The synchronous relationship between somatic symptoms and psychological distress in early rheumatoid arthritis : findings from a prospective observational study.

The longitudinal relationship between somatic symptoms and psychological distress in rheumatoid arthritis (RA) is often assumed to be strong and bidirectional. However, despite previous research identifying strong cross-sectional associations, only weak longitudinal associations have been observed. This may be due to the failure to differentiate the impact of symptoms relating to underlying disease progression on distress, from symptoms relating to disease flare. Using data from a prospective observational study, synchronous changes in distress and symptoms of pain and functional limitation over 5 years are assessed, differentiating between the impact of disease progression and disease-flare