The contribution of hypogonadism to the development of osteoporosis in thalassaemia major: new therapeutic approaches

Bone Health Impairment in Patients with Hemoglobinopathies: From Biological Bases to New Possible Therapeutic Strategies

Hemoglobinopathies are monogenic disorders affecting hemoglobin synthesis. Thalassemia and sickle cell disease (SCD) are considered the two major hemoglobinopathies. Thalassemia is a genetic disorder and one of the major hemoglobinopathies determined by an impairment of globin chain production, which causes an alteration of erythropoiesis, an improvement in hemolysis, and an alteration of iron homoeostasis. In SCD, the mutations are on the β-globin chain of hemoglobin which results in a substitution of glutamic acid by valine with consequent formation of Hemoglobin S (HbS). Several factors are involved in bone metabolism alteration in patients with hemoglobinopathies, among them hormonal deficiency, bone marrow hyperplasia, iron overload, inflammation, and increased bone turnover. Bone metabolism is the result of balance maintenance between bone deposition and bone resorption, by osteoblasts (OBs) and osteoclasts (OCs). An impairment of this balance is responsible for the onset of bone diseases, such as osteoporosis (OP). Therefore, here we will discuss the alteration of bone metabolism in patients with hemoglobinopathies and the possible therapeutic strategies to contain and/or counteract bone health impairment in these patients, taking into consideration not only the pharmacological treatments already used in the clinical armamentarium, but also the new possible therapeutic strategies.

Association of osteoporosis and sarcopenia with fracture risk in transfusion-dependent thalassemia

Patients with transfusion-dependent thalassemia (TDT) have an increased risk of osteoporosis and fractures. They also have several potential factors associated with sarcopenia. There has been currently no study on sarcopenia and its association with falls and fractures in TDT. This study aims to determine the prevalence of and factors associated with osteoporosis, fragility fractures, and sarcopenia in adults with TDT. A cross-sectional study was conducted at the hematologic clinic at King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Clinical data and laboratory testing were collected. Bone mineral density and morphometric vertebral fracture were assessed. Sarcopenia was defined using the 2014 and 2019 Asian Working Group for Sarcopenia (AWGS) criteria. We included 112 TDT patients aged 35.1 ± 12.5 years. The prevalence of osteoporosis was 38.4%. Fragility fractures were found in 20.5% of patients. Lower BMI (OR 0.29; 95% CI 0.12-0.72, P = 0.007) and hypogonadal state (OR 3.72; 95% CI 1.09-12.74, P = 0.036) were independently associated with osteoporosis. According to the 2014 AWGS criteria, the prevalence of overall sarcopenia and severe sarcopenia was 44.6% and 13.4%, respectively. Severe sarcopenia was strongly associated with fragility fractures (OR 4.59, 95% CI 1.21-17.46, P = 0.025). In conclusion, osteoporosis, fragility fractures, and sarcopenia were prevalent in adults with TDT. Severe sarcopenia was associated with fragility fractures. Early osteoporosis and sarcopenia screening and prevention may reduce fracture risk and its complications in these patients.

Treatment for osteoporosis in people with beta-thalassaemia

BACKGROUND

Osteoporosis is characterized by low bone mass and micro-architectural deterioration of bone tissue leading to increased bone fragility. In people with beta-thalassaemia, osteoporosis represents an important cause of morbidity and is due to a number of factors. First, ineffective erythropoiesis causes bone marrow expansion, leading to reduced trabecular bone tissue with cortical thinning. Second, excessive iron loading causes endocrine dysfunction, leading to increased bone turnover. Lastly, disease complications can result in physical inactivity, with a subsequent reduction in optimal bone mineralization. Treatments for osteoporosis in people with beta-thalassaemia include bisphosphonates (e.g. clodronate, pamidronate, alendronate; with or without hormone replacement therapy (HRT)), calcitonin, calcium, zinc supplementation, hydroxyurea, and HRT alone (for preventing hypogonadism). Denosumab, a fully human monoclonal antibody, inhibits bone resorption and increases bone mineral density (BMD). Finally, strontium ranelate simultaneously promotes bone formation and inhibits bone resorption, thus contributing to a net gain in BMD, increased bone strength, and reduced fracture risk. This is an update of a previously published Cochrane Review.

OBJECTIVES

To review the evidence on the efficacy and safety of treatment for osteoporosis in people with beta-thalassaemia.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, which includes references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also searched online trial registries. Date of most recent search: 4 August 2022.

SELECTION CRITERIA

Randomized controlled trials (RCTs) in people with beta-thalassaemia with: a BMD Z score below -2 standard deviations (SDs) for children aged under 15 years, adult males (aged 15 to 50 years) and premenopausal females aged over 15 years; or a BMD T score below -2.5 SDs for postmenopausal females and males aged over 50 years.

DATA COLLECTION AND ANALYSIS

Two review authors assessed the eligibility and risk of bias of the included RCTs, and extracted and analysed data. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included six RCTs (298 participants). Active interventions included bisphosphonates (3 trials, 169 participants), zinc supplementation (1 trial, 42 participants), denosumab (1 trial, 63 participants), and strontium ranelate (1 trial, 24 participants). The certainty of the evidence ranged from moderate to very low and was downgraded mainly due to concerns surrounding imprecision (low participant numbers), but also risk of bias issues related to randomization, allocation concealment, and blinding. Bisphosphonates versus placebo or no treatment Two RCTs compared bisphosphonates to placebo or no treatment. After two years, one trial (25 participants) found that alendronate and clodronate may increase BMD Z score compared to placebo at the femoral neck (mean difference (MD) 0.40, 95% confidence interval (CI) 0.22 to 0.58) and the lumbar spine (MD 0.14, 95% CI 0.05 to 0.23). One trial (118 participants) reported that neridronate compared to no treatment may increase BMD at the lumbar spine and total hip at six and 12 months; for the femoral neck, the study found increased BMD in the neridronate group at 12 months only. All results were of very low-certainty. There were no major adverse effects of treatment. Participants in the neridronate group reported less back pain; we considered this representative of improved quality of life (QoL), though the certainty of the evidence was very low. One participant in the neridronate trial (116 participants) sustained multiple fractures as a result of a traffic accident. No trials reported BMD at the wrist or mobility. Different doses of bisphosphonate compared One 12-month trial (26 participants) assessed different doses of pamidronate (60 mg versus 30 mg) and found a difference in BMD Z score favouring the 60 mg dose at the lumbar spine (MD 0.43, 95% CI 0.10 to 0.76) and forearm (MD 0.87, 95% CI 0.23 to 1.51), but no difference at the femoral neck (very low-certainty evidence). This trial did not report fracture incidence, mobility, QoL, or adverse effects of treatment. Zinc versus placebo One trial (42 participants) showed zinc supplementation probably increased BMD Z score compared to placebo at the lumbar spine after 12 months (MD 0.15, 95% CI 0.10 to 0.20; 37 participants) and 18 months (MD 0.34, 95% CI 0.28 to 0.40; 32 participants); the same was true for BMD at the hip after 12 months (MD 0.15, 95% CI 0.11 to 0.19; 37 participants) and 18 months (MD 0.26, 95% CI 0.21 to 0.31; 32 participants). The evidence for these results was of moderate certainty. The trial did not report BMD at the wrist, fracture incidence, mobility, QoL, or adverse effects of treatment. Denosumab versus placebo Based on one trial (63 participants), we are unsure about the effect of denosumab on BMD Z score at the lumbar spine, femoral neck, and wrist joint after 12 months compared to placebo (low-certainty evidence). This trial did not report fracture incidence, mobility, QoL, or adverse effects of treatment, but the investigators reported a reduction in bone pain measured on a visual analogue scale in the denosumab group after 12 months of treatment compared to placebo (MD -2.40 cm, 95% CI -3.80 to -1.00). Strontium ranelate One trial (24 participants) only narratively reported an increase in BMD Z score at the lumbar spine in the intervention group and no corresponding change in the control group (very low-certainty evidence). This trial also found a reduction in back pain measured on a visual analogue scale after 24 months in the strontium ranelate group compared to the placebo group (MD -0.70 cm (95% CI -1.30 to -0.10); we considered this measure representative of improved quality of life.

AUTHORS' CONCLUSIONS

Bisphosphonates may increase BMD at the femoral neck, lumbar spine, and forearm compared to placebo after two years' therapy. Zinc supplementation probably increases BMD at the lumbar spine and hip after 12 months. Denosumab may make little or no difference to BMD, and we are uncertain about the effect of strontium on BMD. We recommend further long-term RCTs on different bisphosphonates and zinc supplementation therapies in people with beta-thalassaemia-associated osteoporosis.

The association of growth differentiation factor-15 levels and osteoporosis in patients with thalassemia

INTRODUCTION

Ineffective erythropoiesis (IE) is a significant risk factor for osteoporosis in individuals with thalassemia. Growth differentiation factor-15 (GDF15), a biomarker of IE, was found to be elevated in thalassemia patients. This study aimed to examine the association between GDF15 levels and osteoporosis in patients with thalassemia.

METHODS

A cross-sectional study was conducted in 130 adult patients with thalassemia in Thailand. Bone mineral density (BMD) at the lumbar spine was evaluated by dual-energy X-ray absorptiometry (DXA), and with a Z-score of less than -2.0 SD was defined as osteoporosis. GDF-15 was measured using the enzyme-linked immunosorbent assay (ELISA). Logistic regression analysis was used to examine the associated factors with the development of osteoporosis. Receiver operator characteristic (ROC) curve analysis was used to estimate the threshold of GDF15 in predicting osteoporosis.

