High Pain Sensitivity in Axial Spondyloarthritis Is Linked with Worse Disease

Pain is one of the defining symptoms of axial spondyloarthritis (axSpA), a type of inflammatory arthritis that predominantly affects the back and sacroiliac joints (where the spine connects with the pelvis). Pain in other joints is also well-characterized as “peripheral manifestation” (meaning, joints aside from those in the spine and chest) of axSpA.

However, recent research suggests that rheumatologists (specialists who treat axSpA) should be taking a closer look at the distinct characteristics of your axSpA pain when considering your treatment and how to manage your disease.

In particular, an important area of research has to do with pain sensitivity — or how your body interprets the pain you experience. People with more pain sensitivity feel pain more acutely than those with less pain sensitivity.

A recent study published in the Journal of Rheumatology found that in patients with axial spondyloarthritis, having higher pain sensitivity is associated with worse disease and health outcomes — including worse physical and mental health — regardless of whether you have radiographic damage to your sacroiliac joints signaling ankylosing spondylitis (AS) or have non-radiographic axSpA (nr-axSpA).

Axial spondyloarthritis is an umbrella term for inflammatory arthritis that includes both ankylosing spondylitis (when joint damage is visible on X-rays) and non-radiographic axial spondyloarthritis (has similar symptoms and disease burden but no damage that is visible on X-rays).

A Closer Look at What axSpA Pain Is Telling Us

This study, conducted between 2015 and 2017, included 175 axSpA patients in Sweden. Participants were classified as having AS or nr-axSpA. They were evaluated for pain through questionnaires asking about pain intensity, duration, and distribution. Researchers assessed pain sensitivity with something called computerized cuff pressure algometry (CPA), which is a special cuff that applies pressure to the muscle and deep tissue.

From these data, the researchers highlighted several key findings, including:

• 44 percent of patients reported chronic widespread pain and 33 percent of patients reported chronic regional pain.
• No significant differences in pain measures were seen between AS and nr-axSpA patients.
• Patients with a low pain tolerance had axSpA for a longer duration of time, worse disease activity, more pain regions, unacceptable pain intensity, worse enthesitis, fatigue, and anxiety.

When it comes to different pain aspects, patients with AS and nr-axSpA, had a comparable burden of disease, which signals that “chronic pain remains an important treatment target,” for all subtypes of axSpA, the authors noted.

They suggested their current findings provide further evidence that “local and central sensitization could contribute to pain [in all axSpA patients], based on heightened pain sensitivity” and “highlight the need for a better understanding of the mechanisms behind increased pain sensitivity in patients with axSpA.”

How AxSpA Pain Is Linked to Chronic Widespread Pain

Pain in axial spondyloarthritis is complex. A growing body of research is revealing more about how inflammatory pain can affect the way the central nervous system processes painful and nonpainful signals to create non-inflammatory central nerve pain. This, in turn, which can create chronic pain in a region of the body (chronic regional pain) or can trigger pain felt throughout the body (chronic widespread pain).

Chronic widespread pain is a hallmark symptom of pain conditions such as fibromyalgia, which researchers are finding is common in patients with axSpA.

For example, a 2021 study by British researchers found that axSpA patients with high pain scores were experiencing overlapping pain caused by both axSpA and by fibromyalgia. They also found that when patients were treated with a tumor necrosis factor (TNF) inhibitor biologic medication, which decreases immune system-driven inflammation, they subsequently had lower levels of widespread pain and were more likely to recover from fibromyalgia.

How to Understand and Communicate Your axSpA Pain

It’s important to be as detailed as possible when describing your pain to your rheumatologist or other health care providers. Sharing this information can help your provider better understand your pain burden and determine whether your current treatments are managing it appropriately.

Remember to also tell your doctor about pain beyond your lower back or joints, because if this Swedish study cohort is a reflection of the broader population of patients with axial spondyloarthritis, you could be experiencing local and chronic pain that each need to be addressed.

• Where on your body the pain occurs (which joints, regions, or parts are affected)
• When the pain occurs
• How long the pain lasts
• Your own description of pain intensity (if you say your pain is a 5 on a 0-10 scale, what does that mean for you?)
• What makes the pain feel better
• What makes the pain feel worse
• How the pain interferes with your daily activities
• How does the pain feel (throbbing, aching, sharp, shooting, etc.)
• Whether you think your current medications are helping or perhaps are no longer as effective
• How you’re feeling emotionally (depression and anxiety can impact pain)

Track Your AxSpA Symptoms with ArthritisPower

Join CreakyJoints’ patient-centered research registry and track symptoms like fatigue and pain. Learn more and sign up here.

This educational resource was made possible with support from UCB, a global biopharmaceutical company focused on neurology and immunology.