In this study, we aimed to develop a theoretical framework for a multimodal, integrative, exercise, anti-inflammatory and dietary counselling (MMIEAD) intervention for patients with renal cachexia with reference to how this addresses the underlying causal pathways for renal cachexia, the outcomes anticipated, and how these will be evaluated. We used a Theory of Change (ToC) approach to guide six steps. Step 1 included inputs from a workshop to obtain key stakeholder views on the potential development of a multimodal intervention for renal cachexia. Step 2 included the findings of a mixed-methods study with Health Care Practitioners (HCPs) caring for individuals with End Stage Kidney Disease (ESKD) and cachexia. Step 3 included the results from our systematic literature review on multimodal interventions for cachexia management. In step 4, we used the body of our research team's cachexia research and wider relevant research to gather evidence on the specific components of the multimodal intervention with reference to how this addresses the underlying causal pathways for renal cachexia. In steps 5 and 6 we developed and refined the ToC map in consultation with the core research team and key stakeholders which illustrates how the intervention components of MMIEAD interact to achieve the intended long-term outcomes and anticipated impact. The results of this study provide a theoretical framework for the forthcoming MMIEAD intervention for those with renal cachexia and in subsequent phases will be used to determine whether this intervention is effective. To the best of our knowledge no other multimodal intervention trials for cachexia management have reported a ToC. Therefore, this research may provide a useful framework and contribute to the ongoing development of interventions for cachexia management.

Renal cachexia is an important consideration in the person-centred care that is needed in end-stage renal disease (ESRD). However, given that clinical guidelines relating to renal cachexia are largely absent, this is an unmet care need. To inform guidelines and future renal service planning, there is an urgency to understand individuals' experiences of renal cachexia and the interrelated experiences of the carers in their lives. We report here the protocol for an interpretative phenomenological study which will explore this lived experience. A purposive sampling strategy will recruit individuals living with ESRD who have cachexia and their carers. A maximum of 30 participants (15 per group) dependent on saturation will be recruited across two nephrology directorates, within two healthcare trusts in the United Kingdom. Individuals with renal cachexia undergoing haemodialysis will be recruited via clinical gatekeepers and their carers will subsequently be invited to participate in the study. Participants will be offered the opportunity to have a face-to-face, virtual or telephone interview. Interviews will be audio-recorded, transcribed verbatim and analysed using interpretative phenomenological analysis. NVivo, will be used for data management. Ethical approval for this study was granted by the Office for Research Ethics Committees Northern Ireland (REC Reference: 22/NI/0107). Scientific evidence tends to focus on measurable psychological, social and quality of life outcomes but there is limited research providing in-depth meaning and understanding of the views of individuals with renal disease who are experiencing renal cachexia. This information is urgently needed to better prepare healthcare providers and in turn support individuals with ESRD and their carers. This study will help healthcare providers understand what challenges individuals with ESRD, and their carers face in relation to cachexia and aims to inform future clinical practice guidelines and develop supportive interventions which recognise and respond to the needs of this population.

BACKGROUND: Chronic kidney disease is common, affecting up to 13 % of the global population, and is predicted to become the fifth leading cause of life years lost by 2040. Individuals with end-stage kidney disease commonly develop complications such as protein-energy wasting and cachexia which further worsens their prognosis. The syndrome of renal cachexia is poorly understood, under-diagnosed and even if recognised has limited treatment options. OBJECTIVE: To explore the lived experience of renal cachexia for individuals with end-stage kidney disease and the interrelated experiences of their carers. DESIGN: This interpretive phenomenological study was designed to facilitate an in-depth exploration of how patients and carers experience of renal cachexia. To improve and document the quality, transparency, and consistency of patient and public involvement in this study the Guidance for Reporting Involvement of Patients and the Public-Short Format was followed. SETTING: The study was conducted across two nephrology directorates, within two healthcare trusts in the United Kingdom. PARTICIPANTS: Seven participants who met the inclusion criteria were recruited for this study, four patients (three female, one male) and three carers (two male, one female). METHODS: We employed a purposive sampling strategy. Data collection was conducted between July 2022 and December 2023. Interviews were semi-structured, audio-recorded, transcribed verbatim and analysed in six steps by two researchers using interpretive phenomenological analysis. Ethical approval was approved by the Office for Research Ethics Committees Northern Ireland (Reference: 22/NI/0107). RESULTS: Analysis generated six group experiential themes: the lived experience of appetite loss, functional decline and temporal coping, weight loss a visual metaphor of concern, social withdrawal and vulnerability, the emotional toll of eating challenges and psychological strain amidst a lack of information about cachexia. CONCLUSION: This is the first qualitative study exploring the lived experience of renal cachexia for patients and carers. Our study highlights that psycho-social and educational support is urgently needed. Additionally, healthcare professionals need better information provision to help them to recognise and respond to the needs of this population. Further research is required to develop models of holistic support which could help patients and carers cope with the impact of renal cachexia and optimally manage this syndrome within the family unit. REGISTRATION: N/A.