Delirium in older hospitalized patients—A prospective analysis of the detailed course of delirium in geriatric inpatients

PLOS ONE RESEARCH ARTICLE Delirium in older hospitalized patients—A prospective analysis of the detailed course of delirium in geriatric inpatients Skadi Wilke1☯, Edgar Steiger ID2☯, Tanja L. Bärwolff1, Justus F. Kleine3, Ursula MüllerWerdan1, Adrian Rosada ID1* 1 Department of Geriatrics, Charité-Universitätsmedizin Berlin, Berlin, Germany, 2 Central Research Institute of Ambulatory Health Care in Germany (Zi), Berlin, Germany, 3 Department of Neuroradiology, Charité-Universitätsmedizin Berlin, Berlin, Germany ☯ These authors contributed equally to this work. * a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 Abstract Background Delirium in older hospitalized patients (> 65) is a common clinical syndrome, which is frequently unrecognized. OPEN ACCESS Aims Citation: Wilke S, Steiger E, Bärwolff TL, Kleine JF, Müller-Werdan U, Rosada A (2023) Delirium in older hospitalized patients—A prospective analysis of the detailed course of delirium in geriatric inpatients. PLoS ONE 18(3): e0279763. https://doi. org/10.1371/journal.pone.0279763 We aimed to describe the detailed clinical course of delirium and related cognitive functioning in geriatric patients in a mainly non-postoperative setting in association with demographic and clinical parameters and additionally to identify risk factors for delirium in this common setting. Editor: Hikaru Hori, Fukuoka University, JAPAN Methods Received: July 8, 2022 Inpatients of a geriatric ward were screened for delirium and in the case of presence of delirium included into the study. Patients received three assessments including Mini-Mental-Status-Examination (MMSE) and the Delirium Rating Scale Revised 98 (DRS-R-98). We conducted correlation and linear mixed-effects model analyses to detect associations. Accepted: December 14, 2022 Published: March 16, 2023 Copyright: © 2023 Wilke et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Results Data Availability Statement: All study files are available from the database https://zenodo.org/ record/7361883#.Y4DfanbMKUk. Overall 31 patients (82 years (mean)) met the criteria for delirium and were included in the prospective observational study. Within one week of treatment, mean delirium symptom severity fell below the predefined cut-off. While overall cognitive functioning improved over time, short- and long-term memory deficits remained. Neuroradiological conspicuities were associated with cognitive deficits, but not with delirium severity. Funding: The author(s) received no specific funding for this work. Discussion Competing interests: The authors have declared that no competing interests exist. The temporal stability of some delirium symptoms (short-/long-term memory, language) on the one hand and on the other hand decrease in others (hallucinations, orientation) shown PLOS ONE | https://doi.org/10.1371/journal.pone.0279763 March 16, 2023 1 / 17 PLOS ONE Delirium in older hospitalized patients in our study visualizes the heterogeneity of symptoms attributed to delirium and their different courses, which complicates the differentiation between delirium and a preexisting cognitive decline. The recovery from delirium seems to be independent of preclinical cognitive status. Conclusion Treatment of the acute medical condition is associated with a fast decrease in delirium severity. Given the high incidence and prevalence of delirium in hospitalized older patients and its detrimental impact on cognition, abilities and personal independence further research needs to be done. Introduction Delirium in older hospitalized patients (> 65 years) is a common clinical syndrome defined by the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) [1] as an acute and fluctuating disturbance in attention and awareness as a direct consequence of a physiological condition (i.e. medical conditions, substance intoxication, or withdrawal, exposure to a toxin [1]. Although well discussed in the literature, delirium remains unrecognized in many patients. Estimations of incidence and prevalence of delirium vary a lot. On admission 18– 35% (prevalence) of older hospitalized patients show symptoms of delirium and 11–29% (incidence) develop a delirium in the course of their hospital stay [2], whereas certain patient groups are more susceptible than others–especially patients with cancer, any terminal illness and patients after surgery are more vulnerable [3] As hospitalized geriatric patients frequently suffer from multimorbidity, delirium is multifactorial [4] Decades of research could already show a complex interaction between predisposing and precipitating factors [2]. Combined with precipitating factors predisposing factors are presumably triggering inflammatory processes and yielding to imbalances in neurotransmitter levels [5] As an early marker for inflammation or infection, laboratory parameters such as the C-reactive protein (CRP) and white blood cell count (WBC) levels are used [6]. Among others, elevated CRP [7] and WBC levels have been found in patients with delirium symptoms [8]. Structural brain risk factors include atrophy and white matter hyperintensities (WMH) [9]. There is evidence for delirium being a strong predictor for cognitive decline and the incidence of dementia in later life as both an independent [10] and accelerating [11] risk factor. In addition, some longitudinal studies reported an association between delirium in connection with intensive care treatment, hip surgery and hematopoietic cell transplantation and lower abilities in basic activities of daily living (ADL), worsening in quality of life at 6-month-followup [12], loss of personal independence and even showing a link to symptoms of depression and post-traumatic stress [12–15]. Whereas most studies concentrated on postoperative delirium and its risk factors [16, 17], only a few described the clinical course and outcome of delirium in in-hospital older patients, showing adverse effects in cognitive and functional status [18, 19]. When it comes to delirium in the non-postoperative setting, symptoms are frequently unrecognized [20] or misdiagnosed as other psychiatric disorders [21]. However, in accordance with the DSM-5, the diagnosis of delirium has to remain uncertain until sufficient information about the patient’s baseline mental status and acute changes from a competent proxy has been acquired [1]. The first clinical impression can only be an indication. A better PLOS ONE | https://doi.org/10.1371/journal.pone.0279763 March 16, 2023 2 / 17 PLOS ONE Delirium in older hospitalized patients understanding of delirium, its course and association with clinical characteristics and cognitive functioning could be helpful for diagnosis and treatment. Here, we aimed to conduct an (...truncated)