Preliminary data examining associations of fatigue subtypes with pain, pain interference, sleep quality, and affect across 14 days in adolescents with chronic musculoskeletal pain and pain-free controls.

OBJECTIVE

This preliminary study analyzed existing data from a larger study to characterize fatigue subtypes (general, cognitive, and sleep-related) across 14 days in adolescents with chronic musculoskeletal (MSK) pain and pain-free controls. A secondary exploratory aim was to determine whether fatigue subtypes were associated with next-day pain intensity, pain interference, sleep quality, or positive or negative affect.

METHODS

Participants were 26 adolescents with chronic MSK pain and 26 pain-free controls matched on age and sex who completed a daily diary assessing fatigue subtypes, pain intensity, pain interference, sleep quality, and affect for 14 consecutive nights. Data were aggregated across all nights for between-group comparisons, and dynamic structural equation models were used to determine how fatigue subtypes were associated with pain, sleep, and affect from one day to the next.

RESULTS

Averaging across 14 days, participants in the MSK group reported greater total fatigue and fatigue subtypes than participants in the control group (all p's < .001). Averaging across days, participants in the MSK group reported higher general fatigue than cognitive (p = .03) or sleep-related fatigue (p = .053). In the exploratory within-person analysis, previous day's cognitive fatigue (-0.10, p < .01) and general fatigue (-0.08, p < .01) were associated with worse next-day sleep quality in the MSK pain group. In the control group, cognitive fatigue was associated with greater next-day pain intensity (.04; p < .01) but lower next day pain interference (-0.03; p < .001).

CONCLUSIONS

Results preliminarily suggest fatigue subtypes are prevalent and impactful in adolescents with chronic MSK pain. Future replication of results is needed.