If patients could determine how symptoms might relate to one another, doctors might do a better job of individualizing care for people with fibromyalgia. For example, if pain is your number one treatment priority, what are the odds that you will want your physician to address issues related to sleep, fatigue, cognition, mood, or physical function? Also, are there any symptoms that tend to go hand in hand with one another (e.g., cluster together)? These are the types of questions that a recent study attempted to answer. *

“The presence and severity of a particular symptom may not necessarily equate with patients’ preferences for its treatment,” write the authors Robert M. Bennett, M.D., of Oregon Health and Sciences University, and I. Jon Russell, M.D., Ph.D., of the University of Texas at San Antonio. So this new study took a different approach. More than 750 fibromyalgia patients enrolled in a multi-center treatment trial for Lyrica agreed to also rank the top five symptoms (from a list of 20) that they would like to have treated. The list of 20 symptoms was developed by a previous research study involving fibromyalgia patient focus groups who were asked to describe their most relevant clinical features or symptoms.

Due to the large number of patients involved in this study, researchers were able to apply statistical programs that mathematically determined which symptoms were most likely to cluster together. As a result, six cluster categories were identified: pain, fatigue, domestic, impairment, affective (mood-related), and social. Each individual cluster group and specific clinical features that tended to occur most related to one another (out of the 20) are shown in the table. As you will note, symptoms in the pain cluster were endorsed by the patients almost as frequently as those in the fatigue category (they differ by only 1%).

If you are wondering why disturbed sleep is in the pain (rather than fatigue) cluster, it is because the statistical analysis found pain and sleep to be more closely related. A patient who endorsed “disturbed sleep” was found to be 2.4 times more likely to also have endorsed “pain or discomfort” in their top five symptom treatment priorities.

“While pain and sleep have been suggested to have a reciprocal relationship in chronic pain conditions including fibromyalgia,” write the authors, “our results raise the question as to whether pain causes disturbed sleep or pain is a result of disturbed sleep.” Yet, difficulty thinking or fibro fog clustered with symptoms of fatigue when it came to patients ranking their treatment priorities. In other words, a person wanting their fatigue to be treated was also more likely to request that attention be given to their fibro fog.

Although the symptoms contained in the pain and fatigue clustered were virtually equal in terms of treatment priority for the group of 750 fibromyalgia patients, this was not the case for the other symptoms. “The psychosocial clusters were not considered to be as high a priority,” write Bennett and Russell, adding that greater than 70% of the patients did not even rank the symptoms listed for these categories in their top five treatment priorities.

The many symptoms of fibromyalgia can certainly complicate the treatment of people with this disease and it would be beneficial for doctors (and their patients) if they could subgroup each patient according to how they rank the treatment of symptoms. As illustrated by this study, patients who want their pain treated will also probably want their physician to help with improving sleep. Patients who rank fatigue as the top symptom that they want treated will probably also want their fibro fog addressed.

“Understanding the full complexity of the clinical features of fibromyalgia is becoming increasingly important with the availability of newer pharmacologic therapies that have significant effects on pain and other clinical features, such as sleep (Lyrica and Xyrem), affective symptoms (Cymbalta), and fatigue/fibro fog (Savella),” write Bennett and Russell. As more studies like this one become published, the next step will be apply multi-drug therapies to target specific symptom clusters to determine how well subgrouping patients can improve their overall care.

* Bennett RM, et al. BMC Musculoskeletal Disorders 11:134-143, 2010.