If you have read the short report on the ACR criteria you would have been introduced to the OMERACT group of physicians. Back in 2004 it was recognized that to provide some consistency in FMS research there would be needed some standardization in what should be measured. These were called the “core set of domains,” where domain referred to exactly what was measured, e.g. pain, sleep disturbance, fatigue, etc. The need for scientific validation of this core set of domains in FMS for use in clinical study trials led to a 2004 workshop for Outcome Measures in Rheumatology Clinical Trials (OMERACT).  Academicians, clinicians, and pharmaceutical researchers participated in a series of Delphi exercises.

The Delphi technique was developed by the Rand Corporation in the 1950s and involved a structured discussion with selected experts on a specific area with the purpose of guiding the discussion towards a general consensus opinion. When properly administered a Delphi consensus process can be up to five times more accurate than results from traditional groups and twelve times superior than statistical surveys. The results of the 2004 OMERACT 7 and the 2006 OMERACT 8 were published in 2005 and 2007, respectively.

Building on these results the findings of OMERACT 9, published in 2009, determined that the core set of domains for FMS to be assessed in all clinical trials of fibromyalgia should include pain, tenderness, fatigue, sleep disturbance, assessments of different types of function, and a term called “patient global.”  The latter is a conglomeration of patient satisfaction and global impressions of change. Next to pain, fatigue was the number two symptom that was rated as being important to include in studies of FMS.

The National Fibromyalgia Association conducted a survey in 2006 of 2,597 people and the German Fibromyalgia Association likewise conducted a similar survey in 2007 of 3,996 people – both found fatigue was the number two symptom of concern, after pain. Dr. Jon Bennett, a leading FMS researcher, explains that the fatigue of fibromyalgia is one of “a weariness of mind and body that impairs productivity and enjoyment of life.” Does that sound about right?

Dr. Harold Moldofsky, the fibromyalgia researcher and physician who conducted the first studies that looked at sleep and FMS over 35 years ago has written about the pattern of fatigue he has noted in his patients. Although there is no such thing as a “typical” FMS patient, here is what he feels is the most common pattern. People with FMS awaken unrefreshed and it isn’t until about 10 or 11 am that they start to feel ‘normal.’ The best time of the day is from about 11 am to 2 or 3 in the afternoon; after that, it’s downhill. People with FMS also tend to feel less fatigue near the beginning of the week and worse near the end of the week.

This is the opposite pattern noted in the general population where the afternoon “lull” usually occurs around 2 pm to 4 pm followed by an early evening peak of alertness between 7 pm and 9 pm. As for pain and sleep, patients with FMS also feel the most general fatigue from November to March and the most improvement from May to August.

Unfortunately, there is considerable morbidity associated with fatigue and an applicable question for patients with FMS is not whether they have it, but how much does it interfere with their lives. One of my patients once related the energy needed to get through the day being similar to the effort needed to drive a car when the power steering had failed.

The origin of fatigue is certainly multifactorial – chronic pain, nonrestorative sleep, and psychological strain from depression and anxiety so it’s difficult to assess. After World War I, one of the assignments of the British Industrial Fatigue Board was to develop a measure of fatigue; they could not, and the conclusion was reached that it was impossible to test for fatigue.

Depression may be a contributor to fatigue in FMS patients. In comparing fatigue to major depressive disorder one FMS physician compared how fatigue and depression look very much alike. Both have a physical component - (low energy, weakness), a cognitive component - (poor concentration), and emotional dimensions (decreased motivation or sense of being over-whelmed). The difficulty is that if you ask a patient with FMS they will admit to all three, even if depression is not part of their clinical picture.

A 2010 study that looked at FMS in Germany, France, and the United States was trying to develop a cross-cultural model of fatigue. Fatigue in FMS patients in all three of these countries was “described as being an overwhelming feeling of tiredness that was not relieved by sleep or rest and is often not in proportion to the effort exerted.” Participants in the study related having to “force themselves” to accomplish tasks and differentiated between fatigue due to FMS and normal tiredness by the degree to which FMS fatigue limited their normal activities, impaired their ability to concentrate, think clearly, and remember things.

In this study, as a percentage of participants, fatigue induced lack of motivation in 83%, affected cognition in 68%, and made it difficult to engage in activities, even as slight as pouring a cup of coffee, in 60%; 38% were “overwhelmed” by their fatigue. Although in the interviews males tended to concentrate more on pain than females, there was no gender difference in the descriptions of fatigue or its impact on the individual’s life; both sexes related fatigue as “one of the worst symptoms of FMS” that “necessitated pacing the activities of their lives.”

Even if you get your sleep stabilized this may not provide substantial relief of fatigue. We’ll talk about ways that fatigue can be addressed, including some newer medications, in a later short report. But perhaps this is a good time for you to read the short report on sleep.