Tens of millions of people in the United States struggle with chronic back pain. Typical culprits are sprains, strains, soft tissue injuries, herniated discs and fractures. For a relatively small but significant percentage of sufferers, though, the source of the pain is less common and more elusive. It’s spondyloarthritis, an autoimmune and inflammatory disease that attacks the spine and small joints.

Spondyloarthritis (SpA), which affects as many as 3 million people in the United States – the number in Colorado is among the highest – encompasses a group of conditions with a common cause: inflammation triggered by the body mistakenly believing it is under attack. The result is persistent back and other joint pain, stiffness, swelling and even fusion of the vertebrae in a form called ankylosing spondylitis.

The true source of the pain may go undiagnosed for long periods of time, said Dr. Liron Caplan, associate professor of Medicine-Rheumatology with the University of Colorado School of Medicine. Caplan specializes in the study of SpA and treats patients at the Rocky Mountain Regional Veterans Administration Medical Center and UCHealth University of Colorado Hospital.

Caplan said SpA affects about as many people as rheumatoid arthritis, but is less well known and understood. “That can lead to unfortunate delays in diagnosis,” Caplan said. People may also mistakenly attribute their back discomfort to common “mechanical issues” – heavy lifting and overuse, for example – rather than the rarer autoimmune and inflammatory causes, and lose treatment time, sometimes for years, as the disease progresses and wreaks havoc on joints, he added.

Trying to catch spondyloarthritis early

There is no cure for SA, but it can be effectively managed with NSAIDs (non-steroidal anti-inflammatory medications), like celecoxib and ibuprofen, and drugs that suppress the immune system, as well as physical therapy and exercise. But a big key to success is early detection and treatment. To that end, Caplan leads a trial at the University of Colorado that aims to enroll those at risk for the disease and search for factors in their biology and environment that may trigger it.

The study, dubbed PIERS (Program for Individuals with an Elevated Risk of Spondyloarthritis), has thus far enrolled more than 100 people, Caplan said. It originated through the University of Colorado Program for Advancing Spondyloarthritis Treatment (C.U. PAST), which he co-directs with fellow rheumatologist Dr. Kristi Kuhn. Kuhn treats patients at the UCHealth Rheumatology Clinic – Anschutz Medical Campus and heads the University of Colorado School of Medicine’s Division of Rheumatology.

The key recruits for the PIERS study are those individuals who are at high risk of SpA, but do not yet have it. (People with back pain who do not have SpA and are not at risk for it and people who have SpA are also part of the study for comparison purposes.) The high-risk recruits fall into two groups, Caplan explained: those with immediate family members who suffered from the disease, and those with other diseases that often “travel together” with SA. These include inflammatory bowel disease (ulcerative colitis and Crohn’s disease), psoriasis and uveitis, which inflames the eye.

Chronic back pain: Clinical trail aims at early detection of spondyloarthritis

Simply put, back pain in people who fall into one or both of these groups is more likely to be caused by SpA than in it is in people in the general population, Caplan said. By pinpointing as many of these high-risk individuals as possible, Caplan and his colleagues hope to put them on alert for SpA and, if they get it, head it off before it becomes severe.

“The approach of the study is to identify these folks before they even develop the disease,” he noted. “We don’t have a cure [for SpA], but we do know from studies that if you intervene early enough, and if you use the appropriate medications, you can substantially affect the long-term prognosis in terms of the damage that we see on X-rays in the spine and lower back,” Caplan said.

The research team collects clinical information, blood and other biologic samples at the beginning of the study and can use them for comparison if an individual develops SpA later to probe what happened in that transition period, Caplan said. Changes in blood biomarkers, immune cells or tissue might provide the clues that lead to early detection, he added.

The C.U. PAST team has made significant contributions in that area already. For example, Kuhn and Caplan were coauthors of a study that examined changes in the microbiome associated with the presence of SpA and IBD.

Participants also get the benefit of the trained eyes of a research and clinical team, he added. “If they don’t have the disease, we can touch base with them once a year to see whether they are developing symptoms that might indicate they are undergoing that transition,” Caplan said. And of course, if they develop SpA, they will be able to start treatment during the crucial early phase of the disease, he added.

In addition to driving earlier intervention in patients with SpA, information from the PIERS study could spawn new therapies. In the long term, “that’s the home run we are all looking for,” Caplan said.

For more information on the PIERS study, contact Andrew Stahly at [email protected].