The consistent burden in published estimates of delirium occurrence in medical inpatients over four decades: a systematic review and meta-analysis study

Delirium and frailty in older adults: Clinical overlap and biological underpinnings

Frailty and delirium are two common geriatric syndromes sharing several clinical characteristics, risk factors, and negative outcomes. Understanding their interdependency is crucial to identify shared mechanisms and implement initiatives to reduce the associated burden. This literature review summarizes scientific evidence on the complex interplay between frailty and delirium; clinical, epidemiological, and pathophysiological commonalities; and current knowledge gaps. We conducted a PubMed systematic search in June 2023, which yielded 118 eligible articles out of 991. The synthesis of the results-carried out by content experts-highlights overlapping risk factors, clinical phenotypes, and outcomes and explores the influence of one syndrome on the onset of the other. Common pathophysiological mechanisms identified include inflammation, neurodegeneration, metabolic insufficiency, and vascular burden. The review suggests that frailty is a risk factor for delirium, with some support for delirium associated with accelerated frailty. The proposed unifying framework supports the integration and measurement of both constructs in research and clinical practice, identifying the geroscience approach as a potential avenue to develop strategies for both conditions. In conclusion, we suggest that frailty and delirium might be alternative-sometimes coexisting-manifestations of accelerated biological aging. Clinically, the concepts addressed in this review can help approach older adults with either frailty or delirium from a different perspective. From a research standpoint, longitudinal studies are needed to explore the hypothesis that specific pathways within the biology of aging may underlie the clinical manifestations of frailty and delirium. Such research will pave the way for future understanding of other geriatric syndromes as well.

The Relationship between Delirium and Dementia

Delirium and dementia are common causes of cognitive impairment in older adults. They are distinct but interrelated. Delirium, an acute confusional state, has been linked to the chronic and progressive loss of cognitive ability seen in dementia. Individuals with dementia are at higher risk for delirium, and delirium itself is a risk factor for incident dementia. Additionally, delirium in individuals with dementia can hasten underlying cognitive decline. In this review, we summarize recent literature linking these conditions, including epidemiological, clinicopathological, neuroimaging, biomarker, and experimental evidence supporting the intersection between these conditions. Strategies for evaluation and diagnosis that focus on distinguishing delirium from dementia in clinical settings and recommendations for delirium prevention interventions for patients with dementia are presented. We also discuss studies that provide evidence that delirium may be a modifiable risk factor for dementia and consider the impact of delirium prevention interventions on long-term outcomes.

Substance use problems and disorders among adults 50 years and older receiving mental health treatment for a primary neurocognitive disorder

OBJECTIVES

This study sought to (1) identify the percentage of high-risk substance use or substance use disorder (SUD) and (2) examine the factors associated with high-risk substance use or SUD in adults aged 50 years and older receiving mental health treatment with a primary delirium or dementia diagnosis.

METHOD

This study used 7 years (2013-2019) of national administrative data on community mental health center patients aged 50 years and older with a primary delirium or dementia diagnosis receiving treatment in the United States (U.S.). To examine factors associated with the dependent variable (high-risk substance use or SUD), a multivariable binary logistic regression model was utilized.

RESULTS

The sample included 77,509 individuals who were mostly aged 65 years and older (69.7%), and did not have co-occurring high-risk substance use or SUD (90.1%). Receiving treatment in a U.S. region other than the Northeast, being younger, male, not non-Hispanic White, and having multiple mental health diagnoses had greater odds of co-occurring high-risk substance use or SUD.

CONCLUSION

One in ten persons in this sample having high-risk substance use or SUD highlights the clinical necessity for screening and subsequent treatment for co-occurring high-risk substance use among persons receiving treatment for a neurocognitive disorder.

Pharmacologic Treatment Strategies for Delirium in Hospitalized Adults: Past, Present, and Future

Despite the use of multidomain prevention strategies, delirium still frequently occurs in hospitalized adults. With delirium often associated with undesirable symptoms and deleterious outcomes, including cognitive decline, treatment is important. Risk-factor reduction and the protocolized use of multidomain, nonpharmacologic bundles remain the mainstay of delirium treatment. There is a current lack of strong evidence to suggest any pharmacologic intervention to treat delirium will help resolve it faster, reduce its symptoms (other than agitation), facilitate hospital throughput, or improve post-hospital outcomes including long-term cognitive function. With the exception of dexmedetomidine as a treatment of severe delirium-associated agitation in the ICU, current practice guidelines do not recommend the routine use of any pharmacologic intervention to treat delirium in any hospital population. Future research should focus on identifying and evaluating new pharmacologic delirium treatment interventions and addressing key challenges and gaps surrounding delirium treatment research.

Non-pharmacological delirium detection and management interventions for informal caregivers of older people at home: A scoping review protocol

OBJECTIVE

The objective of this proposed scoping review is to identify and map the available evidence on interventions that aim to help informal caregivers identify and/or manage delirium in an older person at home.

INTRODUCTION

Delirium is a neurocognitive condition characterized by acute confusion and is associated with increased risk of morbidity and mortality. Research estimates delirium to be present in 17% of community-dwellers aged 85 and older, increasing proportionally with age to 45% in those aged 90 and older. Delirium often occurs at the onset of an older person's acute illness or exacerbation of a chronic illness (sometimes while at home) and, because of its protracted nature, usually continues after a hospital stay. Even when an older person's delirium resolves during hospitalization, they remain at risk of its recurrence after discharge home. Consequently, knowing how to detect and manage delirium is critical for informal caregivers of older people at home. However, there are no reviews focused exclusively on this topic in this setting.

INCLUSION CRITERIA

The population of interest includes informal caregivers of a person aged 65+. Concepts of interest include delirium detection and/or management interventions. The context of interest is any setting where informal care is delivered, including the transition from hospital to home, in any geographical area.

MATERIALS AND METHODS

The review will be conducted according to the JBI guidelines for scoping reviews. A three-step search strategy will be used to locate both published and unpublished papers in MEDLINE, Embase, CINAHL, PsycINFO, Web of Science Core Collection, ProQuest Nursing & Allied Health, SCOPUS, LILACS, and SciELO, PQD&T, NDLTD, Google Scholar and Google. No language restrictions will be placed on the review. Papers will be screened for eligibility at the title, abstract, and full text level by two independent reviewers. Data will be extracted by two independent reviewers and managed in Covidence. Any disagreements in screening or data extraction will be resolved by consensus or a third reviewer. Results will be summarised in narrative and tabular formats.

How much risk does delirium represent for the development of dementia?: Retrospective cohort study from over 260,000 patients record in a solitary institution

Background

Delirium frequently affects the consciousness of the elderly, particularly those in hospitals. Evidence increasingly associates linking delirium history to an increased risk of dementia. However, most studies are limited in scope, focusing mainly on postoperative or intensive care units with small patient samples, which affects the broader applicability of their findings.

Aims

To elucidate the precise incidence of delirium and the subsequent onset of dementia within whole inpatients. Additionally, we aimed to explore the correlation between the emergence of delirium during hospitalization and the subsequent manifestation of dementia.

Design setting and participants

We conducted a retrospective cohort analysis employing a decade-long electronic medical record dataset consisted of 261,123 patients in Osaka Medical and Pharmaceutical University Hospital. Key analyses were performed October 2022 to January 2023.

Main outcomes and measures

The primary outcome, dementia onset, was determined by prescriptions for the anti-dementia drugs donepezil, galantamine, memantine, or rivastigmine, which are approved for use in Japan.

Results

10,781 patients met the inclusion criteria. The median interval between the onset of dementia was 972.5 days for individuals without a history of delirium, whereas for those with a history of delirium, it was notably shorter at 592.5 days. This disparity culminated in a hazard ratio of 5.29 (95% confidence interval: 1.35-20.75) for subsequent dementia onset.

Conclusions and relevance

This investigation underscores the imperative significance of directing attention toward preventive measures against delirium during hospitalization, alongside the necessity of diligent monitoring and intervention for cognitive decline in patients who encounter delirium.

DeltaScan for the Assessment of Acute Encephalopathy and Delirium in ICU and non-ICU Patients, a Prospective Cross-Sectional Multicenter Validation Study

OBJECTIVES

To measure the diagnostic accuracy of DeltaScan: a portable real-time brain state monitor for identifying delirium, a manifestation of acute encephalopathy (AE) detectable by polymorphic delta activity (PDA) in single-channel electroencephalograms (EEGs).

DESIGN

Prospective cross-sectional study.

SETTING

Six Intensive Care Units (ICU's) and 17 non-ICU departments, including a psychiatric department across 10 Dutch hospitals.

PARTICIPANTS

494 patients, median age 75 (IQR:64-87), 53% male, 46% in ICUs, 29% delirious.

MEASUREMENTS

DeltaScan recorded 4-minute EEGs, using an algorithm to select the first 96 seconds of artifact-free data for PDA detection. This algorithm was trained and calibrated on two independent datasets.

METHODS

Initial validation of the algorithm for AE involved comparing its output with an expert EEG panel's visual inspection. The primary objective was to assess DeltaScan's accuracy in identifying delirium against a delirium expert panel's consensus.

RESULTS

DeltaScan had a 99% success rate, rejecting 6 of the 494 EEG's due to artifacts. Performance showed and an Area Under the Receiver Operating Characteristic Curve (AUC) of 0.86 (95% CI: 0.83-0.90) for AE (sensitivity: 0.75, 95%CI=0.68-0.81, specificity: 0.87 95%CI=0.83-0.91. The AUC was 0.71 for delirium (95%CI=0.66-0.75, sensitivity: 0.61 95%CI=0.52-0.69, specificity: 72, 95%CI=0.67-0.77). Our validation aim was an NPV for delirium above 0.80 which proved to be 0.82 (95%CI: 0.77-0.86). Among 84 non-delirious psychiatric patients, DeltaScan differentiated delirium from other disorders with a 94% (95%CI: 87-98%) specificity.

