Divergent 12-Month Changes in Bone Mineral Density and Trabecular Bone Score With Menopausal Hormone Therapy Versus Alendronate: A Retrospective Comparative Cohort Study

Background/Objectives: Menopausal hormone therapy (MHT) and alendronate improve bone mineral density (BMD), but their comparative effects on trabecular bone score (TBS) are unclear. We compared 12-month changes in TBS and site-specific BMD in postmenopausal women treated with MHT or alendronate. Methods: This retrospective cohort included 172 treatment-naïve postmenopausal women with newly diagnosed osteoporosis who initiated MHT (n=87) or alendronate 70 mg/week (n=85). Complete baseline and approximately 12-month DXA/TBS data were available for 164 women (MHT, n=83; alendronate, n=81). The primary outcome was the adjusted between-group difference in lumbar spine TBS at follow-up, assessed by analysis of covariance. Results: The adjusted MHT-minus-alendronate difference in TBS was 0.023 (95% CI, 0.010–0.036; P<0.001). TBS showed no significant within-group change with MHT (0.002 ± 0.044; P=0.699) but decreased with alendronate (−0.018 ± 0.040; P<0.001). BMD increased significantly in both groups, with greater gains with alendronate at the lumbar spine (adjusted difference, −0.014 g/cm²; 95% CI, −0.019 to −0.009; P<0.001), femoral neck (−0.005 g/cm²; 95% CI, −0.009 to −0.001; P=0.013), and total hip (−0.007 g/cm²; 95% CI, −0.011 to −0.003; P<0.001). Conclusions: Both treatments improved BMD, but alendronate produced larger gains, whereas no significant within-group change in TBS was observed with MHT. These findings suggest discordant treatment-related changes in BMD and TBS and warrant cautious interpretation because of the observational design and limitations of serial TBS monitoring.