Real-life effects of pharmacological osteoporosis treatments on bone mineral density by quantitative computed tomography

Introduction Monitoring of bone mineral density (BMD) is used to assess pharmacological osteoporosis therapy. This study examined the real-life effects of antiresorptive and osteoanabolic treatments on volumetric BMD (vBMD) of the spine by quantitative computed tomography (QCT). Materials and Methods Patients aged >= 50 years with a vBMD < 120 mg/ml had >= 2 QCT. For analysis of therapy effects, the pharmacological treatment and the duration of each therapy were considered. Identical vertebrae were evaluated in all vBMD measurements for each patient. A linear mixed model with random intercepts was used to estimate the effects of pharmacological treatments on vBMD. Results A total of 1145 vBMD measurements from 402 patients were analyzed. Considering potential confounders such as sex, age, and prior treatment, a reduction in trabecular vBMD was estimated for oral bisphosphonates (- 1.01 mg/ml per year; p < 0.001), intravenous bisphosphonates (- 0.93 mg/ml per year; p = 0.015) and drug holiday (- 1.58 mg/ml per year; p < 0.001). Teriparatide was estimated to increase trabecular vBMD by 4.27 mg/ml per year (p = 0.018). Patients receiving denosumab showed a statistically non-significant decrease in trabecular vBMD (- 0.44 mg/ml per year; p = 0.099). Compared to non-treated patients, pharmacological therapy had positive effects on trabecular vBMD (1.35 mg/ml; p = 0.001, 1.43 mg/ml; p = 0.004, 1.91 mg/ml; p < 0.001, and 6.63 mg/ml; p < 0.001 per year for oral bisphosphonates, intravenous bisphosphonates, denosumab, and teriparatide, respectively). Conclusion An increase in trabecular vBMD by QCT was not detected with antiresorptive agents. Patients treated with teriparatide showed increasing trabecular vBMD. Non-treatment led to a larger decrease in trabecular vBMD than pharmacological therapy.