CONCLUSIONS

DeltaScan can diagnose AE at bedside and shows a clear relationship with clinical delirium. Further research is required to explore its role in predicting delirium-related outcomes.

Long-Term Impact of Delirium on the Risk of Dementia in Hospitalized Older Patients: A Real-World Multicenter Study

BACKGROUND

The association between delirium and dementia has been suggested, but mostly in the postoperative setting. This study aims to explore this relationship in a broader inpatient population, leveraging extensive real-world data to provide a more generalized understanding.

METHODS

In this retrospective cohort study, electronic health records of 11,970,475 hospitalized patients aged over 60 from nine institutions in South Korea were analyzed. Patients with and without delirium were identified, and propensity score matching (PSM) was used to create comparable groups. A 10-year longitudinal analysis was conducted using the Cox proportional hazards model, which calculated the hazard ratio (HR) and 95% confidence interval (CI). Additionally, a meta-analysis was performed, aggregating results from all nine medical institutions. Lastly, we conducted various subgroup and sensitivity analyses to demonstrate the consistency of our study results across diverse conditions.

RESULTS

After 1:1 PSM, a total of 47,306 patients were matched in both the delirium and nondelirium groups. Both groups had a median age group of 75-79 years, with 43.1% being female. The delirium group showed a significantly higher risk of all dementia compared with the nondelirium group (HR: 2.70 [95% CI: 2.27-3.20]). The incidence risk for different types of dementia was also notably higher in the delirium group (all dementia or mild cognitive impairment, HR: 2.46 [95% CI: 2.10-2.88]; Alzheimer's disease, HR: 2.74 [95% CI: 2.40-3.13]; vascular dementia, HR: 2.55 [95% CI: 2.07-3.13]). This pattern was consistent across all subgroup and sensitivity analyses.

CONCLUSIONS

Delirium significantly increases the risk of onset for all types of dementia. These findings highlight the importance of early detection of delirium and prompt intervention. Further research studies are warranted to investigate the mechanisms linking delirium and dementia.

Effects of Exercise Intervention for the Management of Delirium in Hospitalized Older Adults: A Randomized Clinical Trial

OBJECTIVE

Delirium is a serious neuropsychiatric syndrome frequently occurring in hospitalized older adults, for which pharmacological treatments have shown limited effectiveness. Multicomponent physical exercise programs have demonstrated functional benefits; however, the impact of exercise on the course of delirium remains unexplored. The aim of this study was to investigate the effect of an individualized, multicomponent exercise intervention on the evolution of delirium and patient outcomes.

DESIGN

A single-center, single-blind randomized controlled trial.

SETTING AND PARTICIPANTS

Medical inpatients with delirium in an acute geriatric unit of a tertiary public hospital.

METHODS

Thirty-six patients (mean age 87 years) were recruited and randomized into 2 groups. The control group received usual care and the intervention group received individualized physical exercise (1 daily session) for 3 consecutive days. Primary endpoints were the duration and severity of delirium (4-AT, Memorial Delirium Assessment Scale) and change in functional status [Barthel Index, Short Physical Performance Battery, Hierarchical Assessment of Balance and Mobility (HABAM), and handgrip strength]. Secondary endpoints included length of stay, falls, and health outcomes at 1- and 3-month follow-up.

RESULTS

The intervention group showed more functional improvement at discharge (HABAM, P = .015) and follow-up (Barthel, P = .041; Lawton P = .027). Less cognitive decline was observed at 1 and 3 months (Informant Questionnaire on Cognitive Decline in the Elderly, P = .017). Exercise seemed to reduce delirium duration by 1 day and contribute to delirium resolution at discharge, although findings did not reach statistical significance. No exercise-related adverse events occurred.

CONCLUSION AND IMPLICATIONS

Findings suggest that individualized exercise in acutely hospitalized older patients with delirium is safe, may improve delirium course and help preserve post-hospitalization function and cognition.

Association of triglyceride-glucose index and delirium in patients with sepsis: a retrospective study

OBJECTIVE

It is well known that glucose and lipid metabolism disorders and insulin resistance are common in sepsis, which affect the occurrence and prognosis of multiple organ dysfunction in septic patients. Previous study reported the predictive value of triglyceride-glucose index (TyG), a clinical indicator for insulin resistance, in postoperative delirium patients. However, it remains unclear whether the TyG index is a novel predictive biomarker for sepsis-associated delirium. The aim of this study is to explore the relationship between TyG index and the risk of delirium in patients with sepsis.

METHODS

Adult septic patients were identified from the MIMIC-IV database and divided into four groups based on the mean value of TyG. The primary outcome was the incidence of delirium. The association between TyG and the risk of developing delirium was evaluated by restricted cubic spline (RCS), multivariate logistic regression and subgroup analysis. Propensity Score Matching (PSM) method was used to balance the baseline data.

RESULTS

A total of 3,331 septic patients were included in the analysis, and further divided into four groups: Q1 (TyG ≤ 8.67), Q2 (8.67 < TyG ≤ 9.08), Q3 (9.08 < TyG ≤ 9.61), and Q4 (TyG > 9.61). The RCS curves demonstrated a non-linear positive relationship between TyG index and the risk of developing delirium, and an optimal cut-of value 9.09 was recommended. After balancing the baseline information by PSM, patients in the TyG > 9.09 group had a significant higher incidence of delirium compared with those in the TyG ≤ 9.09 group. In logistic regression analysis, TyG > 9.09 was significantly associated with lower risk of developing delirium in both original cohort (OR 1.54-1.78, all P < 0.001) and the PSM cohort (OR 1.41-1.48, all P < 0.001). No association was found between the TyG index and mortality (all P > 0.05). In subgroup analysis, our findings were consistent (all OR > 1 in all subgroups).

CONCLUSION

Our study demonstrated an independent association between TyG index and increased risk of delirium in septic patients, indicating that TyG index can serve as a biomarker for delirium in sepsis.

Blowing the whistle on mixed gender hospital rooms in Australia and New Zealand: a human rights issue

The practice of placing men and women in the same hospital room (mixed gender rooms) has been prohibited in the UK National Health Service for over a decade. However, recent research demonstrates that the practice is common and increasing in a major New Zealand public hospital. Reports and complaints show that the practice also occurs in Australia. We argue that mixed gender rooms violate the fundamental human rights of personal security and dignity. The high rates of cognitive impairment, sensory impairment and frailty in hospital wards exacerbates the risk for these violations and subsequent harm. We argue for the adoption of specific national policies prohibiting mixed gender rooms and public reporting of breaches. Importantly, these guidelines can be adopted without compromising the rights of gender minorities. In the long term, hospitals should be built with single occupancy rooms.

Sex-stratified analyses of comorbidities associated with an inpatient delirium diagnosis using real world data

Delirium is a detrimental mental condition often seen in older, hospitalized patients and is currently hard to predict. In this study, we leverage electronic health records (EHR) to identify 7,492 UCSF patients and 19,417 UC health system patients with an inpatient delirium diagnosis and the same number of control patients without delirium. We found significant associations between comorbidities or laboratory values and an inpatient delirium diagnosis, including metabolic abnormalities and psychiatric diagnoses. Some associations were sex-specific, including dementia subtypes and infections. We further explored the associations with anemia and bipolar disorder by conducting longitudinal analyses from the time of first diagnosis to development of delirium, demonstrating a significant relationship across time. Finally, we show that an inpatient delirium diagnosis leads to increased risk of mortality. These results demonstrate the powerful application of the EHR to shed insights into prior diagnoses and laboratory values that could help predict development of inpatient delirium and the importance of sex when making these assessments.

Refeeding hypophosphatemia is a common cause of delirium in critically ill patients: A retrospective study

BACKGROUND

The purpose was to explore the correlation between refeeding hypophosphatemia and delirium and analyze the related factors in critically ill patients.

METHODS

We conducted a retrospective review of critically ill patients admitted to Nanjing Drum Tower Hospital between September 2019 and March 2021. The patients were divided into delirium and nondelirium groups. Demographic data, underlying diseases, laboratory findings, comorbidities, nutritional intake and overall prognosis were collected and analyzed.

RESULTS

In total, 162 patients were included and divided into delirium (n=54) and nondelirium (n=108) groups. Serum phosphorus levels in the two groups decreased significantly in the first three days (P1, P2, P3) after nutrient intake compared with baseline before nutrient intake (Ppre). P1 and P2 were significantly lower in the delirium group compared to the nondelirium group. The maximum blood phosphorus reduction (Pmax) in the first three days after nutrient intake was significantly higher in the delirium group than in the nondelirium group. The time of Pmax in the delirium group was on the first day after nutrient intake. Multivariable logistic regression analysis identified starting route of nutrition and P1< 0.845 mmol/L as the independent predictors of delirium development in critically ill patients.

CONCLUSION

The incidence of delirium in critically ill patients is high and associated with refeeding hypophosphatemia. Delirium may occur with serum phosphorus levels less than 0.845 mmol/L on the first day.

Delirium prevalence and delirium literacy across Italian hospital wards: a secondary analysis of data from the World Delirium Awareness Day 2023

PURPOSE

Delirium, a common medical emergency among hospitalized patients, requires effective detection and management protocols. This study aims to evaluate the delirium point prevalence and its management across Italian hospitals, categorized by delirium literacy levels. Additionally, it seeks to identify prevailing barriers and future priorities in delirium practice and research.