RESULTS

Osteoporosis was detected in 55.4% (72/130) of the patients. Advanced age and high GDF15 levels were positively associated with osteoporosis, while an increased hemoglobin level was negatively associated with osteoporosis in patients with thalassemia. In this study, the GDF15 level's ROC demonstrated a good performance in predicting osteoporosis (AUC=0.77).

CONCLUSIONS

The prevalence of osteoporosis is high among adult thalassemia patients. Age and high GDF15 levels were significantly associated with osteoporosis in this study. A higher hemoglobin level is associated with a lower risk of osteoporosis. This study suggest that GDF15 could be used as a predictive biomarker for osteoporosis in patients with thalassemia. Adequate red blood cell transfusions and suppression of GDF15 function may be beneficial in preventing osteoporosis.

Fracture prevalence in thalassemia: a systematic review and meta-analysis

BACKGROUND

Multiple observational studies have reported high prevalence of fracture in patients with thalassemia. However, most of these studies have included limited number of patients, and only few of them have reported prevalence of fracture among patients with different types and severity of thalassemia.

OBJECTIVE

This systematic review and meta-analysis was conducted to summarize all available data of fracture prevalence among patients with thalassemia.

METHODS

A systematic review was conducted using EMBASE and MEDLINE databases from inception to June 2021 to determine studies that reported prevalence of fracture in thalassemia patients. The pooled prevalence with 95% confidence interval (95%CI) of fracture across studies was determined using a random-effect, generic inverse variance method.

RESULTS

After two rounds of systematic review, a total of 25 studies with 4934 patients were included in the meta-analysis. The pooled prevalence of fracture among patients with thalassemia was 16% (95%CI, 15-17%, I² = 94.3%). The subgroup analyses showed that the pooled prevalence of fracture was 4% (95%CI, 2-6%; I² = 70.4%) among patients with alpha thalassemia, 17% (95%CI, 16-19%; I² = 93.2%) among patients with beta thalassemia, 18% (95%CI, 16-19%; I² = 89.0%) among patients with transfusion-dependent thalassemia, and 7% (95%CI, 4-10%; I² = 94.2%) among patients with non-transfusion-dependent thalassemia.

CONCLUSION

Fracture is common in patients with thalassemia, and may be more prevalent in beta thalassemia and transfusion-dependent thalassemia than in alpha thalassemia and non-transfusion-dependent thalassemia.

Bone mineral density in transfusion-dependent thalassemia patients and its associated factors in Southern Iran

Despite the significant improvements in the management of thalassemia, there are growing concerns regarding their long-term complications. We showed that low bone mass is one of the most prevalent complications among these patients. Insufficient physical activity and hypogonadism are the main possible associated factors followed by DM and insufficient sun exposure.

PURPOSE

Despite the significant improvements in the management of transfusion-dependent thalassemia (TDT), there are growing concerns regarding their long-term complications.

METHODS

This cross-sectional study included 615 TDT patients who were registered and followed in a comprehensive thalassemia clinic in Southern Iran. We measured serum biochemical tests and bone mineral density in all patients. We recorded physical activity and sun exposure subjectively, and an endocrinologist visited and examined all the patients. A group of age- and gender-matched healthy volunteers participated in the study as the control group.

RESULTS

The mean age of the studied population was 28.4 ± 7.7 years, and 55.8% were female. The prevalence of vitamin D deficiency was 45.6% and 54.4% in TDT patients and the control group. A portion of TDT patients suffered from different endocrinopathies, which included hypogonadism (49.8%), diabetes mellitus (17.2%), hypoparathyroidism (14.6%), and hypothyroidism (6.3%). The prevalence of low bone mass in patients with TDT was 48.3 and 74.6% in the femoral and lumbar bones, respectively. Low physical activity, insufficient sun exposure, diabetes mellitus, and hypogonadism were associated with low bone mass.

CONCLUSION

Low bone mass is highly prevalent among TDT patients in Southern Iran. Insufficient physical activity and hypogonadism are the main possible associated factors, followed by DM and insufficient sun exposure.

The Trabecular Bone Score as a Predictor for Thalassemia-Induced Vertebral Fractures in Northeastern Thailand

Introduction

Thalassemia bone disease is one of the disease-related complications in patients with thalassemia. Prevalence of fractures and the role of a trabecular bone score (TBS) as a predictive factor for fractures were evaluated in patients with thalassemia.

Methods

A cross-sectional study was conducted in patients with thalassemia aged ≥18 years at Srinagarind Hospital, Khon Kaen University, Thailand. A lateral thoracolumbar radiograph and bone mineral density (BMD) at the lumbar spine and hip, as well as the TBS measured by dual-energy X-ray absorptiometry (DXA), were evaluated in all patients.

Results

Among 86 patients, 14 patients were found to have radiographic vertebral fracture yielding a prevalence of 16.3%. All patients who had fractures were β-thalassemia/Hb E. Combined low BMD and TBS at lumbar spines and a presence of endocrinopathies were significantly associated with vertebral fractures.

Conclusions

The prevalence of vertebral fractures in patients with thalassemia was not uncommon. A combined low BMD and TBS and a presence of endocrinopathies were associated with vertebral fractures. These findings suggested that BMD testing and TBS measurement have a clinical implication as a screening tool for evaluating the risk of vertebral fractures in thalassemic patients, particularly in β-thalassemia/Hb E who have endocrinopathies.

Hematological Diseases and Osteoporosis

Secondary osteoporosis is a common clinical problem faced by bone specialists, with a higher frequency in men than in women. One of several causes of secondary osteoporosis is hematological disease. There are numerous hematological diseases that can have a deleterious impact on bone health. In the literature, there is an abundance of evidence of bone involvement in patients affected by multiple myeloma, systemic mastocytosis, thalassemia, and hemophilia; some skeletal disorders are also reported in sickle cell disease. Recently, monoclonal gammopathy of undetermined significance appears to increase fracture risk, predominantly in male subjects. The pathogenetic mechanisms responsible for these bone loss effects have not yet been completely clarified. Many soluble factors, in particular cytokines that regulate bone metabolism, appear to play an important role. An integrated approach to these hematological diseases, with the help of a bone specialist, could reduce the bone fracture rate and improve the quality of life of these patients.

Dual-energy X-ray absorptiometry pitfalls in Thalassemia Major

BACKGROUND

Low mineral mass and reduced bone strength with increased fracture risk are the main causes of morbidity in Thalassemia Major (TM). The pathogenesis is multifactorial and includes ineffective erythropoiesis with medullary expansion, multiple endocrine dysfunctions, direct iron bone deposition, deferoxamine-induced bone dysplasia, and reduced physical activity associated with disease complications. Dual-energy X-ray absorptiometry (DXA) is the "gold standard" for bone mineral density (BMD) assessment and for bone strength and quality evaluation. This method identifies patients at greater risk of fragility fractures, guiding treatment and monitoring response to therapy. In TM, DXA shows limitations concerning BMD calculation accuracy and fracture risk prediction. One of the main challenges in the assessment of bone health in patients with TM is the accurate interpretation of densitometric results.

PURPOSE

This review investigates the major pitfalls in DXA implementation and interpretation in TM.

METHODS

Available literature has been assessed.

CONCLUSIONS

DXA shows limitations in assessing bone mineral "status" in TM, especially in the paediatric population, due to the peculiar characteristics of bone architecture and deformities associated with the disease. A radiological technique adjustment in this population is mandatory.

Pathogenesis of Thalassemia Major-associated Osteoporosis: A Review with Insights from Clinical Experience

Due to increasing life expectancy in thalassemia major (TM), osteoporosis is emerging as a significant problem. Its aetiology is multifactorial, culminating in increased bone resorption and impaired remodelling. Hypogonadism and marrow expansion seem to play an important role, but iron overload, deferoxamine toxicity, a defective growth hormone-insulin-like growth factor-1 axis and multiple endocrinopathies may represent additional causes of bone damage. Many of these patients, though under appropriate treatment programs, do not achieve normal peak bone mass. The receptor activator of nuclear factor kappa-ß (RANK)/RANK ligand/osteoprotegerin and the Wnt/β-catenin systems work as major mediators of imbalanced bone turnover and bone loss. Additional genetic factors, such as collagen type 1 alpha 1 and vitamin D receptor gene polymorphisms, may exert some influence on the enhanced fracture risk observed in TM. To date, in spite of adequate hormone replacement, chelating therapy and acceptable haemoglobin levels, subjects with TM display impaired bone density and imbalanced bone turnover, thus the puzzle of the pathogenesis of TM-induced osteoporosis remains far from being solved.

