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

Bone quality is associated with fragility fracture in patients with hemoglobinopathies

BACKGROUND

Low bone mass, defined as a bone mineral density (BMD) Z-score ≤-2.0, is common in adults with thalassemia (Thal) and sickle cell disease (SCD), though disease-specific artifacts may contribute to inaccuracies in BMD assessment. Trabecular bone score (TBS), an indicator of bone quality, is not susceptible to these challenges and may improve fracture risk prediction.

METHODS

A retrospective chart review was conducted in patients with Thal or SCD who had at least one spine BMD scan by DXA in the past 10 years. The most recent scan was reanalyzed for bone quality with abnormal defined as TBS <1.2. Fracture prevalence was determined by patient report with medical record validation. Patients were compared to healthy controls who participated in previous research.

RESULTS

Data were abstracted from 126 patients with Thal (31.7 ± 11.9 yrs, 51 % Male), 170 with SCD (24.6 ± 13.5 yrs, 43 % Male), and 64 controls (25.9 ± 8.0 yrs, 17 % Male). Abnormal TBS was more common in Thal (26 %) or SCD (7 %) compared to controls (0 %, p < 0.001). Fracture prevalence was greater in Thal (36 %) compared to SCD (23 %) and controls (16 %, p = 0.005). Fragility fractures were not observed in controls but constituted 21 % of fractures in Thal and 15 % in SCD. After adjusting for age and hypogonadism, low bone mass was associated with an increased fracture prevalence (OR: 1.8, 95 % CI: 1.03, 3.23; p = 0.041), but not with fragility fracture. In contrast, abnormal TBS was strongly associated with fragility fracture after adjustment for age, sex, and BMI (OR: 11.4, 95 % CI: 2.2, 59.1, p = 0.004).

CONCLUSIONS

Bone quality by TBS may be a valuable tool in predicting the risk of fragility fractures in young adults with hemoglobinopathies and should be considered when making decisions for anti-resorptive therapy in those with low BMD naive to fracture or where disease-specific artifacts complicate accurate spine assessment by BMD alone.

Aetiology, diagnosis and treatment of thalassemia-associated osteoporosis of the adult

AIM

This review aims to overview factors contributing to TAO development and addresses the targeted diagnostic work-up and treatment management in adult thalassemic patients.

RESULTS

Osteoporosis management in Thalassemia is challenging because several factors contributing to its pathogenesis should be considered and controlled starting from child- hood. A multidisciplinary approach is crucial. Evidence concerning the efficacy of available anti-osteoporosis drugs in thalassemic patients is scarce. In this scenario, clinical experience and center resources often guide the treatment choice. More efforts should be made to share knowledge in this field in order to indicate specific treatment strategies for TAO management.

METHODS

We performed a literature search in Pubmed from 1992 to March 2024 using the words Thalassemia and: osteoporosis, Bisphosphonates, Denosumab, Teriparatide, Romosozumab, hormone replacement therapy, growth hormone, hypogonadism, calcium, vitamin D, bone disease, sarcopenia. The search was limited to English literature including original studies, reviews, meta-analyses, case reports.

Impaired physical ability in patients with transfusion-dependent β-thalassaemia: Can regular physical activity be a countermeasure?

Transfusion-dependent β-thalassaemia (TDβT) is a genetic disorder characterised by reduced or absent β-globin chain synthesis, resulting in chronic anaemia. Treatment consists of regular blood transfusions and chelation therapy to limit iron overload and its negative effects on organs (e.g. heart, lungs and liver). Despite improved life expectancy with transfusions and chelation therapy, TDβT patients experience poor quality of life and impaired exercise capacity (mainly due to muscle deconditioning and reduced cardiac inotropism). The aims of this review are (i) to discuss the role of organ dysfunction in the impairment of exercise capacity and reduced quality of life of TDβT patients; and (ii) to discuss physical activity as a potential therapeutic strategy to alleviate the multifactorial impact of the disease.

Bone turnover, areal BMD, and bone microarchitecture by second-generation high-resolution peripheral quantitative computed tomography in transfusion-dependent thalassemia

Thalassemic osteopathy includes low bone mass and impaired bone microarchitecture. We aimed to evaluate the prevalence and determinants of bone quantity (osteoporosis) and quality (microarchitecture) in a cohort of adult patients with transfusion-dependent thalassemia (TDT). Patients with TDT (n = 63) and age- and BMI-matched controls (n = 63) were recruited in the study. Areal bone mineral density (BMD) was measured using DXA Hologic scanner. P1NP and β-CTX were estimated by electrochemiluminescence assay. Bone geometry and volumetric BMD (vBMD) were estimated by second-generation high-resolution peripheral quantitative computed tomography. Bone turnover marker β-CTX was significantly lower in the TDT group, but there was no difference in P1NP levels. Low bone mass (Z ≤ -2) was present in greater proportion of patients both at lumbar spine (LS) (54 vs 0%; p = .001) and femoral neck (FN) (33 vs 8%; p = .001). Hypogonadism was associated with low BMD at FN (OR 10.0; 95% CI, 1.2-86; p = .01) and low hemoglobin with low BMD at LS (OR 1.58; 95% CI, 0.96-2.60; p = .07). The mean trabecular bone score was also significantly lower in patients compared with controls (1.261 ± 0.072 vs 1.389 ± 0.058). Total, cortical and trabecular vBMD were significantly lower in cases than controls. The trabecular number and cortical thickness were significantly lower and trabecular separation higher in cases than controls. Adults with TDT have significantly lower areal, cortical and trabecular vBMD. The bone microarchitecture is also significantly impaired in terms of lower number and wider spacing of trabeculae as well as lower cortical thickness and area at both radius and tibia.

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.