Association of Delirium With Cognitive Decline in Late Life: A Neuropathologic Study of 3 Population-Based Cohort Studies

Effect of the Tailored, Family-Involved Hospital Elder Life Program on Postoperative Delirium and Function in Older Adults: A Randomized Clinical Trial

IMPORTANCE

Postoperative delirium (POD) is a common condition for older adults, contributing to their functional decline.

OBJECTIVE

To investigate the effectiveness of the Tailored, Family-Involved Hospital Elder Life Program (t-HELP) for preventing POD and functional decline in older patients after a noncardiac surgical procedure.

DESIGN, SETTING, AND PARTICIPANTS

A 2-arm, parallel-group, single-blind, cluster randomized clinical trial was conducted from August 24, 2015, to February 28, 2016, on 6 surgical floors (gastric, colorectal, pancreatic, biliary, thoracic, and thyroid) of West China Hospital in Chengdu, China. Eligible participants (n = 281) admitted to each of the 6 surgical floors were randomized into a nursing unit providing t-HELP (intervention group) or a nursing unit providing usual care (control group). All randomized patients were included in the intention-to-treat analyses for the primary outcome of POD incidence. Statistical analysis was performed from April 3, 2016, to December 30, 2017.

INTERVENTIONS

In addition to receiving usual care, all participants in the intervention group received the t-HELP protocols, which addressed each patient's risk factor profile. Besides nursing professionals, family members and paid caregivers were involved in the delivery of many of the program interventions.

MAIN OUTCOMES AND MEASURES

The primary outcome was the incidence of POD, evaluated with the Confusion Assessment Method. Secondary outcomes included the pattern of functional and cognitive changes (activities of daily living [ADLs], instrumental activities of daily living [IADLs], Short Portable Mental Status Questionnaire [SPMSQ]) from hospital admission to 30 days after discharge, and the length of hospital stay (LOS).

RESULTS

Of the 475 patients screened for eligibility, 281 (171 [60.9%] male, mean [SD] age 74.7 [5.2] years) were enrolled and randomized to receive t-HELP (n = 152) or usual care (n = 129). Postoperative delirium occurred in 4 participants (2.6%) in the intervention group and in 25 (19.4%) in the control group, with a relative risk of 0.14 (95% CI, 0.05-0.38). The number needed to treat to prevent 1 case of POD was 5.9 (95% CI, 4.2-11.1). Participants in the intervention group compared with the control group showed less decline in physical function (median [interquartile range] for ADLs: -5 [-10 to 0] vs -20 [-30 to -10]; P < .001; for IADLs: -2 [-2 to 0] vs -4 [-4 to -2]; P < .001) and cognitive function (for the SPMSQ level: 1 [0.8%] vs 8 [7.0%]; P = .009) at discharge, as well as shorter mean (SD) LOS (12.15 [3.78] days vs 16.41 [4.69] days; P < .001).

CONCLUSIONS AND RELEVANCE

The findings suggest that t-HELP, with family involvement at its core, is effective in reducing POD for older patients, maintaining or improving their physical and cognitive functions, and shortening the LOS. The results of this t-HELP trial may improve generalizability and increase the implementation of this program.

TRIAL REGISTRATION

Chinese Clinical Trial Registry Identifier: ChiCTR-POR-15006944.

Process of implementing and delivering the Prevention of Delirium system of care: a mixed method preliminary study

BACKGROUND

Delirium is a frequent complication of hospital admission among older people. Multicomponent interventions which can reduce incident delirium by ≈one-third are recommended by the National Institute of Health and Care Excellence. Currently, a standardised delirium prevention system of care suitable for adoption in the UK National Health Service does not exist. The Prevention of Delirium (POD) system of care is a theory informed, multicomponent intervention and systematic implementation process which includes a role for hospital volunteers. We report POD implementation and delivery processes in NHS hospital wards, as part of a feasibility study.

METHODS

A comparative case study design and participatory, multi-method evaluation was performed with sequential six month preparatory and six month delivery stages. Six wards in five hospitals in Northern England were recruited. Methods included: facilitated workshops; observation of POD preparatory activities; qualitative interviews with staff; collection of ward organisational and patient profiles; and structured observation of staff workload.

RESULTS

POD implementation and delivery was fully accomplished in four wards. On these wards, implementation strategies informed by Normalization Process Theory operated synergistically and cumulatively. An interactive staff training programme on delirium and practices that might prevent it among those at risk, facilitated purposeful POD engagement. Observation of practice juxtaposed to action on delirium preventive interventions created tension for change, legitimating new ways of organising work around it. Establishing systems, processes and documentation to make POD workable in the ward setting, enhanced staff ownership. 'Negotiated experimentation' to involve staff in creating, appraising and modifying systems and practices, helped integrate the POD care system in ward routines. Activating these change mechanisms required a particular form of leadership: pro-active 'steer', and senior ward 'facilitator' to extend 'reach' to the staff group. Organisational discontinuity (i.e. ward re-location and re-modelling) disrupted and extended POD implementation; staff shortages adversely affected staff capacity to invest in POD. Findings resulted in the development of 'site readiness' criteria without which implementation of this complex intervention was unlikely to occur.

CONCLUSIONS

POD implementation and delivery is feasible in NHS wards, but a necessary context for success is 'site readiness.'

Delirium is prevalent in older hospital inpatients and associated with adverse outcomes: results of a prospective multi-centre study on World Delirium Awareness Day

BACKGROUND

Delirium is a common severe neuropsychiatric condition secondary to physical illness, which predominantly affects older adults in hospital. Prior to this study, the UK point prevalence of delirium was unknown. We set out to ascertain the point prevalence of delirium across UK hospitals and how this relates to adverse outcomes.

METHODS

We conducted a prospective observational study across 45 UK acute care hospitals. Older adults aged 65 years and older were screened and assessed for evidence of delirium on World Delirium Awareness Day (14th March 2018). We included patients admitted within the previous 48 h, excluding critical care admissions.

RESULTS

The point prevalence of Diagnostic and Statistical Manual on Mental Disorders, Fifth Edition (DSM-5) delirium diagnosis was 14.7% (222/1507). Delirium presence was associated with higher Clinical Frailty Scale (CFS): CFS 4-6 (frail) (OR 4.80, CI 2.63-8.74), 7-9 (very frail) (OR 9.33, CI 4.79-18.17), compared to 1-3 (fit). However, higher CFS was associated with reduced delirium recognition (7-9 compared to 1-3; OR 0.16, CI 0.04-0.77). In multivariable analyses, delirium was associated with increased length of stay (+ 3.45 days, CI 1.75-5.07) and increased mortality (OR 2.43, CI 1.44-4.09) at 1 month. Screening for delirium was associated with an increased chance of recognition (OR 5.47, CI 2.67-11.21).

CONCLUSIONS

Delirium is prevalent in older adults in UK hospitals but remains under-recognised. Frailty is strongly associated with the development of delirium, but delirium is less likely to be recognised in frail patients. The presence of delirium is associated with increased mortality and length of stay at one month. A national programme to increase screening has the potential to improve recognition.

