The prevalence, associated factors, clinical impact, and state of diagnosis of delirium in palliative care patients

Abstract

Purpose The aim of this study is to establish the prevalence, associated factors, and clinical impact of delirium in newly referred palliative care patients and the percentage of delirium diagnoses missed by primary medical teams. Methods Newly referred palliative care patients were evaluated and were reviewed for possible associated factors of delirium. Univariable and multivariable analysis were used to identify associated factors. Median overall survival and survival curves were analyzed. The percentage of missed diagnosis in IPD patients was identified. Results We included 350 palliative care patients. Nearly all patients had cancer diagnosis (96.6%). The overall prevalence of delirium was 44.0%. The independent associated factors of delirium were age ≥ 63 years (adjusted odds ratio [aOR], 7.0; 95% CI, 2.2–22.9), palliative performance scale ≤ 20% (aOR, 54.5; 95% CI, 13.1–228.0), brain metastasis (aOR, 15.6; 95% CI, 3.7–66.7), urinary tract infection (aOR, 18.8; 95% CI, 4.7–75.5), sepsis (aOR, 59.0; 95% CI, 4.4–797.8), hyponatremia (aOR, 8.8; 95% CI, 2.6–29.8), and hypercalcemia (not applicable). Interestingly, opioids and benzodiazepines were not associated with delirium. Delirious patients had significantly shorter survival (median survival 11 days). Delirium diagnoses were missed for 76.1%. Conclusion Nearly half of the palliative care patients had delirium, which was associated with noticeably short survivals. We identified the independent factors associated with the delirium. Despite having a remarkably high prevalence rate and being a well-known poor prognostic factor, there was still a very high rate of missed delirium diagnoses. Effective, routine, delirium screening of palliative care patients needs to be emphasized.

A simple risk score list can be used to predict the occurrence of delirium in patients admitted to inpatient hospice care: A medical record study

“…Although the prevalence of delirium in our study (61%) is comparable to that in previous studies (Watt et al, 2019 ), the percentage of terminal delirium (20%) is significantly lower. For instance, a study by Klankluang et al ( 2021 ) in both outpatient and inpatient palliative care wards of a university hospital showed a prevalence of 89% in the last few days of life. In the study of Klankluang et al, delirium was diagnosed by a psychiatrist.…”

“…We therefore might have missed patients that could have been diagnosed with a delirium by the GP. Besides, while previous studies on terminal delirium focused on palliative wards in hospitals (Klankluang et al, 2021 ; Seiler et al, 2020 ), we focused on an inpatient hospice care facility. This difference is important due to the nature of the population.…”

“…However, since two of the three hospices only used the DOS ‘on indication’, when symptoms of delirium already were apparent, one might argue that the use of the DOS comes too late. Mapping risk factors at time of admission is important, since it has been shown that up to 76% of delirium diagnoses are missed (de la Cruz, Fan, et al, 2015 ; Klankluang et al, 2021 ). Besides, a large part of palliative patients who develop delirium are likely to die without recovering from delirium (de la Cruz, Ransing, et al, 2015 ; Leonard et al, 2008 ).…”

“…Treating delirium results in a decrease of symptoms in approximately half of the patients (Lawlor et al, 2000 ; Leonard et al, 2008 ). However, when patients are in the dying phase, delirium proves often to be “terminal” and irreversible, as a result of the dying process (Klankluang et al, 2021 ). Especially in the last months of the patient's life, occurrence of delirium disrupts the quality of life.…”

Prevalence and risk factors of delirium in psychiatric patients with critical illness

“…Such being the case, the misdiagnosis rate of delirium is still very high. Emphasis should be put on effective delirium-related risk screening [9]. Delirium could be misdiagnosed due to a psychiatric history [10].…”