Hyperparathyroidism in patients with low bone mineral density treated with zoledronic acid or denosumab.

Objective: To analyze the prevalence of hyperparathyroidism in patients treated with zoledronic acid (ZA) or denosumab, its relationship with other parameters and how it affects on bone mineral density (BMD) evolution.

Methods: Retrospective observational study in patients with osteoporosis or osteopenia and high risk of fracture, who have received denosumab or ZA for at least two years. Patients diagnosed with hyperparathyroidism or glomerular filtration rate <30ml/min at baseline visit were excluded from the study.

Results: Ninety patients (ZA: 54.44%) were included. 18.36% of ZA-treated patients had elevated PTH levels at some time compared to 36.58% denosumab-treated patients (p>0.05). Patients with persistently elevated PTH were 6.13% in the AZ group and 19.51% in the denosumab group (p<0.04). We found a statistically significant inverse association between elevated PTH levels, glomerular filtration rate (p=0.007), and albumin-corrected calcium (p <0.001). We did not find an association between hyperparathyroidism and BMD evolution.

Conclusions: A high incidence of hyperparathyroidism was observed in patients treated with AZ and especially denosumab. Hyperparathyroidism correlated inversely with glomerular filtration rate and albumin-corrected calcium. Elevated PTH does not appear to affect short-term bone mineral density evolution.