Clinicians love the World Health Organization’s online Fracture Risk Assessment Tool (FRAX) despite its flaws. As in any realistic love affair, they adapt to FRAX’s shortcomings and find ways to make it work because they know they’re better off with FRAX than without it.
“I think FRAX is incredibly useful in managing individual patients,” Dr. Steven T. Harris said at a conference on osteoporosis sponsored by the University of California, San Francisco. “I use this all the time in my office interactively.” Dr. Harris turns his laptop so that both he and the patient can see the screen, and together they answer FRAX’s questions about the patient’s characteristics, from which it computes the patient’s likelihood of having an osteoporotic fracture during the next 10 years.
Nearly all of the other online sites that patients often visit when researching their risk of osteoporosis or fracture provide estimates of relative risk, but FRAX estimates the absolute risk of fracture. “It makes a huge difference in treatment decisions,” said Dr. Harris of the university.
Discussing whether to treat an individual to lower their risk of fracture is “an incredibly nuanced issue,” he added. Once he and a patient get the fracture risk from FRAX, they may discuss whether the patient wants to take medications to reduce that risk by half.
The FRAX site gets around 35 million hits per year, so plenty of people are using it, Dr. Dolores Shoback said in a separate presentation at the meeting. Dr. Shoback, professor of medicine at the university, and Dr. Harris agreed that clinicians and patients must use their own judgment to supplement the FRAX information in deciding whether to start treatment.
The caveats to FRAX are many. The model is based only on femoral neck bone mineral density and it ignores spine bone mineral density. Some clinicians complain that many risk factors are not quantified in FRAX, Dr. Shoback said. In the family history section, only a parental history of hip fracture is considered. FRAX does not account for Vitamin D status, exercise habits, the individual’s propensity for falls, a history of multiple fractures, the presence of multiple secondary risk factors, and the dose or duration of some of the risk factors that are included in FRAX, such as smoking, alcohol or steroid use.
FRAX has no mechanism to weight a particular risk factor over another, and it’s not clear what margin of error is present in FRAX’s fracture risk estimates.
All this leads some to question FRAX estimates, but Dr. Harris stands by them. “There is some debate about whether the numbers are real, or off. I suspect they are true,” he said.
FRAX is not valid for premenopausal women, patients younger than 50 years, or someone who previously received treatment for osteoporosis.
When Dr. Harris sees a patients on osteoporosis therapy, however, he still may use FRAX and explain that the treatment probably reduces the patient’s risk estimate by 20%-50%. Or, he may run FRAX using the patient’s data from a few years earlier, before the patient started treatment, to help guide management decisions.
“It’s a very subtle discussion,” he said.
And while we’re on the topic of Internet tools, here’s a tip presented at the meeting by Dr. Deborah Sellmeyer, director of the Metabolic Bone Center at Johns Hopkins University, Baltimore. The Dairy Council of California offers a free Calcium Quiz that helps users estimate whether they’re getting enough dietary calcium. Not surprisingly, if your numbers come up short, the site recommends consuming more dairy products instead of, say, more almonds, corn tortillas, or tofu. Still, it’s a starting point for one of those subtle, nuanced discussions between clinicians and patients.
Speaking of potential conflicts of interest, Dr. Shoback and Dr. Sellmeyer said they have none. Dr. Harris has had financial relationships with Amgen, Eli Lilly & Co., Genentech, Gilead Sciences, Merck, Novartis, Roche, sanofi-aventis, and Warner Chilcott.
–Sherry Boschert (@sherryboschert)