Distress in delirium: causes, assessment and management

Purpose

Delirium is a common clinical syndrome associated with increased physical and psychological morbidity, mortality, inpatient stay and healthcare costs. There is growing interest in understanding the delirium experience and its psychological impact, including distress, for patients and their relatives, carers and healthcare providers.

Methods

This narrative review focuses on distress in delirium (DID) with an emphasis on its effect on older patients. It draws on qualitative and quantitative research to describe patient and environmental risk factors and variations in DID across a number of clinical settings, including medical and surgical inpatient wards and end of life care. The article provides an overview of the available distress assessment tools, both for clinical and research practice, and outlines their use in the context of delirium. This review also outlines established and emerging management strategies, focusing primarily on prevention and limitation of distress in delirium.

Results

Both significant illness and delirium cause distress. Patients who recall the episode of delirium describe common experiential features of delirium and distress. Relatives who witness delirium also experience distress, at levels suggested to be greater than that experienced by patients themselves. DID results in long-term psychological sequelae that can last months and years. Preventative actions, such pre-episode educational information for patients and their families in those at risk may reduce distress and psychological morbidity.

Conclusions

Improving clinicians’ understanding of the experience and long term psychological harm of delirium will enable the development of targeted support and information to patients at risk of delirium, and their families or carers.

Delirium superimposed on dementia

PURPOSE

Delirium superimposed on dementia (DSD) is a frequent and growing emerging clinical challenge, given the increasing prevalence of dementia.

METHODS

This narrative review focuses on and discusses the current knowledge on epidemiology, pathogenesis, diagnosis and management of DSD.

RESULTS

There is a close interaction between delirium and dementia since dementia is a risk factor for delirium and delirium is a known risk factor for newly developed dementia or worsening of dementia. The occurrence of DSD causes adverse clinical outcomes. However, DSD is often under-recognized or is frequently considered as the regular course of dementia. Indeed, especially in the advance stages of dementia, DSD diagnosis is challenging since a clear distinction between symptoms attributable to delirium and to dementia is difficult. Given the importance of DSD, it is essential to educate health care providers on the best approach for delirium management and treatment. It is now well recognized that delirium can be prevented using multicomponent interventions carried out by a multidisciplinary team targeting predisposing and precipitating risk factors for delirium. On the contrary, antipsychotics should only be used in patients with severe distressing symptoms and whose behavior means their safety or the safety of those around them is compromised, given the harmful of these medications in patients with pre-existing dementia.

CONCLUSIONS

It is essential to improve health care providers knowledge on DSD to improve the quality of care for an epidemiologically relevant though understudied population.

Long-term cognitive impairment after acute respiratory distress syndrome: a review of clinical impact and pathophysiological mechanisms

Acute respiratory distress syndrome (ARDS) survivors experience a high prevalence of cognitive impairment with concomitantly impaired functional status and quality of life, often persisting months after hospital discharge. In this review, we explore the pathophysiological mechanisms underlying cognitive impairment following ARDS, the interrelations between mechanisms and risk factors, and interventions that may mitigate the risk of cognitive impairment. Risk factors for cognitive decline following ARDS include pre-existing cognitive impairment, neurological injury, delirium, mechanical ventilation, prolonged exposure to sedating medications, sepsis, systemic inflammation, and environmental factors in the intensive care unit, which can co-occur synergistically in various combinations. Detection and characterization of pre-existing cognitive impairment imparts challenges in clinical management and longitudinal outcome study enrollment. Patients with brain injury who experience ARDS constitute a distinct population with a particular combination of risk factors and pathophysiological mechanisms: considerations raised by brain injury include neurogenic pulmonary edema, differences in sympathetic activation and cholinergic transmission, effects of positive end-expiratory pressure on cerebral microcirculation and intracranial pressure, and sensitivity to vasopressor use and volume status. The blood-brain barrier represents a physiological interface at which multiple mechanisms of cognitive impairment interact, as acute blood-brain barrier weakening from mechanical ventilation and systemic inflammation can compound existing chronic blood-brain barrier dysfunction from Alzheimer’s-type pathophysiology, rendering the brain vulnerable to both amyloid-beta accumulation and cytokine-mediated hippocampal damage. Although some contributory elements, such as the presenting brain injury or pre-existing cognitive impairment, may be irreversible, interventions such as minimizing mechanical ventilation tidal volume, minimizing duration of exposure to sedating medications, maintaining hemodynamic stability, optimizing fluid balance, and implementing bundles to enhance patient care help dramatically to reduce duration of delirium and may help prevent acquisition of long-term cognitive impairment.

Hospitalization, Alzheimer's Disease and Related Neuropathologies, and Cognitive Decline

Objective

To test the hypothesis that Alzheimer's disease and related neuropathologies contribute to the association between hospitalization and cognitive decline in old age.

Methods

As part of a longitudinal clinical–pathologic cohort study, 526 older persons (mean age at death = 90.9 years, 71% female) without dementia at baseline completed annual cognitive testing and were autopsied at death. Hospitalization information was obtained from linked Medicare claims records. Neuropathologic examination assessed β‐amyloid burden, tau tangle density, neocortical Lewy bodies, hippocampal sclerosis, chronic gross and microscopic cerebral infarcts, and transactive response DNA binding protein 43 kDa.

Results

Over a mean of 5.1 years, a total of 1,383 hospitalizations occurred, and the mean annual rate of hospitalization was 0.5 (standard deviation = 0.6, median = 0.4). Higher rate of hospitalization was not directly related to higher burden for any of the neuropathologic markers. Higher rate of hospitalization was associated with more rapid cognitive decline (estimate = −0.042, standard error [SE] = 0.012, p < 0.001), and after controlling for all 7 neuropathologic markers, the association was essentially the same (estimate = −0.040, SE = 0.013, p = 0.002). In a multivariable model with 3‐way interactions of neuropathologic markers with hospitalization rate and time, the association between hospitalization rate and faster cognitive decline was greater in persons with more tangle pathology (estimate for interaction = −0.007, SE = 0.002, p = 0.002) and in persons with neocortical Lewy bodies (estimate for interaction = −0.117, SE = 0.042, p = 0.005).

Interpretation

Older persons with more hospitalizations experienced faster rates of cognitive decline, and this association was more pronounced in persons with more tau tangle density and with neocortical Lewy body pathologies. ANN NEUROL 2019;86:844–852

An interdisciplinary statement of scientific societies for the advancement of delirium care across Europe (EDA, EANS, EUGMS, COTEC, IPTOP/WCPT)

Background

Delirium is a geriatric syndrome that presents in 1 out of 5 hospitalized older patients. It is also common in the community, in hospices, and in nursing homes. Delirium prevalence varies according to clinical setting, with rates of under 5% in minor elective surgery but up to 80% in intensive care unit patients. Delirium has severe adverse consequences, but despite this and its high prevalence, it remains undetected in the majority of cases. Optimal delirium care requires an interdisciplinary, multi-dimensional diagnostic and therapeutic approach involving doctors, nurses, physiotherapists, and occupational therapists. However, there are still important gaps in the knowledge and management of this syndrome.

