Non-response to osteoporosis treatment.

There are now a number of effective treatments for osteoporosis, which increase bone mineral density (BMD) and decrease the risk of fractures. There is no clear consensus on the optimal method for assessing response to treatment in the individual patient. The goal of osteoporosis treatment is to prevent fractures after minimal trauma, but these are relatively uncommon events and cannot be totally avoided by the use of currently available therapies. Alternative methods of assessing response to treatment include serial measurement of BMD or the biochemical markers of bone turnover, but the observed changes may be misleading if they do not exceed the least significant change. The proportion of patients who fail to respond to osteoporosis treatments is difficult to quantify. Clinical trials show continuing bone loss in up to 15% of participants on hormone replacement therapy or bisphosphonates. Non-response to treatment is probably more common in clinical practice, but may be due to poor adherence to treatment recommendations. Other potential causes of an apparent failure to respond to treatment include the use of a weak antiresorptive agent, differences in bioavailability, low dietary calcium intake, vitamin D insufficiency and underlying causes of secondary osteoporosis. The management of patients who fail to respond to treatment includes confirmation that they are adhering to treatment and have an adequate dietary calcium intake and vitamin D status and excluding causes of secondary osteoporosis. Consideration should also be given to the addition of calcium and vitamin D supplementation and the use of alternative treatments for osteoporosis.