.

MATERIALS AND METHODS

Fasting Blood Glucose (FBS) was determined using fasting blood samples in 148 TM patients. Demographical data was collected by a questionnaire. Clinical and laboratory variables including cell blood counts, pre-transfusion Haemoglobin (Hb) level, and five-year ferritin were extracted from medical records. Statistical analysis was performed in SPSS19.0 software using chi-square, student t-test and logistic regression.

RESULTS

Females and males comprised 83 (56.1%) and 65 (43.9%) subjects respectively. The mean age and mean five-year ferritin were 17.3±6.1 year-old and 5060.6±2395 ng/ml respectively. Overall, 39 (26.4%) patients had IFG, while 13 (8.8%) were diagnosed with DM. Significant differences were identified in the mean age, volume of transfused blood per occasion, and mean five-years ferritin between the patients with IFG or DM and the patients with normal fasting glucose level. Patients with age >25-year-old had an increased risk of both IFG (OR=4.7,95% CI: 1.3-17, p=0.01) and DM (OR= 7.1, 95% CI: 1-49.2, p=0.04). In addition, splenectomized patients showed a higher risk for IFG (OR=4.3, 95% CI: 1.5-12.1, p=0.005), and ferritin value >6000 ng/ml were associated with an elevated risk of DM (OR=7, 95% CI: 0.8-60.1, p=0.07).

CONCLUSION

Our results indicated that higher age, mean five-years ferritin, volume of blood transfused per occasion, as well as splenectomy were risk factors of IFG and DM in TM patients.

Endocrine and bone complications in β-thalassemia intermedia: current understanding and treatment

Thalassemia intermedia (TI), also known as nontransfusion dependent thalassemia (NTDT), is a type of thalassemia where affected patients do not require lifelong regular transfusions for survival but may require occasional or even frequent transfusions in certain clinical settings and for defined periods of time. NTDT encompasses three distinct clinical forms: β-thalassemia intermedia (β-TI), Hb E/β-thalassemia, and α-thalassemia intermedia (Hb H disease). Over the past decade, our understanding of the molecular features, pathophysiology, and complications of NTDT particularly β-TI has increased tremendously but data on optimal treatment of disease and its various complications are still lacking. In this paper, we shall review a group of commonly encountered complications in β-TI, mainly endocrine and bone complications.

The Frequency of Adrenal Insufficiency in Adolescents and Young Adults with Thalassemia Major versus Thalassemia Intermedia in Iran

BACKGROUND

Endocrine dysfunction is not uncommon complication in patients with transfusion-dependent thalassemia and is thought to occur as a consequence of excessive iron overload. The primary objective of this study is to determine the frequency of adrenal insufficiency in patients with thalassemia major and thalassemia intermediate.

METHODS

This cross-sectional study was done at the Shiraz University of Medical Sciences, Shiraz, Southern Iran, in 2013. One hundred and ninety patients were divided into two groups; thalassemia major(TM) and thalassemia intermediate (TI) groups. We measured 8 AM serum cortisol, ACTH and ferritin concentrations in all patients.

RESULTS

The mean age of the TM and TI group were 22.5±5.7 and 23.8±6 years, respectively. 90 patients (47.4%) were splenectomized, 34 (36.2%) with TM and 56 (58.2%) with TI (p :<0.001). The median and interquartile range of serum ferritin levels were 2184±3700 ng/ml and 437±443ng/ml in TM and TI respectively (p< 0.001). Three patients with TM (1.6%) had low basal cortisol and ACTH levels. However, their cortisol response to ACTH stimulation was normal.

CONCLUSIONS

Low basal concentrations of cortisol and ACTH occurred in 1.6% of our adolescents young adult patients with TM suggesting a central defect in cortisol secretion at the basal state. However, cortisol response to standard - dose ACTH was normal in all patients with TM and TI.

Study of thyroid function in Egyptian children with β-thalassemia major and β-thalassemia intermedia

BACKGROUND

Thyroid dysfunction is a known complication of transfusion-dependent β-thalassemia. However, information on its frequency and risk factors among Egyptian Children is still unclear.

OBJECTIVE

We aimed to determine the frequency of functional thyroid abnormalities among young patients with β-thalassemia and compare the thyroid function status among patients with β-thalassemia major (TM) and β-thalassemia intermedia (TI).

MATERIALS AND METHODS

This was a cross-sectional study that included 52 β-thalassemia children [27 boys and 25 girls; 34 (65.4%) with TM and 18 (34.6%) with TI]. Their mean age was 16.0±1.91 (range: 12-18) years. Thyroid function and iron load status were assessed by measurement of free tetraiodothyronine, free triiodothyronine, thyroid stimulating hormone (TSH), and serum ferritin concentrations.

RESULTS

Serum TSH of the studied cases ranged from 0.28 to 25 μIU/ml with a mean of 4.5±4.8 μIU/ml. None of the studied cases had overt primary hypothyroidism and the frequency of subclinical hypothyroidism was 19.2%. No risk factors for thyroid dysfunction could be identified among our cases. The thyroid profile was comparable in TM and TI patients (P>0.05) and the frequency of subclinical hypothyroidism among TM cases was 20.6% and it was comparable to the 16.7% found among TI patients (P>0.05). No correlations were found between TSH, serum ferritin, chelation therapy, and frequency of blood transfusion.

