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.