Risk factors for nonresponse to 2 years of denosumab administration in patients with osteoporosis: A retrospective single-center cohorts study.

ABSTRACT

Background and Aims: To investigate the factors associated with changes in bone mineral density (BMD) and the incidence of fractures in osteoporotic patients treated with denosumab. Methods: This retrospective study included 162 osteoporotic patients treated with denosumab for 24 months between 2013 and 2019. Patients were divided according to the changes in BMD as nonresponders (NL group <3% increase in lumbar spine BMD [LBMD], NH group <0% increase in femoral neck BMD [FNBMD]) or responders (RL group ≥3% increase in LBMD, RH group ≥0% increase in FNBMD). Results: The respective changes in the LBMD and FNBMD after 24 months of denosumab treatment were 9.3% (95% confidence interval [CI] 8.1-10.6) and 3.3% (95% CI 2.1-4.5). Twenty-eight (17.3%) patients were in the NL group, and 134 (82.7%) were in the RL group. A history of bisphosphonate treatment was a risk factor for being in the NL group (odds ratio [OR] 3.84, 95% CI 1.38-10.71, p = 0.007; adjusted OR 3.21, 95% CI 1.01-10.19, p = 0.048). Although the NH (n = 48; 30.8%) and RH (n = 108; 69.2%) groups had similar baseline characteristics, the NH group had a significantly higher baseline FNBMD than the RH group (p = 0.003). The change in FNBMD was negatively associated with the FNBMD at baseline (r = -0.34, p < 0.001). No new osteoporotic fractures occurred in either group during follow-up. Conclusion: In osteoporotic patients receiving denosumab treatment, a history of bisphosphonate treatment was a risk factor for a lack of increase in LBMD, and a higher FNBMD at baseline was negatively associated with the change in FNBMD.