Dual-Energy X-ray Absorptiometry Predictors of Vertebral Deformities in Beta-Thalassemia Major

Vertebral fractures in beta-thalassemia major are increasingly found because of the longer life expectancy of patients, with a major negative impact on their quality of life. We performed a retrospective cross-sectional study to investigate the prevalence of vertebral deformities in thalassemic patients and to identify their best dual-energy X-ray absorptiometry (DXA) predictor among trabecular bone score (TBS), bone mineral density (BMD), and Z-score. Eighty-two outpatients with beta-thalassemia major on regular conventional treatment were studied at a single academic center. All patients underwent plain thoracic-lumbar spine X-rays and lumbar DXA to assess the number and the severity of vertebral deformities (Genant's method), the spinal deformity index, lumbar spine DXA parameters (BMD, TBS, and Z-score), and the presence of platyspondyly. Twenty-nine patients (35%) had vertebral deformities and showed significantly lower TBSs than the remainders (1.141 ± 0.083 vs 1.254 ± 0.072, p < 0.0001). The analysis of variance of the TBS between the group of patients without vertebral deformities (spinal deformity index = 0) and the remaining groups showed a significant difference (p < 0.001). The TBS had better sensitivity (86.2%), specificity (75.5%), and diagnostic accuracy (79.3%) than BMD and Z-score in discriminating patients with and without vertebral deformities. Combining the TBS with the BMD or the Z-score showed that the diagnostic accuracy of the first in discriminating patients with and without vertebral deformities improved from 79.3% to 85.4% and 87.8%, respectively. The presence of platyspondyly was a significant predictor of vertebral deformities in the multivariate model. Vertebral deformities in well-treated patients with beta-thalassemia major are common and are often unrecognized. In our hands, the TBS was better than the BMD and the Z-score in predicting vertebral deformities. Plain X-rays of the spine should be performed also in asymptomatic patients, especially when the TBS is low.

Dysregulation of the RANKL/RANK/OPG axis in thalassemia intermedia patients

Objective

Thalassemia intermedia (TI) describes a disease ranging in severity between β thalassemia major (TM) and β thalassemia trait. Osteoporosis is observed in TI and TM. The exact reason of osteoporosis in TI could be hypogonadism and/or an increase in erythropoietin (EPO) levels. The carboxy-terminal collagen cross links (CTX), a marker of bone resorption, and the N-terminal propeptide of type 1 collagen (P1NP), a marker of bone formation are serum markers of osteoporosis. The receptor activator of NF-kappaB ligand (RANKL)/receptor activator of NF-kappaB (RANK)/osteoprotegerin (OPG) axis plays an important role in metabolic bone diseases. Herein, we tested the relationship between the RANKL/RANK/OPG axis and the bone-turnover markers CTX and P1NP in TI.

Results

We recruited 44 TI patients and 33 non-thalassemic controls and measured the serum levels of hemoglobin, sex steroid hormones, CTX, P1NP, RANKL and OPG. We then used a general linear model to test the association of the above variables with CTX and P1NP as outcome variables. We showed that EPO levels were the strongest predictor of CTX change (P < 0.000), followed by RANKL (P = 0.017). On the other hand, RANKL was the strongest predictor of P1NP change (P < 0.000), followed by OPG (P = 0.009) and EPO (P = 0.024).

The role of biphosphonates in the management of thalassemia-induced osteoporosis: a systematic review and meta-analysis

Thalassemia Major (TM) is a clinical entity with a high prevalence of low bone mass. The aim of the present study was to perform a meta-analysis of all available data on the role of bisphosphonates (BPs) in the therapy of thalassemia major-induced osteoporosis. The PRISMA recommendations for reporting systematic reviews and meta-analyses were used to guide the present study. We searched PubMed and the Cochrane Central Register of Controlled Trials (CENTRAL) through March 31, 2017 for articles related to thalassemia and BPs. To meta-analytically synthesize the primary endpoint, we used the standardized mean difference (SMD) after Hedges's g transformation under the scenario of a random effects model. Heterogeneity across studies was examined using the I² statistic. Nine randomized controlled trials (RCTs) containing original data were included in this review. Three studies were performed in Italy, one in Australia, three in Greece, one in Cyprus, and one in China. The BPs investigated included zoledronate, alendronate, pamidronate, clodronate, and neridronate. Zoledronate and alendronate showed a tendency to perform best as compared to neridronate and the placebo effect with respect to femoral neck, lumbar spine, total hip, and total body in terms of bone mass density (g/cm²). BPs and in particular, zolendronate, were quite effective in the treatment of osteoporosis. These findings suggested that bisphosphonates are still a front-line treatment of osteoporosis in TM. However, to draw more meaningful and significant conclusions for the use and efficacy of BP in TM, larger and more complete RCTs should be conducted.

A contemporary therapeutic approach to bone disease in beta-thalassemia - a review

Homozygous beta-thalassemia represents a serious hemoglobinopathy, in which an amazing prolongation in the survival rate of patients has been achieved over recent decades. A result of this otherwise positive evolution is the fact that bone problems have become a major issue in this group of patients. Through an in-depth review of the related literature, the purpose of this study is to present and comment on the totality of the data that have been published to date pertaining to the prevention and treatment of thalassemia bone-disease, focusing on: the contribution of diet and lifestyle, the treatment of hematologic disease and its complications, the management of hypercalciuria, the role of vitamins and minerals and the implementation of anti-osteoporosis medical regimen. In order to comprehensively gather the above information, we mainly reviewed the international literature through the PubMed database, searching for the preventive and therapeutic data that have been published pertaining to thalassemia bone-disease over the last twenty-nine years. There is no doubt that thalassemia bone-disease is a complication of a multi-factorial etiopathology, which does not follow the rules of classical postmenopausal osteoporosis. Bisphosphonates have been the first line of treatment for many years now, with varied and usually satisfactory results. In addition, over the last few years, more data have arisen for the use of denosumab, teriparatide, and other molecules that are in the clinical trial phase, in beta-thalassemia.

Bone disease in β thalassemia patients: past, present and future perspectives

Bone disorders in patients with thalassemia major (TM) and intermedia (TI) constitute complex conditions that result from various factors affecting the growing skeleton. Although much progress has been made in our understanding of the natural history, pathogenesis and clinical manifestations of β- and δβ-thalassemia, bone manifestations remain a puzzle for the clinician. In this review, we outline the key points in the current literature on the pathogenesis and management of bone disease in patients with TM and TI who were conventionally treated in recent decades with frequent blood transfusions and iron chelation. Prevention, early recognition and treatment are the most effective strategies for the management of bone disease in these patients. However, further studies are required to maintain optimal bone health for both TM and TI patients. Studying bone disease in patients with non-transfusion dependent TI, which seems to worsen considerably with age, is important to delineate the effect of the disease itself on bone health without the intervening factors of transfusions, iron intoxication and chelation.

Prevalence of low bone mass among adolescents with nontransfusion-dependent hemoglobin E/β-thalassemia and its relationship with anemia severity

BACKGROUND

Low bone mass is common among adolescents with transfusion-dependent β-thalassemia despite adequate transfusion and iron chelation. However, there are few reports regarding bone mineral density (BMD) among adolescents with nontransfusion-dependent thalassemia (NTDT). Indeed, only BMD data in patients with nontransfusion-dependent (NTD) β-thalassemia intermedia have been reported. No previous study has investigated BMD among adolescents with NTD hemoglobin (Hb) E/β-thalassemia.

OBJECTIVE

To determine the prevalence of low bone mass among adolescents with NTD Hb E/β-thalassemia and factors relating to low bone mass.

METHODS

We investigated BMD of lumbar spine (L2-L4; BMDLS) and total body (BMDTB), as measured by dual-energy X-ray absorptiometry, in 22 adolescents (aged 13.2-20 years) with NTD Hb E/β-thalassemia.

RESULTS

Low bone mass was found to be 18.2% and 22.7% at the lumbar spine (BMDLS Z-score adjusted for bone age and height age) and 13.6% and 9.1% at the total body (BMDTB Z-score adjusted for bone age and height age). Patients with mean Hb level <8 g/dl were more likely to have low bone mass (BMDLS and BMDTB Z-scores adjusted for bone age) compared to those with Hb level ≥ 8 g/dl. Mean Hb level correlated with BMDLS and BMDTB Z-scores adjusted for bone age.

CONCLUSION

We demonstrated that a low Hb level was associated with low bone mass among adolescents with NTD Hb E/β-thalassemia. A significant proportion of low bone mass among these patients highlights the importance of appropriate management, including red cell transfusion, vitamin D and calcium supplementation for improved long-term bone health.

Thalassemia-associated osteoporosis: a systematic review on treatment and brief overview of the disease

Thalassemia-associated osteoporosis constitutes a major complication in patients with thalassemia. This review presents the existing studies on the treatment of thalassemia-associated osteoporosis and discusses the management of this debilitating complication. A brief presentation of the disease characteristics and pathogenetic mechanisms is also provided. The life expectancy of patients with thalassemia has increased markedly in recent years resulting in the aging of the population and the emergence of new comorbidities. The majority of patients with thalassemia have low bone mineral density and experience lifelong fracture rates as high as 71 %. The pathogenesis of thalassemia-associated osteoporosis (TAO) is multifactorial with anemia and iron overload playing crucial role in its development. Data concerning the prevention and treatment of TAO are extremely limited. We performed a literature research in Pubmed and Scopus to identify interventional studies evaluating the effects of various agents on TAO. Seventeen studies were retrieved. We present the results of these studies as well as a brief overview of TAO including presentation, pathogenesis, and management. Most of the studies identified are of poor quality, are not randomized controlled, and include small number of participants. There are no data concerning effects on fracture rates. Bisphosphonates are the most widely studied agents and among them zoledronic acid is the most well studied. Hormone replacement treatment (HRT) shows beneficial but small effects. Denosumab and strontium ranelate have each been evaluated in only a single study, while there are no data about the effects of anabolic agents. Given the increased life expectancy and the increase in fracture rates with age, more data about the management of TAO are warranted. Moreover, due to the need for lifelong management starting at young age, careful treatment plans which may include sequential treatment may often be required. However, currently, there are no relevant data available.

