History of affective disorder and the temporal trajectory of fatigue in rheumatoid arthritis.

This study examines whether the general level and rate of change of fatigue over time is different for those rheumatoid arthritis (RA) patients with and those without a history of affective disorder (AD). Four hundred fifteen RA patients from a national panel had yearly telephone interviews to obtain fatigue and distress reports, and a one-time semistructured assessment of the history of depression and generalized anxiety disorder Growth-curve analysis was used to capture variations in initial fatigue levels and changes in fatigue over 7 years for those with and without a history. RA patients with a history of major AD reported levels of fatigue that were 10% higher than those without a history in the 1st year of the study. Their fatigue reports remained elevated over 7 years. Further analysis showed that the effects of a history of AD on fatigue are fully mediated through current distress, although those with a history had a significantly smaller distress-fatigue slope. Thus, a history of AD leaves RA patients at risk for a 7-year trajectory of fatigue that is consistently higher than that of patients without a history. The elevation in fatigue reports is, at least in part, a function of enduring levels of distress.