Tender points no more??

For the last 20 years the American College of Rheumatology (ACR) criteria has been the method for diagnosing people with fibromyalgia. To achieve this diagnosis, patients were required to have:

• had pain in all four quadrants of the body for at least 3 months
• patients also need to have 11 out of 18 specifically chosen tender points

These tender points are areas of the body where it was easiest to test pain sensitivity in fibromyalgia patients.

So why do we need a new diagnostic test?
Well the tender point test was often not performed by GP's or rheumatologists, and when it was it was sometimes not performed correctly. A lot more is now known about additional symptoms like cognitive dysfunction and the new criteria allows for a severity score that will help evaluation of patients with marked symptom variability.

The provisional ACR 2010 criteria which has been published in the may issue of Arthritis Care Research provides a new definition for fibromyalgia where a tender point exam is no longer required to result in a diagnosis for the patient.

The ACR 2010 team's objective was:

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.

So how did the team hope to find this new criteria?

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).

In the team's conclusion they compared the results of the ACR 1990 and the new 2010 criteria:

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.

So what happens next for fibromyalgia sufferers? Well some people with fibromyalgia have commented that the removal of the tender point test may encourage the use of fibromyalgia as a "wastebasket diagnosis" by some medical professionals.  Robert S. Katz, one of the authors of the new criteria said this recently:

“These new criteria recognize that fibromyalgia is more than just body pain. 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.

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. 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.”

It will take time for this criteria to be approved and then accepted but even longer for it to be used and understood by rheumatologists in regular contact with fibromyalia patients. It is concerning how long it will take for GPs to become aware of this new criteria if it is accepted. It may continue that the diagnosis of fibromyalgia remains with rheumatologists for the time being and the future?

We will of course be keeping an eye on developments and bringing you more information on this subject.