Study objectives: To evaluate the relation among several symptoms that occur commonly in cancer patients: trouble sleeping, fatigue/sleepiness, depressed mood, and pain in a large cohort of cancer patients undergoing treatment in a community oncology practice.
Methods: Demographic, clinical, and patient reported outcomes data from 11,445 cancer patients undergoing treatment in a large community oncology practice were analyzed using structural equation modeling. The data were split so that a model was constructed using half of the patients; this model was then cross-validated on the remaining patients.
Results: Fatigue was best represented as a latent variable, and significant direct effects were found for trouble sleeping, depressed mood, and pain. Also, there were significant indirect effects of these variables on fatigue. The effect of depressed mood on fatigue and pain was mediated by trouble sleeping, and the effect of trouble sleeping on fatigue was mediated by pain.
Conclusions: These results predict that interventions aimed at treatment of trouble sleeping, depressed mood, and pain will improve fatigue in patients with cancer. Further, these data predict that treatment of trouble sleeping will improve pain management in this population.