CONCLUSION AND RECOMMENDATIONS

Both TM and TI patients are at risk for subclinical thyroid failure regardless of their iron overload status. Early evaluation of thyroid function in β-thalassemia children and thyroid replacement therapy for subclinical hypothyroidism should be introduced in the treatment protocols.

Cortisol response to low dose versus standard dose (back-to-back) adrenocorticotrophic stimulation tests in children and young adults with thalassemia major

BACKGROUND

Thalassemia major patients with repeated blood transfusion have high prevalence of endocrinopathies due to iron overload.

MATERIALS AND METHODS

We examined the adrenocortical function in 23 thalassemic patients (10 children and 13 young adults) aged 8-26 years. Serum cortisol and dehydroepiandrosterone sulfate (DHEA-S) concentrations were determined in each subject before blood transfusion both in basal condition and after low dose (LD) (1 μg), followed by standard dose (SD) (250 μg, respectively) with synthetic corticotrophin beta 1-24 ACTH (Synacthen, Ciba). Normal controls were a group of 13 age- and sex-matched normal subjects.

RESULTS

Using a peak total cortisol cutoff level of 550 nmol/L and increments of 200 μg above basal cortisol, adrenal insufficiency (AI) was demonstrated in 8 patients (34.7%) after the LD ACTH and in 2 patients (8.7%) after SD cosyntropin (ACTH) test, but none of the controls. Using a peak total cortisol cutoff level of 420 nmol/L and increments of 200 μg above basal cortisol, AI was demonstrated in 5 patients (21.7%) after the LD ACTH and in 2 patients after SD ACTH test (8.7%), but none of controls. All patients with biochemical AI were asymptomatic with normal serum sodium and potassium concentrations and had no history suggestive of adrenal pathology. The peak cortisol concentrations in thalassemic patients with impaired adrenal function both after 1 μg and 250 μg cosyntropin (294 ± 51 nmol/L and 307 ± 58.6) were significantly lower than those with patients with normal (454 ± 79.7 nmol/L and 546.1 ± 92.2 nmol/L, respectively) and controls (460.2 ± 133.4 nmol/L and 554.3 ± 165.8 nmol/L, respectively). Adolescents and young adults, but not children with thalassaemia, had significantly lower peak cortisol concentration after SD ACTH versus controls. Peak cortisol response to LD ACTH was correlated significantly with peak cortisol response to SD in all patients (r = 0.83, P < 0.0001). In adolescents and young adults with thalassemia, DHEA-S levels before and after LD ACTH stimulation were significantly lower and the cortisol/DHEA-S ratios were significantly higher than the controls.

CONCLUSION

The use of LD ACTH test diagnoses more adrenal abnormalities versus SD ACTH in thalassemic patients. The relatively high prevalence of AI in thalassemic adolescents and young adults necessitates that these patients have to be investigated for AI before major surgery and those with impaired cortisol secretion should receive stress doses of corticosteroids during the stressful event.

Increased oxidative stress and iron overload in Jordanian β-thalassemic children

β-Thalassemia (β-thal) is associated with abnormal synthesis of hemoglobin (Hb). Repeated blood transfusions in patients with β-thal major (β-TM) leads to an enhanced generation of reactive oxygen species (ROS), and subjects patients to peroxidative injury. We studied the antioxidant status and oxidative damage to children with β-thal in Jordan. Samples from 40 children with β-thal and 40 healthy controls were used. All children were under 13 years of age. Our results showed that plasma thiobarbituric acid reactive substances (TBARS) were elevated in β-thalassemic children compared to controls together with compensatory increase in superoxide dismutase (SOD) activity and decrease in catalase (CAT) activity. Elevated serum ferritin showed positive correlation with elevated liver enzyme levels except gamma glutamyl transferase (GGT), confirming liver involvement due to iron overload. Serum ferritin also showed a positive correlation with elevated TBARS and SOD, suggesting that iron overload is involved in the oxidative stress shown in cells.

Causes for hospitalization and death in Iranian patients with β-thalassemia major

There are limited studies that have focused on the causes for hospitalization as an indicator of morbidity in patients with β-thalassemia major (BTM). A cross-sectional study was conducted to determine the main causes for hospitalization and death in hospitalized BTM patients in a referral hospital in Shiraz, southern Iran. During a 5-year period, 555 BTM patients were admitted to the hospital, of which 390 (67.7%) were 10 to 20 years of age. The most frequent causes for hospitalization were splenectomy (23%), heart failure (22.6%), liver biopsy (22.2%), uncontrolled diabetes (10.9%), arrhythmia (7.2%), cholecystectomy (3.8%), hypoparathyroidism (2.1%), and sepsis (2%). Of the hospitalized patients, 65 (11%), with a mean age of 16.1 ± 4.2 years, died. The most common causes of death were cardiomyopathy (72.3%), infections (17%), malignancies (3.1%), and cerebrovascular accidents (3.1%). Survival of our patients was less than in developed countries and cardiac complications were the most common cause of mortality and morbidity in these patients. Regarding the key role of iron chelation in prevention of different complications in BTM, correction of iron chelation regimen should be well considered.