Physical and mental health related factors associated with critical illness requiring intensive care, post intensive care syndrome and causes of death of intensive care survivors

Surviving a condition that requires care in an intensive care unit (ICU) has increased during the last decades. Patients recovering often suffer from limitations in their everyday life. Survivors have high post-hospital mortality compared to the general population. This thesis evaluates pre-intensive care factors associated with a future critical illness, factors affecting physical functioning and mental health and causes of death among ICU-survivors after hospital discharge.
Pre-intensive care factors were studied among Northern Finland Birth Cohort 1966 participants ́ at the age of 31. Factors associated with poor physical functioning and mental health were evaluated at post-ICU clinic. The study considering causes of deaths was conducted among a national Finnish prospective cohort of patients with or without acute kidney injury.
The rate of neurological diseases, malignancy, alcohol abuse and smoking were higher among ICU-treated individuals compared to those hospitalized in regular wards. Also, the patients with future and later ICU admission practiced less strenuous physical activity compared to those treated in regular wards. At the post-ICU clinic, patients with poor physical function outcome had a longer hospital stay, had more memories of pain, achieved worse results in a six-minute walking test and were less likely to be able to move independently. Those with impaired mental health outcome had a higher rate of delirium and fewer memories of relatives' and treating nurses. The three most common causes of death in the AKI-group were cardiovascular diseases, malignancies, and neurological diseases.
According to the main results of this thesis the main factors associated with future critical illness are neurological comorbidities, malignancy, alcohol misuse, smoking, and less frequent hard physical exercise. Memories of pain, multiple trauma and longer hospital stay are associated with poor physical functioning. Delirium and lack of memories are associated with impaired mental health. Cardiovascular causes and malignancies account for more than half of the causes of death among patients who had an acute kidney injury.