METHODS

We analyzed data from World Delirium Awareness Day (WDAD) on March 15th, 2023, collected by participating clinicians in Italian hospitals. High delirium literacy (HL) was determined based on the use of validated delirium assessment tools and the presence of a written protocol for delirium management. Conversely, low delirium literacy (LL) was determined by meeting only one or neither of these criteria.

RESULTS

Fifty-eight hospital wards participated in the survey, with 25 (43.1%) classified as HL. The overall reported point prevalence of delirium was found to be approximately 10%. Notably, the reported prevalence was twice as high in the HL group compared to the LL group. Despite minimal differences compared to the other group, the HL group demonstrated greater adherence to appropriate delirium management strategies, encompassing both non-pharmacological and pharmacological strategies. Critical gaps in delirium care emerged, including suboptimal management practices, barriers to implementing evidence-based strategies, and insufficient awareness and training among professionals.

CONCLUSION

The study highlights the suboptimal identification and management of delirium among Italian hospitals, emphasizing the necessity of enhancing awareness and implementing evidence-based strategies. Addressing these shortcomings is crucial for optimizing delirium care, improving patient outcomes, and mitigating the burden of delirium in hospital settings.

The genetic relationship between hypotension and delirium: a Mendelian randomization study

Background

Observational research suggests that hypotension is a potential hazard factor of delirium. Nevertheless, previous observational articles are limited in their ability to establish causality between hypotension and delirium. The present study was sought to explore the genetic causal relationship between these two conditions using two-sample Mendelian randomization (MR).

Methods

Genome-wide association study (GWAS) summarized data for hypotension and delirium were obtained from the FinnGen Consortium. The researchers utilized several statistical methods, such as inverse-variance weighted (IVW), weighted median, MR Egger, weighted mode, and simple mode in conducting the MR statistical analysis. In order to identify heterogeneity among the MR outcomes, we employed the Cochrane's Q test. Furthermore, we used the MR-Egger intercept test and MR pleiotropy residual sum and outliers (MR-PRESSO) test to examine horizontal pleiotropy.

Results

The findings revealed that hypotension was identified as an independent hazard variable for delirium (p = 0.010, odds ratio [OR] [95% confidence interval (CI)] = 1.302 [1.066-1.592]) using the IVW method. The presence of horizontal pleiotropy was found to have minimal impact on establishing causal relationship (p = 0.999), and there was no evidence to suggest heterogeneity between genetic variations (p = 0.379). Additionally, the leave-one-out method demonstrated the stability and robustness of this association.

Conclusion

We performed two-sample MR analyses and found evidence of a genetic causal relationship between hypotension and delirium. Our findings suggest that individuals with a genetic predisposition for hypotension may have a higher risk of developing delirium. This suggests that interventions aimed at improving perioperative hypotension could aid in limiting the incidence of delirium.

Barriers to healthcare professionals recognizing and managing delirium in older adults during a hospital stay: A mixed-methods systematic review

AIM

To investigate barriers to healthcare professionals recognizing and managing delirium in hospitalized older people.

DESIGN

A mixed-methods systematic review.

PROSPERO ID

CRD42020187932.

DATA SOURCES

MEDLINE, EMBASE, PsycINFO and CINAHL were searched (2007 to February 2023).

REVIEW METHODS

Included studies focused on healthcare professionals' recognition and management of delirium for patients aged 65 years and over in a hospital ward or emergency department. Enhancing rigour, screening of results was conducted independently by two researchers. Qualitative and quantitative data were tabulated separately and grouped. Data were compared to identify similarities and differences. All studies were quality appraised.

RESULTS

43 studies were included; 24 quantitative, 16 qualitative and three mixed-methods. Data synthesis highlighted synergy between qualitative and quantitative findings. Barriers were reflected in six themes: (1) healthcare professionals' knowledge and understanding; (2) communication; (3) workforce development; (4) interprofessional working; (5) confounders; and (6) organizational constraints.

CONCLUSIONS

Of significance, for older adults in hospital experiencing delirium, there is variability in whether and how well it is recognized and managed. To prevent adverse outcomes best practice guidance for screening, recognizing, diagnosing and managing delirium in older people needs to be agreed and disseminated widely. Supporting healthcare professionals to care for this patient population using an integrated approach is essential, how to involve and communicate with patients and their family and friends, how to recognize and manage delirium for patients with additional needs, e.g., those living with dementia and/or a learning disability. Hospitals need to have policy and guidance in place for the recognition and management of delirium in older adults presenting to a ward or to an emergency department. An IT infrastructure is needed that integrates assessments and care management plans in patient electronic records and makes them accessible within and across teams in hospital, primary and community care settings.

PATIENT OR PUBLIC CONTRIBUTION

There was no patient or public contribution to this systematic review.

IMPLICATIONS FOR THE PROFESSION AND PATIENT CARE

Healthcare professionals can be better supported to be able to recognize and manage delirium during an acute hospital stay for older adults. This includes maximizing best care for those patients living with dementia, involving families and friends to help understand patients' baseline status and changes and supporting families and friends during this process. Of significance, attention to hospital IT infrastructures is warranted, integrating screening, assessment and care management plans in patients' electronic records and making these accessible to healthcare professionals caring for this patient population across care settings.

IMPACT

What problem did the study address? Delirium is a common condition experienced by older hospitalized patients, but it is consistently under-recognized which has implications for patient and organization outcomes. To help address this, understanding barriers to healthcare professionals recognizing and managing delirium for this patient population is paramount. What were the main findings? Barriers to healthcare professionals recognizing and managing delirium for this patient population were synthesized in six themes: (1) healthcare professionals' knowledge and understanding, (2) communication; (3) workforce development; (4) interprofessional working; (5) confounders; and (6) organizational constraints. Where and on whom will the research have an impact? The findings of this original systematic review can contribute to hospital policy and protocol for the recognition and management of delirium in older patients. The findings can meaningfully contribute to workforce professional development for practitioners caring for older people during an acute hospital stay and for practitioners in primary and community settings involved in the follow-up of patients post hospital discharge. For researchers, the findings indicate several research recommendations including investigating the impact of an education programme for nurses and other healthcare professionals on the recognition and management of the condition and understanding and investigating how best to support delirium-related distress experienced by patients and their families and practitioners.

REPORTING METHOD

This systematic review was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (Page et al., 2021).

Diagnostic Accuracy of the Recognizing Acute Delirium as Part of Your Routine (RADAR) Scale for Delirium Assessment in Hospitalized Older Adults: A Cross-Sectional Study

Delirium is highly prevalent among hospitalized older adults and is associated with unfavorable outcomes. However, delirium often remains undiagnosed in the hospital context. Having a valid, simple, and fast screening tool could help in limiting the additional workload for healthcare professionals, without leaving delirium undetected. The aim of this study was to estimate the sensitivity and specificity of the Recognizing Acute Delirium As part of your Routine (RADAR) scale in an Italian hospital. An observational cross-sectional study was conducted. A total of 150 patients aged ≥70 years were enrolled. Receiver operating characteristic (ROC) curves using the Confusion Assessment Method (CAM) criterion-defined delirium as the gold standard were plotted to evaluate the performance of the RADAR scale. The cut-off suggested by previous research was used to estimate the sensitivity, specificity, and positive and negative predictive values of the RADAR scale. The involved patients were mostly females (60%; n = 90), with a median age of 84 years (I-III quartiles: 80-88). According to the CAM and the RADAR scale, 37 (25%) and 58 (39%) patients were classified as experiencing delirium, respectively. The area under the ROC curve of the RADAR scale was 0.916. Furthermore, the RADAR scale showed robust sensitivity (95%), specificity (80%), and positive (60%) and negative predictive values (98%). The RADAR scale is thus suggested to be a valid tool for screening assessment of delirium in hospitalized older adults.

Interventions to prevent and treat delirium: An umbrella review of randomized controlled trials

Delirium is a common condition across different settings and populations. The interventions for preventing and managing this condition are still poorly known. The aim of this umbrella review is to synthesize and grade all preventative and therapeutic interventions for delirium. We searched five databases from database inception up to March 15th, 2023 and we included meta-analyses of randomized controlled trials (RCTs) to decrease the risk of/the severity of delirium. From 1959 records after deduplication, we included 59 systematic reviews with meta-analyses, providing 110 meta-analytic estimates across populations, interventions, outcomes, settings, and age groups (485 unique RCTs, 172,045 participants). In surgery setting, for preventing delirium, high GRADE evidence supported dexmedetomidine (RR=0.53; 95%CI: 0.46-0.67, k=13, N=3988) and comprehensive geriatric assessment (OR=0.46; 95%CI=0.32-0.67, k=3, N=496) in older adults, dexmedetomidine in adults (RR=0.33, 95%CI=0.24-0.45, k=7, N=1974), A2-adrenergic agonists after induction of anesthesia (OR= 0.28, 95%CI= 0.19-0.40, k=10, N=669) in children. High certainty evidence did not support melatonergic agents in older adults for delirium prevention. Moderate certainty supported the effect of dexmedetomidine in adults and children (k=4), various non-pharmacological interventions in adults and older people (k=4), second-generation antipsychotics in adults and mixed age groups (k=3), EEG-guided anesthesia in adults (k=2), mixed pharmacological interventions (k=1), five other specific pharmacological interventions in children (k=1 each). In conclusion, our work indicates that effective treatments to prevent delirium differ across populations, settings, and age groups. Results inform future guidelines to prevent or treat delirium, accounting for safety and costs of interventions. More research is needed in non-surgical settings.

