• To develop simple, practical criteria for clinical diagnosis of fibromyalgia that are suitable for use in primary and specialty care and that do not require a tender point examination,
• And to provide a severity scale for characteristic fibromyalgia symptoms.
Methods: We performed a multicenter study of 829 previously diagnosed fibromyalgia patients and controls using physician physical and interview examinations, including a widespread pain index (WPI), a measure of the number of painful body regions. Random forest and recursive partitioning analyses were used to guide the development of a case definition of fibromyalgia, to develop criteria, and to construct a symptom severity (SS) scale.
• Approximately 25% of fibromyalgia patients did not satisfy the American College of Rheumatology (ACR) 1990 classification criteria at the time of the study.
• The most important diagnostic variables were widespread pain index (WPI) and categorical scales for cognitive symptoms, unrefreshed sleep, fatigue, and number of somatic symptoms. The categorical scales were summed to create a symptom severity (SS) scale.
• We combined the symptom severity (SS) scale and the widespread pain index (WPI) to recommend a new case definition of fibromyalgia:
– WPI 7 or more AND SS 5 or more,
– OR WPI 3-6 AND SS 9 or more.
• This simple clinical case definition of fibromyalgia correctly classifies 88.1% of cases classified by the ACR classification criteria, and does not require a physical or tender point examination.
• The symptom severity (SS) scale enables assessment of fibromyalgia symptom severity in persons with current or previous fibromyalgia, and in those to whom the criteria have not been applied.
• It will be especially useful in the longitudinal evaluation of patients with marked symptom variability.
[Note: Though the full text of this article is not yet available free, to view a pdf of “Appendix A: Fibromyalgia Diagnostic Criteria,” click here]
Source: Arthritis Care & Research, May 2010;62(5):600-10. PMID: 20461783, by Wolfe F, Clauw DJ, Fitzcharles MA, Goldenberg DL, Katz RS, Mease P, Russell AS, Russell IJ, Winfield JB, Yunus MB. National Data Bank for Rheumatic Diseases and University of Kansas School of Medicine, Wichita; University of Michigan Medical School, Ann Arbor; Newton-Wellesley Hospital, Tufts University School of Medicine, Boston, Massachusetts; Rush University Medical Center, Chicago, Illinois; Seattle Rheumatology Associates and Swedish Medical Center, Seattle, Washington; University of Texas Health Sciences Center, San Antonio; University of North Carolina, Chapel Hill; University of Illinois College of Medicine, Peoria, USA; Montreal General Hospital and McGill University, Montreal, Quebec; University of Alberta, Edmonton, Alberta, Canada. [Email: Frederick Wolfe, firstname.lastname@example.org]