Motoric Subtypes of Delirium and Long-Term Functional and Mental Health Outcomes in Adults After Critical Illness

Data-derived subtypes of delirium during critical illness

BACKGROUND

To understand delirium heterogeneity, prior work relied on psychomotor symptoms or risk factors to identify subtypes. Data-driven approaches have used machine learning to identify biologically plausible, treatment-responsive subtypes of other acute illnesses but have not been used to examine delirium.

METHODS

We conducted a secondary analysis of a large, multicenter prospective cohort study involving adults in medical or surgical ICUs with respiratory failure or shock who experienced delirium per the Confusion Assessment Method for the ICU. We used data collected before delirium diagnosis in an unsupervised latent class model to identify delirium subtypes and then compared demographics, clinical characteristics, and outcomes between subtypes in the final model.

FINDINGS

The 731 patients who developed delirium during critical illness had a median age of 63 [IQR, 54-72] years, a median Sequential Organ Failure Assessment score of 8.0 [6.0-11.0] and 613 [83.4%] were mechanically ventilated at delirium identification. A four-class model best fit the data with 50% of patients in subtype (ST) 1, 18% in subtype 2, 17% in subtype 3, and 14% in subtype 4. Subtype 2-which had more shock and kidney impairment-had the highest mortality (33% [ST2] vs. 17% [ST1], 25% [ST3], and 17% [ST4], p = 0.003). Subtype 4-which received more benzodiazepines and opioids-had the longest duration of delirium (6 days [ST4] vs. 3 [ST1], 4 [ST2], and 3 days [ST3], p < 0.001) and coma (4 days [ST4] vs. 2 [ST1], 1 [ST2], and 2 days [ST3], p < 0.001). Each of the four data-derived delirium subtypes was observed within previously identified psychomotor and risk factor-based delirium subtypes. Clinically significant cognitive impairment affected all subtypes at follow-up, but its severity did not differ by subtype (3-month, p = 0.26; 12-month, p = 0.80).

INTERPRETATION

The four data-derived delirium subtypes identified in this study should now be validated in independent cohorts, examined for differential treatment effects in trials, and inform mechanistic work evaluating treatment targets.

FUNDING

National Institutes of Health (T32HL007820, R01AG027472).

Overview of late-onset psychoses

BACKGROUND

Several etiologies can underlie the development of late-onset psychosis, defined by first psychotic episode after age 40 years. Late-onset psychosis is distressing to patients and caregivers, often difficult to diagnose and treat effectively, and associated with increased morbidity and mortality.

METHODS

The literature was reviewed with searches in Pubmed, MEDLINE, and the Cochrane library. Search terms included "psychosis," "delusions," hallucinations," "late onset," "secondary psychoses," "schizophrenia," bipolar disorder," "psychotic depression," "delirium," "dementia," "Alzheimer's," "Lewy body," "Parkinson's, "vascular dementia," and "frontotemporal dementia." This overview covers the epidemiology, clinical features, neurobiology, and therapeutics of late-onset psychoses.

RESULTS

Late-onset schizophrenia, delusional disorder, and psychotic depression have unique clinical characteristics. The presentation of late-onset psychosis requires investigation for underlying etiologies of "secondary" psychosis, which include neurodegenerative, metabolic, infectious, inflammatory, nutritional, endocrine, and medication toxicity. In delirium, psychosis is common but controlled evidence is lacking to support psychotropic medication use. Delusions and hallucinations are common in Alzheimer's disease, and hallucinations are common in Parkinson's disease and Lewy body dementia. Psychosis in dementia is associated with increased agitation and a poor prognosis. Although commonly used, no medications are currently approved for treating psychosis in dementia patients in the USA and nonpharmacological interventions need consideration.

CONCLUSION

The plethora of possible causes of late-onset psychosis requires accurate diagnosis, estimation of prognosis, and cautious clinical management because older adults have greater susceptibility to the adverse effects of psychotropic medications, particularly antipsychotics. Research is warranted on developing and testing efficacious and safe treatments for late-onset psychotic disorders.

