Abstract

Osteoporosis is characterised by reduced bone mass, deteriorated bone architecture and increased risk of fractures. A fracture in a patient with osteoporosis is therefore not uncommon, not even in treated patients as none of the available treatments can prevent fractures completely. Despite this knowledge a fracture is a disturbing event for the patient and should prompt the treating physician to consider the situation. First of all, compliance with the treatment including supplementation with calcium and vitamin D should be checked. Secondly, competing diseases and treatments and other risk factors may have emerged since the patient was diagnosed and started on treatment, and these conditions may attenuate the anti-fracture efficacy of the treatment (thyrotoxicosis, prednisolone, aromatase inhibitors etc). If compliance is good and no new risk factors have emerged, treatment failure should be considered.

Treatment failure can be assessed by new fractures, changes in BMD or bone turnover markers. Treatment failure is suggested if treatment has been ongoing for more than 12 months with good compliance and 2 or more new fractures occur or 1 new fracture in combination with declining BMD or non-suppressed bone turnover markers or BMD declines in combination with non-suppressed bone turnover markers.

If treatment failure is demonstrated then the treatment should be reconsidered. The absorption of oral bisphosphonates is 1–2% under optimal conditions, so the first alternative would be intravenous zoledronic acid or alternatively denosumab. Both are strong antiresorptives which have been proven to be able to increase BMD and suppress bone turnover in patients previously treated with oral bisphosphonates. If the incident fracture is a vertebral fracture, it could also be considered to change to teriparatide, a bone forming treatment with very prominent effects on spine BMD and vertebral fractures.