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.