Uncertainty, mood states, and symptom distress in patients with primary brain tumors: Analysis of a conceptual model using structural equation modeling

BACKGROUND Patients with primary brain tumors (PBTs) face uncertainty related to prognosis, symptoms, treatment response, and toxicity. The authors of this report examined the direct/indirect relations among patients' uncertainty, mood states, and symptoms. METHODS In total, 186 patients with PBTs were accrued at various points in the illness trajectory. Data-collection tools included an investigator-completed clinician checklist, a patient-completed demographic data sheet, the Mishel Uncertainty in Illness Scale-Brain Tumor Form (MUIS-BT), the MD Anderson Symptom Inventory-Brain Tumor Module (MDASI-BT), and the Profile of Mood States-Short Form (POMS-SF). Structural equation modeling was used to explore correlations among variables. RESULTS Participants were primarily white (80%) men (53%) with a variety of brain tumors. They ranged in age from 19 to 80 years (mean ± standard deviation, 44.2 ± 12.6 years). Lower functional status and earlier point in the illness trajectory were associated with greater uncertainty (P <.01 for both). Uncertainty (P <.05), except in the model of "confusion," and the 5 negative mood states measured by the POMS-SF were directly associated with symptom severity perceived by patients (P <.01 for all). The impact of uncertainty on perceived symptom severity also was mediated significantly by mood states. CONCLUSIONS The results from the study clearly demonstrated distinct pathways for the relations between uncertainty-mood states-symptom severity for patients with PBTs. Uncertainty in patients with PBTs is higher for those who have a poor performance status and directly impacts negative mood states, which mediate patient-perceived symptom severity. This conceptual model suggests that interventions designed to reduce uncertainty or that target mood states may help lessen patients' perception of symptom severity, which, in turn, may result in better treatment outcomes and quality of life.