Preliminary diagnostic criteria for fibromyalgia should be partially revised: Comment on the article by Wolfe et al

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Preliminary Diagnostic Criteria for Fibromyalgia should be Partially Revised: Comment on the Article by Wolfe et al

To the Editors:

In a recently published article in Arthritis Care & Research, Wolfe et al reported preliminary diagnostic criteria for fibromyalgia (Wolfe F, Clauw DJ, Fitzcharles MA, Goldenberg DL, Katz RS, Mease P, et al. The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity. Arthritis Care Res [Hoboken] 2010;62:600–10). The new criteria are completely different from the American College of Rheumatology 1990 criteria for the classification of fibromyalgia (Wolfe F, Smythe HA, Yunus MB, Bennett RM, Bombardier C, Goldenberg DL, et al. The American College of Rheumatology 1990 criteria for the classification of fibromyalgia: report of the Multicenter Criteria Committee. Arthritis Rheum 1990;33:160–72). However, I am concerned that parts of the new criteria are ambiguous.

In the 1990 criteria, the presence of a second clinical disorder did not exclude the diagnosis of fibromyalgia. Although this has been the subject of criticism, it does facilitate a diagnosis of fibromyalgia, and less-experienced physicians can easily diagnose fibromyalgia without additional testing such as imaging or a blood test if fibromyalgia alone is diagnosed. In Japan, many physicians have ignored fibromyalgia. Therefore, patients with fibromyalgia are often diagnosed with psychogenic pain or somatoform disorder (pain disorder or somatization disorder). Based on the 1990 criteria, psychogenic pain or somatoform disorder does not exclude a diagnosis of fibromyalgia. The new criteria state, “The patient does not have a disorder that would otherwise explain the pain.” This exclusionary regulation should be eliminated and the 1990 criteria (the presence of a second clinical disorder does not exclude the diagnosis of fibromyalgia) should be reinstated.

First, it is difficult for less-experienced physicians to diagnose fibromyalgia based on the new criteria. If a patient who meets the new criteria also has hypothyroidism or rheumatoid arthritis, is that patient automatically excluded from a diagnosis of fibromyalgia? Patients with rheumatoid arthritis alone who meet the new criteria and patients with combined rheumatoid arthritis and fibromyalgia cannot be distinguished based on the new criteria.

Second, based on the new criteria, psychogenic pain or somatoform disorder may exclude a diagnosis of fibromyalgia. In Japan, few physicians administer treatment for fibromyalgia and many physicians do not believe in fibromyalgia. Patients with fibromyalgia are frequently left untreated, treated with nonsteroidal antiinflammatory drugs, or diagnosed with psychogenic pain or somatoform disorder. Therefore, in Japan psychogenic pain or somatoform disorder will exclude a diagnosis of fibromyalgia based on the new criteria.

Third, survey studies will become almost impossible if the new criteria are used from the viewpoint of cost. Blood tests are needed to confirm that the patient does not have a disorder that would otherwise explain the pain. It is almost impossible to perform blood tests in survey studies from the viewpoint of cost.

The number of somatic symptoms in the new criteria is ambiguous. How many symptoms are “few symptoms,” “a moderate number of symptoms,” and “a great deal of symptoms,” respectively? Who decides the number of somatic symptoms in the new criteria? Do physicians decide it? Do patients decide it?

Further consideration of these issues is warranted before the new criteria are implemented.

Katsuhiro Toda MD, PhD*, * Hatsukaichi Memorial Hospital, Hiroshima, Japan.

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