Delirium During Critical Illness and Subsequent Change of Treatment in Patients With Cancer: A Mediation Analysis

OBJECTIVES

To assess whether delirium during ICU stay is associated with subsequent change in treatment of cancer after discharge.

DESIGN

Retrospective cohort study.

SETTING

A 50-bed ICU in a dedicated cancer center.

PATIENTS

Patients greater than or equal to 18 years old with a previous proposal of cancer treatment (chemotherapy, target therapy, hormone therapy, immunotherapy, radiotherapy, oncologic surgery, and bone marrow transplantation).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We considered delirium present if Confusion Assessment Method for the ICU was positive. We assessed the association between delirium and modification of the treatment after discharge. We also performed a mediation analysis to assess both the direct and indirect (i.e., mediated by the development of functional dependence after discharge) of delirium on modification of cancer treatment and whether the modification of cancer treatment was associated with mortality at 1 year. We included 1,134 patients, of whom, 189 (16.7%) had delirium. Delirium was associated with the change in cancer treatment (adjusted odds ratio [OR], 3.80; 95% CI, 2.72-5.35). The association between delirium in ICU and change of treatment was both direct and mediated by the development of functional dependence after discharge. The proportion of the total effect of delirium on change of treatment mediated by the development of functional dependence after discharge was 33.0% (95% CI, 21.7-46.0%). Change in treatment was associated with increased mortality at 1 year (adjusted OR, 2.68; 95% CI, 2.01-3.60).

CONCLUSIONS

Patients who had delirium during ICU stay had a higher rate of modification of cancer treatment after discharge. The effect of delirium on change in cancer treatment was only partially mediated by the development of functional dependence after discharge. Change in cancer treatment was associated with increased 1-year mortality.

Natural language processing diagnosed behavioural disturbance phenotypes in the intensive care unit: characteristics, prevalence, trajectory, treatment, and outcomes

BACKGROUND

Natural language processing (NLP) may help evaluate the characteristics, prevalence, trajectory, treatment, and outcomes of behavioural disturbance phenotypes in critically ill patients.

METHODS

We obtained electronic clinical notes, demographic information, outcomes, and treatment data from three medical-surgical ICUs. Using NLP, we screened for behavioural disturbance phenotypes based on words suggestive of an agitated state, a non-agitated state, or a combination of both.

RESULTS

We studied 2931 patients. Of these, 225 (7.7%) were NLP-Dx-BD positive for the agitated phenotype, 544 (18.6%) for the non-agitated phenotype and 667 (22.7%) for the combined phenotype. Patients with these phenotypes carried multiple clinical baseline differences. On time-dependent multivariable analysis to compensate for immortal time bias and after adjustment for key outcome predictors, agitated phenotype patients were more likely to receive antipsychotic medications (odds ratio [OR] 1.84, 1.35-2.51, p < 0.001) compared to non-agitated phenotype patients but not compared to combined phenotype patients (OR 1.27, 0.86-1.89, p = 0.229). Moreover, agitated phenotype patients were more likely to die than other phenotypes patients (OR 1.57, 1.10-2.25, p = 0.012 vs non-agitated phenotype; OR 4.61, 2.14-9.90, p < 0.001 vs. combined phenotype). This association was strongest in patients receiving mechanical ventilation when compared with the combined phenotype (OR 7.03, 2.07-23.79, p = 0.002). A similar increased risk was also seen for patients with the non-agitated phenotype compared with the combined phenotype (OR 6.10, 1.80-20.64, p = 0.004).

CONCLUSIONS

NLP-Dx-BD screening enabled identification of three behavioural disturbance phenotypes with different characteristics, prevalence, trajectory, treatment, and outcome. Such phenotype identification appears relevant to prognostication and trial design.

