Researchers then surveyed a random sample of adults in the county using the revised 2010 checklist. Of those who responded, 5.3 percent met the criteria for fibromyalgia. Researchers again accounted for age and sex, and then calculated that fibromyalgia affected 6.4 percent of the county’s population, suggesting that it might be more common than the number of officially diagnosed cases indicates.

Based on the survey, the rate of fibromyalgia in women was three times higher than officially diagnosed; in men it was 20 times higher.

Dr. Vincent says the low percentage of men diagnosed with fibromyalgia using the tender-point criteria makes sense.

“Men are innately less tender than women and they’re less likely to pay attention to pain or seek medical attention for it,” she says. “What this study shows is that men who meet the 2010 criteria for fibromyalgia are unlikely to have been diagnosed [using earlier standards].”

In addition to improving diagnosis, Dr. Vincent says broadening the definition of fibromyalgia to include symptoms other than pain is likely to improve treatment, too.

“Fibromyalgia is multidimensional,” she says. “Patients have pain receptors firing all the time. This generates a lot of pain, to which the body gradually becomes sensitized. And in fighting that pain, people become fatigued, have unrefreshing sleep and cognitive problems. It’s important for primary providers to recognize that chronic pain kicks the symptom burden much higher and that symptom management [is important].”

Dr. Clauw adds, “Some of the same neurotransmitter abnormalities that cause fibromyalgia pain are driving memory and sleep disturbances. [Traditional] pain medications only make pain better, whereas fibromyalgia drugs like Lyrica (pregabalin) and Cymbalta (duloxetine) also make sleep, anxiety, depression and fatigue better.”

Both doctors emphasize that the 2010 guidelines are intended to complement, not replace, the 1990 criteria. Dr. Vincent says, “The most important finding of our study is that the new criteria provide a more comprehensive way for clinicians to recognize fibromyalgia.”

Lesley Arnold, MD, professor of psychiatry and director of the Women’s Health Research Program at the University of Cincinnati College of Medicine in Ohio, agrees.

“The 1990 criteria are still the gold standard for research,” she says. “Combined with the 2010 criteria, they do a very good job of identifying people thought to have fibromyalgia. And the 2010 criteria, by leaving out the tenderness requirement, may allow more men to be identified who may benefit from some of the treatments that are effective for fibromyalgia.”

At the same time, she urges caution in interpreting the prevalence data.

“One of the limitations of the study is the low participation rate in the random survey. Only 27 percent of people responded overall, and those patients are more likely to have symptoms, so [the results] don’t represent actual prevalence,” says Dr. Arnold. “But it does raise the possibility that [fibromyalgia] is more common than originally thought, and certainly more common in men.”