A Better Way to Diagnose Fibromyalgia Proposed

The American College of Rheumatology (ACR) has proposed new diagnostic criteria for fibromyalgia that include common symptoms such as fatigue, sleep disturbances, and cognitive problems, as well as pain. This could mean saying goodbye to counting tender points and facilitate more appropriate diagnoses.

Writing in the May issue of Arthritis Care & Research a team of investigators describe a multicenter assessment of 829 previously diagnosed patients with fibromyalgia and controls [Wolfe et al. 2010]. They used physician physical and interview examinations, including a newly-developed widespread pain index (WPI) and a symptom severity (SS) scale. Previous diagnostic criteria, established in 1990 by the ACR, required patients to have widespread pain in all 4 quadrants of their body for a minimum duration of 3 months and experience moderate pain and tenderness at a minimum of 11 of 18 specified tender points.

The new criteria keep the requirements that other causes be ruled out and that symptoms must have persisted for at least 3 months. The WPI lists 19 areas of the body and patients indicate where they have had pain during the past week (total score 0-19). For the SS scale score, the patient ranks the following specific symptoms on a scale of 0 to 3: fatigue, waking unrefreshed, cognitive symptoms, and somatic symptoms in general (such as headache, weakness, bowel problems, nausea, dizziness, numbness/tingling, hair loss) — total score 0-12. [The scoring criteria from the article are available here.]

A diagnosis of fibromyalgia requires a WPI score ≥7 and SS score ≥5 or a WPI 3 to 6 and SS ≥9. In this way, the scoring has built-in flexibility, recognizing that fibromyalgia affects patients differently and symptoms can fluctuate; it also allows for persons with fewer painful areas but greater symptom severity to be diagnosed. According to the researchers, this newer clinical case definition of fibromyalgia correctly classifies 88% of cases diagnosed by the older ACR classification criteria, and it does not require a physical or tender point examination.

COMMENTARY: In a press release [Newswise 2010], Robert S. Katz, MD, one of the authors of the new criteria and a rheumatologist at Rush University Medical Center, noted, “These new criteria recognize that fibromyalgia is more than just body pain,” which is important for patients who suffer symptoms in addition to pain and have had no diagnosis of fibromyalgia. “The tender point test also has a gender bias because men may report widespread pain, but they generally aren’t as tender as women.”

Furthermore, due to confusion regarding counting tender points, Katz noted, most primary care physicians do not check tender points at all or they are not checking them correctly. Consequently, fibromyalgia diagnosis in actual practice has often been symptom-based and the new ACR criteria take this into account. It also should be noted that this approach is not entirely new; about a year ago William S. Wilke, MD, of the Cleveland Clinic published an excellent paper [Wilke 2009; available here] reviewing deficiencies of diagnostic approaches to fibromyalgia and proposing a Symptom Intensity Scale (SIS). This is very similar to the latest ACR criteria for assessing regional pain along with other cooccurring symptoms, and can be used to establish a diagnosis of fibromyalgia syndrome and its severity without the need to count tender points.

REFERENCES:
> Newswise. New Criteria Proposed for Diagnosing Fibromyalgia Suggests No Longer Focusing on Tender Points. Rush University Medical Center [press release]. 2010(May 24) [available here].
> Wilke WS. New Developments in the Diagnosis of Fibromyalgia Syndrome: Say Goodbye to Tender Points? Cleveland Clinic J Med. 2009:76(6):345-352 [available here].
> Wolfe F, Clauw DJ, Fitzcharles M-A, et al. The American College of Rheumatology Preliminary Diagnostic Criteria for Fibromyalgia and Measurement of Symptom Severity. Arthritis Care & Research. 2010;62(5):600-610 [abstract].