The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity.
OBJECTIVE
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.


RESULTS
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 WPI and categorical scales for cognitive symptoms, unrefreshed sleep, fatigue, and number of somatic symptoms. The categorical scales were summed to create an SS scale. We combined the SS scale and the WPI to recommend a new case definition of fibromyalgia: (WPI > or =7 AND SS > or =5) OR (WPI 3-6 AND SS > or =9).


CONCLUSIONS
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 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.
Wolfe
Frederick
F
National Data Bank for Rheumatic Diseases and University of Kansas School of Medicine, Wichita, KS 67214, USA. fwolfe@arthritis-research.org
Clauw
Daniel J
DJ
Fitzcharles
Mary-Ann
MA
Goldenberg
Don L
DL
Katz
Robert S
RS
Mease
Philip
P
Russell
Anthony S
AS
Russell
I Jon
IJ
Winfield
John B
JB
Yunus
Muhammad B
MB
D005356:Fibromyalgia / Q000145:classification* / Q000150:complications / Q000175:diagnosis; D006305:Health Status Indicators; D006801:Humans; D008490:Medical Informatics; D010146:Pain / Q000145:classification* / Q000150:complications / Q000175:diagnosis; D015203:Reproducibility of Results; D012219:Rheumatology / Q000592:standards*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012955:Societies, Medical; D014481:United States