Predictors of functional disability in rheumatoid arthritis: results from a 13-year prospective study.

Purpose: To explore the role of distress and social support as modifiers of functional disability in rheumatoid arthritis (RA). We hypothesized that: (a) higher inflammatory activity, more joint tenderness and more pain lead to more disability, and (b) that more distress and less social support lead to more disability and accelerate the disablement process by moderating the effects of inflammatory activity, joint tenderness and pain.

Methods: The study is a Dutch extension of the European Research on Incapacitating Diseases and Social Support (EURIDISS) which started with 292 patients. After five waves of data collection 129 still participated. Correlational and hierarchical regression analyses were performed.

Results: In short-term RA, 68% of the variance in disability could be explained primarily by mean disability over the prior years. Other important predictors were inflammatory activity and pain. In long-term RA, 56% of the variance in disability could be explained primarily by mean disability over the prior years. Other important predictors were joint tenderness and pain. No clear moderator effects of distress and social support were found in short-term or long-term RA.

Conclusions: The results confirm the main pathway from pathology to disability in short-term and long-term RA, but do not provide support for the influence of distress and social support on the disablement process.