AS patients on opioids twice as likely to have fracture: Study

Age, fracture history also ID'd as risk factors for Medicare patients in US

Margarida Maia PhD avatar

by Margarida Maia PhD |

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Note: This story was updated Oct. 31, 2023, to clarify that opioid use correlates with, rather than causes, an increased risk of bone fractures.

People with ankylosing spondylitis (AS) who are taking opioids — to relieve pain or for other reasons — are up to almost twice as likely to experience a fracture as those who are not taking opioids, a study of Medicare beneficiaries found.

Being older and having a history of fracture also was linked with increased odds of breaking a bone, by up to more than five times. But unlike opioid use, the researchers noted, these risk factors cannot be modified.

“To our knowledge, this is the first study demonstrating that opioid use is associated with a higher odds of fracture among adults with AS,” the team wrote, adding “this high-risk population should be considered for interventions to mitigate risk.”

Overall, AS patients with a history of fractures should be “prioritized for fracture prevention interventions, such as fall avoidance programs and osteoporosis treatment,” used for brittle, fragile bones, the researchers wrote.

The study, “Incidence Rate and Factors Associated With Fractures Among Medicare Beneficiaries With Ankylosing Spondylitis in the United States,” was published in Arthritis Care & Research.

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Osteoporosis more common with AS than general population: Study

More than 10% of AS patients found during follow-up to have fractures

AS is a type of arthritis that affects the joints along the spine (backbone) and other parts of the body, causing them to become inflamed. Inflammation results in back pain and stiffness, among a range of other symptoms.

Over time, AS can lead to osteoporosis, a condition that causes the bones to become weaker and to break more easily. However, how common fractures are, and why some patients are more prone to break a bone, is unclear.

To know more, researchers drew on data from the Rheumatology Informatics System for Effectiveness (RISE) registry, which stores electronic health records from rheumatology practices across the U.S.

These data were crossed with Medicare insurance claims from 2016 to 2018. This approach “allowed us to study a large number of patients with AS from a large group of community practices,” the researchers wrote.

The study included 1,426 adults — 794 men and 632 women — with a confirmed diagnosis of AS. Their mean age was 69.4 years, and just more than half (51.3%) were in the age range of 65 to 75.

The patients scored a median 11.2 points on the Routine Assessment of Patient Index Data 3 (RAPID3), which the researchers said was consistent with disease activity that was moderate. RAPID3 is a clinical tool that measures disease activity on a scale from 0 to 30, with a higher score indicating more disease activity.

Nearly 1 in 5 patients (19.4%) had a diagnosis of osteoporosis, and a slightly higher proportion (20.5%) were taking medications to treat this condition.

Over a follow-up period of at least one year, 197 patients (13.8%) had a total of 260 fractures. More than three-quarters — 153 patients or 77.7% — had one fracture, while 44 (22.3%) had two or more.

Fractures occurred both in women (52.3%) and men (47.7%).

“Men and women with AS were equally likely to have a fracture, unlike in the general population where women are known to be at higher risk,” the researchers wrote.

The overall incidence or number of new cases of fractures was 76.7 per 1,000 person-years. A person-year is a measure of time calculated based on the sum of the follow-up time contributed by all patients in the study.

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The most common fracture location was the spine (27.4%), in more than one-quarter of patients. This was followed by the forearm, wrist or hand in 22.8% of cases, the ankle or foot in 16.8%, and the hip, femur (thigh bone) or pelvis in 14.7% of cases.

Patients who were age 85 or older were 2.8 times as likely to experience a fracture compared with those who were younger than 65. Having a history of broken bones increased the odds further, by 5.24 times.

Those who had been prescribed opioids for one month at least one time also were more likely to experience a fracture, the researchers found.

Moreover, patients on a dose equivalent to more than 30 milligrams of morphine were 1.86 times as likely as those who did not take opioids to have a fracture.

We found that opioid use was associated with higher odds of fracture in AS, [making it a] “potentially modifiable risk [factor] for fracture occurrence among individuals with AS.

“Patients with AS may receive opioids for many reasons, including to address ongoing inflammatory pain and because of long-standing inflammation leading to joint damage and thus chronic pain,” the scientists wrote, noting that “multiple studies have shown 25% to 78% of patients with AS use opioids.”

“We found that opioid use was associated with higher odds of fracture in AS,” the team wrote, calling it a “potentially modifiable risk [factor] for fracture occurrence among individuals with AS.”

Special care should be exercised among elderly patients in starting on opioid treatments, according to the team.

“Importantly, … older adults with AS are already at higher risk of falls compared with the general population, and opioids may amplify this risk,” they wrote.

Because men and women experienced fractures at similar rates, “fracture prevention programs should be geared towards both men and women with AS,” the researchers concluded.