Main body

The objective of this paper is to promote the interdisciplinary approach in the prevention and management of delirium as endorsed by a delirium society (European Delirium Association, EDA), a geriatrics society (European Geriatric Medicine Society, EuGMS), a nursing society (European Academy of Nursing Science, EANS), an occupational therapy society (Council of Occupational Therapists for European Countries, COTEC), and a physiotherapy society (International Association of Physical Therapists working with Older People of the World Confederation for Physical Therapy, IPTOP/WCPT).

Short conclusion

In this paper we have strongly promoted and supported interdisciplinary collaboration underlying the necessity of increasing communication among scientific societies. We have also provided suggestions on how to fill the current gaps via improvements in undergraduate and postgraduate delirium education among European Countries.

Postoperative Delirium and Postoperative Cognitive Dysfunction: Overlap and Divergence

BACKGROUND

Postoperative delirium and postoperative cognitive dysfunction share risk factors and may co-occur, but their relationship is not well established. The primary goals of this study were to describe the prevalence of postoperative cognitive dysfunction and to investigate its association with in-hospital delirium. The authors hypothesized that delirium would be a significant risk factor for postoperative cognitive dysfunction during follow-up.

METHODS

This study used data from an observational study of cognitive outcomes after major noncardiac surgery, the Successful Aging after Elective Surgery study. Postoperative delirium was evaluated each hospital day with confusion assessment method-based interviews supplemented by chart reviews. Postoperative cognitive dysfunction was determined using methods adapted from the International Study of Postoperative Cognitive Dysfunction. Associations between delirium and postoperative cognitive dysfunction were examined at 1, 2, and 6 months.

RESULTS

One hundred thirty-four of 560 participants (24%) developed delirium during hospitalization. Slightly fewer than half (47%, 256 of 548) met the International Study of Postoperative Cognitive Dysfunction-defined threshold for postoperative cognitive dysfunction at 1 month, but this proportion decreased at 2 months (23%, 123 of 536) and 6 months (16%, 85 of 528). At each follow-up, the level of agreement between delirium and postoperative cognitive dysfunction was poor (kappa less than .08) and correlations were small (r less than .16). The relative risk of postoperative cognitive dysfunction was significantly elevated for patients with a history of postoperative delirium at 1 month (relative risk = 1.34; 95% CI, 1.07-1.67), but not 2 months (relative risk = 1.08; 95% CI, 0.72-1.64), or 6 months (relative risk = 1.21; 95% CI, 0.71-2.09).

CONCLUSIONS

Delirium significantly increased the risk of postoperative cognitive dysfunction in the first postoperative month; this relationship did not hold in longer-term follow-up. At each evaluation, postoperative cognitive dysfunction was more common among patients without delirium. Postoperative delirium and postoperative cognitive dysfunction may be distinct manifestations of perioperative neurocognitive deficits.

Post-traumatic stress disorder (PTSD) related symptoms following an experience of delirium

AIM

To evaluate the prevalence of symptoms of PTSD and its correlates after 2 weeks of recovery, among patients, who developed delirium.

METHODOLOGY

A prospective study designed was followed, in which subjects diagnosed with delirium were evaluated 2 weeks after resolution of symptoms of delirium, for PTSD symptoms by using Impact of Events Scale-Revised version (IES-R).

RESULTS

59 patients were evaluated for PTSD 2 weeks after resolution of delirium and the total mean IES-R score was 27.81 (SD-11.41). Based on the IES-cut-off scores of the scale, 30.5% of the patients (n = 18) were considered to have substantial symptoms of PTSD, 22% (n = 13) had probable symptoms of PTSD and 15.3% were considered to have partial symptoms of PTSD after resolution of delirium. None of the demographic or clinical factors were associated with development of PTSD. Those with PTSD symptoms had significantly higher prevalence of fluctuation of symptoms, while experiencing delirium and had significantly higher mean scores for the items of motor agitation, attentional deficits, higher total severity score on the Delirium Rating Scale-revised-98 version (DRS-R98) and higher DRS-R-98 total score. Higher severity of delirium as indicated by the total DRS-R98 score and the total DRS-R98 severity score were associated with higher severity of PTSD symptoms. The IES-R total score did not have any significant correlation with duration of illness, duration of delirium or Charlson Co-morbidity index.

CONCLUSIONS

This study suggests that about one-third of patients who develop delirium go on to develop symptoms of PTSD, after recovery from delirium. Development of PTSD symptoms is associated with severity of delirium. Hence, it is important to treat the delirium adequately and provide psychological support to the patients who develop delirium, after recovery from delirium.

Delirium detection in older acute medical inpatients: a multicentre prospective comparative diagnostic test accuracy study of the 4AT and the confusion assessment method

BACKGROUND

Delirium affects > 15% of hospitalised patients but is grossly underdetected, contributing to poor care. The 4 'A's Test (4AT, www.the4AT.com ) is a short delirium assessment tool designed for routine use without special training. The primary objective was to assess the accuracy of the 4AT for delirium detection. The secondary objective was to compare the 4AT with another commonly used delirium assessment tool, the Confusion Assessment Method (CAM).

METHODS

This was a prospective diagnostic test accuracy study set in emergency departments or acute medical wards involving acute medical patients aged ≥ 70. All those without acutely life-threatening illness or coma were eligible. Patients underwent (1) reference standard delirium assessment based on DSM-IV criteria and (2) were randomised to either the index test (4AT, scores 0-12; prespecified score of > 3 considered positive) or the comparator (CAM; scored positive or negative), in a random order, using computer-generated pseudo-random numbers, stratified by study site, with block allocation. Reference standard and 4AT or CAM assessments were performed by pairs of independent raters blinded to the results of the other assessment.

RESULTS

Eight hundred forty-three individuals were randomised: 21 withdrew, 3 lost contact, 32 indeterminate diagnosis, 2 missing outcome, and 785 were included in the analysis. Mean age was 81.4 (SD 6.4) years. 12.1% (95/785) had delirium by reference standard assessment, 14.3% (56/392) by 4AT, and 4.7% (18/384) by CAM. The 4AT had an area under the receiver operating characteristic curve of 0.90 (95% CI 0.84-0.96). The 4AT had a sensitivity of 76% (95% CI 61-87%) and a specificity of 94% (95% CI 92-97%). The CAM had a sensitivity of 40% (95% CI 26-57%) and a specificity of 100% (95% CI 98-100%).

CONCLUSIONS

The 4AT is a short, pragmatic tool which can help improving detection rates of delirium in routine clinical care.

TRIAL REGISTRATION

International standard randomised controlled trial number (ISRCTN) 53388093 . Date applied 30/05/2014; date assigned 02/06/2014.

Systemic inflammation and modifiable risk factors for cognitive impairment in older persons: Findings from a British birth cohort

Serum pro‐inflammatory markers may contribute to dementia pathophysiology and cognitive impairment. In a population‐representative birth cohort, serum C‐reactive protein (CRP), interleukin‐6 (IL‐6), and white cell count (WCC) were measured at age 60‐64 years and cognition was assessed using the Addenbrooke's Cognitive Examination (ACE‐III) at age 69 years. Higher baseline CRP and IL‐6 were associated with lower ACE‐III scores, but associations were attenuated on adjustment for educational attainment, sex, and other modifiable life course factors. No associations were found for CRP, IL‐6, and WCC with visual search speed or verbal memory. In conclusion, the relationship between increased baseline systemic inflammation and poorer cognition in later life may be explained by, or share pathways with, education and other modifiable life course factors.

