Controversies in the treatment of postmenopausal osteoporosis: How long to treat with bisphosphonates?

Osteoporosis is a systemic skeletal disease characterized by reduced bone mass and deterioration of bone tissue microarchitecture leading to an increased risk of fractures. Fragility fractures, especially hip fractures, are associated with a significant reduction in the physical function and quality of life of affected patients, as well as increased mortality, leading to a major financial impact on health care. Many drugs have been registered for the treatment of osteoporosis and very recently, a new anabolic agent, romosozumab, has been approved in some countries. Despite the expansion of efficacious antiresorptive and anabolic therapies in recent years, a concomitant increase in concerns have been raised by physicians, patients and the lay press about the potential for adverse events, especially atypical femoral fractures (AFF) following prolonged use of bisphosphonates. Whatever the mechanism(s) may be, direct or indirect, linking prolonged bisphosphonate use to atypical femoral fractures, this adverse event is very rare in comparison to the magnitude of risk reduction of typical osteoporotic fractures. An estimated 162 osteoporosis-related fractures are prevented for each atypical femoral fracture associated with an anti-resorptive medication. Until a risk calculator for predicting risk of atypical fractures, becomes available in clinical practice, and we view this as an unlikely scenario, it is up to the physician to consider continuing or discontinuing bisphosphonate use after the critical 3-5 year period of treatment with zoledronic acid or alendronate, but close monitoring for the residual bone effects overtime should be planned. For other bisphosphonates, in which no residual effects are expected, drug holiday is usually not applied.