Observational Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Psychiatr. Sep 19, 2020; 10(9): 212-222
Published online Sep 19, 2020. doi: 10.5498/wjp.v10.i9.212
Delirium, insulin-like growth factor I, growth hormone in older inpatients
Dimitrios Adamis, Iulian Coada, Piet Eikelenboom, Che-Sheng Chu, Karen Finn, Vincent Melvin, John Williams, David James Meagher, Geraldine McCarthy
Dimitrios Adamis, Iulian Coada, Vincent Melvin, Geraldine McCarthy, Department of Psychiatry, Sligo/Leitrim Mental Health Services, Sligo F91 CD34, Ireland
Dimitrios Adamis, Department of Psychiatry, Research and Academic Institute of Athens, Athens 11742, Greece
Dimitrios Adamis, David James Meagher, Department of Psychiatry, University Hospital Limerick, Limerick V94 F858, Ireland
Piet Eikelenboom, Department of Psychiatry, GGZinGeest and VuMC, Amsterdam 1081 HV, the Netherlands
Che-Sheng Chu, Department of Psychiatry and Center for Geriatric and Gerontology, Kaohsiung Veterans General Hospital, Kaohsiung 81362, Taiwan
Karen Finn, Department of Biopharmaceutical and Medical Science, School of Science and Computing, Galway-Mayo Institute of Technology, Galway H91 T8NW, Ireland
John Williams, Department of Pathology, Sligo University Hospital, Sligo F91 H684, Ireland
Author contributions: Adamis D was involved in the conceptualization of the project, data curation, statistical analysis, supervision of the project, writing-original draft; Coada I was involved in data entry, curation, writing-original draft; Eikelenboom P was involved in the conceptualization, supervision of the project, writing-original draft; Chu C was involved in the conceptualization, supervision, and writing-original draft; Finn K was involved in the biochemical analysis, data entry, data curation, writing-original draft; Melvin V was involved in the clinical data collection, data entry and curation, writing-original draft; Williams J was involved in the conceptualization, biochemical analysis, supervision, funding acquisition and writing the original draft; Meagher D was involved in the conceptualization, supervision, and writing the original draft; McCarthy G was involved in the conceptualization, supervision, funding acquisition and writing the original draft; all authors have contributed read and approve the final manuscript.
Supported by Research Seed grant from the Research and Education Foundation, Sligo University Hospital, Sligo, Ireland.
Institutional review board statement: The study has been approved from the Sligo University Hospital ethical committee.
Informed consent statement: The informed consents were waived.
Conflict-of-interest statement: All authors have no any conflicts of interest.
Data sharing statement: No sharing of data.
STROBE statement: The authors have read the STROBE Statement, and the manuscript was prepared and revised according to the STROBE Statement.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Dimitrios Adamis, MD, MSc, Academic Research, Department of Psychiatry, Sligo/Leitrim Mental Health Services, Clarion Road, Sligo F91 CD34, Ireland. dimaadamis@yahoo.com
Received: December 30, 2019
Peer-review started: December 27, 2019
First decision: April 2, 2020
Revised: June 16, 2020
Accepted: August 24, 2020
Article in press: August 24, 2020
Published online: September 19, 2020

Delirium is a common disorder in elderly medical inpatients with serious adverse outcomes and is characterized by sudden onset, disturbance in attention, awareness, consciousness and cognition, and often with behavioural disturbances. Central to understanding delirium, is understanding mechanisms by which body and brain wellbeing are linked and in particular how brain responses to bodily homeostatic stress is mediated. A number of studies have investigated the relationship between insulin-like growth factor I (IGF-I) and delirium in medically ill hospitalised patients with conflicting results. However, none have investigated growth hormone (GH) which is related to IGF-I via negative feedback.


To investigate the relationship between serum levels of IGF-I and GH, and the occurrence of delirium.


Prospective, longitudinal, observational study. Consecutive elderly inpatients (aged 70+), were assessed twice weekly with Montreal cognitive assessment (MoCA), Confusion assessment method (CAM), Acute Physiology and Chronic Health Evaluation II. Delirium was defined using CAM. Previous history of dementia was evaluated with the Informant Questionnaire on Cognitive Decline in the Elderly. IGF-I and GH levels were estimated with the ELISA method. Generalized estimating equations (GEE) model was applied for the first five assessments to analyze those longitudinal data.


The sample consisted of 198 participants (mean age 80.63 ± 6.81; range 70-97). Of these 92 (46.5%) were females. Eighty six (43.4%) were identified with a history of dementia. Incident or prevalent delirium during hospitalisation was identified with CAM in 40 participants (20.2%). Evaluation of missing values with Little's MCAR test indicated that they were missing completely at random (MCAR χ2 = 12.24, u: 9, P = 0.20). Using GEE for the analysis we found that low MoCA scores, low levels of IGF-I and high levels of GH were significantly associated with any delirium (prevalence, incident, or fluctuating , during the study period (Wald χ2 = 12.231; u: 1, P < 0.001, Wald χ2 = 7.196, u: 1, P = 0.007, Wald χ2 = 6.210; : u: 1, P = 0.013 respectively).


The results show that low levels of IGF-I, high levels of GH and low scores in cognition are independently associated with the occurrence of any delirium during the hospitalisation of medically ill older people. The results of the study supports the hypothesis that deficits in the immunoreactivity of the brain (low cerebral reserve) may be associated with delirium.

Keywords: Delirium, Pathophysiology, Insulin-like growth factor-I, Growth hormone, Older people, Physical illness, Cognition, Old age psychiatry

Core Tip: The present work investigates the association of serum levels of insulin-like growth factor I (IGF-I) and growth hormone (GH) with delirium presence in older medically ill hospitalised people. We found, in accordance with previous studies, that low levels of serum IGF-I and high levels of GH together with cognitive deficits are associated with the occurrence of delirium.