Risk of drug-induced delirium in older patients- a pharmacovigilance study of FDA adverse event reporting system database

BACKGROUND

Drug-induced delirium is known risk factors associated with increased morbidity and mortality in older patients. The objective was to evaluate the risk of drug-related delirium in older patients based on the FDA Adverse Event Reporting System (FAERS).

RESEARCH DESIGN AND METHODS

Delirium reports in older patients (age ≥65) extracted from the FAERS database using Open Vigil 2.1. The reported odds ratio and the proportional reported ratio were calculated to detect the adverse reaction signal of delirium. Combined with published evidence, suspected drugs were categorized as known, possible, or new potential delirium-risk-increasing drugs.

RESULTS

Of the 130,885 reports (including 28,850 delirium events and 1,857 drugs) analyzed for this study, 314 positive signal drugs were detected. Positive signal drugs are mainly concentrated on the drug of nervous system, cardiovascular system , alimentary tract and metabolism and anti-infectives for systemic use. Of the positive signal drugs, 26.11% (82/314) were known delirium-risk increasing drugs, 44.90% (141/314) were possible and 28.98% (91/314) were new potential.

CONCLUSION

Drug-induced delirium risk is prevalent in older patients, according to the FAERS. The risk level of drug-induced delirium should be taken into account to optimize drug therapy in clinical practice.

Delirium detection tools show varying completion rates and positive score rates when used at scale in routine practice in general hospital settings: A systematic review

BACKGROUND

Multiple short delirium detection tools have been validated in research studies and implemented in routine care, but there has been little study of these tools in real-world conditions. This systematic review synthesized literature reporting completion rates and/or delirium positive score rates of detection tools in large clinical populations in general hospital settings.

METHODS

PROSPERO (CRD42022385166). Medline, Embase, PsycINFO, CINAHL, and gray literature were searched from 1980 to December 31, 2022. Included studies or audit reports used a validated delirium detection tool performed directly with the patient as part of routine care in large clinical populations (n ≥ 1000) within a general acute hospital setting. Narrative synthesis was performed.

RESULTS

Twenty-two research studies and four audit reports were included. Tools used alone or in combination were the Confusion Assessment Method (CAM), 4 'A's Test (4AT), Delirium Observation Screening Scale (DOSS), Brief CAM (bCAM), Nursing Delirium Screening Scale (NuDESC), and Intensive Care Delirium Screening Checklist (ICDSC). Populations and settings varied and tools were used at different stages and frequencies in the patient journey, including on admission only; inpatient, daily or more frequently; on admission and as inpatient; inpatient post-operatively. Tool completion rates ranged from 19% to 100%. Admission positive score rates ranged from: CAM 8%-51%; 4AT 13%-20%. Inpatient positive score rates ranged from: CAM 2%-20%, DOSS 6%-42%, and NuDESC 5-13%. Postoperative positive score rates were 21% and 28% (4AT). All but two studies had moderate-high risk of bias.

CONCLUSIONS

This systematic review of delirium detection tool implementation in large acute patient populations found clinically important variability in tool completion rates, and in delirium positive score rates relative to expected delirium prevalence. This study highlights a need for greater reporting and analysis of relevant healthcare systems data. This is vital to advance understanding of effective delirium detection in routine care.

Single-channel qEEG characteristics distinguish delirium from no delirium, but not postoperative from non-postoperative delirium

OBJECTIVE

This exploratory study examined quantitative electroencephalography (qEEG) changes in delirium and the use of qEEG features to distinguish postoperative from non-postoperative delirium.

METHODS

This project was part of the DeltaStudy, a cross-sectional,multicenterstudy in Intensive Care Units (ICUs) and non-ICU wards. Single-channel (Fp2-Pz) four-minutes resting-state EEG was analyzed in 456 patients. After calculating 98 qEEG features per epoch, random forest (RF) classification was used to analyze qEEG changes in delirium and to test whether postoperative and non-postoperative delirium could be distinguished.

RESULTS

An area under the receiver operatingcharacteristic curve (AUC) of 0.76 (95% Confidence Interval (CI) 0.71-0.80) was found when classifying delirium with a sensitivity of 0.77 and a specificity of 0.63 at the optimal operating point. The classification of postoperative versus non-postoperative delirium resulted in an AUC of 0.50 (95%CI 0.38-0.61).

CONCLUSIONS

RF classification was able to discriminate delirium from no delirium with reasonable accuracy, while also identifying new delirium qEEG markers like autocorrelation and theta peak frequency. RF classification could not distinguish postoperative from non-postoperative delirium.

SIGNIFICANCE

Single-channel EEG differentiates between delirium and no delirium with reasonable accuracy. We found no distinct EEG profile for postoperative delirium, which may suggest that delirium is one entity, whether it develops postoperatively or not.

Mitochondrial dysfunction precedes hippocampal IL-1β transcription and cognitive impairments after low-dose lipopolysaccharide injection in aged mice

Acute cognitive impairments termed delirium often occur after inflammatory insults in elderly patients. While previous preclinical studies suggest mitochondria as a target for reducing neuroinflammation and cognitive impairments after LPS injection, fewer studies have evaluated the effects of a low-grade systemic inflammation in the aged brain. Thus, to identify the significance of mitochondrial dysfunction after a clinically relevant systemic inflammatory stimulus, we injected old-aged mice (18-20 months) with low-dose lipopolysaccharide (LPS, 0.04 mg/kg). LPS injection reduced mitochondrial respiration in the hippocampus 24 h after injection (respiratory control ratio [RCR], state3u/state4o; control = 2.82 ± 0.19, LPS = 2.57 ± 0.08). However, gene expression of the pro-inflammatory cytokine IL-1β was increased (RT-PCR, control = 1.00 ± 0.30; LPS = 2.01 ± 0.67) at a more delayed time point, 48 h after LPS injection. Such changes were associated with cognitive impairments in the Barnes maze and fear chamber tests. Notably, young mice were unaffected by low-dose LPS, suggesting that mitochondrial dysfunction precedes neuroinflammation and cognitive decline in elderly patients following a low-grade systemic insult. Our findings highlight mitochondria as a potential therapeutic target for reducing delirium in elderly patients.

Delirium and incident dementia in hospital patients in New South Wales, Australia: retrospective cohort study

OBJECTIVES

To determine the strength and nature of the association between delirium and incident dementia in a population of older adult patients without dementia at baseline.

DESIGN

Retrospective cohort study using large scale hospital administrative data.

SETTING

Public and private hospitals in New South Wales, Australia between July 2001 and March 2020.

PARTICIPANTS

Data were extracted for 650 590 hospital patients aged ≥65 years. Diagnoses of dementia and delirium were identified from ICD-10 (international classification of diseases, 10th revision) codes. Patients with dementia at baseline were excluded. Delirium-no delirium pairs were identified by matching personal and clinical characteristics, and were followed for more than five years.

MAIN OUTCOME MEASURES

Cox proportional hazards models and Fine-Gray hazard models were used to estimate the associations of delirium with death and incident dementia, respectively. Delirium-outcome dose-response associations were quantified, all analyses were performed in men and women separately, and sensitivity analyses were conducted.

RESULTS

The study included 55 211 matched pairs (48% men, mean age 83.4 years, standard deviation 6.5 years). Collectively, 58% (n=63 929) of patients died and 17% (n=19 117) had a newly reported dementia diagnosis during 5.25 years of follow-up. Patients with delirium had 39% higher risk of death (hazard ratio 1.39, 95% confidence interval 1.37 to 1.41) and three times higher risk of incident dementia (subdistribution hazard ratio 3.00, 95% confidence interval 2.91 to 3.10) than patients without delirium. The association with dementia was stronger in men (P=0.004). Each additional episode of delirium was associated with a 20% increased risk of dementia (subdistribution hazard ratio 1.20, 95% confidence interval 1.18 to 1.23).

CONCLUSIONS

The study findings suggest delirium was a strong risk factor for death and incident dementia among older adult patients. The data support a causal interpretation of the association between delirium and dementia. The clinical implications of delirium as a potentially modifiable risk factor for dementia are substantial.

Effect of hospital elder life program on the incidence of delirium: A systematic review and meta-analysis of clinical trials

OBJECTIVE

This meta-analysis aims to investigate the effect of the Hospital Elder Life Program (HELP) on the incidence of delirium, delirium scores, length of hospital stay, and incidence of falls.

METHODS

Four databases (PubMed, Embase, Cochrane Library, and Web of Science) were searched from inception until January 18, 2024. The search specifically targeted randomized controlled trials (RCTs). Two independent researchers conducted literature screening, quality assessment, and data extraction. The meta-analysis was performed using Review Manager 5.4.1 and Stata 15.1 software.

RESULTS

The final analysis included a total of 9 RCTs with 2583 patients. The findings from the meta-analysis indicated that HELP was found to considerably reduce the incidence of delirium and the length of hospital stay when compared to the control group. Nevertheless, no statistically significant differences were observed between the two groups in terms of delirium scores and fall rates.

CONCLUSION

In this meta-analysis, HELP can effectively reduce the incidence of delirium and lead to a shorter hospital stay.

Delirium is associated with low levels of upright activity in geriatric inpatients-results from a prospective observational study

BACKGROUND

Delirium is common in geriatric inpatients and associated with poor outcomes. Hospitalization is associated with low levels of physical activity. Motor symptoms are common in delirium, but how delirium affects physical activity remains unknown.

AIMS

To investigate differences in physical activity between geriatric inpatients with and without delirium.

