The following is a summary of “Good Response to Nonsteroidal Antiinflammatory Drugs Does Not Discriminate Patients With Longstanding Axial Spondyloarthritis From Controls With Chronic Back Pain,” published in the March 2024 issue of Rheumatology by Baraliakos et al.

Researchers conducted a retrospective study to assess the differential response to nonsteroidal anti-inflammatory drugs (NSAIDs) between patients with longstanding axial spondyloarthritis (axSpA) and control individuals experiencing back pain (non-spondyloarthritis [non-SpA]).

They enrolled consecutive outpatients experiencing chronic back pain (axSpA or non-SpA). Participants underwent withdrawal from any prior NSAIDs two days before the study commenced (baseline). Back pain, evaluated using a numerical rating scale (NRS; range 0-10), was monitored starting 2 hours post-baseline and at various intervals over 4 weeks. “Any response” to NSAIDs was defined as a back pain improvement exceeding 2 units on the NRS, while a “good response” was characterized by an improvement exceeding 50% compared to baseline.

The results showed that among the 233 patients included, 68 (29.2%) had axSpA, and 165 (70.8%) had non-SpA back pain. The mean age was 42.7 (SD 10.7) years for axSpA patients and 49.3 (SD 11.1) years for non-SpA back pain patients, with symptom durations of 15.1 (SD 11.1) years and 14.6 (SD 11.9) years. Pain scores were 5.9 (SD 2.3) for axSpA patients and 6.3 (SD 2.0) for non-SpA back pain patients. 30.9% of axSpA patients and 29.1% of non-SpA back pain patients showed any response after 4 weeks, while 23.5% of axSpA patients and 16.4% of non-SpA back pain patients showed a good response (P value not significant). No differences were found in the rapidity of response or between subgroups of patients based on demographics, including different stages of axSpA.

Investigators concluded that there is no clear distinction in response to NSAIDs between axSpA and non-axSpA chronic back pain and suggested the need for further evaluation of this classification criteria.

Source: jrheum.org/content/51/3/250