Study Suggests Axial Spondyloarthritis Treatment Should Target ‘Low Disease Activity’

Rheumatologists often use a “treat-to-target” approach — which means establishing a set target, such as remission, and continuing to adjust a patient’s medication regimen to get them there — to manage conditions such as rheumatoid arthritis. But figuring out how to employ this strategy for axial spondyloarthritis (axSpA) patients has been a little trickier. 

In recent years, the Assessment of Spondyloarthritis international Society (ASAS) and the European League of Rheumatology (EULAR) have recommended using treat-to-target for people with axSpA, but the exact target that doctors and patients ought to aim for remains unclear. While some experts have suggested striving for “inactive disease,” a new study suggests that “low disease activity” might be a more reasonable option. 

Inactive disease is defined as having an Ankylosing Spondylitis Disease Activity Score (ASDAS) of 1.3 or less. Low disease activity refers to an ASDAS score that’s between 1.3 and 2.1.  

While a lower ASDAS number is objectively better, it’s far more difficult to achieve inactive disease, and many patients never get there. Might aiming for low disease activity, rather than inactive disease, be a good-enough goal for most axSpA patients?     

A new study, published in the journal Arthritis Research & Therapy, was designed to determine what level of disease activity would be sufficient for stemming radiographic progression of the disease (meaning joint damage visible on X-rays or MRIs is curtailed).

The researchers analyzed data on 101 axSpA patients in the Spanish Register of Biological Therapy in Spondyloarthritides (REGISPONSERBIO) study. They broke them into two groups based on how long they had been on a TNF inhibitor biologic. The long-term group used these drugs for at least four years; the short-term group had been on them for less than that.

The researchers also analyzed the patients’ imaging tests, which had been scored based on a standard assessment called the Stoke Ankylosing Spondylitis Spine Score (mSASSS).

As expected, the results “showed that disease activity measured by ASDAS is clearly associated with radiographic spinal progression in patients on TNFi treatment,” meaning that those with lower ASDAS scores had far less progression of damage compared to those with high ASDAS scores.

What’s more, those who at least achieved low disease activity — and maintained low levels while taking a TNF biologic for at least four years — were very likely to have avoided significant radiographic progression. (This benefit wasn’t generally seen until patients had been on TNFi for at least three years, so it applied to only some people in the short-term TNFi group.) 

“Our results showed that patients on long-term treatment with a mean sustained average of low disease activity measured by ASDAS over time show significantly less progression rates than those with high ASDAS averages,” the authors wrote. “Hence, our data supports previous studies that suggest a slowdown effect on radiographic progression associated to the maintenance of disease control in patients with axSpA treated with TNFi.” 

Found This Study Interesting? Get Involved

If you are diagnosed with arthritis or another musculoskeletal condition, we encourage you to participate in future studies by joining CreakyJoints’ patient research registry, ArthritisPower. ArthritisPower is the first-ever patient-led, patient-centered research registry for joint, bone, and inflammatory skin conditions. Learn more and sign up here.