The study aims to estimate the prevalence of post-intensive care syndrome (PICS) 12 months after ICU admission among adult ICU survivors in Denmark and to describe how this prevalence is distributed across the physical, cognitive, and mental health domains. By conducting follow-up assessments at 3, 6, and 12 months post-discharge, the study further seeks to determine the prevalence of PICS at each time point, characterise its temporal trajectory, and explore patients' symptom burden over time.

Research question

• What is the prevalence of PICS and its specific components (physical, cognitive, and mental health domains) among ICU survivors 12 months after ICU admission?
• How do the components of PICS evolve during the follow-up period (trajectory)?
• What risk factors are associated with the development of PICS in ICU survivors?
• Are there differences in PICS prevalence based on demographic or clinical characteristics (e.g., age, comorbidities, ICU length of stay)?

The hypothesis is that the prevalence of post-intensive care syndrome (PICS) in a Danish cohort of adult ICU survivors at 12 months will be approximately one third, defined as impairment in at least one of the three PICS domains (physical, cognitive, or mental health), measured using validated instruments with pre-specified cut-offs.

Inclusion Criteria:

• Adult patients ≥ 18 years of age
• Admitted to the intensive care unit for ≥48 hours
• Acutely admitted to the intensive care unit

Exclusion Criteria:

• Patients with limited treatment
• Foreign patients
• Pregnant women
• Patient with impaired cognitive function (e.g. dementia, intellectual disability)
• Patient without Danish citizenship
• Patient with limited proficiency in the Danish language

Danish ICU-patients admitted to an intensive care unit at any of the participating hospitals in Denmark.