In RA It's More Than Joints
Saturday, March 14, 2015 01:38 PM

Potentially reversible variables, such as psychosocial factors, joint symptoms, and body composition had more impact on the walking speed of rheumatoid arthritis (RA) patients than articular characteristics, according to researchers.  "The assumption that articular features are the largest contributor to mobility limitation in RA may be unfounded, as other characteristics such as generalized pain, depression, and fatigue are also potential contributors," the authors wrote.

Gait velocity has been previously identified as a single predictor of adverse events in healthy seniors in the general population, they explained.  The largest single negative indicator of walking speed was higher age, which accounted for 27% of explainable variability. The next strongest indicator was articular signs, with replaced joints accounting for double the explainable variability of swollen joints (8.7% versus 4.4%). Sex, interstitial lung disease, RA duration, autoantibody status, inflammatory markers, and radiographic scores did not independently associate with gait velocity.

According to data from 132 RA patients several significant nonarticular indicators of a slower walking speed accounted for 60% of the observed variation in walking speed, while specific articular features, such as upper/lower extremity or large/small joint involvement, accounted for just 21% of explainable variation.  These variables were:
  • Older age

  • Higher depression scores

  • Higher reported pain and fatigue

  • Higher numbers of swollen and replaced joints

  • Higher cumulative prednisone exposure

  • Lack of treatment with disease modifying antirheumatic drugs (DMARDs)

The only positive indicator studied was better body composition -- in those with more lean muscle mass and density, the association of articular features with performance measures was minimal.  "Better body composition negated much of the detrimental impact of symptomatic joints on physical impairment," the authors wrote. "Lifestyle modifications to optimize body composition may be an important adjunct to intensive medical management with DMARDs, as recent investigations have shown that through structured physical training RA patients are able to alter body composition, decrease disability, and improve physical performance."