Women with rheumatoid arthritis (RA) reported higher levels of pain intensity and sensitivity compared with men, according to study results published in Arthritis Care & Research.
Investigators assessed differences in pain intensity, interreference, and measures of central nervous system pain regulation, independent of inflammation, between women and men with RA.
A post-hoc analysis of data collected in the observational Central Pain in Rheumatoid Arthritis study was conducted. Patients diagnosed with confirmed, active RA were included in the analysis.
Pain intensity and interference were the primary outcomes, assessed via a numeric rating scale ranging from 0 to 10 and an adaptive, computerized test administered using a Patient-Reported Outcomes Measurement Information System (PROMIS), respectively. Quantitative sensory testing (QST) was used to assess pain detection thresholds, temporal summation, and conditioned pain modulation.
Results for women vs men were compared using multiple linear regression, after adjusting for age, education, race, research site, depression, obesity, duration of RA, swollen joint count, and level of C-reactive protein.
A total of 268 patients (220 women and 48 men) were included in the analysis. Levels of disease severity and pain medication use were similar between women and men.
The investigators found that mean pain intensity was greater among women (5.32) vs men (4.60) with RA (adjusted difference, 0.83; 95% CI, 0.14-1.53). Pain interference scores according to PROMIS testing did not differ significantly between women and men (adjusted difference, 1.12; 95% CI, -1.04 to 3.28).
In contrast, pressure pain detection thresholds were lower among women vs men, with adjusted differences in thresholds of -1.22 (95% CI, -1.73 to -0.72) at the trapezius, -0.57 (95% CI, -1.07 to -0.06) at the wrist, and -1.10 (95% CI, -2.00 to -0.21) at the knee.
The investigators found no statistically significant differences in pain interference, temporal summation, or conditioned pain modulation between the sexes.
These findings led the researchers to conclude that women were more sensitive to pain than men. Differences between women and men in pain intensity and pressure pain detection thresholds remained when analysis was controlled for peripheral and systemic inflammation.
Limitations of the study included the post-hoc nature of the analysis and inclusion of a patient population that may not be representative of all patients with RA. Finally, the sample size for men vs women was much smaller, potentially limiting the ability to detect sex differences.
The study authors concluded, “These results indicate that sex-based differences impact neurobiological functioning and, ultimately, the pain experience, in patients with RA.”
Disclosure: One or more of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
This article originally appeared on Rheumatology Advisor
Vogel K, Muhammad LN, Song J, et al. Sex differences in pain and quantitative sensory testing in patients with rheumatoid arthritis. Arthritis Care Res. Published online June 26, 2023. doi:10.1002/acr.25178