Hypogonadism in thalassemia major patients

Despite recent advances in iron chelation therapy, excess iron deposition in pituitary gonadotropic cells remains one of the major problems in thalassemic patients. Hypogonadism, mostly hypogonadotropic hypogonadism, is usually detected during puberty. Early diagnosis and treatment are crucial for normal pubertal development and to reduce the complications of hypogonadism. The risks and benefits of hormonal replacement therapy, especially regarding the thromboembolic event, remain a challenge for providers caring for thalassemic patients.

Treatment for osteoporosis in people with ß-thalassaemia

BACKGROUND

Osteoporosis is a systemic skeletal disease characterized by low bone mass and micro-architectural deterioration of bone tissue with a consequent increase in bone fragility and susceptibility to fracture. Osteoporosis represents an important cause of morbidity in people with beta-thalassaemia and its pathogenesis is multifactorial. Factors include bone marrow expansion due to ineffective erythropoiesis, resulting in reduced trabecular bone tissue with cortical thinning; endocrine dysfunction secondary to excessive iron loading, leading to increased bone turnover; and lastly, a predisposition to physical inactivity due to disease complications with a subsequent reduction in optimal bone mineralization.A number of therapeutic strategies have been applied to treat osteoporosis in people with beta-thalassaemia, which include bisphosphonates, with or without, hormone replacement therapy. There are various forms of bisphosphonates, such as clodronate, pamidronate, alendronate and zoledronic acid. Other treatments include calcitonin, calcium, zinc supplementation, hydroxyurea and hormone replacement therapy for preventing hypogonadism.

OBJECTIVES

To review the evidence on the efficacy and safety of treatment for osteoporosis in people with beta-thalassaemia.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Date of most recent search: 04 February 2016.

SELECTION CRITERIA

Randomised, placebo-controlled trials in people with thalassaemia with a bone mineral density z score of less than -2 standard deviations for: children less than 15 years old; adult males (15 to 50 years old); and all pre-menopausal females above 15 years and a bone mineral density t score of less than -2.5 standard deviations for post-menopausal females and males above 50 years old.

DATA COLLECTION AND ANALYSIS

Two review authors assessed the eligibility and risk of bias of the included trials, extracted and analysed data and completed the review. We summarised results using risk ratios or rate ratios for dichotomous data and mean differences for continuous data. We combined trial results where appropriate.

MAIN RESULTS

Four trials (with 211 participants) were included; three trials investigated the effect of bisphosphonate therapies and one trial investigated the effect of zinc supplementation. Only one trial was judged to be of good quality (low risk of bias); the remaining trials had a high or unclear risk of bias in at least one key domain.One trial (data not available for analysis) assessing the effect of neridronate (118 participants) reported significant increases in favour of the bisphosphonate group for bone mineral density at the lumbar spine and hip at both six and 12 months. For the femoral neck, a significant difference was noted at 12 months only. A further trial (25 participants) assessed the effect of alendronate and clodronate and found that after two years, bone mineral density increased significantly in the alendronate and clodronate groups as compared to placebo at the lumbar spine, mean difference 0.14 g/cm(2) (95% confidence interval 0.05 to 0.22) and at the femoral neck, mean difference 0.40 g/cm(2) (95% confidence interval 0.22 to 0.57). One 12-month trial (26 participants) assessed the effects of different doses of pamidronate (30 mg versus 60 mg) and found a significant difference in bone mineral density in favour of the 60 mg dose at the lumbar spine and forearm, mean difference 0.43 g/cm(2) (95% CI 0.10 to 0.76), mean difference 0.87 g/cm(2) (95% CI 0.23 to 1.51), respectively, but not at the femoral neck.In a zinc sulphate supplementation trial (42 participants), bone mineral density increased significantly compared to placebo at the lumbar spine after 12 months (37 participants), mean difference 0.15 g/cm(2) (95% confidence interval 0.10 to 0.20) and after 18 months (32 participants), mean difference 0.34 g/cm(2) (95% confidence interval 0.28 to 0.40). The same was true for bone mineral density at the hip after 12 months, mean difference 0.15 g/cm(2) (95% confidence interval 0.11 to 0.19) and after 18 months, mean difference 0.26 g/cm(2) (95% confidence interval 0.21 to 0.31).Fractures were not observed in one trial and not reported in three trials. There were no major adverse effects reported in two of the bisphosphonate trials; in the neridronate trial there was a reduction noted in the use of analgesic drugs and in the reported back pain score in favour of bisphosphonate treatment. Adverse effects were not reported in the trial of different doses of pamidronate or the zinc supplementation trial.

AUTHORS' CONCLUSIONS

There is evidence to indicate an increase in bone mineral density at the femoral neck, lumbar spine and forearm after administration of bisphosphonates and at the lumbar spine and hip after zinc sulphate supplementation. The authors recommend that further long-term randomised control trials on different bisphosphonates and zinc supplementation therapies in people with beta-thalassaemia and osteoporosis are undertaken.

Molecular Aspects of Bone Resorption in β-Thalassemia Major

β-thalassemia is the most common single gene disorder worldwide, in which hemoglobin β-chain production is decreased. Today, the life expectancy of thalassemic patients is increased because of a variety of treatment methods; however treatment related complications have also increased. The most common side effect is osteoporosis, which usually occurs in early adulthood as a consequence of increased bone resorption. Increased bone resorption mainly results from factors such as delayed puberty, diabetes mellitus, hypothyroidism, ineffective hematopoiesis as well as hyperplasia of the bone marrow, parathyroid gland dysfunction, toxic effect of iron on osteoblasts, growth hormone (GH) and insulin-like growth factor-1 (IGF-1) deficiency. These factors disrupt the balance between osteoblasts and osteoclasts by interfering with various molecular mechanisms and result in decreased bone density.

Given the high prevalence of osteopenia and osteoporosis in thalassemic patients and complexity of their development process, the goal of this review is to evaluate the molecular aspects involved in osteopenia and osteoporosis in thalassemic patients, which may be useful for therapeutic purposes.

Thalassemia bone disease: a 19-year longitudinal analysis

Thalassemia is an inherited disorder of alpha or beta globin chain synthesis leading to ineffective erythropoiesis requiring chronic transfusion therapy in its most severe form. This leads to iron overload, marrow expansion, and hormonal complications, which are implicated in bone deformity and loss of bone mineral density (BMD). In this 19-year retrospective longitudinal study, the relationships between BMD (determined by dual-energy X-ray absorptiometry) and risk factors for osteoporosis in 277 subjects with transfusion-dependent thalassemia were examined. The mean age at first review was 23.2 ± 11.9 years and 43.7% were male. Hypogonadism was present in 28.9%. Fractures were confirmed in 11.6% of subjects and were more frequent in males (16.5%) compared with females (7.7%). Lumbar spine (LS), femoral neck (FN), and total body (TB) Z-scores were derived. Patients with transfusion-dependent thalassemia had a significant longitudinal decline in BMD at the FN and TB. In the linear mixed-model analysis of BMD and risk factors for bone loss, FN Z-score was more significantly associated with risk factors compared with the LS and TB. The rate of decline at the FN was 0.02 Z-score per year and was 3.85-fold greater in males. The decline in FN Z-score over the last 5 years (years 15 to 19) was 2.5-fold that of the previous 7 years (years 8 to 14) and coincided with a change in iron chelator therapy from desferrioxamine to deferasirox. Hemoglobin (Hb) levels positively correlated with higher TB and LS Z-scores. In conclusion, the FN is the preferred site for follow-up of BMD. Male patients with β-thalassemia experienced a greater loss of BMD and had a higher prevalence of fractures compared with females. Transfusing patients (particularly males) to a higher Hb target may reduce the decline in BMD. Whether deferasirox is implicated in bone loss warrants further study.

Thalassemia major and sickle cell disease in adolescents and young adults

The increased longevity of patients with thalassemia and sickle cell disease (SCD) introduces new clinical challenges due to the accumulation of disease-related morbidity, psychosocial issues and health care adjustments. Patients with thalassemia major now live into adulthood without suffering heart failure but must confront delayed puberty, impaired fertility and progressive bone disease. The increased survival in SCD brings to the front previously unrecognized complications including pulmonary hypertension, silent cerebral infarcts and also reproductive dysfunction. Adolescents and young adults (AYAs) have age-related psychosocial needs in their transition from the pediatric health care environment to the adult system. In this review we present the uniquely age-related medical issues facing the AYA thalassemia and SCD cohort in their transition into adulthood.

Thalassaemic osteopathy: a cross-sectional preliminary study from Sri Lanka

INTRODUCTION

The objectives of this study were to demonstrate the presence of low bone mineral density (BMD) and to examine the association of known risk factors for low BMD in patients with beta thalassaemia major in Sri Lanka.

METHOD

Thirty-eight patients were studied. Their examination and laboratory investigation findings were recorded (haematology, biochemistry, hormonal profile, COL1A1 rs1800012G>T genotype, dual energy X-ray absorptiometry (DXA) scanning).