An Interdisciplinary Reappraisal of Delirium and Proposed Subtypes

An interdisciplinary plenary session entitled "Rethinking and Rehashing Delirium" was held during the 2021 Annual Meeting of the Academy of Consultation-Liaison Psychiatry to facilitate dialog on the prevalent approach to delirium. Panel members included a psychiatrist, neurointensivist, and critical care specialist, and attendee comments were solicited with the goal of developing a statement. Discussion was focused on a reappraisal of delirium and, in particular, its disparate terminology and history in relation to acute encephalopathy. The authors endorse a recent joint position statement that describes acute encephalopathy as a rapidly evolving (<4 weeks) pathobiological brain process that presents as subsyndromal delirium, delirium, or coma and suggest the following points of refinement: (1) to suggest that "delirium disorder" describe the diagnostic construct including its syndrome, precipitant(s), and unique pathophysiology; (2) to restrict the term "delirium" to describing the clinical syndrome encountered at the bedside; (3) to clarify that the disfavored term "altered mental status" may occasionally be an appropriate preliminary designation where the diagnosis cannot yet be specified further; and (4) to provide rationale for rejecting the terms acute brain injury, failure, or dysfunction. The final common pathway of delirium appears to involve higher-level brain network dysfunction, but there are many insults that can disrupt functional connectivity. We propose that future delirium classification systems should seek to characterize the unique pathophysiological disturbances ("endotypes") that underlie delirium and delirium's individual neuropsychiatric symptoms. We provide provisional means of classification in hopes that novel subtypes might lead to specific intervention to improve patient experience and outcomes. This paper concludes by considering future directions for the field. Key areas of opportunity include interdisciplinary initiatives to harmonize efforts across specialties and settings, enhance underrepresented groups in research, integration of delirium and encephalopathy in coding, development of relevant quality and safety measures, and exploration of opportunities for translational science.

Revelations of delirium subtype research: A bibliometric analysis of publications in the past twenty years in the field

BACKGROUND

Delirium is an acute confusion state that is common and costly. According to different clinical manifestations, delirium can be divided into three subtypes: hyperactive, hypoactive and mixed. Subtype research has become a necessary branch. However, it is difficult to record all the changes in subtype research.

METHODS

Publications on delirium subtypes in the Web of Science Core Collection (WOSCC) were identified and analyzed by visualization software VOSviewer and CiteSpace.

RESULTS

A total of 247 articles published from 1999 to 2022 were identified in the WOSCC, and the largest number of articles was published in 2021 (n = 33). The top three countries that contributed publications were the USA (n = 75), Ireland (n = 26), and the United Kingdom (n = 25), which communicated more often and focused on delirium subtypes earlier. Critical Care Medicine published the most articles regarding delirium subtypes, with 11 publications. Three instrument validation studies were cited most frequently. Six clusters were summarized, including descriptions of delirium among elderly people, delirium research, postoperative delirium, delirium motor subtype validation, critical delirium, and motor characteristics. The "postoperative delirium", "intensive care unit", and "cardiac surgery" keywords were seen in recent years.

CONCLUSION

Based on this bibliometric analysis of the publications in the last twenty years, a comprehensive analysis of the literature clarified the contributions, changes, and evolution regarding delirium subtypes. This research can provide medical staff and researchers with revelations into future directions of delirium subtype advancements.

Utility of Screening for Cognitive Impairment at Hospital Discharge in Adult Survivors of Critical Illness

BACKGROUND

Few studies have explored the utility of screening for cognitive impairment near hospital discharge in intensive care unit survivors.

OBJECTIVES

To explore baseline and hospitalization characteristics associated with cognitive impairment at hospital discharge and the relationship between cognitive impairment and 6-month disability and mortality outcomes.

METHODS

Hospital disability status and treatment variables were collected from 2 observational cohort studies. Patients were screened for cognitive impairment at hospital discharge using the Montreal Cognitive Assessment (MoCA)-Blind, and telephone follow-up was conducted 6 months after discharge to assess vital and physical disability status.

RESULTS

Of 423 patients enrolled, 320 were alive at hospital discharge. A total of 213 patients (66.6%) were able to complete the MoCA near discharge; 47 patients (14.7%) could not complete it owing to cognitive impairment. In MoCA completers, the median (IQR) score was 17 (14-19). Older age (β per year increase, -0.09 [95% CI, -0.13 to -0.05]) and blood transfusions during hospitalization (β, -1.20 [95% CI, -2.26 to -0.14]) were associated with lower MoCA scores. At 6-month follow-up, 176 of 213 patients (82.6%) were alive, of whom 41 (23.3%) had new severe physical disabilities. Discharge MoCA score was not significantly associated with 6-month mortality (adjusted odds ratio, 1.03 [95% CI, 0.93-1.14]) but was significantly associated with risk of new severe disability at 6 months (adjusted odds ratio, 0.85 [95% CI, 0.76-0.94]).

