Bone Abstracts

No treatment for osteoporosis abolishes the risk of fracture. Even under the ‘ideal’ conditions of adherence and monitoring, in the controlled pivotal trials, a significant proportion of individuals receiving the active drug still suffer new fractures. In everyday practice the situation is even more challenging. Adherence to medication is poor, patients are often older than in trials, or suffer from a number of comorbidities that could have excluded them from the original trials. Moreover receive a number of medications that make the treatment cumbersome and potentially interfere with the drug we prescribe for their osteoporosis. Underlying diseases, sometimes not clinically apparent, may also limit or totally cancel the efficacy of the drugs. Therefore, in clinical practice, a proportion of patients are not responding to the treatment in the way that the caregiver or the patient expects.

Bone density is one of the tools for monitoring the response. However, needs long observation periods and the increment in BMD should be superior to the least significant change for the technique. But, even in those that show significant reduction in BMD, the risk of fracture is reduced in some degree. Biochemical markers have experienced recent progress making them more suitable for clinical use. These markers assess the direct ‘tissue effect’ of the drugs, and are modified very early after starting treatment. However, still suffer from some practical limitations as the need for quite large variations, accessibility and biological variability. Finally, incident fractures are probably the most impactful event. Since their avoidance is the ultimate goal of a treatment, both the patient and the physician consider its occurrence as a possible treatment failure. However, since no treatment reduces the risk to zero, one incident fracture may be simply a chance event.

With these premises, treatment failure has been defined as the occurrence of two or more incident fractures in patients with good compliance. BMD and bone markers are also criteria for judgment. The clinician should, in these cases, assess compliance, rule out secondary causes of osteoporosis and other factors interfering with the effect of the drug. In some cases, however, the disease is too advanced and the bone strength so deteriorated that the available treatments are not enough to stop the fracture cascade.