Protocol for EXICODE: the EXIstential health COhort DEnmark-a register and survey study of adult Danes.

INTRODUCTION: We established the EXIstential health COhort DEnmark (EXICODE) to examine how existential and spiritual needs, practices and orientations in a secular culture are linked to health outcomes, illness trajectory and overall cost of care in patients. Substantial literature demonstrates that existential and spiritual well-being has positive effects on health. While people turn to existential and spiritual orientations and practices during ageing, struggle with illness and approaching death, patients with severe illnesses like, for example, cancer similarly experience existential and spiritual needs. These needs are often unmet in secular societies leading to spiritual pain, unnecessary suffering, worse quality of life and higher medical costs of care. METHODS AND ANALYSIS: EXICODE is a national cohort comprising a 10% random sample of the adult Danish population with individual-level register and survey data. Specific patient subgroups are oversampled to ensure diseased respondents. The questionnaire used in the survey consists of a collection of validated instruments on existential and spiritual constructs suited for secular culture as well as some ad hoc questions compiled in the comprehensive EXICODE Questionnaire. ETHICS AND DISSEMINATION: The project is registered for legal and GDPR concerns by the University of Southern Denmark, journal number: 10.367. Ethical approval was not required by Danish law since EXICODE collects only interview, survey and register data, but due to institutional best-practice policy an ethical evaluation and approval were nevertheless obtained from the University of Southern Denmark Research Ethics Committee (institutional review board), journal number: 20/39546. The project follows The Danish Code of Conduct for Research Integrity and is carried out in accordance with the Helsinki Declaration. Results will be disseminated widely through publications in peer-reviewed scientific journals, international conferences, patient societies as well as mass and social media. © Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.