Pre-Existing Mental Health Disorders in Patients Admitted to the Intensive Care Unit: Prevalence, Characteristics and Outcomes

Pilowsky, Julia Kuiper

Pre-Existing Mental Health Disorders in Patients Admitted to the Intensive Care Unit: Prevalence, Characteristics and Outcomes

Pilowsky, Julia Kuiper

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Publication Type:: Thesis
Issue Date:: 2023

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Field	Value	Language
dc.contributor.author	Pilowsky, Julia Kuiper
dc.date.accessioned	2024-04-12T03:46:38Z
dc.date.available	2024-04-12T03:46:38Z
dc.date.issued	2023
dc.identifier.uri	http://hdl.handle.net/10453/177817
dc.description	University of Technology Sydney. Faculty of Health.	en_US.UTF-8
dc.description.abstract	Background: Mental health disorders are known to adversely affect the physical health of patients in primary and acute care settings; however, their impact on critically ill patients is less well studied. To develop strategies to better support patients with mental health disorders during and after an intensive care unit (ICU) admission, their characteristics and long-term outcomes need to be understood. Aim: The aim of this thesis is to understand the characteristics and outcomes of patients with pre-existing mental health disorders who are treated in Australian adult ICUs, to facilitate the future development of targeted strategies to support their mental and physical health during and after an ICU admission. Methods: First, a classification algorithm to identify mental health disorders in the clinical progress notes was developed using natural language processing techniques and validated against a manual chart review. Second, a retrospective cohort study was conducted to determine the prevalence of pre-existing mental health disorders in ICU patients and investigate any associations with short-term outcomes such as ICU length of stay. Finally, data linkage was performed to determine the 12-month outcomes of the cohort and develop a predictive model to identify ICU survivors at greatest risk of unplanned readmission. Results: The classification algorithm was developed using 163,522 progress note excerpts from 17,183 patients and demonstrated an accuracy rate of 90.0% (95%CI 86.6-92.8%). After excluding readmissions, 16,228 patients from eight ICUs were included in the second study, of which 5,044 (31.1%) had a documented pre-existing mental health disorder. Patients with a pre-existing mental health disorder had a longer ICU length of stay (β-coefficient, 0.12; 95%CI, 0.10–0.15) and were more likely to experience invasive ventilation (odds ratio, 1.42; 95%CI, 1.30–1.56). Finally, 12,862 ICU survivors were included in the long-term outcomes study of which 5,940 (46.2%) experienced unplanned readmission or death. The prediction model demonstrated reasonable discrimination (area under the receiver operating characteristic curve 0.68, 95%CI 0.67-0.69) and overall performance (scaled Brier score 0.10) with the presence of a pre-existing mental health disorder identified as a strong predictor (OR 1.52, 95%CI 1.40-1.65). Conclusion: Patients with pre-existing mental health disorders form a significant subgroup within the ICU and the presence of a pre-existing mental health disorder is associated with poorer outcomes during and after the ICU admission. Further research is needed to understand the mechanisms underlying these associations and to develop targeted strategies to support these patients during and after critical illness.	en_US.UTF-8
dc.format	Thesis (PhD)
dc.language.iso	en_US	en_US.UTF-8
dc.relation	https://opus.lib.uts.edu.au/bitstream/10453/177817/1/thesis.pdf
dc.rights	info:eu-repo/semantics/openAccess
dc.rights	The author owns the copyright in this thesis including all reproduction and reuse rights for the work. The work may not be altered without the permission of the copyright owner. Attribution is essential when quoting or paraphrasing from this thesis.
dc.rights	© 2023 Julia Kuiper Pilowsky
dc.rights	au.edu.uts.lib/cph
dc.title	Pre-Existing Mental Health Disorders in Patients Admitted to the Intensive Care Unit: Prevalence, Characteristics and Outcomes	en_US.UTF-8
dc.type	Thesis
utslib.copyright.status	open_access	*

Abstract:

Background: Mental health disorders are known to adversely affect the physical health of patients in primary and acute care settings; however, their impact on critically ill patients is less well studied. To develop strategies to better support patients with mental health disorders during and after an intensive care unit (ICU) admission, their characteristics and long-term outcomes need to be understood. Aim: The aim of this thesis is to understand the characteristics and outcomes of patients with pre-existing mental health disorders who are treated in Australian adult ICUs, to facilitate the future development of targeted strategies to support their mental and physical health during and after an ICU admission. Methods: First, a classification algorithm to identify mental health disorders in the clinical progress notes was developed using natural language processing techniques and validated against a manual chart review. Second, a retrospective cohort study was conducted to determine the prevalence of pre-existing mental health disorders in ICU patients and investigate any associations with short-term outcomes such as ICU length of stay. Finally, data linkage was performed to determine the 12-month outcomes of the cohort and develop a predictive model to identify ICU survivors at greatest risk of unplanned readmission. Results: The classification algorithm was developed using 163,522 progress note excerpts from 17,183 patients and demonstrated an accuracy rate of 90.0% (95%CI 86.6-92.8%). After excluding readmissions, 16,228 patients from eight ICUs were included in the second study, of which 5,044 (31.1%) had a documented pre-existing mental health disorder. Patients with a pre-existing mental health disorder had a longer ICU length of stay (β-coefficient, 0.12; 95%CI, 0.10–0.15) and were more likely to experience invasive ventilation (odds ratio, 1.42; 95%CI, 1.30–1.56). Finally, 12,862 ICU survivors were included in the long-term outcomes study of which 5,940 (46.2%) experienced unplanned readmission or death. The prediction model demonstrated reasonable discrimination (area under the receiver operating characteristic curve 0.68, 95%CI 0.67-0.69) and overall performance (scaled Brier score 0.10) with the presence of a pre-existing mental health disorder identified as a strong predictor (OR 1.52, 95%CI 1.40-1.65). Conclusion: Patients with pre-existing mental health disorders form a significant subgroup within the ICU and the presence of a pre-existing mental health disorder is associated with poorer outcomes during and after the ICU admission. Further research is needed to understand the mechanisms underlying these associations and to develop targeted strategies to support these patients during and after critical illness.

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http://hdl.handle.net/10453/177817