METHODS

We included acutely admitted patients ≥ 75 years in a prospective observational study at a medical geriatric ward at a Norwegian University Hospital. Delirium was diagnosed according to the DSM-5 criteria. Physical activity was measured by an accelerometer-based device worn on the right thigh. The main outcome was time in upright position (upright time) per 24 h (00.00 to 23.59) on the first day of hospitalization with verified delirium status. Group differences were analysed using t test.

RESULTS

We included 237 patients, mean age 86.1 years (Standard Deviation (SD) 5.1), and 73 patients (30.8%) had delirium. Mean upright time day 1 for the entire group was 92.2 min (SD 84.3), with 50.9 min (SD 50.7) in the delirium group and 110.6 min (SD 89.7) in the no-delirium group, mean difference 59.7 minutes, 95% Confidence Interval 41.6 to 77.8, p value < 0.001.

DISCUSSION

Low levels of physical activity in patients with delirium raise the question if immobilization may contribute to poor outcomes in delirium. Future studies should investigate if mobilization interventions could improve outcomes of delirium.

CONCLUSIONS

In this sample of geriatric inpatients, the group with delirium had lower levels of physical activity than the group without delirium.

Spanish transcultural adaptation of the 4AT score for the evaluation of delirium in the emergency department: a prospective diagnostic test accuracy study

BACKGROUND

Delirium is one of the most common adverse events in older people during hospitalization, especially in the emergency department. Reliable, easy-to-use instruments are necessary to properly manage delirium in this setting. This study aims to evaluate the diagnostic validity of the Spanish version of the 4 'A's Test (4AT) in the ED.

METHODS

A diagnostic accuracy study was conducted in patients over 65 years old admitted to the Emergency Department who did not have a formal diagnosis of dementia or a severe mental health disorder. Face and content validity were evaluated by an expert panel. Emergency nurses performed the evaluation with 4AT, whilst blinded and trained researchers assessed patients with the Revised Delirium Rating Scale as the gold standard. The content validity index, sensitivity, specificity, positive and negative predictive values, likelihood ratios, Youden's Index and ROC curves were calculated to evaluate the diagnostic accuracy of the instrument.

RESULTS

Of 393 eligible patients, 380 were finally analyzed. Content validity yielded a median content validity index of 4 (interquartile range: 0). The Spanish 4AT sensitivity (95.83%; 95% ECI: 78.9-99.9%), specificity (92.98%; 95% CI: 89.8-95.4%), positive predictive value (47.92%) and negative predictive value (99.7%) were satisfactory. Youden's index was 0.89. Positive likelihood ratio was 13.65, and negative likelihood ratio 0.045. The area under the curve was 0.97.

CONCLUSIONS

The Spanish version of the 4AT for use in the Emergency Departments is easy-to-use and applicable. The validation results indicate that it is a valid instrument with sufficient predictive validity to identify patients at risk of delirium in the Emergency Departments. Moreover, it is a tool that facilitates the management of an adverse event that is associated with increased mortality and morbidity.

Delirium is frequently underdiagnosed among older hospitalised patients despite available information in hospital medical records

BACKGROUND

In-hospital delirium is associated with adverse outcomes and is underdiagnosed, limiting research and clinical follow-up.

OBJECTIVE

To compare the incidence of in-hospital delirium determined by chart-based review of electronic medical records (D-CBR) with delirium discharge diagnoses (D-DD). Furthermore, to identify differences in symptoms, treatments and delirium triggers between D-CBR and D-DD.

METHOD

The community-based cohort included 2,115 participants in the Hordaland Health Study born between 1925 and 1927. Between 2018 and 2022, we retrospectively reviewed hospital electronic medical records from baseline (1997-99) until death prior to 2023. D-DD and D-CBR were validated using The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, criteria for delirium.

RESULTS

Of the 2,115 participants, 638 had in-hospital delirium. The incidence rate (IR) of D-CBR was 29.8 [95% confidence interval 28, 32] per 1,000 person-years, whereas the IR by D-DD was 3.4 [2.8, 4.2]. The IR ratio was 9.14 (P < 0.001). Patients who received pharmacological treatment for delirium (n = 121, odds ratio (OR) 3.4, [2.1, 5.4], P < 0.001), who were affected by acute memory impairment (n = 149, OR 2.8, [1.8, 4.5], P < 0.001), or change in perception (n = 137, OR 2.9, [1.8, 4.6] P < 0.001) had higher odds for D-DD. In contrast, post-operative cases (OR 0.2, [0.1, 0.4], P < 0.001) had lower odds for D-DD.

CONCLUSION

Underdiagnosis of in-hospital delirium was a major issue in our study, especially in less severe delirium cases. Our findings emphasise the need for integrating systematic delirium diagnostics and documentation into hospital admission and discharge routines.

Impaired glucose utilization in the brain of patients with delirium following hip fracture

Alterations in brain energy metabolism have long been proposed as one of several neurobiological processes contributing to delirium. This is supported by previous findings of altered CSF lactate and neuron-specific enolase concentrations and decreased glucose uptake on brain-PET in patients with delirium. Despite this, there are limited data on metabolic alterations found in CSF samples, and targeted metabolic profiling of CSF metabolites involved in energy metabolism has not been performed. The aim of the study was to investigate whether metabolites related to energy metabolism in the serum and CSF of patients with hip fracture are associated with delirium. The study cohort included 406 patients with a mean age of 81 years (standard deviation 10 years), acutely admitted to hospital for surgical repair of a hip fracture. Delirium was assessed daily until the fifth postoperative day. CSF was collected from all 406 participants at the onset of spinal anaesthesia, and serum samples were drawn concurrently from 213 participants. Glucose and lactate in CSF were measured using amperometry, whereas plasma glucose was measured in the clinical laboratory using enzymatic photometry. Serum and CSF concentrations of the branched-chain amino acids, 3-hydroxyisobutyric acid, acetoacetate and β-hydroxybutyrate were measured using gas chromatography-tandem mass spectrometry (GC-MS/MS). In total, 224 (55%) patients developed delirium pre- or postoperatively. Ketone body concentrations (acetoacetate, β-hydroxybutyrate) and branched-chain amino acids were significantly elevated in the CSF but not in serum among patients with delirium, despite no group differences in glucose concentrations. The level of 3-hydroxyisobutyric acid was significantly elevated in both CSF and serum. An elevation of CSF lactate during delirium was explained by age and comorbidity. Our data suggest that altered glucose utilization and a shift to ketone body metabolism occurs in the brain during delirium.

[Multicenter cross-sectional study on the prevalence of delirium in orthogeriatric units: «DELFRA 24 study» protocol]

INTRODUCTION

Delirium is the most common perioperative complication in older adults with hip fracture (HF), leading to a catastrophic impact on their functional recovery and cognitive status. Currently, the true prevalence of this syndrome is unknown as its detection and management are not standardized in clinical practice.

METHODS

A multicenter observational cross-sectional study will be conducted nationwide, involving different orthogeriatric units in Spain. The prevalence of delirium will be assessed using the 4AT scale, along with its characteristics and its relationship with other geriatric syndromes, sociodemographic variables, surgical characteristics, and laboratory parameters.

RESULTS

Data collection is scheduled to take place on World Delirium Day (Wednesday, March 13, 2024), and therefore, the results are expected during the second or third quarter of 2024.

CONCLUSIONS

Understanding the real prevalence and characteristics of delirium in older adults with HF could contribute to the development of strategies for its detection and management, reducing the impact of its consequences.

Sex-stratified phenotyping of comorbidities associated with an inpatient delirium diagnosis using real world data

Delirium is a heterogeneous and detrimental mental condition often seen in older, hospitalized patients and is currently hard to predict. In this study, we leverage large-scale, real- world data using the electronic health records (EHR) to identify two cohorts comprised of 7,492 UCSF patients and 19,417 UC health system patients (excluding UCSF patients) with an inpatient delirium diagnosis and the same number of propensity score-matched control patients without delirium. We found significant associations between comorbidities or laboratory test values and an inpatient delirium diagnosis which were validated independently. Most of these associations were those previously-identified as risk factors for delirium, including metabolic abnormalities, mental health diagnoses, and infections. Some of the associations were sex- specific, including those related to dementia subtypes and infections. We further explored the diagnostic associations with anemia and bipolar disorder by conducting longitudinal analyses from the time of first diagnosis of the risk factor to development of delirium demonstrating a significant relationship across time. Finally, we show that an inpatient delirium diagnosis leads to dramatic increases in mortality outcome across both cohorts. These results demonstrate the powerful application of leveraging EHR data to shed insights into prior diagnoses and laboratory test values that could help predict development of inpatient delirium and emphasize the importance of considering patient demographic characteristics including documented sex when making these assessments.

One Sentence Summary

Longitudinal analysis of electronic health record data reveals associations between inpatient delirium, comorbidities, and mortality.

Inflammatory and nutritional markers predict the risk of post-operative delirium in elderly patients following total hip arthroplasty

Objectives

This study intended to explore whether albumin-associated inflammatory and nutritional markers could predict post-operative delirium (POD) in older patients after total hip arthroplasty (THA). In addition, we established a nomogram model for POD prediction.

Methods

Totally, 254 elderly cases who received THA were included. Clinical and laboratory data of these patients were retrospectively collected. Albumin-associated inflammatory and nutritional markers included neutrophil-to-albumin ratio (NAR), CRP-to-albumin ratio (CAR), prognostic nutritional index (PNI), and systemic inflammation score (SIS). The LASSO, univariate and multivariate logistic regression analyses were utilized to screen risk factors. A nomogram model was developed according to the results of multivariate regression analyses.

