Predicting Fractures in RA: Is FRAX Useful in the Modern Treatment Era?

AUSTIN, Texas – The Fracture Risk Assessment Tool (FRAX) for predicting risk of osteoporotic fractures appeared valid for rheumatoid arthritis (RA) patients treated in the era of biologics.

In a Canadian database study, the mean predicted 10-year risk of major osteoporotic fractures (MOF) among patients with RA treated over the past 20 years came in at 13.2% per FRAX with bone mineral density, which was spot on for the observed 10-year risk of MOF, “indicating good overall calibration,” reported Ceri Richards, MD, of the University of Manitoba in Winnipeg, Canada.

“In populations similar to this, clinicians can continue to use FRAX for osteoporosis management of rheumatoid arthritis patients,” Richards said in a presentation at the American Society for Bone and Mineral Research (ASBMR) annual meeting.

However, only about 10% of the patients with RA were taking biologics; the vast majority (81%) were on other disease-modifying agents. Richards acknowledged that the low exposure to biologics may have influenced the outcome of the trial, and that the researchers “had originally thought that biologics would result in lower risk of major osteoporotic fractures.”

ASBMR session co-moderator Maria Danila, MD, of the University of Alabama at Birmingham, said it was surprising that such a small number of RA patients in the study were on biologics, which “were approved for use in the late 1990s.”

“Most of us practicing clinicians in the United States have been using them more frequently than in this study,” said Danila.

She speculated that the Canadian cohorts in the study were overall healthier than what she sees in her clinical practice, possibly with disease not severe enough to require biologics. “The restrictions for reimbursement in Canada may be different than what we see in the United States as well,” Danila told MedPage Today.

“This is a study we need to do again to see if there is an impact of biologics on FRAX outcomes,” she said. “I would not think that the biologics would be a risk factor for osteoporosis. I would think it would be vice versa, because the biologics control inflammation, and inflammation is what can worsen bone health.”

The study presented by Richards included 2,099 RA patients from the Manitoba Bone Mineral Density Testing Program from 2000-2018, whose fracture outcomes were compared with an equal number of individuals without RA.

Patients ranged in age from 62 to 65, the majority were female and white, and around 20% had a prior fracture. Glucocorticosteroids were more commonly used in the RA group (28% vs 4%). MOF outcomes were obtained from population-based data linkage. The primary endpoint was MOF in a 10-year period.

ASBMR co-moderator Radhika Narla, MD, of the University of Washington/Puget Sound Veterans Affairs in Seattle, told MedPage Today that FRAX scores can be helpful in making treatment decisions in RA due to the higher fracture risk in this patient population.

In this study, 15.6 cases of MOF per 1,000 person-years were recorded in the RA group versus 11.7 per 1,000 person-years in the non-RA group.

FRAX incorporates several factors — including age, sex, height, weight, smoking, history of prior fracture, and use of glucocorticoids — to estimate the risk of having a MOF or hip fracture over the next 10 years, Narla noted.

“That can guide treatment in patients who are on the fence,” she said, such as those who don’t meet the definition of osteoporosis (T-score of -2.5) but have an elevated score on FRAX.

“If you have a -2.3 but have an elevated FRAX score, that could also mean that you need treatment,” she said.