Neurofilament Light in Serum and Cerebrospinal Fluid of Hip Fracture Patients with Delirium

BACKGROUND

Delirium is associated with new-onset dementia, suggesting that delirium pathophysiology involves neuronal injury. Neurofilament light (NFL) is a sensitive biomarker for neuroaxonal injury.

METHODS

NFL was measured in cerebrospinal fluid (CSF) (n = 130), preoperative serum (n = 192), and postoperative serum (n = 280) in hip fracture patients, and in CSF (n = 123) and preoperative serum (n = 134) in cognitively normal older adults undergoing elective surgery. Delirium was diagnosed with the Confusion Assessment Method.

RESULTS

Median serum NFL (pg/mL) was elevated in delirium in hip fracture patients (94 vs. 54 pre- and 135 vs. 92 postoperatively, both p < 0.001). Median CSF NFL tended to be higher in hip fracture patients with delirium (1,804 vs. 1,636, p = 0.074). Serum and CSF NFL were positively correlated (ρ = 0.56, p < 0.001).

CONCLUSION

Our findings support an association between neuroaxonal injury and delirium. The correlation between serum and CSF NFL supports the use of NFL as a blood biomarker in future delirium studies.

Cognitive outcomes following coronary artery bypass grafting: A systematic review and meta-analysis of 91,829 patients

Background

Cognitive impairments, including delirium, are common after coronary artery bypass grafting (CABG) surgery, as described in over three decades of research. Our aim was to pool estimates across the literature for the first-time, relative to time (from pre- to post-CABG) and diagnosis (cognitive impairment, delirium and dementia).

Methods

A systematic search of four databases was undertaken. 215 studies incorporating data from 91,829 patients were used to estimate the prevalence of cognitive impairments pre- and post-CABG, including delirium and dementia post-CABG, using random effects meta-analyses.

Results

Pre-surgical cognitive impairment was seen in 19% of patients. Post-operatively, cognitive impairment was seen in around 43% of patients acutely; this resolved to 19% at 4–6 months and then increased to 25% of patients between 6-months to 1-year post-operatively. In the long term, between 1 and 5-years post-operatively, cognitive impairment increased and was seen in nearly 40% of patients. Post-operative delirium was apparent in 18% of CABG patients which increased to 24% when a diagnostic instrument was utilized alongside clinical criteria. Dementia was present in 7% of patients 5–7 years post-surgery.

Conclusion

The results of this meta-analysis demonstrate that cognitive impairment and delirium are major issues in CABG patients which require specific attention. It is imperative that appropriate methods for investigating cognitive impairment, and screening for delirium using a diagnostic instrument, occur in both pre-and post-CABG settings.

•

This meta-analysis pooled results of 91,829 patients, including 215 studies.

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Cognitive impairment and delirium are seen in up to 40% of CABG patients.

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Appropriate methods investigating cognitive impairment are crucial post-CABG.

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Appropriate methods of screening for delirium are crucial post-CABG.

Causes and outcomes of hospitalization in Lewy body dementia: A retrospective cohort study

INTRODUCTION

Understanding hospitalization in Lewy body dementia (LBD) is a known knowledge gap. We aimed to identify common causes, medication profiles, complications, and outcomes of hospitalization in LBD.

METHODS

A retrospective cohort study investigated details of academic medical center hospitalizations over a two-year period for patients with LBD. Data collected included demographics, home medications, pre-hospital living status, reason for admission, admission service, inpatient medications, complications, and discharge status. Non-parametric statistics assessed associations between variables and length of stay. Odds of a change in living situation based on admission variables was calculated.

RESULTS

The study included 178 hospitalizations (117 individuals). Neuropsychiatric symptoms were the most common admission reason (40%), followed by falls (24%) and infection (23%). Patients were usually admitted to medicine services; neurology or psychiatric consultations occurred less than 40% of the time. Antipsychotics were administered during 38% of hospitalizations. Use of antipsychotics other than quetiapine or clozapine was associated with longer length of stay and increased odds of discharge to a higher level of care. One-third of hospitalizations resulted in transition to a higher level of care; 15% ended in hospice care or death.

CONCLUSION

The most common reasons for hospitalization in LBD are potentially modifiable. Opportunities for improved care include increased involvement of neurological and psychiatric services, delirium prevention strategies, and reduced antipsychotic use. Clinicians should counsel patients and families that hospitalizations in LBD can be associated with end of life. Research is needed to identify strategies to prevent hospitalization and optimal standards for inpatient care.

FUNDING

Lewy body dementia research at the University of Florida is supported by the University of Florida Dorothy Mangurian Headquarters for Lewy Body Dementia and the Raymond E. Kassar Research Fund for Lewy Body Dementia.

Delirium, Frailty, and Mortality: Interactions in a Prospective Study of Hospitalized Older People

Background

It is unknown whether the association between delirium and mortality is consistent for individuals across the whole range of health states. A bimodal relationship has been proposed, where delirium is particularly adverse for those with underlying frailty, but may have a smaller effect (perhaps even protective) if it is an early indicator of acute illness in fitter people. We investigated the impact of delirium on mortality in a cohort simultaneously evaluated for frailty.

Methods

We undertook an exploratory analysis of a cohort of consecutive acute medical admissions aged ≥70. Delirium on admission was ascertained by psychiatrists. A frailty index (FI) was derived according to a standard approach. Deaths were notified from linked national mortality statistics. Cox regression was used to estimate associations between delirium, frailty, and their interactions on mortality.

Results

The sample consisted of 710 individuals. Both delirium and frailty were independently associated with increased mortality rates (delirium: HR 2.4, 95% CI 1.8–3.3, p < .01; frailty (per SD): HR 3.5, 95% CI 1.2–9.9, p = .02). Estimating the effect of delirium in tertiles of FI, mortality was greatest in the lowest tertile: tertile 1 HR 3.4 (95% CI 2.1–5.6); tertile 2 HR 2.7 (95% CI 1.5–4.6); tertile 3 HR 1.9 (95% CI 1.2–3.0).

Conclusion

Although delirium and frailty contribute to mortality, the overall impact of delirium on admission appears to be greater at lower levels of frailty. In contrast to the hypothesis that there is a bimodal distribution for mortality, delirium appears to be particularly adverse when precipitated in fitter individuals.

Acute neuropathological consequences of short-term mechanical ventilation in wild-type and Alzheimer's disease mice

Background

Mechanical ventilation is strongly associated with cognitive decline after critical illness. This finding is particularly evident among older individuals who have pre-existing cognitive impairment, most commonly characterized by varying degrees of cerebral amyloid-β accumulation, neuroinflammation, and blood-brain barrier dysfunction. We sought to test the hypothesis that short-term mechanical ventilation contributes to the neuropathology of cognitive impairment by (i) increasing cerebral amyloid-β accumulation in mice with pre-existing Alzheimer’s disease pathology, (ii) increasing neurologic and systemic inflammation in wild-type mice and mice with pre-existing Alzheimer’s disease pathology, and (iii) increasing hippocampal blood-brain barrier permeability in wild-type mice and mice with pre-existing Alzheimer’s disease pathology.