RESULTS

Mean age was 10.95 years (range 5-21.4). 20 (52.6%) were male. BMD was low (z score ≤-2.0) in 12 (31.5%). Regression analysis of BMD on known risk factors (age, sex, pubertal stage, ferritin level, average pre-transfusion haemoglobin, serum calcium level and COL1A1 rs1800012G>T genotype) controlling for confounding factors on each comparison, showed that only age was significantly associated with low BMD (p=0.005).

CONCLUSIONS

Approximately one-third of patients had a low BMD. Only age was significantly associated with a low BMD.

Children with hemoglobin E/β-thalassemia have a high risk of being vitamin D deficient even if they get abundant sun exposure: a study from Thailand

BACKGROUND

Vitamin D is a key component in calcium homeostasis, bone mineralization and immune function, and people with a vitamin D deficiency may therefore be at higher risk of osteoporosis, osteopenia, delayed growth and fractures. Vitamin D deficiency is a known clinical complication of patients with β-thalassemia major; however, as yet there are limited data on the vitamin D status of patients with Hb E/β-thalassemia. Hb E/β-thalassemia is characterized by a wide clinical heterogeneity ranging from non-transfusion dependency to transfusion dependency. Because patients with Hb E/β-thalassemia are so clinically diverse, the prevalence of vitamin D deficiency might differ among Hb E/β-thalassemia patients.

PROCEDURE

We investigated the vitamin D status of 109 children with Hb E/β-thalassemia who attended the Pediatric Hematology Clinic at the Siriraj Hospital in Bangkok, Thailand, from April 2009 to March 2010.

RESULTS

Forty-nine of the children were classified as transfusion-dependent (TD) and the remainder (n = 60) as non-transfusion-dependent (NTD). Only 10.1% of the children in our study had normal vitamin D levels, despite Thailand's geographic position 15° N and 100° E and climate, which provides abundant sunlight exposure and therefore efficient vitamin D synthesis. In addition, NTD children were significantly more likely to be vitamin D deficient than TD children (P = 0.01).

CONCLUSIONS

Our results highlight the importance of monitoring serum vitamin D levels in children with Hb E/β-thalassemia regardless of their clinical severity or the amount of sunlight they are exposed to.

Chemical characterization and varying level of the proteoglycans

Proteoglycans are a major component of the animal extracellular matrix, the "filler" substance existing between cells in an organism. Here they form large complexes, both to other proteoglycans, to hyaluronan and to fibrous matrix proteins (such as collagen). Proteoglycans are heavily glycosylated glycoproteins. In this study, we evaluate effect of collagen and proteoglycan on osteoporosis. Rats were treated with ovariectomy (OVX) for 4 weeks to induce osteoporosis. In OVX rats, the levels of collagen and proteoglycan in knee joint cartilage and anterior cruciate ligament were significantly decreased in the OVX group animals compared to the sham group. OVX rats showed decreased levels of magnesium (Mg(2+)) and calcium (Ca(2+)), increased concentrations of alkaline phosphatase (ALP) and phosphorus (P) in the serum. We conclude that osteoporosis is closely associated to decreased collagen and proteoglycan levels in knee joint cartilage and anterior cruciate ligament.

Bone health evaluation of children and adolescents with homozygous β-thalassemia: implications for practice

OBJECTIVE

Bone tissue is adversely affected in patients with homozygous β-thalassemia. The aim of this study was to find warning signs of bone loss in young patients with β-thalassemia and allow prompt therapeutic interventions.

METHODS

Thirty-eight patients were studied, 20 boys and 18 girls, aged 5 to 18 years (median = 14.13 y), on regular transfusions and chelation treatments. Their bone mineral density (BMD) was measured with dual x-ray absorptiometry. The recorded parameters were weight, height, bone age (BA), transfusion adequacy (mean fetal hemoglobin value), and chelation efficacy (mean ferritin value, compliance). Tanner stage was also evaluated: 8 prepubertal subjects (stage 1), 18 peripubertal subjects (stages 2 and 3), and 12 postpubertal patients (stages 4 and 5). Blood and urine samples were collected for biochemical analysis.

RESULTS

Mean BMD z score was -1.56 ± 1.25. Thirteen patients had normal BMD (z score >-1), 17 patients had low BMD (z score: -1 up to -2.4), and 8 patients had very low BMD (z score <-2.5). Low BMD was observed in patients older than 12 years and was associated with short stature (r = 0.33, P = 0.04), delayed BA (r = 0.61, P = 0.01), and increased bone formation markers. There was no correlation of BMD z score with sex, fetal hemoglobin value, ferritin, and compliance. Regarding Tanner stage, it was associated strongly with short stature (r = 0.57, P = 0.01), ferritin (r = -0.38, P = 0.02), and compliance (r = 0.58, P = 0.01).

CONCLUSIONS

[corrected] The decline in BMD may start early, even in the well-transfused patients. This study targets the young patients who are mostly at the risk for bone loss, that is short adolescents with delayed BA. Their prompt recognition in everyday practice is important, as they will need close monitoring of their BMD and metabolic bone profile. In addition, therapeutic interventions, such as adequate calcium intake and sunlight exposure, weight-bearing exercise and, in cases of vitamin D insufficiency, proper supplementation could be suggested.

Use of hormone replacement therapy for correction of high turnover bone disease in hypogonadal β-Thalassemia major patients presenting with osteoporosis: comparison with idiopathic premature ovarian failure

Osteopenia-osteoporosis syndrome (OOS) causes considerable morbidity in 60-80% β-thalassemia major (β-TM) patients. We evaluated the effect of sex hormone replacement therapy (HRT) in β-TM patients with hypogonadism presenting with OOS using premature ovarian failure (POF) for comparative purposes. We undertook a 10-year prospective study of in 50 β-TM and 375 patients with POF and OOS. All were treated with HRT for 2-5 years. We used dual X-ray absorptiometry (DEXA), and plasma type 1-collagen markers of bone turnover for monitoring of response to therapy. Our results suggest that prior to HRT, both groups had comparable degrees of OOS. Both groups had significant improvement but the POF group had normalization of spinal T scores following HRT in contrast to the β-TM patients. Femoral T scores did not normalize in both groups. These data indicate for the first time from comparative POF control studies that hypogonadism is not the only cause of OOS in β-TM.

The spine in β-thalassemia syndromes

STUDY DESIGN

Literature review.

OBJECTIVE

To present a comprehensive overview of spinal involvement in patients with β-thalassemia, aiming to orient the spinal surgeon to these potentially disabling complications.

SUMMARY OF BACKGROUND DATA

β-thalassemia, an inherited disorder of hemoglobin synthesis, is the most common monogenetic disease worldwide. Patients with thalassemia major (TM) suffer a severe anemia that requires regular blood transfusions for survival and iron chelation therapy to control transfusional iron overload. Thalassemia intermedia is a phenotype of thalassemia with a milder course and anemia, wherein most patients remain transfusion independent. Spinal involvement related to disease course and treatment is common in patients with thalassemia syndromes, yet it has not been constructively reviewed in the literature.

METHODS

Potentially relevant studies were identified from an electronic search of MEDLINE (1966 to the second week of May 2010).

RESULTS

In patients with TM, genetic and acquired risk factors lead to osteoporosis, pathologic fractures of the spine, and back pain. Osteoporosis in TM patients is progressive; thus, early diagnosis and treatment are recommended. Bisphosphonates are relatively safe and effective in this patient population. Characteristic intervertebral disc degeneration is also seen in patients with TM who have evidence of severe iron overload or those who receive the subcutaneous iron chelator deferoxamine. Spinal asymmetry and overt scoliosis are common in patients with TM. The prognosis seems favorable, with many patients showing spontaneous resolution without the need for intervention. In patients with thalassemia intermedia, ineffective erythropoiesis drives extramedullary hematopoietic tissue formation, which is mostly evident on magnetic resonance imaging. Paraspinal involvement is of greatest concern because of the associated spinal cord compression. Several treatment options have been described, including transfusion therapy, laminectomy, radiotherapy, and the use of fetal hemoglobin-inducing agents that decrease the hematopoietic drive.

CONCLUSION

Current knowledge supports that spinal involvement in patients with β-thalassemia is common and diverse yet still requires further prospective evaluation.

Bone mineral density in thalassemia major patients from antalya, Turkey

Aim. We assessed the bone mineral density and related parameters in nine adults, thirty-eight pubertal, prepubertal totally forty-seven patients with thalassemia major living in Antalya, Turkey. Materials and Methods. We measured height and pubertal staging in last five years by six-month intervals. Average ferritin and hemoglobin concentrations were calculated for last three years. The levels of hydroxyproline, calcium, phosphorus, and creatinine were measured in 24 h urine, and those of parathormone, IGF 1, osteocalcine, alkaline phosphatase, calcium, ionized calcium, magnesium, phosphorus, creatine, blood glucose, thyroid stimulating hormone, alanine transaminase, and aspartate transaminase were determined in serum, and also the bone mineral density was measured. Results. The average L1-L4 bone mass density was 27.1 ± 10.1 g cm(-2); the average bone mineral content was 0.65  ±  0.11 g. of the patients with a Z-score under 2.5. A moderate relationship was found between the bone mass density age and height. Subjects in low pubertal staging and short stature (<3% percentile) have significantly lower bone mass densities P < 0.001. Conclusion. he prevalence of osteoporosis is high in patients with thalassemia major, possibly related to delayed puberty.

