The risk of vertebral fractures in patients with differentiated thyroid cancer undergoing TSH suppression therapy

BackgoundSuppression of thyroid-stimulating hormone (TSH) can adversely affect bone tissue in individuals with differentiated thyroid cancer (DTC).In a multi-center setting, this study aim to examine vertebral fractures (VF) and bone mineral density (BMD) in DTC patients receiving levothyroxine (LT4) suppression therapy. MethodsClinical measurements done in the last visit, laboratory and radiologic data extracted from patients files. Serum TSH concentrations were divided into four groups based on the American Thyroid Associations guidelines for TSH suppression: 0.01 mu/L, 0.01-0.1, 0.1-0.5 mu/L, and >0.5 mu/L. Within the preceding year, the BMD measurements obtained in the lumbar and femoral regions with a DXA scanner were recorded. Lateral spinal X-rays obtained within the previous year were evaluated. ResultsThe study comprised 990 people with DTC. The DXA showed 545 patients with normal BMD, 82 (8.2%) with osteoporosis, and 363 (36.6%). patients had osteopenia. The osteoporotic group exhibited older age (p = 0.001), lower BMI (p = 0.001), and comparable TSH levels compare to the osteopenia and normal BMD groups. In 476 lateral vertebral x-rays, 200 (42%), 131 (27.5%) were significant or severe VF. The severe TSH suppression group had a greater fracture rate than the moderate, mild, and non-suppressed groups(p=0.013). VF patients were older (p = 0.001) and had lower femur neck and L1-L4 BMD. Disease duration, FT4 level, and femur neck BMD affected fracture risk (p = 0.001, pseudo R2: 0.028). Age, femur neck BMD, L1-L4 BMD, and osteocalcin levels were linked with osteoporosis in a multivariate analysis (p = 0.001, pseudo R2: 0.427). TSH subgroups had similar femur neck (p = 0.61) and L1-L4 BMD (p = 0.89). ConclusionFindings suggest that DTC patients undergoing TSH suppression have a significant risk of VF. Assessment of VF should be integrated into the routine care of DTC survivors to ensure long-term skeletal safety.