Methods

We subjected double transgenic Alzheimer’s disease (APP/PSEN1) and wild-type mice to mechanical ventilation for 4 h and compared to non-mechanically ventilated Alzheimer’s disease model and wild-type mice. Cerebral soluble/insoluble amyloid-β_1–40/amyloid-β_1–42 and neurological and systemic markers of inflammation were quantified. Hippocampal blood-brain barrier permeability was quantified using a novel methodology that enabled assessment of small and large molecule permeability across the blood-brain barrier.

Results

Mechanical ventilation resulted in (i) a significant increase in cerebral soluble amyloid-β_1–40 (p = 0.007) and (ii) significant increases in neuroinflammatory cytokines in both wild-type and Alzheimer’s disease mice which, in most cases, were not reflected in the plasma. There were (i) direct correlations between polymorphonuclear cells in the bronchoalveolar fluid and cerebral soluble amyloid-β_1–40 (p = 0.0033), and several Alzheimer’s disease-relevant neuroinflammatory biomarkers including cerebral TNF-α and IL-6; (iii) significant decreases in blood-brain barrier permeability in mechanically ventilated Alzheimer’s disease mice and a trend towards increased blood-brain barrier permeability in mechanically ventilated wild-type mice.

Conclusions

These results provide the first evidence that short-term mechanical ventilation independently promotes the neuropathology of Alzheimer’s disease in subjects with and without pre-existing cerebral Alzheimer’s disease pathology. Future studies are needed to further clarify the specific mechanisms by which this occurs and to develop neuroprotective mechanical ventilation strategies that mitigate the risk of cognitive decline after critical illness.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2356-2) contains supplementary material, which is available to authorized users.

Systems Delivery Innovation for Alzheimer Disease

OBJECTIVE

The authors describe a comprehensive care model for Alzheimer disease (AD) that improves value within 1-3 years after implementation by leveraging targeted outpatient chronic care management, cognitively protective acute care, and timely caregiver support.

METHODS

Using current best evidence, expert opinion, and macroeconomic modeling, the authors designed a comprehensive care model for AD that improves the quality of care while reducing total per capita healthcare spending by more than 15%. Cost savings were measured as reduced spending by payers. Cost estimates were derived from medical literature and national databases, including both public and private U.S. payers. All estimates reflect the value in 2015 dollars using a consumer price index inflation calculator. Outcome estimates were determined at year 2, accounting for implementation and steady-state intervention costs.

RESULTS

After accounting for implementation and recurring operating costs of approximately $9.5 billion, estimated net cost savings of between $13 and $41 billion can be accomplished concurrently with improvements in quality and experience of coordinated chronic care ($0.01-$6.8 billion), cognitively protective acute care ($8.7-$26.6 billion), timely caregiver support ($4.3-$7.5 billion), and caregiver efficiency ($4.1-$7.2 billion).

CONCLUSION

A high-value care model for AD may improve the experience of patients with AD while significantly lowering costs.

Delirium etiology subtypes and their effect on six-month function and cognition in older emergency department patients

ABSTRACTBackground:Delirium is heterogeneous and can vary by etiology.

OBJECTIVES

We sought to determine how delirium subtyped by etiology affected six-month function and cognition.

DESIGN

Prospective cohort study.

SETTING

Tertiary care, academic medical center.

PARTICIPANTS

A total of 228 hospitalized patients &gt; 65 years old were admitted from the emergency department (ED).

MEASUREMENTS

The modified Brief Confusion Assessment Method was used to determine delirium in the ED. Delirium etiology was determined by three trained physician reviewers using a Delirium Etiology checklist. Pre-illness and six-month function and cognition were determined using the Older American Resources and Services Activities of Daily Living (OARS ADL) questionnaire and the short-form Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). Multiple linear regression was performed to determine if delirium etiology subtypes were associated with six-month function and cognition adjusted for baseline OARS ADL and IQCODE. Two-factor interactions were incorporated to determine pre-illness function or cognition-modified relationships between delirium subtypes and six-month function and cognition.

RESULTS

In patients with poorer pre-illness function only, delirium secondary to metabolic disturbance (β coefficient = -2.9 points, 95%CI: -0.3 to -5.6) and organ dysfunction (β coefficient = -4.3 points, 95%CI: -7.2 to -1.4) was significantly associated with poorer six-month function. In patients with intact cognition only, delirium secondary to central nervous system insults was significantly associated with poorer cognition (β coefficient = 0.69, 95%CI: 0.19 to 1.20).

CONCLUSIONS

Delirium is heterogeneous and different etiologies may have different prognostic implications. Furthermore, the effect of these delirium etiologies on outcome may be dependent on the patient's pre-illness functional status and cognition.

Combining modifiable risk factors and risk of dementia: a systematic review and meta-analysis

OBJECTIVE

To systematically review the literature relating to the impact of multiple co-occurring modifiable risk factors for cognitive decline and dementia.

DESIGN

A systematic review and meta-analysis of the literature relating to the impact of co-occurring key risk factors for incident cognitive decline and dementia. All abstracts and full text were screened independently by two reviewers and each article assessed for bias using a standard checklist. A fixed effects meta-analysis was undertaken.

DATA SOURCES

Databases Medline, Embase and PsycINFO were searched from 1999 to 2017.

ELIGIBILITY CRITERIA

For inclusion articles were required to report longitudinal data from participants free of cognitive decline at baseline, with formal assessment of cognitive function or dementia during follow-up, and an aim to examine the impact of additive or clustered comorbid risk factor burden in with two or more core modifiable risk factors.

RESULTS

Seventy-nine full-text articles were examined. Twenty-two articles (18 studies) were included reporting data on >40 000 participants. Included studies consistently reported an increased risk associated with greater numbers of intraindividual risk factors or unhealthy behaviours and the opposite for healthy or protective behaviours. A meta-analysis of studies with dementia outcomes resulted in a pooled relative risk for dementia of 1.20 (95% CI 1.04 to 1.39) for one risk factor, 1.65 (95% CI 1.40 to 1.94) for two and 2.21 (95% CI 1.78 to 2.73) for three or more, relative to no risk factors. Limitations include dependence on published results and variations in study outcome, cognitive assessment, length of follow-up and definition of risk factor exposure.

CONCLUSIONS

The strength of the reported associations, the consistency across studies and the suggestion of a dose response supports a need to keep modifiable risk factor exposure to a minimum and to avoid exposure to additional modifiable risks. Further research is needed to establish whether particular combinations of risk factors confer greater risk than others.

PROSPERO REGISTRATION NUMBER

42016052914.

Cognitive decline after elective and nonelective hospitalizations in older adults

OBJECTIVE

To determine whether emergent and urgent (nonelective) hospitalizations are associated with faster acceleration of cognitive decline compared to elective hospitalizations, accounting for prehospital decline.