Bone disease and skeletal complications in patients with β thalassemia major

Increased survival in patients with β thalassemia major (TM) allowed for several complications of the disease and its treatment to manifest, one of which is bone disease. Osteoporosis in this patient population results from a variety of genetic and acquired factors. Early diagnosis and prevention are essential and several measures have been evaluated for management including bisphosphonates. Fracture prevalence in TM patients seems to be clustered in mid adulthood, and is related to vitamin D deficiency and low bone mineral density. Fracture healing in patients with TM does not seem to be different from that in normal individuals. Bone and joint pain are a common manifestation of the underlying pathophysiology or may be related to iron chelator intake. Intervertebral disc changes are seen in patients who are heavily iron overloaded or those who are chelated with deferoxamine. Spinal deformity is common in TM, yet the prognosis is benign with spontaneous resolution frequently observed. Further research is warranted to evaluate the mechanisms, clinical implications, and optimal management of bone disease in this patient population.

Quantitative computed tomography is unreliable for measurement of bone mineral density in inadequately chelated adolescent patients with β-thalassemia major: a case-control study

BACKGROUND

Utility of quantitative computed tomography (QCT) for assessment of bone mineral density (BMD) in patients with thalassemia is not fully established. Majority of patients with thalassemia in India receive suboptimal iron chelation. There is paucity of data on BMD in this population. Aim was to assess BMD by lumbar QCT in adolescent patients with transfusion dependent β-thalassemia major and compare with controls.

PROCEDURE

Study was conducted prospectively, over 15 months. Single energy QCT was performed through first three lumbar vertebrae.

RESULTS

Forty-five patients were enrolled (age: 10-19 years). Thirty-eight normal siblings of patients with thalassemia patients served as controls. Forty percent patients weighed <3rd percentile, 64% were stunted, and 40% had suboptimal sexual maturity scores. Eighteen (40%) patients were on iron chelation with deferiprone. Mean serum ferritin was 2,800 ± 1,473 ng/ml. Mean BMD (mg/cu mm) of cases and controls was 194.5 ± 27.1 and 170.4 ± 28.84, respectively (P = 0.0002). The mean BMD of patients with ferritin <2,000 ng/ml and those with a higher ferritin was 181.2 ± 14.9 and 196.7 ± 25, respectively (P = 0.07). The finding of increased BMD in patients with thalassemia is in stark contrast to published reports. Patients had several risk factors for low BMD, including growth retardation, delayed puberty, and iron overload.

CONCLUSION

Single energy QCT of lumbar vertebrae is not reliable for measurement of BMD in inadequately chelated patients with β-thalassemia major. The deposition of iron in bone tissue may result in increased X-ray attenuation values of trabecular bone.

Treatment options for thalassemia patients with osteoporosis

Osteoporosis represents a prominent cause of morbidity in patients with thalassemia. The delay in sexual maturation, the presence of diabetes and hypothyroidism, the parathyroid gland dysfunction, the progressive marrow expansion, the iron toxicity on osteoblasts, the iron chelators, and the deficiency of growth hormone or insulin growth factors have been identified as major causes of osteoporosis in thalassemia. Adequate hormonal replacement, effective iron chelation, improvement of hemoglobin levels, calcium and vitamin D administration, physical activity, and smoking cessation are the main to-date measures for the management of the disease. During the last decade, novel pathogenetic data suggest that the reduced osteoblastic activity, which is believed to be the basic mechanism of bone loss in thalassemia, is accompanied by a comparable or even greater increase in bone resorption. Therefore, the role of bisphosphonates, potent inhibitors of osteoclast activation, arises as a major factor in the management of osteoporosis in thalassemia patients.

Osteoporosis syndrome in thalassaemia major: an overview

Osteoporosis in thalassaemia major (TM) represents a prominent cause of morbidity. The mechanism of pathogenesis of bone disease (BD) in TM is multifactorial and complicated. Peak bone mass is achieved shortly after completion of puberty and normally remains stable until the third decade of life when age-related bone mass begins. Growth hormone (GH) and sex steroids play a crucial role in bone remodeling and in the maintenance of skeletal architecture during adult life. GH and insulin growth factors (IGFs) have anabolic effect in bone formation. Sex steroids act probably by increasing the expression of RANKL by osteoblastic cells and alterations in the RANK/RANKL/OPG system in favor of osteoclasts. Impaired GH secretion and lack of sex steroids in thalassemic patients due to pituitary damage, contribute to failure of achieving optimal peak bone mass. Other endocrine complications such as hypoparathyroidism and vitamin D deficiency have also a detrimental role on bones in TM. It is still questionable whether the international criteria for defining osteopenia and osteoporosis are relevant to patients with TM; also a question arises for the diagnostic methods such as DEXA scan and management of osteoporosis with known treatment protocols, in the thalassaemic patient.

Thalassaemia and aberrations of growth and puberty

Endocrine dysfunction in Thalassaemia major (TM) is a common and disturbing complication, which requires prompt recognition and treatment. The contribution of the underlying molecular defect in TM to the development of endocrinopathies is significant because the patients with the more severe genetic defects have a greater rate of iron loading through higher red cell consumption. TM patients frequently present delay of growth and puberty with reduction of final height. The pathogenesis of growth failure is multifactorial and is mainly due to chronic anemia and hypoxia, chronic liver disease, zinc and folic acid deficiency, iron overload, intensive use of chelating agents, emotional factors, and endocrinopathies (hypogonadism, delayed puberty, hypothyroidism) and GH-IGF-1 axis dysregulation. Although appropriate iron chelation therapy can improve growth and development, TM children and adolescents treated intensively with desferrioxamine remain short as well, showing body disproportion between the upper and lower body segment. Body disproportion is independent of pubertal or prepubertal period of greater height gain. Treatment with recombinant GH (rhGH) is recommended when GH deficiency is established, and even so, the therapeutic response is often non satisfactory. Growth acceleration is mostly promoted with sex steroids in children with associated pubertal delay. Sexual complications in TM, which include Delayed Puberty, Arrested Puberty and Hypogonadism, present the commonest endocrine complication. Iron deposition on gonadotroph cells of the pituitary leads to disruption of gonadotrophin production which is proven by the poor response of FSH and LH to GnRH stimulation. In the majority of patients gonadal function is normal as most women with Amenorrhea are capable of achieving pregnancy with hormonal treatment and similarly men with azoospermia become fathers. Secondary Hypogonadism appears later in life, and is manifested in women as Secondary Amenorrhea and in men as decline in sexual drive and azzoospermia. The damage to the hypothalamus and pituitary is progressive, even when intensive chelating therapy is given and the appearance of Hypogonadism in both sexes is often unavoidable. Close follow up and proper management is crucial for every patient with TM. Early recognition of growth disturbance and prevention of hypogonadism by early and judicious chelation therapy is mandatory for the improvement of their quality of life. Patients with TM can now live a better life due to modern advances in their medical care and our better understanding in the pathogenesis, manifestation and prevention of endocrine complications.

Bone disease in thalassemia: a frequent and still unresolved problem

Adults with beta thalassemia major frequently have low BMD, fractures, and bone pain. The purpose of this study was to determine the prevalence of low BMD, fractures, and bone pain in all thalassemia syndromes in childhood, adolescence, and adulthood, associations of BMD with fractures and bone pain, and etiology of bone disease in thalassemia. Patients of all thalassemia syndromes in the Thalassemia Clinical Research Network, > or =6 yr of age, with no preexisting medical condition affecting bone mass or requiring steroids, participated. We measured spine and femur BMD and whole body BMC by DXA and assessed vertebral abnormalities by morphometric X-ray absorptiometry (MXA). Medical history by interview and review of medical records, physical examinations, and blood and urine collections were performed. Three hundred sixty-one subjects, 49% male, with a mean age of 23.2 yr (range, 6.1-75 yr), were studied. Spine and femur BMD Z-scores < -2 occurred in 46% and 25% of participants, respectively. Greater age, lower weight, hypogonadism, and increased bone turnover were strong independent predictors of low bone mass regardless of thalassemia syndrome. Peak bone mass was suboptimal. Thirty-six percent of patients had a history of fractures, and 34% reported bone pain. BMD was negatively associated with fractures but not with bone pain. Nine percent of participants had uniformly decreased height of several vertebrae by MXA, which was associated with the use of iron chelator deferoxamine before 6 yr of age. In patients with thalassemia, low BMD and fractures occur frequently and independently of the particular syndrome. Peak bone mass is suboptimal. Low BMD is associated with hypogonadism, increased bone turnover, and an increased risk for fractures.

Assessment of puberty in relation to L-carnitine and hormonal replacement therapy in beta-thalassemic patients

OBJECTIVE

To investigate puberty in a group of thalassemic patients with delayed or arrested pubertal development and to compare the effects of hormonal and L-carnitine therapy on puberty in those patients.

PATIENTS

Thirty-two -thalassemic patients with arrested or failure of puberty were enrolled for 1 year in this study.

METHOD

Clinical pubertal assessment and laboratory investigations were done for all patients at the beginning, 6 months later clinical pubertal assessment was done. Patients were divided into two groups (16 each): first group received L-carnitine therapy, while the second group received hormonal therapy. Pubertal and laboratory assessment were done 6 months after hormonal and L-carnitine therapy.