Results

Among 254 patients, 49 cases had POD with an incidence of 19.3%. LASSO regression and multivariate logistic analyses suggested that preoperative NAR, preoperative PNI, preoperative SIS, and age >75 years were risk factors for POD. A nomogram model was developed according to the results of multivariate logistic analyses. The calibration curve suggested that the predicted probability of this nomogram model was in good line with the actual probability. The DCA showed that this nomogram model had net benefits for the prediction of POD for elderly patients following THA.

Conclusion

Albumin-associated inflammatory and nutritional markers including NAR, PNI, and SIS could predict POD in elderly patients following THA.

Aesthetic ways of knowing: exploring mental health nurses' experiences of delirium superimposed on dementia

BACKGROUND

In the UK, people with delirium superimposed on dementia may be cared for by mental health nurses, however there is little in the literature about the experience of caring for people with the condition from the perspective of mental health nurses.

AIM

To illuminate the experiences of mental health nurses caring for people with delirium superimposed on dementia and to explore how mental health nurses 'know' the people they care for using 'aesthetic ways of knowing'.

METHOD

A mixed-methods design was used guided by the principles of activity theory. Participants were registered mental health nurses with experience of caring for people with delirium superimposed on dementia within a 24-hour care environment, including an NHS mental health foundation trust and care homes. Data were collected in two ways and at two different time points: first via semi-structured interviews (n=7), second via a questionnaire (n=25). Thematic analysis of the qualitative data was paired with simple descriptive statistics of the quantitative data to describe participants' experience.

FINDINGS

This article discusses one finding from the larger study, which was undertaken as part of the author's PhD, in relation to the way in which mental health nurses 'know' the people they care for. Overall, participants showed a preference for aesthetic ways of knowing, rather than the use of formal assessment tools or scores. Participants experienced caring for people with delirium superimposed on dementia by valuing the person and concentrating on their behaviours, responses and personality, thus enabling them to anticipate and/or recognise potential triggers, precipitating factors and any changes in behaviours.

CONCLUSION

The ways in which mental health nurses know the people they care for influences their care delivery. Mental health nurses' use of aesthetic ways of knowing should be recognised and valued as a way of better understanding and supporting the person with delirium superimposed on dementia.

Occurrence and predictors of delirium in critically ill older patients: a prospective cohort study

Objectives

This study aims to analyze the occurrence of delirium in critically ill older patients and to identify predictors of delirium.

Methods

This prospective study included critically ill older patients admitted into level II units of Intensive Care Medicine Department of a University Hospital. Patients with Glasgow Coma Scale score ≤11, traumatic brain injury, terminal disease, history of psychosis, blindness/deafness, or inability to understanding/speaking Portuguese were excluded. The Confusion Assessment Method-Short Form (CAM-4) was used to assess the presence of delirium.

Results

The final sample (n = 105) had a median age of 80 years, most being female (56.2%), widowed (49.5%), and with complete primary education (53%). Through CAM-4, 36.2% of the patients had delirium. The delirium group was more likely to have previous cognitive decline (48.6% vs 19.6%, P = .04) and severe dependency in instrumental activities of daily living (34.3% vs 14.8%, P = .032), comparing with patients without delirium. The final multiple logistic regression model explained that patients with previous cognitive decline presented a higher risk for delirium (odds ratio: 4.663, 95% confidence Interval: 1.055-20.599, P = .042).

Conclusions

These findings corroborate previous studies, showing that cognitive decline is an independent predictor for delirium in older patients. This study is an important contribution for the knowledge regarding the predictors of delirium. The recognition of these factors will help to identify patients who are at high risk for this syndrome and implement early screening and prevention strategies. However, further studies with larger samples, recruited from other clinical settings as well as analyzing other potential factors for delirium, will be needed.

The relationship between major depression and delirium: A two-sample Mendelian randomization analysis

BACKGROUND

Major depression (MD) is a well-recognized risk factor for delirium. However, observational studies cannot provide direct evidence of causality between MD and delirium.

METHODS

This study explored the genetic causal association between MD and delirium using two-sample Mendelian randomization (MR). Genome-wide association study (GWAS) summary data for MD were obtained from the UK Biobank. GWAS summary data for delirium were obtained from the FinnGen Consortium. Inverse-variance weighted (IVW), MR Egger, weighted median, simple mode, and weighted mode were used to perform the MR analysis. In addition, the Cochrane's Q test was used to detect heterogeneity in the MR results. Horizontal pleiotropy was detected using the MR-Egger intercept test and MR pleiotropy residual sum and outliers (MR-PRESSO) test. Leave-one-out analysis was used to investigate the sensitivity of this association.

RESULTS

The IVW method showed that MD was an independent risk factor for delirium (P = 0.013). Horizontal pleiotropy was unlikely to bias causality (P > 0.05), and no evidence of heterogeneity was found between the genetic variants (P > 0.05). Finally, a leave-one-out test showed that this association was stable and robust.

LIMITATIONS

All participants included in the GWAS were of European ancestry. Due to database limitations, the MR analysis did not conduct stratified analyses for different countries, ethnicities, or age groups.

CONCLUSION

We conducted a two-sample MR analysis and found the evidence of genetic causal association between MD and delirium.

Association of silodosin, tamsulosin, and naftopidil with delirium: analysis of the pharmacovigilance database in Japan

BACKGROUND

An association between adrenergic alpha-1 receptor antagonists and delirium has been suggested, but the details are unclear.

AIM

This study investigated the association between adrenergic alpha-1 receptor antagonists and delirium in patients with benign prostatic hyperplasia using the Japanese Adverse Drug Event Report database.

METHOD

First, disproportionality analysis compared the frequency of delirium in the adrenergic alpha-1 receptor antagonists silodosin, tamsulosin, and naftopidil. Next, multivariate logistic analysis was performed to examine the association between delirium and adrenergic alpha-1 receptor antagonists where disproportionality was detected.

RESULTS

A disproportionality in delirium was observed in patients receiving tamsulosin (reporting odds ratio [ROR] 1.85, 95% confidence interval [CI] 1.38-2.44, P < 0.01) compared with those who did not, and also in patients receiving naftopidil (ROR 2.23, 95% CI 1.45-3.28, P < 0.01) compared with those who did not. Multivariate logistic analysis revealed that in addition to previously reported risk factors for delirium, delirium in patients receiving tamsulosin was significantly increased with concomitant use of anticholinergics (odds ratio 2.73, 95% CI 1.41-5.29, P < 0.01) and delirium in patients receiving naftopidil was significantly increased with concomitant use of beta3-adrenergic receptor agonists (odds ratio 4.19, 95% CI 1.66-10.6, P < 0.01).

CONCLUSION

Anticholinergics or beta3-adrenergic receptor agonists to treat overactive bladder in patients receiving tamsulosin and naftopidil was strongly associated with delirium. Confirming the medical history and concomitant medications of patients receiving tamsulosin or naftopidil may contribute to preventing delirium in patients with benign prostatic hyperplasia and to improving their outcomes.

Associations between delirium and SARS-CoV-2 pandemic visitor restrictions among hospitalized patients

OBJECTIVES

Delirium is associated with increased morbidity and mortality, but environmental and behavioral factors may decrease the risk of developing delirium and thus must be considered. To investigate trends in delirium prevalence and examine associations of visitor restrictions with delirium diagnoses among all patients hospitalized during and prior to the novel coronavirus SARS-CoV-2 (COVID-19) pandemic.

STUDY DESIGN

Retrospective epidemiological assessment.

METHODS

The medical records of all patients (n = 33,141) hospitalized within a three-hospital academic medical center system in a large Midwestern metropolitan area from March 20, 2019, through March 19, 2021, were analyzed.

RESULTS

The overall prevalence of delirium during COVID-19 was 11.26% (confidence interval [CI]: 10.79%, 11.73%) compared to 9.28% (CI: 8.82%, 9.73%) before COVID-19. From our adjusted logistic regression analyses, we observed that the odds of delirium among non-isolated patients were significantly higher during COVID-19 visitor restrictions (adjusted odds ratio [aOR]: 1.354; 95% CI: 1.233, 1.488; P < 0.0001) than before. The odds of delirium among isolated patients were not significantly higher during COVID-19 visitor restrictions (aOR: 1.145; 95% CI: 0.974, 1.346; P = 0.1006) than before.

CONCLUSIONS

Medically isolated patients remained at high risk of developing delirium both prior to and during COVID-19 era visitor restrictions. However, non-medically isolated patients had a significantly increased risk of delirium during the social isolation of visitor restrictions compared to prior to visitor restrictions.

Decision-making capacity in older medical in-patients: frequency of assessment and rates of incapacity by decision-type and underlying brain/mind impairment

BACKGROUND

Hospital clinicians find mental capacity assessment challenging and may lack the necessary skills. Given high rates of cognitive impairment, data on mental capacity assessment in real-world hospital cohorts are required to inform the need for staff training and workforce planning.

OBJECTIVES

In unselected medical inpatients, we determined the rate and outcome of mental capacity assessment by decision type and underlying brain/mind disorder, and recorded the discipline of the assessor.

METHODS

We included consecutive patients (October-November 2018; November-December 2019) admitted to the complex medicine unit providing acute multidisciplinary care for multi-morbid patients (age ≥ 16 years, average age > 80 years). Audit data were collected at ward multidisciplinary meetings and extracted from electronic patient records.

