WebMD Medical News
Laura J. Martin, MD
May 26, 2010 -- A new way of diagnosing fibromyalgia, by using a pain index and a measure of key symptoms and severity, may lead to more diagnoses and treatment, a new study says. The findings appear in the May issue of Arthritis Care & Research.
Until now, diagnosing the widespread pain disorder relied mainly on “tender point” exams or tenderness to the touch at 11 or more of 18 specified tender points and widespread pain in all four quadrants of the body for three months.
But this method was not fail-safe, says study author Robert Katz, MD, a rheumatologist and professor of medicine at Rush University Medical Center in Chicago. “Doctors just weren’t comfortable with tender point exams, and these points fluctuate over time.
“The trick to fibromyalgia is diagnosing it,” he says. “A lot of people experience widespread pain, but when do you give it the label of fibromyalgia?"
Fibromyalgia is based on symptoms, so X-rays can’t make definitive a diagnosis as they can in other rheumatic diseases.
The new criteria avoid tender points and tender point exams. Instead, a widespread pain index coupled with a symptom severity scale is used. The pain index is a 19-item checklist; a person marks the number of body parts where they have experienced pain during the last week. The symptom scale comprises unrefreshing sleep, fatigue, and cognitive issues -- three hallmarks of fibromyalgia. Symptoms are rated on an ascending scale of severity from 0 to 3. The diagnosis revolves around the number of painful areas, number of symptoms, and their severity. The American College of Rheumatology gave its stamp of approval to these new criteria.
Using the new set of criteria, “we will be diagnosing more people because we are casting a wider net,” Katz says. Fibromyalgia affects an estimated 10 million people in the U.S. and an estimated 3% to 6% of the population worldwide, according to National Fibromyalgia Association. “The number may double or even triple,” he says.
The researchers developed and tested the new diagnostic criteria on 829 people with fibromyalgia and a matched group of individuals with other pain disorders such as neck or back pain syndromes and osteoarthritis. They found that the widespread pain index, symptom severity, and number of symptoms were the most important variables in making the diagnosis. This new criteria will capture more than 88% of people with fibromyalgia without a physical or tender point exam.
For years, many people were dismissed by doctors and told that their fibromyalgia was “all in their heads.” This attitude has changed in recent years as many in the medical community have begun to accept fibromyalgia as a real ailment, and new medications have been approved to treat its symptoms.
“The new criteria add more credibility to fibromyalgia because all types of doctors, not just rheumatologists, should find it easier to make the diagnosis,” Katz says.
“Now we can make the diagnosis and reassure people that this is a real thing and not in their head, and once you have the diagnosis, you can try lifestyle things, and there are treatment options,” he says.
Daniel J. Clauw, MD, a rheumatologist at the University of Michigan in Ann Arbor, helped develop the new criteria.
He points out that the older criteria were never intended to be diagnostic. “They were intended to be classification criteria to be used to standardize research into fibromyalgia, and they served that purpose very well, and will continue to be used by most researchers for this purpose,” he says.
That said, “the new criteria are intended to offer health care providers an alternative manner of diagnosing fibromyalgia that do not require a tender point count,” he says. “Many physicians do not know how to do a tender point count and thus are not presently comfortable diagnosing fibromyalgia because they think this is ‘necessary’ to make the diagnosis -- now there will be a clear alternative available."
The new study was funded by Lilly Research Laboratories, which manufactures the fibromyalgia drug Cymbalta. “No one at Lilly suggested the study in the first place, nor did they have a single thing to do with design, data collection, analysis, or publications,” Clauw tells WebMD.
Clauw has received consultant fees, speaking fees, and/or honoraria from Pfizer, Lilly, Forest, Cypress Biosciences, Pierre Fabre, UCB, and AstraZeneca.
SOURCES: Wolfe, F. Arthritis Care & Research, May 2010; vol 62: pp 600-610.Daniel J. Clauw, MD, rheumatologist, University of Michigan, Ann Arbor.Robert Katz, MD, professor of medicine, Rush University Medical Center, Chicago.
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