Moment-to-moment relationships between pain, fatigue, and distress as a function of GI symptoms in fibromyalgia

Objective: There is emerging evidence that people with both fibromyalgia and functional gastrointestinal (GI) disorders report more severe psychological symptoms than people with only fibromyalgia or a functional GI disorder. We use Ecological Momentary Assessment (EMA) to examine whether, for people with fibromyalgia, accompanying GI symptoms result in stronger bidirectional relationships between distress and bodily pain or fatigue. Methods: Participants were 67 women with fibromyalgia from a study by Okifuji et al. (2011; 13), in which EMA data on pain, fatigue, and distress was collected over 30 days. Thirty-three participants reported GI symptoms at baseline, and 34 participants reported no GI symptoms but at least one other bodily symptom. Using multilevel linear regressions with interaction terms, we compared the two groups on the strength of reciprocal within-day and day-to-day relationships between pain, fatigue, and distress. Results: GI symptom status did not moderate relationships between distress and pain. However, participants with GI symptoms uniquely reported more distress following increased fatigue within days (b = 0.120, 95%CI: 0.041,0.198), and sharper distress escalations across days (b = 0.078 95%CI: 0.007, 0.149). Conclusion: We do not find evidence of stronger bidirectional within-day and day-to-day relationships between distress and bodily symptoms in this patient group. We do, however, find evidence of heightened fatigue-related distress and escalating distress. These cyclical processes can become a focus for cognitive behavioural therapy, patient education, and physical (exercise/sleep) therapy aimed at addressing fatigue.