Aims: To examine associations between fatigue and poor sleep quality, depression symptoms, and pain intensity in an adult population with chronic arthralgia/myalgia in the temporomandibular region and to test whether fatigue predicted future pain-related interference above and beyond these other constructs.
Methods: The sample included 40 participants with chronic arthralgia and/or myalgia in the temporomandibular region and 21 healthy controls. Participants self-reported fatigue (PROMIS fatigue score), sleep quality (PSQI), depression symptoms (PROMIS depression score), and average pain intensity and completed four weekly surveys of pain-related interference with daily activities.
Results: The chronic arthralgia/myalgia group reported greater fatigue than healthy controls (t = 4.85, P < .001). Fatigue was significantly correlated with poor sleep quality (r = .46), higher depression symptoms (r = .41), and higher pain intensity (r = .46) in the chronic arthralgia/myalgia group, and these three variables together explained 39% of variance in fatigue. Greater fatigue-above and beyond sleep quality, depression symptoms, and average pain intensity-was associated with a higher average level of pain-related interference (β = 0.56, t score = 3.30, P = .002) over the following month. Depression symptoms, poor sleep quality, and pain intensity did not significantly predict pain interference above and beyond fatigue (all P > .05).
Conclusion: The results suggest that fatigue is a clinically relevant symptom distinct from depression, poor sleep quality, or pain intensity and may be related to worse pain outcomes over the following month in adults with chronic temporomandibular arthralgia/myalgia. Clinicians should assess, monitor, and treat fatigue to the best of their abilities when working with this population.