CHICAGO – More than 40% of patients who presented to a tertiary pain center with axial spine pain met the criteria for fibromyalgia. These patients may represent a subset of the spine pain population who will be unresponsive to standard interventions.

The presence of fibromyalgia may undermine the effectiveness of opioids, according to the investigators.

"Our group is very interested in the concept of centralized pain and in trying to better differentiate patients based on phenotype at the point of care. Many patients seek care for axial spine pain, and the outcomes are mixed," Dr. Chad M. Brummett noted at the annual meeting of the American Society of Anesthesiologists.

"Fibromyalgia-positive patients were different in all phenotypic measures of pain, mood, and function assessed."

"We are interested in applying what has been learned about fibromyalgia to the spine community. The field has been writing about personalized care for 20 years, but we still tend to give all patients the same drugs. Our aim is to provide physicians with information that will guide therapy," said Dr. Brummett, director of adult pain research at the University of Michigan Back and Pain Center in Ann Arbor.

He noted that failure rates for facet interventions for the treatment of axial spine pain have ranged from 39% to 47%, and persistent pain is common. There is a growing appreciation in the pain community of a subset of patients with altered central pain processing leading to widespread body pain, such as fibromyalgia, who may require a different treatment approach, he said.

The observational cohort study included 256 new patients categorized as having axial spine pain; of the 244 who completed the American College of Rheumatology fibromyalgia survey, 101 patients (41.4%) met the ACR fibromyalgia criteria.

"We saw profound phenotypic differences between the two groups," Dr. Brummett noted, although he acknowledged that as a tertiary care facility his group is "bound to see a more failed population."

"Some would argue whether this means they have fibromyalgia or not, and that is not clear, but certainly this is a different group," he emphasized.

Dr. Brummett and colleagues observed significant differences in pain, function, mood, and anxiety in the fibromyalgia-positive pain population, compared with patients who did not meet the ACR criteria for fibromyalgia. For example, among the 101 patients with fibromyalgia, the mean pain intensity score on the Brief Pain Inventory was 7.05, while it was 6.10 in those without fibromyalgia. Scores for both depression and anxiety were higher for those with fibromyalgia than those without (mean depression and anxiety scores on the Hospital Anxiety and Depression Scale were 11.33 and 11.38, respectively, for those with fibromyalgia and 7.47 and 6.81, respectively, for those without). Likewise, the mean Patient Reported Outcomes Measurement Information System score for physical function was 27.96 for those with fibromyalgia and 32.24 for those without.

"Fibromyalgia-positive patients were different in all phenotypic measures of pain, mood, and function assessed," reported Dr. Brummett, who along with his colleagues was awarded for having the "Best Clinical Abstract" at the meeting.

The investigators also asked the patients questions about the efficacy of previous interventions. Current use of opioid medications was reported by 60.4% of fibromyalgia-positive patients and 43.4% of fibromyalgia-negative patients (P = .012). Although not significant, fibromyalgia-positive patients taking opioids reported lower efficacy. Epidural interventions were common in both groups, at 37.6% and 43.8%, respectively, but fibromyalgia-positive patients rated the epidurals as being less effective (P = .036).