Session Title: Fibromyalgia and Soft Tissue Disorders
Session Type: Abstract Submissions (ACR)
Background/Purpose: Previous research and clinical observation suggest that patients with chronic disease who are obese report significant fatigue. Our objective was to explore similar relationships in patients with fibromyalgia and the extent to which pain, sleep disturbance, and depression mediated this relationship.
Methods: 3917 patients who consented to be part of a fibromyalgia registry were included in this analysis. Registry measures included demographics, body mass index (BMI), the modified 2010 American College of Rheumatology Fibromyalgia Survey Criteria, and selected items from the Multidimensional Assessment of Fatigue. Data were analyzed using the INDIRECT macro for SPSS which allows multiple mediator models to be specified. All analyses controlled for age and sex. INDIRECT provides unstandardized regression coefficients (reported below as “B”) which are the preferred metric in mediation models.
Results: BMI was positively associated with fatigue (B = .03, p < .0001). BMI was also positively associated with pain (B = .06, p < .0001), sleep disturbance (B = .004, p < .05), and depression (B = .003, p < .01). After controlling for pain, sleep disturbance, and depression, the relationship between BMI and fatigue (B = 02, p < .0001) was reduced by over 33% (.02/.03). In spite of this, pain, sleep disturbance, and depression remained statistically significant (all p’s < .0001). Hence, we examined the partial mediating effects of these variables. Results indicated that pain, sleep disturbance, and depression combined mediate the association between BMI and fatigue (B = .01, p < .05). Additionally, pain (B = .01, p < .05), sleep disturbance (B = .01, p < .05), and depression (B = .002, p < .05) also had unique indirect effects on fatigue.
Conclusion: Statistically significant total and direct effects were present for the association between BMI and fatigue in patients with fibromyalgia. Hence, the association between BMI and fatigue was only partially explained by pain, sleep disturbance, and depression. While these data provide insight into a potential relationship between obesity and fatigue and possible mechanisms, these are cross-sectional results and do not offer insight into causality. These types of analyses should also be examined through longitudinal research.
M. O. Whipple,
L. L. Toussaint,
D. J. Clauw,
D. A. Williams,
T. H. Oh,
J. M. Thompson,
C. A. Luedtke,
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/pain-sleep-disturbance-and-depression-mediate-the-association-between-body-mass-index-and-fatigue-in-fibromyalgia/