A 76 year-old woman is referred for evaluation of multiple non-traumatic vertebral compression fractures developing over the past year. She was initially diagnosed with osteoporosis at age 58 years, with her lowest T-score of -3.2 at her lumbar spine. She was treated with alendronate for one year, but because of significant gastroesophageal irritation, she switched to intravenous zoledronic acid once a year for the next three years without symptoms, followed by a 6-year drug holiday.
Once her bone density began to decrease after 6 years off treatment, she received a second three-year course of intravenous zoledronic acid, again without symptoms. After completing her second course of zoledronic acid, her bone density did not increase as much as it did with her first course, and her primary care physician switched her to denosumab 60 mg subcutaneously every six months. Because her bone density increased significantly after four years of denosumab treatment, her physician discontinued denosumab. One year after her last dose of denosumab, she developed severe back pain without a fall or other injury, and her spine films showed new vertebral compression fractures at L1, L3, and L4.