A prospective multicenter study found that 22.6% of patients with rheumatoid arthritis experienced persistent severe pain despite improvements in disease activity after 24 weeks of disease-modifying antirheumatic drug therapy.
In the study, published in Annals of the Rheumatic Diseases, researchers identified neuropathic pain and pain catastrophizing as factors associated with persistent pain in rheumatoid arthritis. They enrolled 567 patients with active rheumatoid arthritis (RA) (Disease Activity Score 28 [DAS28] > 3.2) and severe pain (Visual Analog Scale [VAS] > 50) who were starting or escalating disease-modifying antirheumatic drug (DMARD) therapy. After 24 weeks, the patients were categorized based on treatment response and pain levels.
Among the key findings were:
- 22.6% (n = 128) of the patients had persistent severe pain (VAS ≥ 50) despite DAS28 improvement or low disease activity.
- 18.0% (n = 102) were nonresponders to treatment.
- 59.4% (n = 337) were classified as treatment responders with pain improvement.
- 35.0% of nonresponders and 26.5% of patients with persistent pain tested positive for neuropathic pain at week 24 compared with 8.8% of responders.
- Pain catastrophizing and higher tender joint count at baseline were independently associated with persistent pain at 24 weeks.
The researchers used the painDETECT Questionnaire to assess neuropathic pain symptoms. Patients scoring ≥ 19 points were considered positive for neuropathic pain.
Multivariable regression analysis found baseline tender joint count and pain catastrophizing score were the strongest predictors of persistent pain at 24 weeks. Each 1-point increase in Pain Catastrophizing Scale score corresponded to a 2.8% higher probability of being in the persistent pain group. Each additional tender joint raised the probability by 4.7%.
The researchers noted that neuropathic pain was present across subgroups regardless of treatment response or pain persistence. They suggested this may reflect underlying mechanisms of neuropathic pain in RA, including peripheral and central sensitization.
Limitations of the study included potential selection bias from patient discontinuation, which could be partly attributed to the COVID-19 pandemic, and the inability to definitively distinguish persistent inflammatory vs pain phenotypes in nonresponders.
The study was funded by AbbVie. Several authors reported consulting relationships or employment with AbbVie.