INCIDENCE OF HYPERPARATHYROIDISM IN PATIENTS WITH OSTEOPOROSIS TREATED WITH ZOLEDRONIC ACID OR DENOSUMAB
Authors: Barcena C et al.
Denosumab and zoledronic acid are antiresorptive drugs commonly used in the treatment of osteoporosis (OP). Both can cause hypocalcemia and parathormone (PTH) elevations. Its prevalence, the mechanism by which it occurs, and the clinical repercussions are unknown. The aim of this retrospective observational study was to analyze the prevalence of PTH elevation above the reference value in patients receiving zoledronic acid or denosumab and its relationship with other clinical-analytical parameters. Patients with OP who have received treatment with denosumab or zoledronic for at least two years were included. 91 patients with a mean age of 68 years at the start of treatment were included. 49 (81.6% women) patients started treatment with zoledronic and 42 (61.9% women) with denosumab.
Patients with persistently elevated PTH during the two visits were 3 (6%) with zoledronic and 9 (21.4%) with denosumab (p< 0.02).
An inverse statistically significant association between corrected calcium and glomerular filtration rate compared to elevated PTH was found. Normal PTH values and female gender were associated in a statistically significant way with a worse evolution of bone mineral density at the lumbar region.
In this study from Spain a high prevalence of hyperparathyroidism in osteoporotic patients treated with zoledronic acid or denosumab was found, higher in those treated with denosumab. The elevation of PTH seemed to be associated, inversely, with serum levels of ionic calcium and the glomerular filtration rate. Elevated PTH levels were associated with a better evolution of bone mineral density. In this context the elevation of PTH could act as a marker of treatment effectiveness. It is also important to know that the increase in PTA, when serum calcium concentration is normal, should not cause further examinations and treatment of this form of «hyperparathyroidism».