RESULTS

Failure of puberty was confirmed in 71.4% of boys and 33.3% of girls, while arrested puberty was observed in 28.6% of boys and 66.7% of girls. All girls had amenorrhea, primary amenorrhea in 88.9% and secondary amenorrhea in 11.1%. Menses occurred in 20% of female patients after L-carnitine therapy and in 37.5% of them after hormonal therapy. Improvement of pubertal staging was observed in 50% of males after L-carnitine therapy compared to 75% of them after hormonal therapy. While improvement of pubertal staging was seen in 90% of females after L-carnitine therapy compared to 100% of females after hormonal treatment. However, these results showed no significant difference between both groups.

CONCLUSION

Delayed puberty in beta-thalassemia major is either due to failure of gonads or failure of the whole hypothalamic pituitary gonadal axis. L-carnitine as well as hormonal replacement therapy had a positive effect on puberty in the thalassemic patients. Further studies are needed to clarify the role of L-carnitine on puberty in these patients.

Dual-energy X-ray aborptiometry assessment in children and adolescents with diseases that may affect the skeleton: the 2007 ISCD Pediatric Official Positions

The Task Force focusing on the use of dual energy X-ray absorptiometry (DXA) in children and adolescents with diseases that may affect the skeleton reviewed over 300 articles to establish the basis for the Official Positions. A significant number of studies used DXA-based outcome measures to assess the effects of specific interventions and charted the natural history of incremental changes in bone size and mass in specific disease states in children. However, the utility of DXA in clinical practice has not been evaluated systematically, in large part due to the lack of a workable definition for childhood osteoporosis. Thus, in combination with the Official Positions addressing the diagnosis of osteoporosis in children, and the reporting of DXA results in children, this document presents clear guidelines from which clinicians and researchers alike can work. This report delineates a set of disorders in which it is appropriate to use DXA as part of the comprehensive assessment of skeletal health in children and adolescents, and provides guidance concerning the initiation of assessment and the frequency of monitoring. Importantly, this document also highlights significant gaps in our knowledge, emphasizing areas for future research.

Bone demineralization in adult thalassaemic patients: contribution of GH and IGF-I at different skeletal sites

BACKGROUND AND OBJECTIVE

GH and IGF-I exert an important role in the control of bone formation, as shown by decreased bone mineral density and increased fracture risk in adult hypopituitary patients untreated for GH deficiency (GHD). Different degrees of bone demineralization are frequently reported in patients affected by beta-thalassaemia. Considering the high prevalence of GHD recently observed by our group among adult thalassaemic patients, we elected to study the possible role of GH-IGF-I abnormalities in the pathogenesis of the osteopenia/osteoporosis of this disease.

DESIGN

Sixty-four adult thalassaemic patients (49 with thalassaemia major and 15 with thalassaemia intermedia, 23 men and 41 women, aged 31.4 +/- 6.8 years) were studied.

METHODS

Bone mineral density was assessed by dual energy X-ray absorptiometry at lumbar spine in 62 patients and at proximal femur in 58. All patients underwent GHRH (1 microg/kg as an i.v. bolus) plus arginine (0.5 g/kg as a 30-min i.v. infusion) testing. Severe GHD was defined by GH peaks < 9 microg/l, whereas partial GHD was defined by GH peaks ranging from 9 to 16.5 microg/l. Blood samples for IGF-I measurement were collected.

RESULTS

Lumbar osteoporosis and osteopenia were demonstrated in 46/62 (74.1%) and 14/62 (22.5%) patients, respectively. Femoral osteoporosis and osteopenia were documented in 22/58 (37.9%) and 32/58 (55.1%) patients, respectively. Severe GHD was demonstrated in 16/64 patients (25%), while 11 additional patients (17.1%) displayed partial GHD. IGF-I standard deviation score (SDS) was low, that is, below -1.88, in the majority (54.6%) of patients. Lumbar T-score values were not correlated with either GH peaks or IGF-I SDS values. Femoral T-score values were positively correlated with GH peaks (r = 0.38, P < 0.005) and IGF-I SDS values (r = 0.39, P < 0.005). Multiple regression analysis pointed to both GH peak and IGF-I SDS as predictors of femoral T-score. Furthermore, mean femoral T-score was significantly lower in patients with severe GHD than in those with normal GH secretion (-2.94 +/- 0.25 vs.-2.15 +/- 0.12, P < 0.01).

CONCLUSION

This study, while confirming the high prevalence of both osteopenia/osteoporosis and somatotropin-somatomedin deficiency in adult thalassaemic patients, indicates that defective GH secretion and diminished serum IGF-I levels may contribute to femoral demineralization in these patients. Further studies are worth carrying out to evaluate the efficacy of biosynthetic GH administration on bone abnormalities of GH-deficient thalassaemic adults.

Thalassemia and its relevance to personalized medicine

Thalassemias are the most common monogenic gene disorders in the world. Patients present with a wide variability of clinical phenotypes ranging from severe phenotype (β-thalassemia major) to a very mild, almost symptomless, condition. This variability is owing to the presence of a large number of genetic modifiers affecting the disease. Patients are treated with blood transfusions and iron chelation therapy. Pharmacological therapies have varying degrees of success depending on the genetic modifiers of the disease present in the patients. Studies undertaken to identify all the modifiers that affect β-thalassemia will lead to more appropriate genetic counseling during prenatal diagnosis and enable targeted and personalized treatment regimens for patients in the future.

Bisphosphonates in the treatment of thalassemia-associated osteoporosis

Thalassemia major is a common cause of skeletal morbidity, as shown by the increased fracture risk in thalassemic patients. The etiology of this bone disease is multifactorial and culminates in a state of increased bone turnover with excessive bone resorption and remodeling. Despite hormonal replacement therapy, calcium and vitamin D administration, effective iron chelation, and normalization of hemoglobin levels, patients with thalassemia major continue to lose bone mass. The increased bone turnover rate observed in thalassemic patients justifies the use of powerful anti-resorption drugs, such as bisphosphonates. To date, alendronate, pamidronate, and zoledronate seem to be effective in increasing bone mineral density and normalizing bone turnover, but more trials are necessary to evaluate their efficacy in reducing fracture risks in larger thalassemic populations.

Markers of bone metabolism in eugonadal female patients with beta-thalassemia major

Osteoprotegerin (OPG) and receptor activator of NF-kappaB ligand (RANKL) have been recently implicated in the pathogenesis of various types of osteoporosis. The aim of this study was to investigate bone turnover in eugonadal female patients with this disease and characterize the possible role of the OPG/RANKL system in thalassemia-related bone loss. Markers of bone turnover and bone mineral density (BMD) were measured in 16 eugonadal young females with beta-thalassemia major and 18 age- and sex-matched healthy controls. Bone turnover was significantly increased in thalassemic patients compared to controls but OPG was significantly higher in healthy subjects. BMD values negatively correlated with urine markers of bone resorption but not with OPG/sRANKL system.

Bone mineral density in Iranian adolescents and young adults with beta-thalassemia major

The authors investigated the prevalence of low bone mass in patients from Tehran, Iran, with beta-thalassemia major (n = 203), aged 10-20 years, and the potential risk factors for osteoporosis in this patient population. Prevalence of osteoporosis was 50.7% in lumbar spine, 10.8% in femur, and 7.9% in both regions with no significant difference between the two genders. The following factors were associated with low BMD: height for age and weight for age below 3rd percentile, delayed puberty or hypogonadism, age when Desferal (for iron chelation) was started, duration of Desferal therapy, and serum zinc. Low serum copper and 25(OH)D were not associated with low BMD.

The "lively" cytokines network in beta-Thalassemia Major-related osteoporosis

Osteoporosis affects approximately 40-50% of adult patients with beta-Thalassemia Major (beta TM). Recent data have implicated an altered modulation of the osteoprotegerin (OPG)/receptor activator of NFkB ligand (RANKL) system in the pathogenesis of beta TM-osteoporosis. OPG/RANKL system acts downstream from IL-1 alpha, IL-6 and TNF-alpha and it may be the final actor mediating the effects of these cytokines on the regulation of both postmenopausal and metabolic bone resorption. However, to date, there are no data on circulating levels of these pro-resorptive cytokines in beta TM patients. We investigated the potential relationships among these cytokines, several markers of bone turnover and bone mineral density (BMD) in beta TM patients. IL-1 alpha, IL-6 and TNF-alpha, OPG and RANKL serum levels, hemato-urinary bone remodeling markers and bone mineral density (BMD) at L2L4 and femoral neck as well as erythropoietin (EPO), 17beta-estradiol, and free-testosterone levels were measured in 30 well treated beta TM patients and in 20 healthy subjects, matched for age, sex and BMI with the patients. beta TM patients showed an altered bone turnover, with increased deoxypyridinoline (D-PYR) levels (P<0.0001), decreased osteocalcin (BGP) concentrations (<0.0001) and significantly lower lumbar (P=0.001) and femoral (P<0.05) BMD values as compared to controls. Circulating levels of IL-1 alpha (P<0.0001), TNF-alpha (P<0.0001) and IL-6 (P<0.05) were all increased in beta TM patients as compared with controls. In beta TM patients, IL-1 alpha was significantly related with D-PYR (r=0.5; P<0.05), RANKL (r=0.7; P=0.03) and IL-6 (r=0.3; P=0.006); IL-6 was also significantly correlated with D-PYR (r=0.5; P<0.05) and EPO levels (r=0.3; P=0.03); TNF-alpha showed a negative correlation with L2L4 BMD (r=-0.4; P<0.05). Our data demonstrate, for the first time, an association between increased circulating levels of pro-resorptive cytokines and an altered bone turnover in beta TM-patients, suggesting their involvement in the pathogenesis of beta TM-osteoporosis.

