Response to NSAIDs does not differ between axSpA, chronic back pain patients

Patients with longstanding axial spondyloarthritis (axSpA) and those with nonspondyloarthritis (non-SpA) with chronic back pain show no significant difference in their response to nonsteroidal anti-inflammatory drugs (NSAIDs), according to a study.

A team of investigators prospectively recruited 233 consecutive patients with chronic back pain (axSpA or non-SpA). Previous use of NSAIDs was withdrawn 2 days prior to study initiation (baseline).

A numerical rating scale (NRS; range 0‒10) was used to assess back pain, starting at 2 hours after baseline and several times thereafter up to 4 weeks. “Any response” to NSAIDs was defined as improvement in back pain on the NRS >2 units, while “good response” referred to improvement >50 percent, relative to baseline.

Of the patients, 68 had axSpA (29.2 percent) and 165 non-SpA back pain (70.8 percent). Participants had a mean age of 42.7 versus 49.3 years, symptom duration of 15.1 versus 14.6 years, and pain score of 5.9 versus 6.3, respectively.

Overall, 30.9 percent of patients with axSpA and 29.1 percent of those with non-SpA back pain showed any response to NSAIDs after 4 weeks, while 23.5 percent and 16.4 percent showed a good response, respectively (p value was nonsignificant).

Differences were not observed in terms of rapidity of response and between subgroups of patients based on demographics, including axSpA stages.

“The item in the Assessment of SpondyloArthritis international Society classification criteria on ‘response to NSAIDs’ needs more study,” according to the investigators.