Pain as an important predictor of psychosocial health in patients with rheumatoid arthritis

Objective

To examine the evolution of psychosocial aspects of health‐related quality of life in rheumatoid arthritis (RA) patients, and to identify their predictors.

Methods

All patients within a Swiss RA cohort and a US RA cohort who completed a Short Form 36 (SF‐36) scale at least twice within a 4‐year period were included. The primary outcome was psychosocial health as measured by the mental component summary (MCS) score of the SF‐36. The evolution of this outcome over time was analyzed using structural equation models, which distinguish between the stable, the variable, and the measurement error components of the outcome's variance.

Results

A total of 15,282 patients (48,323 observations) were included. MCS scores were mostly stable over time (between 69% and 75% of the variance was not due to measurement error). The variable component of the SF‐36 was mostly due to fluctuations at the moment of measurement and not to a global time trend of psychosocial health. Pain was the most important predictor of both the stable and variable components of psychosocial health, explaining ～44% of the observed psychosocial health variance.

Conclusion

This large cohort study demonstrates that pain is the most important predictor of a patient's psychosocial health in RA patients. This suggests that physicians should place greater emphasis on pain management.