Objective: Illness uncertainty is a significant source of psychological distress that affects cancer patients' quality of life (QOL). Mishel's uncertainty in illness theory (UIT) proposes that illness uncertainty influences an individual's use of coping strategies, and directly and indirectly influences their QOL. This study tested the relationships depicted in the adapted UIT in cancer patients.
Methods: This cross-sectional study is a secondary analysis of the baseline data from a randomized clinical trial (N = 263 prostate cancer patients). Patients were diagnosed with localized (64.6%), biochemical recurrent (12.6%), or advanced (22.8%) prostate cancer. Uncertainty, coping (avoidant and active coping strategies), and QOL (physical and mental well-being) were measured using the Mishel's uncertainty of illness scale, Brief COPE, and the Medical Outcomes Study 12-item short form (SF-12), respectively. We used path analysis to achieve the research aim.
Results: Patients' illness uncertainty directly, negatively influenced their physical well-being (P < .001) and mental well-being (P < .05). Patients' illness uncertainty was positively related to their avoidant coping strategies (P < .001). Patients' active and avoidant coping strategies influenced their mental well-being (P < .001). Uncertainty also negatively influenced mental well-being through avoidant coping strategies. The model had excellent fit to the data.
Conclusions: Our findings have indicated the potential of improving QOL by decreasing illness uncertainty and reducing avoidant coping strategies. Future research is needed to better understand the complex relationships between illness uncertainty, coping strategies, and domains of QOL among patients with different types of cancer using longitudinal research.
Keywords: coping; oncology; path analysis; prostate cancer; quality of life; uncertainty.
© 2020 John Wiley & Sons, Ltd.