Autonomic Dysfunction in Fibromyalgia Assessed by the Composite Autonomic Symptoms Scale (COMPASS)

Background: It has been suggested that autonomic nervous system dysfunction may explain all of fibromyalgia (FM) multisystem features. Such proposal is based mostly on the results of diverse heart rate variability analyses. The Composite Autonomic Symptom Scale (COMPASS) is a different validated method to recognize dysautonomia.

Objectives: The main objective of our study was to investigate symptoms of autonomic dysfunction in FM patients by means of COMPASS. A secondary objective was to define whether there is a correlation between COMPASS and Fibromyalgia Impact Questionnaire (FIQ) scores in FM patients.

Methods: Design, analytical cross-sectional study. Our study population included 3 different groups of women: 30 patients with FM, 30 patients with rheumatoid arthritis, and 30 women who considered themselves healthy. All participants filled out COMPASS and FIQ questionnaires.

Results: FM patients had significantly higher values in all COMPASS domains. COMPASS total score (54.6 +/- 20.9; mean +/- standard deviation) clearly differentiated FM patients from the other 2 groups (21.6 +/- 16.5 and 9.5 +/- 10.2, respectively). P < 0.0001. The majority of FM patients gave affirmative answers to questions related to orthostatic, digestive, sleep, sudomotor, or mucosal dysfunction. There was a significant correlation between COMPASS and FIQ scores (Spearman r = 0.5, P < 0.005).

Conclusions: Patients with FM have multiple nonpain symptoms related to different expressions of autonomic dysfunction. There is a correlation between a questionnaire that measures FM severity (FIQ) and an autonomic dysfunction questionnaire (COMPASS). Such correlation suggests that autonomic dysfunction is inherent to FM.