Comparison of Symptoms Among Fibromyalgia Syndrome, Chronic Widespread Pain, and an Incomplete Form of Chronic Widespread Pain

It is proposed that chronic widespread pain [CWP] is an intermediate state in a continuum from an incomplete form of CWP [I-CWP] to the fibromyalgia syndrome [FMS]. If this hypothesis is correct, the relative clinical symptoms severity of three somewhat similar soft tissue pain conditions would be FMS > CWP > I-CWP. The symptoms of outpatients with FMS, CWP, and I-CWP were compared. Eligible subjects were limited to outpatients who were evaluated because a diagnosis of FMS was suspected. Subjects who had experienced pain in five regions, as described in the American College of Rheumatology 1990 criteria, for more than three months with 11 or more tender points [TePs] were diagnosed with FMS, and those with 10 TePs or less were diagnosed with CWP. Subjects without CWP were diagnosed with I-CWP. Seventy-five patients with FMS [59 women and 16 men], 63 patients with CWP [44 women and 19 men], and 59 patients with I-CWP [49 women and 10 men] were studied. There was a significant difference between FMS patients and CWP patients in the number of TePs, number of control sites, and short-form McGill pain questionnaire [sensory pain rating index, affective pain rating index, and total pain rating index]. There was significant difference between CWP patients and I-CWP patients in self-rating depression scale, fibromyalgia impact questionnaire, and present pain intensity of the McGill pain questionnaire. It is proposed that CWP is the end stage in a continuum of I-CWP and FMS is the end stage in a continuum of CWP, rather than any of these representing distinct medical entities. The relative severities of the clinical symptoms in each diagnosis group were FMS > CWP > I-CWP.