Unresolved RA Pain Threatens Treatment Success

June 18, 2014

(EULAR 2014) Predictors of continuing pain after rheumatoid arthritis treatment differ from those that predict inflammation. For TNF inhibitors at least, unresolved pain also contributes to treatment failure.

In general doctors measure inflammation in rheumatoid arthritis (RA), while what troubles patients most is pain. That has been fairly well established by now. But the role of pain in the success of anti-inflammatory treatment is relatively uncharted territory.

Two researchers from the University of Nottingham, rheumatologist David Walsh and research fellow Daniel McWilliams, have explored a British rheumatology registry and found the contours of an answer. Treatment is unlikely to return people to normal, they conclude, unless the pain as well as the inflammation receive adequate treatment.

Whether the treatment is a tumor necrosis factor α inhibitor (TNFi) or a nonbiologic disease modifying drug (DMARD), pain at baseline, mental health and physical function as well as comorbidity strongly predict that RA pain will remain after a year of treatment, they reported last week at the annual meeting of the European League Against Rheumatology (EULAR) in Paris.

Other factors also predict continuing pain with one or the other of the two different classes of drugs.

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Notably, the disease-activity scale DAS28-P, completed by patients, correlates well with pain, while the DAS28, completed by physicians taught to recognize and treat inflammation, does not.

These data come from about 12000 patients on TNFi drugs and about 3600 on DMARDs in the British Society for Rheumatology Biologics Register who had severe pain at baseline and incomplete pain relief a year later.

The study, sponsored by Pfizer (which markets two TNFi drugs,  tofacitinib/Xeljanz and etanercept/Enbrel), also determined that continuing pain is an important predictor for early discontinuation of TNFi treatment.

There's good reason to focus on the role of TNF in pain: Some RA patients report immediate pain relief with TNF inhibitors, well before inflammation declines, McWilliams and Walsh observed last month in a review on RA pain in Nature Reviews Rheumatology. This and other evidence suggests that clinical response to these drugs may depend partly on modulating processing of pain in the brain.

Both the review and the report last week at EULAR stress that pain should be treated alongside inflammation in RA. The review contains guidance as to the best current options for addressing the pain.