CONCLUSION

Assessing for cognitive impairment at hospital discharge may help identify intensive care unit survivors at higher risk of severe physical disabilities after critical illness.

Distribution of delirium motor subtypes in the intensive care unit: a systematic scoping review

Background

Delirium is the most common cerebral dysfunction in the intensive care unit (ICU) and can be subdivided into a hypoactive, hyperactive, or mixed motor subtype based on the clinical manifestation. The aim of this review was to describe the distribution, pharmacological interventions, and outcomes of delirium motor subtypes in ICU patients.

Methods

This systematic scoping review was performed according to the PRISMA-ScR and Cochrane guidelines. We performed a systematic search in six major databases to identify relevant studies. A meta-regression analysis was performed where pooled estimates with 95% confidence intervals were computed by a random effect model.

Results

We included 131 studies comprising 13,902 delirious patients. There was a large between-study heterogeneity among studies, including differences in study design, setting, population, and outcome reporting. Hypoactive delirium was the most prevalent delirium motor subtype (50.3% [95% CI 46.0–54.7]), followed by mixed delirium (27.7% [95% CI 24.1–31.3]) and hyperactive delirium (22.7% [95% CI 19.0–26.5]). When comparing the delirium motor subtypes, patients with mixed delirium experienced the longest delirium duration, ICU and hospital length of stay, the highest ICU and hospital mortality, and more frequently received administration of specific agents (antipsychotics, α2-agonists, benzodiazepines, and propofol) during ICU stay. In studies with high average age for delirious patients (> 65 years), patients were more likely to experience hypoactive delirium.

Conclusions

Hypoactive delirium was the most prevalent motor subtype in critically ill patients. Mixed delirium had the worst outcomes in terms of delirium duration, length of stay, and mortality, and received more pharmacological interventions compared to other delirium motor subtypes. Few studies contributed to secondary outcomes; hence, these results should be interpreted with care. The large between-study heterogeneity suggests that a more standardized methodology in delirium research is warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-03931-3.

Subtypes of delirium after ischaemic stroke-predisposing factors and outcomes: a prospective observational study (PROPOLIS)

BACKGROUND AND PURPOSE

Delirium is a serious complication after stroke. It remains unclear whether different motor subtypes of delirium are associated with diverse risk factors and outcomes. The aim was to investigate if delirium subtypes differ in predisposing factors, clinical characteristics and outcomes.

METHODS

In all, 698 patients with ischaemic stroke or transient ischaemic attack (median age 73 years; 53.7% female) were prospectively included. Core features of delirium during the first 7 days after admission were examined. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for delirium were used. Pre-stroke characteristics were compared between different delirium subtypes and logistic regression and Cox proportional hazard models were used to explore the association between delirium, functional outcome and death.

RESULTS

Hyperactive, hypoactive and mixed delirium were diagnosed in 28, 75 and 66 patients, respectively. Patients with hyperactive delirium had less severe neurological deficit on admission and more often had transient ischaemic attack compared with patients with hypoactive and mixed delirium. Compared with patients with hypoactive delirium, those with hyperactive delirium more often suffered from irritability/lability prior to stroke. Hyperactive and hypoactive delirium did not differ in age, sex, comorbidities, pre-stroke dependency, cognitive decline and severity of delirium. Hyperactive, hypoactive and mixed delirium were associated with an increased risk of poor 3- and 12-month functional outcome compared with patients without delirium. Moreover, patients with hypoactive and mixed delirium had an elevated risk of death.

CONCLUSIONS

Hyperactive delirium is associated with less severe stroke and higher scores of pre-existing irritability/lability. All three motor subtypes of delirium are associated with poor outcome, although hyperactive delirium seems to have a less unfavourable prognosis.

