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

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 (N group: <3% increase in lumbar spine BMD [LBMD], N group: <0% increase in femoral neck BMD [FNBMD]) or responders (R group: ≥3% increase in LBMD, R 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 N group, and 134 (82.7%) were in the R group. A history of bisphosphonate treatment was a risk factor for being in the N group (odds ratio [OR]: 3.84, 95% CI: 1.38-10.71,  = 0.007; adjusted OR: 3.21, 95% CI: 1.01-10.19,  = 0.048). Although the N ( = 48; 30.8%) and R ( = 108; 69.2%) groups had similar baseline characteristics, the N group had a significantly higher baseline FNBMD than the R group ( = 0.003). The change in FNBMD was negatively associated with the FNBMD at baseline ( = -0.34,  < 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.