A study depicted that in patients with RA, inefficient descending inhibitory mechanisms may be a potential treatment target since low conditioned pain modulation (CPM) was significantly linked with lower odds of good European League Against Rheumatism (EULAR) response.

For treatment with cognitive behavioral therapy or centrally acting agents, individuals with abnormalities in their central nervous system (CNS) pain processing pathways may be potent candidates. Detection of pain centralization as a substantial contributor to disease presentation could improve optimizing a patient’s therapy regimen without elevating disease-modifying anti-rheumatic drug (DMARD) therapy, which is linked to inherent risks.

A longitudinal prospective study of participants from the Central Pain in Rheumatoid Arthritis (CPIRA) cohort was conducted to explore the association between dysregulated CNS pain processing and treatment response to DMARD therapy in RA patients.

After initiating DMARD therapy, a total of 182 active RA subjects were followed for 12 weeks. Individuals underwent quantitative sensory testing (QST), including determination of pressure pain detection thresholds (PPTs) at the trapezius muscles, temporal summation (TS), and CPM to determine CNS pain processing.

The QST measures were classified as high and low central dysregulation. Utilizing multiple logistic regression adjusted for demographics, RA-related variables, and psychosocial variables, the link between baseline CNS dysregulation and treatment response was examined. Good response, defined by the EULAR response criteria at the 12-week visit was the primary endpoint.

Compared to participants with low CPM dysregulation, the percentage of participants with high CPM dysregulation attaining a good EULAR response was low as depicted in the following table:

When central dysregulation was examined with TS and PPT, the same trend (though not statistically significant) was witnessed. The adjusted odds ratios (ORs) for the link between good EULAR response and high CNS dysregulation is depicted in the following table: 

In a model examining the combined effects of dysregulated TS and CPM, the dysregulation of both measures was found to be considerably linked with lower odds of good EULAR response.

Thus, in active RA patients, pain centralization is linked with inadequate EULAR response and plays an important role in DMARD response.