Risk factors for poor response to denosumab treatment in Japanese postmenopausal women with osteoporosis

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 (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.

Zinc improves Denosumab and eldecalcitol efficacy for bone mineral density in patients with hypozincemia

INTRODUCTION

We aimed to investigate the effects of zinc deficiency and zinc medication in osteoporosis patients undergoing denosumab (DMAb).

MATERIALS AND METHODS

This retrospective study was conducted at a single hospital. The participants were female osteoporosis patients visiting between April 2019 and April 2020. All patients were treated with DMAb and eldecalcitol and recommended zinc-rich food. Based on zinc medication and serum zinc levels at the 12th month of dietary guidance, patients were categorized into the following four groups: hypozincemia with zinc medication, latent zinc deficiency with zinc medication, without zinc medication, and control without zinc medication. Longitudinal serum zinc concentrations, bone mineral density (BMD), and occurrence of fractures were measured. We investigated the factors influencing no response to DMAb and eldecalcitol treatment.

RESULTS

Among the 145 patients followed up for 24 months, dietary guidance did not change the serum zinc concentration; however, zinc medication significantly increased these levels. The hypozincemia group did not show a significant BMD increase in the lumbar spine and femoral neck after DMAb and eldecalcitol treatment during dietary guidance; however, zinc medication increased these to the same levels as the other groups. In multivariate analyses, hypozincemia and thyroid disease were identified as the factors affecting no response. While 28.2% of patients with latent zinc deficiency without zinc medication suffered fractures, no fractures occurred in hypozincemia patients with zinc medication.

CONCLUSION

Hypozincemia may reduce the efficacy of DMAb and eldecalcitol in increasing BMD and fracture prevention.