RESULTS

Among 892 patients (mean/SD age = 82.8/8.6, 465 male), 140 (16%) required mental capacity assessment (40/140 (29%) had ≥2 assessments) with 203 assessments in total of which 162 (80%) were done by doctors. Capacity was deemed lacking in 124 (61%) assessments, most commonly in delirium with/without other co-morbid conditions (94/114, 82%) or dementia (9/12, 75%) with lower rates in other disorders (15/27, 56%), and no formal diagnosis of brain/mind disorder (6/50, 12%). Cognitive test scores were overall lower in those lacking capacity (mean/SD abbreviated-mental-test-score = 5.2/2.6, range = 0-10 versus 6.8/2.8, P = 0.001, range = 1-10). Decisions involving discharge planning were most often assessed (48%) followed by treatment (29%), discharge against medical advice (12%) and others (11%).

CONCLUSION

Mental capacity assessments were performed frequently and often repeated, justifying the need for robust training in the practical application of the principles of capacity assessment for staff managing complex older patients.

Identification of delirium from real-world electronic health record clinical notes

Introduction

We tested the ability of our natural language processing (NLP) algorithm to identify delirium episodes in a large-scale study using real-world clinical notes.

Methods

We used the Rochester Epidemiology Project to identify persons ≥ 65 years who were hospitalized between 2011 and 2017. We identified all persons with an International Classification of Diseases code for delirium within ±14 days of a hospitalization. We independently applied our NLP algorithm to all clinical notes for this same population. We calculated rates using number of delirium episodes as the numerator and number of hospitalizations as the denominator. Rates were estimated overall, by demographic characteristics, and by year of episode, and differences were tested using Poisson regression.

Results

In total, 14,255 persons had 37,554 hospitalizations between 2011 and 2017. The code-based delirium rate was 3.02 per 100 hospitalizations (95% CI: 2.85, 3.20). The NLP-based rate was 7.36 per 100 (95% CI: 7.09, 7.64). Rates increased with age (both p < 0.0001). Code-based rates were higher in men compared to women (p = 0.03), but NLP-based rates were similar by sex (p = 0.89). Code-based rates were similar by race and ethnicity, but NLP-based rates were higher in the White population compared to the Black and Asian populations (p = 0.001). Both types of rates increased significantly over time (both p values < 0.001).

Conclusions

The NLP algorithm identified more delirium episodes compared to the ICD code method. However, NLP may still underestimate delirium cases because of limitations in real-world clinical notes, including incomplete documentation, practice changes over time, and missing clinical notes in some time periods.

Risk of bias in prognostic models of hospital-induced delirium for medical-surgical units: A systematic review

PURPOSE

The purpose of this systematic review was to assess risk of bias in existing prognostic models of hospital-induced delirium for medical-surgical units.

METHODS

APA PsycInfo, CINAHL, MEDLINE, and Web of Science Core Collection were searched on July 8, 2022, to identify original studies which developed and validated prognostic models of hospital-induced delirium for adult patients who were hospitalized in medical-surgical units. The Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies was used for data extraction. The Prediction Model Risk of Bias Assessment Tool was used to assess risk of bias. Risk of bias was assessed across four domains: participants, predictors, outcome, and analysis.

RESULTS

Thirteen studies were included in the qualitative synthesis, including ten model development and validation studies and three model validation only studies. The methods in all of the studies were rated to be at high overall risk of bias. The methods of statistical analysis were the greatest source of bias. External validity of models in the included studies was tested at low levels of transportability.

CONCLUSIONS

Our findings highlight the ongoing scientific challenge of developing a valid prognostic model of hospital-induced delirium for medical-surgical units to tailor preventive interventions to patients who are at high risk of this iatrogenic condition. With limited knowledge about generalizable prognosis of hospital-induced delirium in medical-surgical units, existing prognostic models should be used with caution when creating clinical practice policies. Future research protocols must include robust study designs which take into account the perspectives of clinicians to identify and validate risk factors of hospital-induced delirium for accurate and generalizable prognosis in medical-surgical units.

Experiences of shared decision making in acute hospitals: A mixed methods secondary analysis of the Irish National Inpatient Experience Survey

INTRODUCTION

This study explored patient experiences of shared decision making (SDM) in public acute hospitals in Ireland.

METHODS

Quantitative and qualitative data from three years of the Irish National Inpatient Experience Survey were analysed. Survey questions were mapped to definitions of SDM and subjected to principal components analysis. Three SDM subscales (care on the ward; treatments; discharge) and one overall SDM scale were created. Differences in experiences of SDM by aspects of care and patient group were assessed. Thematic analysis of qualitative responses was undertaken.

RESULTS

39,453 patients participated in the survey. The mean SDM experience score was 7.60 ± 2.43. Experience scores were highest on the treatments sub-scale, and lowest during discharge. Patients who had a non-emergency admission, those aged 51-80 years and men had more positive experiences than other groups. Patient comments highlighted that opportunities to clarify information and facilitation of families/caregivers in SDM were found to be lacking.

CONCLUSION

There were differences in experiences of SDM by aspects of care and patient group.

PRACTICE IMPLICATIONS

Efforts to improve SDM in acute hospitals are required, particularly at the time of discharge. SDM may be improved by facilitation of more time for discussion between clinicians and patients and/or their families/caregivers.

Lipopolysaccharide-Induced Delirium-like Behaviour in a Rat Model of Chronic Cerebral Hypoperfusion Is Associated with Increased Indoleamine 2,3-Dioxygenase Expression and Endotoxin Tolerance

Indoleamine 2,3-dioxygenase (IDO) and the tryptophan-kynurenine pathway (TRP-KP) are upregulated in ageing and could be implicated in the pathogenesis of delirium. This study evaluated the role of IDO/KP in lipopolysaccharide (LPS)-induced delirium in an animal model of chronic cerebral hypoperfusion (CCH), a proposed model for delirium. CCH was induced by a permanent bilateral common carotid artery ligation (BCCAL) in Sprague Dawley rats to trigger chronic neuroinflammation-induced neurodegeneration. Eight weeks after permanent BCCAL, the rats were treated with a single systemic LPS. The rats were divided into three groups: (1) post-BCCAL rats treated with intraperitoneal (i.p.) saline, (2) post-BCCAL rats treated with i.p. LPS 100 μg/kg, and (3) sham-operated rats treated with i.p. LPS 100 μg/kg. Each group consisted of 10 male rats. To elucidate the LPS-induced delirium-like behaviour, natural and learned behaviour changes were assessed by a buried food test (BFT), open field test (OFT), and Y-maze test at 0, 24-, 48-, and 72 h after LPS treatment. Serum was collected after each session of behavioural assessment. The rats were euthanised after the last serum collection, and the hippocampi and cerebral cortex were collected. The TRP-KP neuroactive metabolites were measured in both serum and brain tissues using ELISA. Our data show that LPS treatment in CCH rats was associated with acute, transient, and fluctuated deficits in natural and learned behaviour, consistent with features of delirium. These behaviour deficits were mild compared to the sham-operated rats, which exhibited robust behaviour impairments. Additionally, heightened hippocampal IDO expression in the LPS-treated CCH rats was associated with reduced serum KP activity together with a decrease in the hippocampal quinolinic acid (QA) expression compared to the sham-operated rats, suggested for the presence of endotoxin tolerance through the immunomodulatory activity of IDO in the brain. These data provide new insight into the underlying mechanisms of delirium, and future studies should further explore the role of IDO modulation and its therapeutic potential in delirium.

Trends in delirium coding rates in older hospital inpatients in England and Scotland: full population data comprising 7.7M patients per year show substantial increases between 2012 and 2020

Background

Little information is available on change in delirium coding rates over time in major healthcare systems. We examined trends in delirium discharge coding rates in older patients in hospital admissions to the National Health Service (NHS) in England and Scotland between 2012 and 2020.

Methods

Hospital administrative coding data were sourced from NHS Digital England and Public Health Scotland. We examined rates of delirium (F05 from ICD-10) in patients aged ≥70 years in 5 year and ≥90 age bands.

Results

There were approximately 7,000,000 discharges/year in England and 700,000/year in Scotland. Substantially increased delirium coding was observed for all age bands between 2012/2013 and 2019/2020 (p<0.001, Mann Kendall's tau). In the ≥90 age band, there was a 4-fold increase between 2012 and 2020.

Conclusion

Delirium coding rates have shown large increases in the NHS in England and Scotland, likely reflecting several factors including policy initiatives, detection tool implementation and education.

The Current of Consciousness: Neural Correlates and Clinical Aspects

PURPOSE OF REVIEW

In this review, we summarize the current understanding of consciousness including its neuroanatomic basis. We discuss major theories of consciousness, physical exam-based and electroencephalographic metrics used to stratify levels of consciousness, and tools used to shed light on the neural correlates of the conscious experience. Lastly, we review an expanded category of 'disorders of consciousness,' which includes disorders that impact either the level or experience of consciousness.

RECENT FINDINGS

Recent studies have revealed many of the requisite EEG, ERP, and fMRI signals to predict aspects of the conscious experience. Neurological disorders that disrupt the reticular activating system can affect the level of consciousness, whereas cortical disorders from seizures and migraines to strokes and dementia may disrupt phenomenal consciousness. The recently introduced memory theory of consciousness provides a new explanation of phenomenal consciousness that may explain better than prior theories both experimental studies and the neurologist's clinical experience. Although the complete neurobiological basis of consciousness remains a mystery, recent advances have improved our understanding of the physiology underlying level of consciousness and phenomenal consciousness.

