Long-term Mental Health Morbidity in Adult Survivors of COVID-19 Critical Illness - A Population-based Cohort Study.

Background: Survivorship after coronavirus disease 2019 (COVID-19) critical illness may be associated with important long-term sequelae, but little is known regarding mental health outcomes.

Research Question: What is the association between COVID-19 critical illness and new post-discharge mental health diagnoses.

Study Design: AND METHODS: We conducted a population-based cohort study in Ontario, Canada (January 1, 2020-March 31, 2022). We included consecutive adult survivors (age ≥ 18 years) of COVID-19 critical illness, and compared them with consecutive adult survivors of critical illness from non-COVID-19 pneumonia. The primary outcome was a new mental health diagnosis (a composite of mood, anxiety, or related disorders; schizophrenia/psychotic disorders; and other mental health disorders) following hospital discharge. We compared patients using overlap propensity score-weighted, cause-specific proportional hazard models.

Results: We included 6,098 survivors of COVID-19 critical illness, and 2,568 adult survivors of critical illness from non-COVID-19 pneumonia at 102 centres. Incidence of new mental health diagnosis among survivors of COVID-19 critical illness was 25.3 per 100-person years (95% confidence interval [CI] 24.0-26.6), and 25.9 per 100-person years (95% CI: 24.0-27.8) among non-COVID-19 pneumonia. Following propensity weighting, COVID-19 critical illness was not associated with increased risk of new mental health diagnosis overall (hazard ratio [HR] 1.08 [95% CI: 0.96-1.23]), but was associated with increased risk in the category of new mood, anxiety, or related disorders (HR 1.21 [95% CI: 1.05-1.40]). No difference was seen in psychotic disorders, other mental health diagnoses, social problems, or deliberate self-harm.

Interpretation: As compared to survival after critical illness from non-COVID-19 pneumonia, survival after COVID-19 critical illness was not associated with increased risk of the composite outcome of new mental health diagnosis, but was associated with elevated risk for new mood, anxiety, or related disorders.