To determine whether fibromyalgia syndrome (FMS) was more common in patients with lupus who were complaining of fatigue.
We interviewed 216 patients attending two lupus clinics, all of whom fulfilled the revised American College of Rheumatology (ACR) criteria for lupus. The patients completed a questionnaire and were examined to determine the presence of fatigue and whether they fulfilled the ACR criteria for FMS. Disease activity was measured using the British Isles Lupus Assessment Group (BILAG) index and the Systemic Lupus International Collaborating Clinics (SLICC)/ACR damage score. Measurements of erythrocyte sedimentation rate, complement C3, lymphocyte count and DNA titre were also performed.
Fifty per cent of our patients complained of fatigue, but only 10% of these patients fulfilled criteria for FMS. FMS did not correlate with any measure of disease activity although patients with FMS had lower mean DNA antibody titres and mean SLICC/ACR damage scores.
A minority of lupus patients with fatigue fulfil the ACR criteria for FMS. Other possible factors leading to fatigue should be considered.