Hip fracture risk after discontinuing bisphosphonate use

A recent article in Osteoporosis International (published online in May 2008) reports the effect on hip fracture risk of a drug-free holiday from bisphosphonates. During two years of follow-up the hip fracture rate in those who discontinued therapy was 8.4 per 1,000 years, significantly higher than those who stayed on therapy (4.7 per 1,000 years). Women who were 80% or more compliant during two years on therapy prior to discontinuation were not at increased risk of hip fracture after discontinuation.

Two points to make here. Firstly patients on appropriate therapy aimed at decreasing hip fracture risk also need to be given as much advice as possible about fall protection and not just rely on medication. Included in this advice is a call to each of us to minimize the use of any medications that might impair balance or cause postural hypotension.

Secondly, effective therapy is only effective if patients take it.

Compliance! Compliance! Compliance! An issue for all diseases and conditions that are asymptomatic.

In osteoporosis the situation is aggravated by the slow response of DEXA scans. I appreciate that I am beginning to sound like a broken record, but I have to re-state my preference for checking a biochemical marker of bone resorption in patients on therapy with inhibitors of bone resorption such as bisphosphonates. These serum-based assays are not yet of proven benefit in deciding whether the patient should be started on an anti-resorptive or an anabolic therapy (teriparatide), but a baseline value with a repeat at three months should show a drop from the pretreatment value by at least 20% in compliant patients.

Failure to demonstrate this response is most likely due to non-compliance but it should also act as a reminder to you to review the history and lab studies to make certain you have not overlooked a potential secondary case of osteoporosis.

Any other advice about optimizing patient compliance would be appreciated.