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.