METHODS

Data came from the Rush Memory and Aging Project, a prospective cohort study of community-dwelling older persons without baseline dementia. Annual measures of cognition via a battery of 19 tests were linked to 1999 to 2010 Medicare claims records.

RESULTS

Of 777 participants, 460 (59.2%) were hospitalized over a mean of 5.0 (SD = 2.6) years; 222 (28.6%) had at least one elective and 418 (53.8%) at least one nonelective hospitalization. Mixed-effects regression models estimated change in global cognition before and after each type of hospitalization compared to no hospitalization, adjusted for age, sex, education, medical conditions, length of stay, surgery, intensive care unit, and comorbidities. Persons who were not hospitalized had a mean loss of 0.051 unit global cognition per year. In comparison, there was no significant difference in rate of decline before (0.044 unit per year) or after (0.048 unit per year) elective hospitalizations. In contrast, decline before nonelective hospitalization was faster (0.076 unit per year; estimate = -0.024, SE = 0.011, p = 0.032), and accelerated by 0.036 unit (SE = 0.005, p < 0.001) to mean loss of 0.112 unit per year after nonelective hospitalizations, more than doubling the rate in those not hospitalized.

CONCLUSIONS

Nonelective hospitalizations are related to more dramatic acceleration in cognitive decline compared to elective hospitalizations, even after accounting for prehospital decline. These findings may inform which hospital admissions pose the greatest risk to the cognitive health of older adults.

Clinical Assessment and Management of Delirium in the Palliative Care Setting

Delirium is a neurocognitive syndrome arising from acute global brain dysfunction, and is prevalent in up to 42% of patients admitted to palliative care inpatient units. The symptoms of delirium and its associated communicative impediment invariably generate high levels of patient and family distress. Furthermore, delirium is associated with significant patient morbidity and increased mortality in many patient populations, especially palliative care where refractory delirium is common in the dying phase. As the clinical diagnosis of delirium is frequently missed by the healthcare team, the case for regular screening is arguably very compelling. Depending on its precipitating factors, a delirium episode is often reversible, especially in the earlier stages of a life-threatening illness. Until recently, antipsychotics have played a pivotal role in delirium management, but this role now requires critical re-evaluation in light of recent research that failed to demonstrate their efficacy in mild- to moderate-severity delirium occurring in palliative care patients. Non-pharmacological strategies for the management of delirium play a fundamental role and should be optimized through the collective efforts of the whole interprofessional team. Refractory agitated delirium in the last days or weeks of life may require the use of pharmacological sedation to ameliorate the distress of patients, which is invariably juxtaposed with increasing distress of family members. Further evaluation of multicomponent strategies for delirium prevention and treatment in the palliative care patient population is urgently required.

Acute transient cognitive dysfunction and acute brain injury induced by systemic inflammation occur by dissociable IL-1-dependent mechanisms

Systemic inflammation can impair cognition with relevance to dementia, delirium and post-operative cognitive dysfunction. Episodes of delirium also contribute to rates of long-term cognitive decline, implying that these acute events induce injury. Whether systemic inflammation-induced acute dysfunction and acute brain injury occur by overlapping or discrete mechanisms remains unexplored. Here we show that systemic inflammation, induced by bacterial LPS, produces both working-memory deficits and acute brain injury in the degenerating brain and that these occur by dissociable IL-1-dependent processes. In normal C57BL/6 mice, LPS (100 µg/kg) did not affect working memory but impaired long-term memory consolidation. However prior hippocampal synaptic loss left mice selectively vulnerable to LPS-induced working memory deficits. Systemically administered IL-1 receptor antagonist (IL-1RA) was protective against, and systemic IL-1β replicated, these working memory deficits. Dexamethasone abolished systemic cytokine synthesis and was protective against working memory deficits, without blocking brain IL-1β synthesis. Direct application of IL-1β to ex vivo hippocampal slices induced non-synaptic depolarisation and irreversible loss of membrane potential in CA1 neurons from diseased animals and systemic LPS increased apoptosis in the degenerating brain, in an IL-1RI-dependent fashion. The data suggest that LPS induces working memory dysfunction via circulating IL-1β but direct hippocampal action of IL-1β causes neuronal dysfunction and may drive neuronal death. The data suggest that acute systemic inflammation produces both reversible cognitive deficits, resembling delirium, and acute brain injury contributing to long-term cognitive impairment but that these events are mechanistically dissociable. These data have significant implications for management of cognitive dysfunction during acute illness.

Performance on bedside tests of attention and organized thinking in patients with dementia free from delirium

ABSTRACTObjectives:Bedside tests of attention and organized thinking were performed in patients with cognitive impairment or dementia but without delirium, to provide estimates of false positive rates for detecting delirium superimposed on dementia (DSD).

DESIGN AND SETTING

This cross-sectional study was conducted in outpatients and institutionalized patients without delirium representing a wide spectrum of severity of cognitive impairments.

PARTICIPANTS

Patients with dementia or a cognitive disorder according to DSM IV criteria, after exclusion of (suspected) delirium according to DSM IV criteria.

MEASUREMENTS

Tests for inattention and disorganized thinking from the CAM-ICU were assessed.

RESULTS

The sample included 163 patients (mean age 83 years (SD 6; 64% women)), with Alzheimer's disease as most prevalent (45%) diagnosis and a mean MMSE-score of 16.8 (SD 7.5). False positive rates of the test of attention varied from 0.04 in patients with normal to borderline cognitive function to 0.8 in those with severe dementia. The false positive rate of the test of disorganized thinking was zero in the normal to borderline group, increasing to 0.67 in patients with severe dementia. When combining test results false positive rates decreased to 0.03 in patients with MMSE scores above 9.

CONCLUSION

Use of simple bedside tests of attention and organized thinking for the clinical diagnosis of DSD will result in high rates of false positive observations if used regardless of the severity of dementia. However, if test results are combined they may be useful to exclude DSD in patients with minimal to moderate degrees of dementia, but not in the severe group.

Prediction of Incident Delirium Using a Random Forest classifier

Delirium is a serious medical complication associated with poor outcomes. Given the complexity of the syndrome, prevention and early detection are critical in mitigating its effects. We used Confusion Assessment Method (CAM) screening and Electronic Health Record (EHR) data for 64,038 inpatient visits to train and test a model predicting delirium arising in hospital. Incident delirium was defined as the first instance of a positive CAM occurring at least 48 h into a hospital stay. A Random Forest machine learning algorithm was used with demographic data, comorbidities, medications, procedures, and physiological measures. The data set was randomly partitioned 80% / 20% for training and validating the predictive model, respectively. Of the 51,240 patients in the training set, 2774 (5.4%) experienced delirium during their hospital stay; and of the 12,798 patients in the validation set, 701 (5.5%) experienced delirium. Under-sampling of the delirium negative population was used to address the class imbalance. The Random Forest predictive model yielded an area under the receiver operating characteristic curve (ROC AUC) of 0.909 (95% CI 0.898 to 0.921). Important variables in the model included previously identified predisposing and precipitating risk factors. This machine learning approach displayed a high degree of accuracy and has the potential to provide a clinically useful predictive model for earlier intervention in those patients at greatest risk of developing delirium.

