Longitudinal Associations Between Fatigue and Perceived Work Ability in Cancer Survivors

Purpose To examine the associations between changes of fatigue and changes of perceived work ability in cancer survivors. Furthermore, to examine the effects of physical job demands on these associations. Methods Data from a feasibility study on a multidisciplinary intervention to enhance return to work in patients with cancer receiving chemotherapy was used. Fatigue (Multidimensional Fatigue Inventory) and perceived work ability (first item of the Work Ability Index) were assessed at baseline, and after 6, 12, and 18 months. Change scores (S1, S2, S3) from each assessment to the next were calculated, thus encompassing three separate time periods of 6 months. Regression analyses were used to quantify associations between change of perceived work ability and (model 1) change of general fatigue, and (model 2) change of mental and physical fatigue for each 6-month period separately. For model 2, interaction effects of perceived physical job demands were studied. Results A total of 89 participants were included for analysis, among which 84% with a diagnosis of breast cancer. On average, in model 1, a reduction of five points on general fatigue was associated with an improvement of one point in perceived work ability in all three 6-month periods. Model 2 showed, similarly, that change of physical fatigue (S1 and S2: B = -0.225; p < .001 and B = -0.162; p = .012) and change of mental fatigue (S3: B = -0.177; p = .027) were significantly inversely associated with change of perceived work ability. Interaction effects were not significant. Conclusion The inverse, longitudinal association between fatigue and perceived work ability supports previous findings from cross-sectional studies and shows potential occupational impact of targeting fatigue in cancer rehabilitation.