Association of Pain Centralization and Patient-Reported Pain in Active Rheumatoid Arthritis

Objective Pain is a significant burden for patients with rheumatoid arthritis (RA) despite advancements in treatment. We undertook this study to examine the independent contribution of pain centralization to the pain experience of patients with activeRA. Methods A total of 263RApatients with active disease underwent quantitative sensory testing (QST), including assessment of extraarticular pressure pain thresholds (PPTs), temporal summation (TS), and conditioned pain modulation (CPM). The pain experience was assessed by a pain intensity numeric rating scale and the Patient-Reported Outcomes Measurement Information System pain interference computerized adaptive test. We examined associations betweenQSTmeasures and pain intensity and pain interference. Multiple linear regression models were adjusted for demographic and clinical variables, including swollen joint count and C-reactive protein level. Results Patients with the lowestPPTs (most central dysregulation) reported higher pain intensity than patients with the highestPPTs (adjusted mean difference 1.02 [95% confidence interval (95%CI) 0.37, 1.67]). Patients with the highestTS(most central dysregulation) had higher pain intensity than those with the lowestTS(adjusted mean difference 1.19 [95%CI0.54, 1.84]).CPMwas not associated with differences in pain intensity.PPTandTSwere not associated with pain interference. Patients with the lowestCPM(most centrally dysregulated) had lower pain interference than patients with the highestCPM(adjusted mean difference -2.35 [95%CI-4.25, -0.44]). Conclusion Pain centralization, manifested by lowPPTs and highTS, was associated with more intense pain. Clinicians should consider pain centralization as a contributor to pain intensity, independent of inflammation.