Fatigue is a common and distressing symptom in patients with rheumatoid arthritis (RA) and other rheumatic diseases. Reports have suggested profound improvements in fatigue after onset of anti-tumor necrosis factor-alpha (anti-TNF) therapy. In addition, physician and patient groups now identify fatigue as a very important symptom. However, data to support these observations are lacking. We evaluate the importance of fatigue in relation to other measures of clinical status, describe predictors of fatigue, and investigate fatigue levels in patients treated with anti-TNF therapy.
A total of 852 patients participated in a symptom-importance preference study. Additional analyses of fatigue and other clinical status variables were performed in up to 21,016 patients with RA and 3815 patients with osteoarthritis (OA) participating in the National Data Bank for Rheumatic Diseases.
In ranking studies of the relative importance of fatigue compared with function, pain, cognition, gastrointestinal symptoms, and sleep, 8.0% of patients ranked fatigue as the most important variable, compared with 32.1% for function and 21.5% for pain. Multivariable studies of clinical change over 6 months found that changes in fatigue were weakly associated with changes in health status, in contradistinction to results for pain, function, and depression. Fatigue levels and fatigue predictors were similar in RA and OA patients. RA patients treated with anti-TNF therapy did not have lower fatigue scores compared with those not treated with this type of therapy.
Among RA patient self-report measures, fatigue is not ranked as important as functional disability, pain, or depression by most patients. This relative ranking is confirmed by examination of clinical improvement data. Fatigue levels and predictors of fatigue are essentially the same in RA and OA. Although anti-TNF therapy lowers fatigue levels, there is no evidence that this effect is greater for anti-TNF therapy than for other RA treatments.