Monitoring May Be Unnecessary After Bisphosphonate Treatment

Bone scans of postmenopausal women treated with the drug may be misleading

25 june 2009-- Postmenopausal women treated with a potent bisphosphonate should not undergo bone mineral density monitoring within the first three years of starting treatment because such tests can give misleading results, according to a study published online on June 23 in BMJ.

Katy J.L. Bell, of the University of Sydney in Australia, and colleagues conducted a trial of 6,459 postmenopausal women with low bone mineral density who were randomized to receive either placebo or the bisphosphonate alendronate, and who were followed up to undergo hip and spine bone density measurements one, two and three years later.

After three years of treatment, hip bone mineral density increased by a mean 0.030 g/cm² and treatment gave 97.5 percent of patients an increase of at least 0.019 g/cm², the researchers found. There was no substantial variation in treatment response from one individual to another, the investigators discovered.

"Clinicians may cite other reasons for monitoring besides estimating the intended effects of treatment," the authors write. "One common reason given is to assess adherence to treatment. However, the large background within-person variation for bone mineral density means that monitoring is unlikely to give reliable information about whether the drugs were taken as prescribed."

The study was supported by Merck. Authors reported relationships with Merck and other pharmaceutical companies.

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