Individual outcomes after tailored versus generic self-management strategies for persistent fatigue in youth with a fatigue syndrome or rheumatic condition: A multiple single-case study.

Objective: To examine individual outcomes after tailored lifestyle (PROfeel) or generic dietary advice as self-management intervention for persistent fatigue in adolescents and young adults with a chronic condition, to compare participants who did and did not benefit and to explore changes to factors in the biopsychosocial model of fatigue after PROfeel.

Method: A multiple single-case AB-phase design was embedded in a randomized crossover trial (N = 45). Intensive longitudinal data (ILD) on outcomes 'fatigue severity', 'self-efficacy' and 'quality of life' (QoL) were collected through weekly smartphone measurement for 20 weeks. ILD on biopsychosocial factors were collected through experience sampling methodology for 28 days pre-post first intervention. Baseline characteristics were compared with t-tests and chi-square tests. Permutation distancing tests were used to assess change over time in all ILD.

Results: Regarding weekly measurements, nineteen participants (42.22%) showed small to large positive outcomes (d = .05 to 2.59), mostly after PROfeel. Eleven participants (24.44%) showed small to moderate negative outcomes (d = -.02 to -2.46), mostly after dietary advice. Fatigue severity improved most, followed by self-efficacy. Participants who benefitted showed higher QoL levels and lower fatigue and pain levels compared with others at baseline (all p < .02). When positive outcomes were observed after PROfeel, typically ≥1 biopsychosocial factor had been targeted successfully.

Conclusion: Self-management advice has more potential when tailored to individual characteristics, including the biopsychosocial model of fatigue. PROfeel appears particularly useful as fatigue intervention for individuals with relatively less severe symptoms.