Assessment for bone health in patients with differentiated thyroid carcinoma after postoperative TSH suppression therapy: A new Fracture Risk Assessment Algorithm

Purpose: In the general population, the Fracture Risk Assessment tool (FRAX) is used to assess the 10-year risk of major site and hip fractures; however, it is unclear whether this tool can be applied to patients receiving levothyroxine-based Thyroid Stimulating Hormone (TSH) suppressive therapy for postoperative differentiated thyroid cancer patients. Methods: Sixty-four postoperative differentiated thyroid cancer patients and 30 gender-and-age-matched controls were selected. The FRAX was used to calculate the fracture risk with and without bone mineral density (BMD). Thyroid function include TSH were detected and then TSH level were converted to an age-weighted score to calculate the fractures risk of postoperative differentiated thyroid cancer patients. Dual-energy X-ray bone mineral density measurement T score was used as the gold standard to diagnose osteoporosis. SPSS 26.0 software was used for statistical analysis. Results: The T score of bone mineral density in the disease group was lower than that in the control group (-1.09 vs -1.36, P<0.05). The area under the curve of FRAX without BMD for predicting major osteoporotic fractures (PMOF) and hip fractures (PHF) was 0.694 and 0.683, respectively. The cut-off values were 2.15% and 0.25%, respectively. The area under the curve of FRAX with BMD for PMOF and PHF was 0.976 and 0.989, respectively, and the cut-off values were 4.15% and 1.1%, respectively. The area under the curve of FRAX without BMD for PMOF and PHF was 0.708 and 0.72 respectively, and the cut-off values were 5.5% and 1.55%, respectively. Conclusions: The FRAX is suitable for postoperative differentiated thyroid cancer patients after TSH suppressive therapy. In the absence of BMD, TSH weighted by age can improve the specificity of FRAX in the diagnosis of osteoporosis in this population.