Circulating osteoprotegerin and receptor activator of NF-kappaB ligand system in patients with beta-thalassemia major

Osteoporosis represents an important cause of morbidity in patients with beta-thalassemia major, and its etiology is multifactorial. Thus, the aim of this study was to characterize the possible role of the osteoprotegerin (OPG) and receptor activator of the NF-kappaB ligand (RANKL) system in thalassemia-related bone loss. Serum concentrations of OPG, soluble RANKL (s-RANKL), markers of bone turnover, and lumbar spine bone mineral density (BMD) were measured in random samples of males (n = 29; mean age +/- SEM, 24.26 +/- 1.29 years; range, 13-41 years) and females (n = 31; age, 24.59 +/- 0.95 years; range, 12-34 years) with beta-thalassemia major and in 30 healthy age-, height-, and weight-matched subjects. Thalassemic patients had significantly lower levels of OPG compared with controls (2.54 +/- 0.12 vs. 3.25 +/- 0.122, respectively; P < 0.05) and higher, albeit not statistically significantly, serum levels of s-RANKL (0.350 +/- 0.03 vs. 0.295 +/- 0.046, respectively; P < 0.05). s-RANKL correlated negatively with age (r = -0.3, P < 0.05), and OPG correlated positively with the duration of the interval between the onset of transfusions and chelation therapy (r = 0.52, P < 0.001). Regarding markers of bone metabolism, plasma values of osteocalcin correlated positively with s-RANKL (r = 0.40, P < 0.05) and negatively with OPG/s-RANKL ratio (r = -0.55, P < 0.01). In multiple regression analysis only cross-linked N-teleopeptide of type I collagen (NTX) significantly accounted for BMD. Although the OPG/RANKL system may have some clinical usefulness as a marker of bone turnover in beta-thalassemia, conventional markers of bone turnover more accurately represent changes in the BMD of these patients.

Medroxyprogesterone - valproic acid - aspirin. MVA regime to reduce transfusion associated mortality in late-term hemoglobinopathies. Hypothesis and rationale

Medroxyprogesterone acetate (MPA) - a safe depot contraceptive - is shown previously to reduce painful crises of sickle cell anemia, which is parallel with the recent findings showing progesterone induction of fetal hemoglobin genes. This would be a way to reduce transfusions for late term thalassemia major and sickle cell-disease cases with no chances left for a stem cell transplantation. In these patients, transfusional hemosiderosis causes irreversible damage to many organs despite the available iron-chelating agents. Pharmacological strategies either target the conformal structure of the defective adult hemoglobin or aim to activate fetal hemoglobin concentrations. The only concern on MPA may be its thromboembolic risks, which may be uncoupled with agents acting both anti-coagulant and inductive on the blood oxygen-carrying affinity. Such agents could be valproic acid and aspirin. Valproic acid is being safely used to treat epilepsy and its histone acetylating function may lead its induction of fetal hemoglobin. Aspirin was shown to increase oxygen affinity of hemoglobin via acetylating lysine residues and its general acetylating activity on proteins such as histones makes it also an interesting candidate to activate fetal hemoglobin. We propose that combining MPA with clinically available doses of valproic acid and aspirin would be beneficial in terms of both reduced coagulation risks and increased oxygen affinity to decrease the transfusions and to improve the prognosis in late-phase hemoglobin disorders.

A randomized, double-blind, placebo-controlled trial of intravenous zoledronic acid in the treatment of thalassemia-associated osteopenia

Beta-thalassaemia major is associated with low bone mass and fractures. We conducted a 2 year randomized controlled trial of zoledronic acid 4 mg administered intravenously every 3 months or placebo in the treatment of beta-thalassaemia-associated osteopenla. We recruited 23 subjects from 2 university hospitals with a T score of less than -1.0 at either the lumbar spine or hip, and 23 subjects completed the study (17 M, 6 F). Treatment groups did not differ significantly with respect to bone mineral density (BMD), age, height, weight and body mass index (BMI) at baseline. BMD was assessed at baseline, 12 months and 24 months by dual-energy X-ray absorptiometry (DXA) at the lumbar spine, femoral reek, total hip and total body. After two years average lumbar spine BMD was 8.9% greater (95%CI 2.3-15.5%, P = 0.011), average femoral neck BMD was 9.1% greater (95%CI 5.5-12.7%, P < 0.0001), average total hip BMD was 9.6% greater (95%CI 6.5-12.6%, P < 0.0001) and average total body BMD was 4.7% greater (95%CI 2.7-6.8%, P < 0.0001) in the treated group compared to placebo. The absolute change in BMD from baseline to 2 years and the annualized rate of change of BMD was significantly greater in treated patients at all four sites. Age, gender, height, weight and BMI did not interact with the effect of treatment and so unadjusted data was used. The serum total ALP decreased 45% by 12 months (P = 0.004) and urinary deoxypyridinoline/creatinine ratio decreased 47% by 3 months (NS). We conclude that zoledronic acid (4 mg i.v. 3 monthly) suppresses bone turnover and increases BMD in beta-thalassaemia-associated osteopenia.

The impact of genotype on endocrine complications in thalassaemia major

BACKGROUND

The clinical severity in thalassaemia major (TM) depends on the underlying mutations of the beta-globin gene and the degree of iron overload.

OBJECTIVE

The aim of the study was to investigate the impact of genotype on the development of endocrine complications in TM in our center.

SUBJECTS AND METHODS

126 (62 males, 64 females) thalassaemic patients of Greek Cypriot origin with a mean age of 31.2 (17-68) yr were included in the study. All patients, who were on the standard treatment protocol, were subsequently divided into two groups according to their genotype, group A (92): TM with no mitigating factor and group B (34): TM carrying one or more mitigating factors in the beta- and/or alpha-globin genes. Iron overload calculation was based on the amount of red cell consumption and the mean ferritin level over a 12-year period. Statistical analysis was performed with the SPSS program.

RESULTS

Patients in group A, who were consuming larger amounts of blood on transfusions, were more likely to develop hypogonadism (P = 0.001) compared with patients in group B, despite their similar mean ferritin levels. The incidence of other endocrinopathies (short stature, hypothyroidism, and diabetes mellitus) was similar in the two groups. The prevalence of hypothyroidism in splenectomized patients was significantly higher (P = 0.005), whereas the presence of hypogonadism, impaired glucose homeostasis and insulin resistance, although more frequent, was not statistically significant. The clinical severity of TM had no impact on bone mineral density (BMD) in both men and women. BMD was only influenced by gonadal function.

CONCLUSIONS

This study demonstrates that the underlying genetic defect in TM is a contributing factor for gonadal dysfunction, because the patients with the more severe defects have a greater rate of iron loading through higher red cell consumption.

Low serum levels of 25-hydroxy vitamin D in adults affected by thalassemia major or intermedia

Adult thalassemic patients have reduced bone mass due to disturbances in several different mechanisms affecting bone turnover. To determine if vitamin D deficiency contributes to the low bone mass of adult thalassemic subjects, we studied serum 25-OH-vitamin D levels in 90 patients (age ranging between 21 and 48 years) affected with thalassemia major (TM) and 35 (age 21-56 years) with thalassemia intermedia (TI). TM patients had been receiving regular transfusions from the age of 2 years and had increased serum ferritin, glutamic oxalacetic transaminase, glutamic piruvic transaminase as well as low bone density (L1-L4 Z score -2.07 +/- 0.2). TI patients did not receive transfusions, but their ferritin levels were increased as well (520.3 +/- 138,1). 8 TM patients (10.1%) and 4 TI (11.4%) had serum 25-OH-vitamin D less than 10.4 ng/ml and were considered presenting an absolute deficiency of vitamin D. Mean 25-OH-vitamin D was significantly (P < 0.01) lower in both TM and TI patients (20.3 +/- 0.7 ng/ml and 20.9 +/- 2.3 ng/ml, respectively) than in 100 healthy control subjects of similar age (25.2 +/- 1 ng/ml). 1,25-OH-vitamin D levels were in the normal-lower levels (45.15 +/- 1.5 mg/dl), while 24 H urinary calcium was below the normal range (15.75 mg/dl). In TM patients, the 25-OH-vitamin D levels correlated negatively with age (P < 0.05) and with serum ferritin (P < 0.05). TM and TI patients with low 25-OH-vitamin D levels (<17.8 ng/ml) presented higher serum ferritin levels (P < 0.01) and higher PTH (P < 0.05) compared to those with normal vitamin D. Moreover, TM patients with low 25-OH-vitamin D levels were significantly older (P < 0.05) and had higher GPT (P < 0.05) than patients with normal vitamin D. In conclusion, calcium metabolism is frequently impaired in adult thalassemic patients. An early and effective medical treatment should be taken in consideration by the clinician in order to improve the bone health in these patients.