Diagnostic accuracy of the Dutch version of the 4AT for delirium detection in a mixed patient population and setting

BACKGROUND

Delirium is an acute disturbance in attention, awareness and cognition. Immediate detection in older adults is recommended because delirium is associated with adverse outcomes. The 4 'A's Test (4AT) is a short screening instrument for delirium. The aim of this study is to evaluate diagnostic accuracy of the Dutch version of the screening tool 4AT for delirium detection in different settings.

METHODS

Prospective observational study conducted in two hospitals in patients aged ≥ 65 years in geriatric wards and the Emergency Department (ED). Each participant underwent two assessments; the index test 4AT, followed by the reference standard for delirium performed by a geriatric care specialist. The reference standard delirium is according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) criteria.

RESULTS

A total of 71 geriatric inpatients and 49 older ED patients were included. The prevalence of delirium was 11.6% in the acute geriatric ward and 6.1% in the ED. The sensitivity and specificity of the 4AT in the acute geriatric ward were 0.88 and 0.69, respectively. In the ED, the sensitivity and specificity were 0.67 and 0.83, respectively. The area under the receiver operating characteristic curve was 0.80 for the acute geriatric ward setting and 0.74 for the ED setting.

CONCLUSION

The Dutch version of the 4AT is a reliable screening tool for delirium detection in both acute geriatric wards and ED. Due to its brevity and practicality (i.e., no special training is required to administer the tool), it is useful in clinical practice.

The Delirium Interview as a new reference standard in studies on delirium assessment tools

BACKGROUND

The reference standard in studies on delirium assessment tools is usually based on the clinical judgment of only one delirium expert and may be concise, unstandardized, or not specified at all. This multicenter study investigated the performance of the Delirium Interview, a new reference standard for studies on delirium assessment tools allowing classification of delirium based on written reports.

METHODS

We tested the diagnostic accuracy of our standardized Delirium Interview by comparing delirium assessments of the reported results with live assessments. Our reference, the live assessment, was performed by two delirium experts and one well-trained researcher who registered the results. Their delirium assessment was compared to the majority vote of three other independent delirium experts who judged the rapportage of the Delirium Interview. Our total pool consisted of 13 delirium experts with an average of 13 ± 8 years of experience.

RESULTS

We included 98 patients (62% male, mean age 69 ± 12 years), of whom 56 (57%) intensive care units (ICUs) patients, 22 (39%) patients with a Richmond Agitation Sedation Scale (RASS) < 0 and 26 (27%) non-verbal assessments. The overall prevalence of delirium was 28%. The Delirium Interview had a sensitivity of 89% (95% confidence interval [CI]: 71%-98%) and specificity of 82% (95% CI: 71%-90%), compared to the diagnosis of an independent panel of two delirium experts and one researcher who examined the patients themselves. Negative and positive predictive values were 95% (95% CI: 86%-0.99%), respectively, 66% (95% CI: 49%-80%). Stratification into ICU and non-ICU patients yielded similar results.

CONCLUSION

The Delirium Interview is a feasible reference method for large study cohorts evaluating delirium assessment tools since experts could assess delirium with high accuracy without seeing the patient at the bedside.

Biomarkers of delirium risk in older adults: a systematic review and meta-analysis

Delirium is a neuropsychiatric syndrome associated with increased morbidity and mortality in older patients. The aim of this study was to review predictive biomarkers of delirium in older patients to gain insights into the pathophysiology of this syndrome and provide guidance for future studies. Two authors independently and systematically searched MEDLINE, Embase, Cochrane Library, Web of Science and Scopus databases up to August 2021. A total of 32 studies were included. Only 6 studies were eligible for the meta-analysis, pooled results showed a significant increase in some serum biomarkers (C-reactive protein [CRP], tumour necrosis factor alpha [TNF-α] and interleukin-6 [IL-6]) among patients with delirium (odds ratio = 1.88, 95% CI 1.01 to 1.637; I2 = 76.75%). Although current evidence does not favour the use of any particular biomarker, serum CRP, TNF-α, and IL-6 were the most consistent biomarkers of delirium in older patients.

Extremes of baseline cognitive function determine the severity of delirium: a population study

Although delirium is a significant clinical and public health problem, little is understood about how specific vulnerabilities underlie the severity of its presentation. Our objective was to quantify the relationship between baseline cognition and subsequent delirium severity. We prospectively investigated a population-representative sample of 1510 individuals aged ≥70 years, of whom 209 (13.6%) were hospitalized across 371 episodes (1999 person-days assessment). Baseline cognitive function was assessed using the modified Telephone Interview for Cognitive Status, supplemented by verbal fluency measures. We estimated the relationship between baseline cognition and delirium severity [Memorial Delirium Assessment Scale (MDAS)] and abnormal arousal (Observational Scale of Level of Arousal), adjusted by age, sex, frailty and illness severity. We conducted further analyses examining presentations to specific hospital settings and common precipitating aetiologies. The median time from baseline cognitive assessment to admission was 289 days (interquartile range 130 to 47 days). In admitted patients, delirium was present on at least 1 day in 45% of admission episodes. The average number of days with delirium (consecutively positive assessments) was 3.9 days. Elective admissions accounted for 88 bed days (4.4%). In emergency (but not elective) admissions, we found a non-linear U-shaped relationship between baseline global cognition and delirium severity using restricted cubic splines. Participants with baseline cognition 2 standard deviations below average (z-score = -2) had a mean MDAS score of 14 points (95% CI 10 to 19). Similarly, those with baseline cognition z-score = + 2 had a mean MDAS score of 7.9 points (95% CI 4.9 to 11). Individuals with average baseline cognition had the lowest MDAS scores. The association between baseline cognition and abnormal arousal followed a comparable pattern. C-reactive protein ≥20 mg/l and serum sodium <125 mM/l were associated with more severe delirium. Baseline cognition is a critical determinant of the severity of delirium and associated changes in arousal. Emergency admissions with lowest and highest baseline cognition who develop delirium should receive enhanced clinical attention.

Diagnostic accuracy of the 3-minute diagnostic interview for confusion assessment method-defined delirium in delirium detection: a systematic review and meta-analysis

BACKGROUND

Delirium is a common complication clinically and is associated with the poor outcomes, yet it is frequently unrecognised and readily disregarded. Although the 3-minute diagnostic interview for confusion assessment method-defined delirium (3D-CAM) has been used in a variety of care settings, a comprehensive evaluation of its accuracy in all available care settings has not been performed.

OBJECTIVE

This study aimed to evaluate the diagnostic test accuracy of the 3D-CAM in delirium detection through a systematic review and meta-analysis.

METHODS

We systematically searched PubMed, EMBASE, the Cochrane Library, Web of Science, CINAHL (EBSCO) and ClinicalTrials.gov published from inception to 10 July 2022. The quality assessment of the diagnostic accuracy studies-2 tool was applied to evaluate methodological quality. A bivariate random effects model was used to pool sensitivity and specificity.

RESULTS

Seven studies with 1,350 participants and 2,499 assessments were included, which were carried out in general medical wards, intensive care units, internal medical wards, surgical wards, recovery rooms and post-anaesthesia care units. The prevalence of delirium ranged from 9.1% to 25%. The pooled sensitivity and specificity were 0.92 (95% confidence interval [CI] 0.87-0.95) and 0.95 (95% CI 0.92-0.97), respectively. The pooled positive likelihood ratio was 18.6 (95% CI 12.2-28.2), the negative likelihood ratio was 0.09 (95% CI 0.06-0.14) and the diagnostic odds ratio was 211 (95% CI 128-349). Moreover, the area under the curve was 0.97 (95% CI 0.95-0.98).

CONCLUSIONS

The 3D-CAM has good diagnostic accuracy for delirium detection in different care settings. Further analyses illustrated that it had comparable diagnostic accuracy in older adults and patients with dementia or known baseline cognitive impairment. In conclusion, the 3D-CAM is recommended for clinical delirium detection.

Incidence and associations of hospital delirium diagnoses in 85,979 people with severe mental illness: A data linkage study

INTRODUCTION

Delirium is an acute neuro-psychiatric disturbance precipitated by a range of physical stressors, with high morbidity and mortality. Little is known about its relationship with severe mental illness (SMI).

METHODS

We conducted a retrospective cohort study using linked data analyses of the UK Clinical Practice Research Datalink (CPRD) and Hospital Episodes Statistics (HES) databases. We ascertained yearly hospital delirium incidence from 2000 to 2017 and used logistic regression to identify associations with delirium diagnosis in a population with SMI.

RESULTS

The cohort included 249,047 people with SMI with median follow-up time in CPRD of 6.4 years. A total of 85,979 patients were eligible for linkage to HES. Delirium incidence increased from 0.04 (95% CI 0.02-0.07) delirium associated admissions per 100 person-years in 2000 to 1.05 (95% CI 0.93-1.17) per 100 person-years in 2017, increasing most notably from 2010 onwards. Delirium was associated with older age at study entry (OR 1.05 per year, 95% CI 1.05-1.06), SMI diagnosis of bipolar affective disorder (OR 1.66, 95% CI 1.44-1.93) or other psychosis (OR 1.56, 95% CI 1.35-1.80) relative to schizophrenia, and more physical comorbidities (OR 1.08 per additional comorbidity of the Charlson Comorbidity Index, 95% CI 1.02-1.14). Patients with delirium received more antipsychotic medication during follow-up (1-2 antipsychotics OR 1.65, 95% CI 1.44-1.90; >2 antipsychotics OR 2.49, 95% CI 2.12-2.92).

CONCLUSIONS

The incidence of recorded delirium diagnoses in people with SMI has increased in recent years. Older people prescribed more antipsychotics and with more comorbidities have a higher incidence. Linked electronic health records are feasible for exploring hospital diagnoses such as delirium in SMI.