Repeat bone scans are often not necessary for people with osteoporosis who are taking medications to increase their bone density, an expert says.
Updating the conference during a session on controversies in bone disease, endocrinologist and bone specialist Professor Mark Bolland from Auckland University said evidence showed there was very little benefit in patients having a dual energy X-ray absorptiometry (DXA) scan while they were on treatment for osteoporosis.
“I do a scan after they’ve finished treatment if I think it is going to change their management,” he said.
“And that depends on what they are taking because the persistence of effects on bone density differs by agent,“ he told delegates.
For example, the effects of risedronate wore off the quickest, followed by alendronate and then zolendronate, he said.
“You can modify how soon you’re going to do your bone density scan depending on what the patient’s baseline bone density was, whether they’ve had a fracture, and their fracture risk”.
The advice is echoed in recently updated RACGP guidelines which state that for patients with confirmed osteoporosis, a repeat BMD test is generally not required, “but may be conducted before initiating a change in, or cessation of, anti-osteoporotic therapy.”
“The message is that we don’t need to do bone density scans as often… probably the most information we’re ever going to get from bone density scans is that first one and subsequent scans aren’t going to give you that much more information,” Professor Bolland said.
He also noted that a number of guidelines had moved away from traditional bone-density based recommendations to measures of absolute risk.
“Absolute risk is established for cardiovascular disease, where we have interventions based on what a person’s five-year CV risk is, osteoporosis has gone that way as well”.
He told delegates a patient’s absolute fracture risk could be estimated from clinical risk factors such as bone density, age, gender, BMI and history of falls and fractures using one of the two available fracture risk calculators – the Fracture Risk Assessment Tool (FRAX) and the Garvan Fracture Risk Calculator.
“I use the Garvan Institute one for a couple of reasons – because I am supporting the Aussies and because the equations are publicly available so you can look at them and work out how the calculator works,” he said.