Abstract
PURPOSE: Purposes of this study were to identify subgroups of patients with distinct trajectories for morning and evening fatigue, evaluate for differences in demographic and clinical characteristics among these subgroups, and compare and contrast the predictors of subgroup membership for morning and evening fatigue. METHODS: Outpatients with breast, gastrointestinal, gynecological, or lung cancer (n = 582) completed questionnaires, a total of six times over two cycles of chemotherapy (CTX). Morning and evening fatigue severity were evaluated using the Lee Fatigue Scale. Latent profile analysis (LPA) was used to identify distinct subgroups. RESULTS: Three latent classes were identified for morning fatigue (i.e., low (31.8 %), high (51.4 %), and very high (16.8 %)) and for evening fatigue (i.e., moderate (20.0 %), high (21.8 %), and very high (58.2 %)). Most of the disease and treatment characteristics did not distinguish among the morning and evening fatigue classes. Compared to the low class, patients in the high and very high morning fatigue classes were younger, had a lower functional status, and higher level of comorbidity. Compared to the moderate class, patients in the very high evening fatigue class were younger, more likely to be female, had child care responsibilities, had a lower functional status, and a higher level of comorbidity. CONCLUSION: LPA allows for the identification of risk factors for more severe fatigue. Since an overlap was not observed across the morning and evening fatigue classes and unique predictors for morning and evening fatigue were identified, these findings suggest that morning and evening fatigue may have distinct underlying mechanisms.