CSF sTREM2 in delirium-relation to Alzheimer's disease CSF biomarkers Aβ42, t-tau and p-tau

BACKGROUND

Delirium and dementia share symptoms of cognitive dysfunctions, and mechanisms of neuroinflammation appear involved in both conditions. Triggering receptor expressed on myeloid cells 2 (TREM2) is linked to dementia and neurodegenerative disease. It encodes expression of an innate immune receptor in the brain expressed by microglia. The level of the soluble fragment of TREM2 (sTREM2) is reported to increase in the cerebrospinal fluid (CSF) already in prodromal and asymptomatic Alzheimer's disease.

METHODS

We analyzed the level of CSF sTREM2 in relation to delirium and dementia. The study included patients with or without pre-existing dementia who underwent acute hip fracture surgery (n = 120), and some of the patients developed delirium (n = 65). A medical delirium cohort (n = 26) was also examined. ELISA was used to determine the level of sTREM2 in CSF.

RESULTS

Delirium was associated with a higher level of CSF sTREM2 only among those without pre-existing dementia (p = 0.046, n = 15, n = 44), particularly among patients developing delirium after CSF sampling (p = 0.02, n = 7, n = 44). Between patients with dementia, there was no group difference, but the CSF sTREM2 level increased with waiting time for surgery (r_S = 0.39, p = 0.002, n = 60) and correlated well with the CSF Alzheimer's disease biomarkers, Aβ42, and t-tau/p-tau (r_S = 0.40, p = 0.002, r_S = 0.46, p < 0.001/ r_S = 0.49, p < 0.001, n = 60). Among patients with dementia, the level of Aβ38 and Aβ40 also correlated positively with sTREM2 in CSF (Aβ38_MSDr_S = 0.44, p = 0.001; Aβ40_MSDr_S = 0.48, p < 0.001; Aβ42_MSDr_S = 0.43, p < 0.001, n = 60).

CONCLUSION

The findings reinforce the involvement of neuroinflammation in delirium, yet with separate responses in patients with or without pre-existing dementia. Our findings support the concept of primed microglia in neurodegenerative disease and central immune activation after a peripheral trauma in such patients. A CSF biomarker panel of neuroinflammation might be valuable to prevent delirium by identifying patients at risk.

Effect of Cognitive Status on the Receipt of Procedures Requiring Anesthesia and Critical Care Admissions in Older Adults

OBJECTIVE

To investigate whether older adults with mild cognitive impairment (MCI) or dementia have higher rates of procedures requiring general anesthesia or intensive care unit (ICU) admissions compared with cognitively normal (CN) patients.

PATIENTS AND METHODS

A population-based cohort, 70 to 89 years old at enrollment, underwent clinical and longitudinal neurocognitive testing to identify those with MCI and dementia. We analyzed the effects of cognitive status (CN, MCI, or dementia) at entry into the study from October 1, 2004, through December 31, 2014, on the risk of receiving procedures requiring surgical anesthesia and ICU admission.

RESULTS

Of 2436 participants, 1977 (81%) were CN, 387 (16%) had MCI, and 72 (3%) had dementia. Cognitively impaired individuals were sicker. Compared with CN individuals, the likelihood of receiving a procedure requiring anesthesia was similar in participants with MCI (adjusted hazard ratio [aHR]=0.98; P=.78). Participants with dementia were less likely to receive these procedures (aHR=0.50; P=.02). Compared with CN participants, the likelihood of ICU admission for any indication was increased for those with MCI (aHR=1.24; P=.03) and dementia (aHR=1.59; P=.04). Admissions to the ICU after procedures were not different in patients with either MCI or dementia (aHR=0.96; P=.83 and aHR=1.01; P=.98, respectively).

CONCLUSION

Patients with MCI or dementia are not more likely to undergo surgery, and neither are they more likely to require ICU admission after procedures. An increased rate of nonsurgical ICU admissions requires vigilance to prevent deterioration of nonsurgical diseases that may lead to ICU admissions.

CSF biomarkers in delirium: a systematic review

OBJECTIVE

In recent years, there has been a blossoming of studies examining cerebrospinal fluid (CSF) as a method of studying the pathophysiology of delirium. We systematically reviewed the literature for CSF studies in delirium and provide here a summary of the implications for our understanding of delirium pathophysiology. We also summarise the methods used for CSF analysis and discuss challenges and implications for future studies.

METHODS

In this systematic review, we screened MEDLINE, EMBASE, PsycINFO, Web of Science, PubMed and the Cochrane Library for articles on CSF biomarkers in delirium, published on 3 September 2016. Studies were required to use Diagnostic and Statistical Manual of Mental Disorders or International Classification of Diseases criteria for delirium or a validated tool. We excluded case reports. There were no other restrictions on study type.

RESULTS

We identified 3280 articles from our initial search, and 22 articles were included in this review. All studies were prospective, including over 400 patients with delirium and 700 controls. More than 70 different biomarkers were studied. Studies could not be compared with each other for meta-analysis because of their heterogeneity and varied widely in their risk of bias and quality assessments.

CONCLUSIONS

The 22 studies identified in this review reveal a small but growing literature, in which many of the important hypotheses in delirium pathogenesis have been examined, but from which few firm conclusions can currently be drawn. Nevertheless, the overall interpretation of the literature supports the vulnerable brain concept, that is, that biomarker evidence of, for example, Alzheimer's disease pathology and/or neuroinflammation, is associated with delirium.

Transcutaneous electrical acupoint stimulation for prevention of postoperative delirium in geriatric patients with silent lacunar infarction: a preliminary study

Purpose

This study aims to investigate the effect of transcutaneous electrical acupoint stimulation (TEAS) on postoperative delirium (POD) in elderly patients with silent lacunar infarct and preliminarily to determine the relationship among TEAS, blood–brain barrier (BBB), neuroinflammation, and POD.

Patients and methods

Sixty-four-old patients with silent lacunar infarct were randomly divided into two groups: group TEAS and control group (group C). Patients in the group TEAS received TEAS (disperse-dense waves; frequency, 2/100 Hz) on acupoints Hegu and Neiguan of both sides starting from 30 minutes before induction of anesthesia until the end of surgery, and the intensity was the maximum current that could be tolerated. In group C, electrodes were placed on the same acupoints before anesthesia induction, but no current was given. At 0 minute before the treatment of TEAS, 30 minutes after skin incision, and after completion of surgery (T_1–3), blood samples were extracted to detect the concentration of serum tumor necrosis factor (TNF)-α, interleukin-6 (IL-6), matrix metalloproteinase-9 (MMP-9), and S100β. We assessed patients for delirium and coma twice daily in the first 3 postoperative days using the Confusion Assessment Method for the intensive care unit and the Richmond Agitation-Sedation Scale.

Results

This study preliminarily suggests that TEAS can reduce the development of POD in elderly patients with silent lacunar infarction (6.3% vs 25.0%; P=0.039). Compared with the baseline value at T₁, the serum concentrations of IL-6, TNF-α, MMP-9, and S100β were significantly increased at T_2–3 in both the groups (P<0.05). Compared with group TEAS, serum levels of TNF-α and IL-6 were higher at T_2–3 and serum levels of MMP-9 and S100β were higher at T₃ in group C (P<0.05). The intraoperative anesthetic consumptions were less in group TEAS than group C.

