Assessing longitudinal quality of life in prostate cancer patients and their spouses: A multilevel modeling approach

Purpose This study aimed at examining the relationship between quality of life (QOL) in prostate cancer (PCa) patients and partners and how baseline demographics, cancer-related factors, and time-varying psychosocial and symptom covariates affect their QOL over time. Methods Guided by a modified Stress-Coping Model, this study used multilevel modeling to analyze longitudinal data from a randomized clinical trial that tested a family-based intervention to improve QOL in couples managing PCa. Patients and partners from the usual-care control group (N = 134 dyads) independently completed the measurements at baseline, and at 4-, 8-, and 12-month follow-ups. Results Correlations of QOL between patients and partners over time were small to moderate. Patients' lower education level, partners' older age, higher family income, and localized cancer at baseline were associated with better QOL in couples. Over time, couples' QOL improved as their social support and cancer-related dyadic communication increased and as couples' uncertainty, general symptoms, and patients' prostate cancer-related sexual and hormonal symptoms decreased. Conclusions Evidence indicates that couples' QOL during cancer survivorship is affected by multiple contextual factors (e.g., baseline demographics and time-varying psychosocial factors and symptoms). Intervention research is needed to explore comprehensive strategies to improve couples' QOL during the continuum of PCa survivorship.