New American College of Rheumatology Criteria for Fibromyalgia: A Twenty-Year Journey

Twenty years have passed since the publication of the American College of Rheumatology (ACR) 1990 criteria for the classification of fibromyalgia (1). In this issue of Arthritis Care & Research, new ACR preliminary diagnostic criteria for fibromyalgia are presented (2). The new criteria accomplish the following: remove tender points from the criteria and as the central element in the fibromyalgia definition; change the case definition of fibromyalgia; recognize the importance of a quantitative measure of widespread pain, the widespread pain index (WPI); incorporate key fibromyalgia symptoms into the criteria; provide severity scales to measure the extent of widespread pain and symptom severity; and make available an alternate conceptualization of fibromyalgia for those who do not think fibromyalgia is a valid diagnostic entity. The new criteria bring together the seemingly conflicting concept of a “disorder” that has strict criteria with the alternative approach of a continuum of symptoms without any clear dividing point. But the sense of continuum can be seen in Figures 1 and 3 in the ACR criteria article (2), and in the dependence of the criteria diagnosis of fibromyalgia on the interaction of varying levels of the WPI and the symptom severity (SS) scale. Pain extent (WPI) and symptom scale variables may seem to represent two dimensions, but factor analysis demonstrates only one factor. Pain extent and SS scale are correlated at 0.733 and they are part of the same process. In fact, it is possible to sum the WPI and SS scale into a single index that represents the essential content of fibromyalgia (3). The ACR diagnostic criteria should not be seen as an endorsement of the legitimacy and existence of fibromyalgia—the criteria are neutral on that point. Existence and legitimacy are concepts that have existential, philosophic, and social components, and are not resolved with the publication of these criteria. The issues that are worrisome about fibromyalgia remain (4). At a practical level, the new criteria abandon the tender point examination, an examination that was difficult for some examiners, and believed to be more honored in the breach than the observance in primary care. Tender points distracted from the important purpose of understanding the patient’s problems. The new ACR criteria replace the 11 tender-point dichotomy as well as the widespread pain dichotomy with the continuous WPI scale that provides much more information about pain threshold and pain extent. For those who feel the research need for a widespread pain indicator, it can easily be derived from the WPI variables. None of this is to suggest that physical examination is not required. In fact, physical examination is strongly recommended as part of the routine examination; however, it is no longer a part of the diagnostic criteria. Elimination of the tender point examination may seem to lighten the physician’s role, but such is not the case. The new criteria require that the examiner fully understand the patient’s problems. You cannot guess at the extent of fatigue, unrefreshed sleep, cognitive problems, multiplicity of symptoms, and extent of pain without a detailed interview. The new criteria obligate you to pay careful attention to the patient if you want to diagnose fibromyalgia. The ACR criteria introduced the SS scale, which is a summary score from scales measuring the extent of fatigue, unrefreshed sleep, cognitive problems, and multiplicity of symptoms. The SS score correlates with the WPI at 0.733 and the tender point count at 0.680, and is used as part of fibromyalgia criteria. The scale captures well the essential content of fibromyalgia or what we have called “fibromyalgianess” (5). The scale can capture differences in severity in patients diagnosed with fibromyalgia, but also in all patients, including those without fibromyalgia, because the scale content is part of the human condition in the presence of physical illness and mental stress. If we conceive of fibromyalgia as the end of a continuum, then this measure of fibromyalgianess is a good tool to assess the continuum. The SS scale has another role in the context of fibromyalgia diagnosis. The ACR criteria article noted that 25% of patients who carried the diagnosis of fibromyalgia did not Frederick Wolfe, MD: University of Kansas School of Medicine and National Data Bank for Rheumatic Diseases, Wichita, Kansas. Address correspondence to Frederick Wolfe, MD, National Data Bank for Rheumatic Diseases, 1035 North Emporia, Suite 288, Wichita, KS 67214. E-mail: fwolfe@ arthritis-research.org. Submitted for publication February 9, 2010; accepted February 10, 2010. Arthritis Care & Research Vol. 62, No. 5, May 2010, pp 583–584 DOI 10.1002/acr.20156 © 2010, American College of Rheumatology