New Fibromyalgia Diagnostic Criteria Proposed
The American College of Rheumatology (ACR) published a new set of diagnostic criteria they are proposing for fibromyalgia in the May issue of the ACR journal Arthritis Care & Research. The new criteria includes common symptoms such as fatigue, sleep disturbances, and cognitive problems, as well as pain.
The original diagnostic criteria, established by the ACR in 1990, required the patient to have:
A history of widespread pain in all four quadrants of the body for a minimum duration of three months, and
Pain in at least 11 of 18 designated tender points when four kilograms (about 10 pounds) of pressure are applied.
Problems With the Old Criteria
"There are numerous shortcomings with the previous criteria, which didn't take into account the importance of common symptoms including significant fatigue, a lack of mental clarity and forgetfulness, sleep problems and an impaired ability to function doing normal activities," said Robert S. Katz, one of the authors of the new criteria and a rheumatologist at Rush University Medical Center.
According to Katz, fibromyalgia pain may fluctuate, which can affect the number of tender points, and the tender point test did not adequately measure symptom severity or the effectiveness of new treatments.
"The tender point test also has a gender bias because men may report widespread pain, but they generally aren't as tender as women. Fibromyalgia may be under-diagnosed in both men and women because of the reliance on 11 tender points, and also due to failing to account for the other central features of the illness," said Katz.
Additionally, due to the confusion regarding the tender point test, the authors note that most primary care doctors don't bother to check tender points or they aren't checking them correctly. Consequently, fibromyalgia diagnosis in practice has often been a symptom-based diagnosis. The new criteria will standardize a symptom-based diagnosis so that all doctors are using the same process.
Proposed New Diagnostic Criteria
The new diagnostic criteria, as proposed, will still require the first part of the old criteria - a history of widespread pain in all four quadrants of the body for a minimum duration of three months - but will replace the second part, the tender point exam, with:
A widespread pain index score which will be determined by counting the number of areas on the body where the patient has felt pain in the last week. The checklist includes 19 specified areas.
A symptom severity score which will be determined by rating on a scale of zero to three (three being the most pervasive) the severity of three common symptoms: fatigue, waking unrefreshed and cognitive symptoms. An additional three points can be added to account for the extent of additional symptoms such as numbness, dizziness, nausea, irritable bowel syndrome or depression. The final score is between 0 and 12.
To meet the criteria for a diagnosis of fibromyalgia a patient would have:
- Seven or more pain areas and a symptom severity score of five or more, or
- Three to six pain areas and a symptom severity score of nine or more.
"These new criteria recognize that fibromyalgia is more than just body pain," said Katz. "This is a big deal for patients who suffer symptoms but have had no diagnosis. A definite diagnosis can lead to more focused and successful treatment and reducing the stress of the unknown."
To develop and test the new criteria, researchers performed a multicenter study of 829 previously diagnosed fibromyalgia patients and a control group of rheumatic patients with non-inflammatory disorders using physician physical and interview examinations. The authors recommend a follow-up test in the primary care setting that includes patients with other rheumatic conditions to determine the rate of misclassification that may occur.
A better and more accurate method for diagnosing fibromyalgia is long overdue, so I'm happy to see this proposal. The original criteria were actually never intended to be used for diagnostic purposes. They were developed as a research tool, to ensure that patients being studied all met a similar set of criteria. However, with no other measures in place to aid in diagnosing FM, the ACR's research criteria was unofficially adopted as the diagnostic criteria.
It's time for the other symptoms of fibromyalgia to finally be taken into account when making a diagnosis. Only time and further studies will tell whether this particular set of criteria will be comprehensive enough to catch most people who have fibromyalgia, but not so inclusive that people with other conditions are misdiagnosed with FM.
Wolfe F, et al. The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity. Arthritis Care Res (Hoboken). 2010 May;62(5):600-10.
New Criteria Proposed for Diagnosing Fibromyalgia Suggests No Longer Focusing on Tender Points. Rush University Medical Center Press Release. May 24, 2010.