Associations of dyadic appraisal of cancer cachexia symptoms with psychological distress and quality of life in dyads of palliative care patients: a longitudinal mixed-methods study protocol.

BACKGROUND

Cancer cachexia (CC) is a fatal syndrome most prevalent in palliative care patients and is typically characterized by a progressive increase in weight loss and anorexia. The inability to detect and accurately appraise CC symptoms early can lead to a delayed diagnosis of CC and late initiation of symptom management, subsequently resulting in shorter survival. Research has shown that both patients and primary family caregivers are burdened by worsening CC symptoms, making them susceptible to reduced quality of life (QOL) and increased psychological distress in particular, and necessitating an exploration of ways to improve their well-being. Guided by the Theory of Dyadic Illness Management supplemented by the Symptom Appraisal Pathway Model, the study will be the first to provide a comprehensive understanding of the role of dyadic appraisal of patients' CC symptoms on psychological distress and QOL of palliative care patients and their primary family caregivers over an eight-week follow-up period.

METHODS

This study will adopt a longitudinal mixed-methods design, combining both quantitative and qualitative data collection at baseline and eight weeks after baseline. 281 dyads of patients with CC and caregivers will be recruited from palliative care units of three hospitals in Hong Kong. Both patients and caregivers will complete a set of questionnaires measuring appraisal of patients' CC symptoms and own psychological distress, and QOL, separately. Semi-structured joint interviews will also be conducted with the same dyads. Quantitative data will be analyzed using the actor-partner interdependence model and the polynomial regression with response surface analysis, while qualitative data will be subjected to qualitative content analysis and trajectory analysis. The findings of the two datasets will be integrated via joint displays.

DISCUSSION: Findings of this study are expected to advance the emerging science on dyadic symptom management by testing the utility of the theory of Dyadic Illness Management and the Symptom Appraisal Pathway Model, but also to inform the design and content of a theory- and evidence-based CC management intervention to reduce psychological distress and to achieve optimal QOL in CC dyads.