Exploring Ketamine Analgosedation Use and Its Effect on Incident Delirium in Critically Ill Adults

Ketamine is increasingly being used for analgosedation, but its effect on delirium remains unclear. We compared delirium risk variables and ketamine analgosedation use between adults who developed incident delirium and those who did not, evaluated whether ketamine analgosedation increases delirium risk, and compared ICU delirium characteristics, treatments, and outcomes between ketamine and nonketamine patients with delirium.

DESIGN

Secondary, subgroup analysis of a cohort study.

SETTING

Single, 36-bed mixed medical-surgical ICU in the Netherlands from July 2016 to February 2020.

PATIENTS

Consecutive adults were included. Patients admitted after elective surgery, not expected to survive greater than or equal to 48 hours, admitted with delirium, or where delirium occurred prior to ketamine use were excluded.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Trained ICU nurses evaluated patients without coma (Richmond Agitation Sedation Scale. -4/-5) every 8 hours with the Confusion Assessment Method ICU; a delirium day was defined by greater than or equal to1 + Confusion Assessment Method ICU and/or scheduled antipsychotic use. Among 11 variables compared between the delirium and nondelirium groups (Baseline: age, Charlson Comorbidity score, cognitive impairment, admission type, and Acute Physiology and Chronic Health Evaluation-IV score, daily ICU [until delirium occurrence or discharge]: Sequential Organ Failure Assessment score, coma, benzodiazepine, opioid, and ketamine use) and total ICU days, 7 (age, Charlson score, Sequential Organ Failure Assessment score, coma, benzodiazepine, opioid, and ketamine use) were significantly different and were entered, along with delirium occurrence, in a logistic regression model. A total of 332 of 925 of patients (36%) developed delirium. Ketamine use was greater in patients with delirium (54 [16%] vs 4 [0.7%]; p < 0.01). Ketamine use (adjusted odds ratio, 5.60; 95% CI, 1.09-29.15), age (adjusted odds ratio, 1.03; 95% CI, 1.01-1.06), coma (adjusted odds ratio, 2.10; 95% CI, 1.15-3.78), opioid use (adjusted odds ratio, 171.17; 95% CI, 66.45-553.68), and benzodiazepine use (adjusted odds ratio, 34.07; 95% CI, 8.12-235.34) were each independently and significantly associated with increased delirium. Delirium duration, motoric subtype, delirium treatments, and outcomes were not different between the ketamine and nonketamine groups.

CONCLUSIONS

Ketamine analgosedation may contribute to increased ICU delirium. The characteristics of ketamine and nonketamine delirium are similar. Further prospective research is required to evaluate the magnitude of risk for delirium with ketamine use.

Phenotypes and subphenotypes of delirium: a review of current categorisations and suggestions for progression

Delirium is a clinical syndrome occurring in heterogeneous patient populations. It affects 45-87% of critical care patients and is often associated with adverse outcomes including acquired dementia, institutionalisation, and death. Despite an exponential increase in delirium research in recent years, the pathophysiological mechanisms resulting in the clinical presentation of delirium are still hypotheses. Efforts have been made to categorise the delirium spectrum into clinically meaningful subgroups (subphenotypes), using psychomotor subtypes such as hypoactive, hyperactive, and mixed, for example, and also inflammatory and non-inflammatory delirium. Delirium remains, however, a constellation of symptoms resulting from a variety of risk factors and precipitants with currently no successful targeted pharmacological treatment. Identifying specific clinical and biological subphenotypes will greatly improve understanding of the relationship between the clinical symptoms and the putative pathways and thus risk factors, precipitants, natural history, and biological mechanism. This will facilitate risk factor mitigation, identification of potential methods for interventional studies, and informed patient and family counselling. Here, we review evidence to date and propose a framework to identify subphenotypes. Endotype identification may be done by clustering symptoms with their biological mechanism, which will facilitate research of targeted treatments. In order to achieve identification of delirium subphenotypes, the following steps must be taken: (1) robust records of symptoms must be kept at a clinical level. (2) Global collaboration must facilitate large, heterogeneous research cohorts. (3) Patients must be clustered for identification, validation, and mapping of subphenotype stability.