Correlation Between the Deltoid Tuberosity Index and DXA Measurements: Feasibility of Opportunistic Osteoporosis...

Osteoporosis is a common metabolic bone disease associated with increased fracture risk and reduced quality of life. The deltoid tuberosity index (DTI), derived from humeral radiographs, reflects cortical thickness and may serve as a simple radiographic indicator of reduced bone mass. However, limited data exist regarding the relationship between DTI and dual-energy X-ray absorptiometry (DXA) parameters across different skeletal regions, particularly using routine chest radiographs. This retrospective study included 318 patients (303 females, 15 males) who underwent DXA measurements and radiographic imaging of the proximal humerus (chest, shoulder, cervical, or humeral radiographs). DTI measurements were independently performed by four observers, and mean values were used for analysis. Associations between DTI, bone mineral density (BMD), and T-scores were evaluated using Pearson correlation analysis. Receiver operating characteristic (ROC) analysis was performed to assess the ability of DTI to predict osteoporosis. DTI showed significant positive correlations with BMD and T-scores in both the lumbar spine (r = 0.295, p < 0.001) and femoral neck (r = 0.525, p < 0.001), with stronger associations observed in the femoral region. The area under the ROC curve (AUC) for predicting osteoporosis was 0.768 for the femoral neck and 0.677 for the lumbar spine. The optimal femoral DTI threshold for identifying femoral osteoporosis was 1.37 (sensitivity 73%, specificity 75%).Lumbar and femoral measurements were strongly correlated (BMD: r = 0.682; T-scores: r = 0.742; both p < 0.001), although femoral T-scores were significantly lower than lumbar values (mean difference = 0.17, p < 0.001). Across all age groups, DTI remained positively correlated with T-scores, with the strongest associations observed in patients aged ≥ 65 years. Interobserver reliability was excellent (intraclass correlation coefficient = 0.92). DTI is a practical, reproducible, and cost-effective radiographic parameter associated with reduced bone mass. Because it can be obtained from routinely performed chest radiographs, one of the most frequently used imaging examinations, DTI may help opportunistically identify individuals, particularly postmenopausal women, who could benefit from further osteoporosis evaluation and referral for formal bone mineral density assessment.Level of Evidence III: Diagnostic Study.