Background The number of people living with dementia is expected to double by 2050. Experiences in advanced illness and at end of life for people with dementia and their carers can be poor. Advance care planning (ACP) is especially challenging in dementia. In this study we will explore how people with dementia and their carers prepare for advanced illness and end of life. Using quantitative and qualitative data, we will look at what factors influence them. We will ask about their experiences, including of advance care planning or other support. We will especially consider how people with dementia and their carers interact and influence each other, and what expectations they have of each other. We will also examine whether preparing, through ACP or other means, makes a difference to end of life outcomes and experiences.

Methods Secondary analysis of data from the Improving the Experience of Dementia and Enhancing Active Life (IDEAL) study (gathered from a cohort of 1500 people with dementia and their carers).

• Qualitative interviews with 40–50 carers (and people with dementia where capacity allows) taking part in the DETERMinants of quality of life, care and costs, and consequences of INequalities in people with Dementia and their family carers (DETERMIND) study (a cohort of 900 people with dementia and their carers)

• Bereavement survey with carers from the DETERMIND study who are bereaved during the course of our study (2018–2023)

Results Findings will be reported over the course of the study in academic papers, blog-posts and at a range of conferences and meetings. We will also produce guidance for policy-makers and practitioners and a short film.