Conclusion

TEAS can alleviate POD in older patients with silent lacunar infarction and may be related to reduce the neuroinflammation by lowering the permeability of BBB.

Risk Factors and Outcomes of Delirium in Older Patients Admitted to Postacute Care with and without Dementia

BACKGROUND

Delirium research is poorly studied in postacute care, a growing setting due to aging populations, as well as in dementia, a critical risk factor for delirium and particularly prevalent in postacute care. We investigated risk factors for delirium and its outcomes in older adults with and without dementia admitted to a subacute care unit (SCU) after exacerbated chronic conditions.

METHODS

This is a prospective cohort study including patients ≥65 years old admitted to an SCU for 12 months. We collected demographics, comprehensive geriatric assessments, and presence of dementia and delirium at admission. Outcomes included discharge to previous living situation, mortality, and functional evolution. Due to the high prevalence of dementia, a subgroup analysis was performed to investigate specific risk factors for delirium and related outcomes.

RESULTS

Of 909 patients (mean age [±SD] 85.8 ± 6.7; 60% women, 47.5% with dementia), 352 (38.7%) developed delirium. The main risk factor for delirium was dementia (HR [95% CI] 5.2 [3.5-7.7]); age, functional status, and urinary tract infections were also independently associated with delirium. In dementia patients, only age (HR [95% CI] 1.0 [1.004-1.1]) and being male (HR [95% CI] 1.7 [1.04-2.6]) were associated with delirium. Delirium was associated with greater mortality (10.8 vs. 3.9%; p < 0.001) and greater functional decline in the entire sample (-12.3 vs. -6.4 Barthel index points; p < 0.001). In the dementia subgroup, patients with delirium experienced greater functional loss (p = 0.013) and less functional recovery (p = 0.025).

CONCLUSIONS

In older patients admitted to postacute care, dementia is the main risk factor for delirium, and delirium carries worse clinical and functional outcomes. In patients with dementia, delirium is also relevant, since it entails a functional loss at admission and lower functional recovery.

Refining Delirium: A Transtheoretical Model of Delirium Disorder with Preliminary Neurophysiologic Subtypes

The development of delirium indicates neurophysiologic disruption and predicts unfavorable outcomes. This relationship between delirium and its outcomes has inspired a generation of studies aimed at identifying, predicting, and preventing both delirium and its associated sequelae. Despite this, evidence on delirium prevention and management remains limited. No medication is approved for the prevention or treatment of delirium or for its associated psychiatric symptoms. This unmet need for effective delirium treatment calls for a refined approach. First, we explain why a one-size-fits-all approach based on a unitary biological model of delirium has contributed to variance in delirium studies and prevents further advance in the field. Next, in parallel with the shift from dementia to "major neurocognitive disorder," we propose a transtheoretical model of "delirium disorder" composed of interactive elements-precipitant, neurophysiology, delirium phenotype, and associated psychiatric symptoms. We explore how these relate both to the biopsychosocial factors that promote healthy cognition ("procognitive factors") and to consequent neuropathologic sequelae. Finally, we outline a preliminary delirium typology of specific neurophysiologic disturbances. Our model of delirium disorder offers several avenues for novel insights and clinical advance: it univocally differentiates delirium disorder from the phenotype of delirium, highlights delirium neurophysiology as a treatment target, separates the core features of delirium from associated psychiatric symptoms, suggests how procognitive factors influence the core elements of delirium disorder, and makes intuitive predictions about how delirium disorder leads to neuropathologic sequelae and cognitive impairment. Ultimately, this model opens several avenues for modern neuroscience to unravel this disease of antiquity.

CSF sodium at toxic levels precedes delirium in hip fracture patients

Delirium is an acute state of confusion and a fluctuating level of consciousness. It is precipitated by physical illness or trauma, such as pneumonia, heart infarction, or hip fracture. Delirium is common among elderly hospitalized patients, and as many as 50% of hip fracture patients may develop delirium. Delirium may precipitate dementia, but recent studies indicate that delirium is caused by unknown neurotoxic mechanisms that are different from those that are associated with dementia. Experimental studies have shown that high extracellular levels of sodium are neurotoxic. We sampled lumbar cerebrospinal fluid (CSF) from hip fracture patients during hip surgery and analyzed metal ions that influence neuronal function. Eight patients who developed delirium after surgery had 21% higher CSF sodium than 17 patients who did not develop delirium (median value 175 mmol/L; range 154-188, vs. 145 mmol/L (112-204; p < 0.008) or 39 patients who underwent elective surgery under spinal anesthesia without developing delirium (145 mmol/L; 140-149; p = 0.0004). Seven patients who had developed delirium before CSF sampling had a median CSF sodium of 150 mmol/L (144-185; p = 0.3). CSF potassium was also 21% higher in patients who developed delirium (p = 0.024), but remained within the physiological range. Serum sodium and potassium were normal in all patient groups. This study, on a small sample of patients, confirms the neurotoxic potential and clinical importance of high extracellular levels of sodium in the brain. High CSF sodium would likely affect cerebral function and could precipitate delirium; further, it could interact with dementia-specific mechanisms to precipitate dementia development.

Correction for retest effects across repeated measures of cognitive functioning: a longitudinal cohort study of postoperative delirium

BACKGROUND

Few studies have compared methods to correct for retest effects or practice effects in settings where an acute event could influence test performance, such as major surgery. Our goal in this study was to evaluate the use of different methods to correct for the effects of practice or retest on repeated test administration in the context of an observational study of older adults undergoing elective surgery.

METHODS

In a cohort of older surgical patients (N = 560) and a non-surgical comparison group (N = 118), we compared changes on repeated cognitive testing using a summary measure of general cognitive performance (GCP) between patients who developed post-operative delirium and those who did not. Surgical patients were evaluated pre-operatively and at 1, 2, 6, 12, and 18 months following surgery. Inferences from linear mixed effects models using four approaches were compared: 1) no retest correction, 2) mean-difference correction, 3) predicted-difference correction, and 4) model-based correction.

RESULTS

Using Approaches 1 or 4, which use uncorrected data, both surgical groups appeared to improve or remain stable after surgery. In contrast, Approaches 2 and 3, which dissociate retest and surgery effects by using retest-adjusted GCP scores, revealed an acute decline in performance in both surgical groups followed by a recovery to baseline. Relative differences between delirium groups were generally consistent across all approaches: the delirium group showed greater short- and longer-term decline compared to the group without delirium, although differences were attenuated after 2 months. Standard errors and model fit were also highly consistent across approaches.

CONCLUSION

All four approaches would lead to nearly identical inferences regarding relative mean differences between groups experiencing a key post-operative outcome (delirium) but produced qualitatively different impressions of absolute performance differences following surgery. Each of the four retest correction approaches analyzed in this study has strengths and weakness that should be evaluated in the context of future studies. Retest correction is critical for interpretation of absolute cognitive performance measured over time and, consequently, for advancing our understanding of the effects of exposures such as surgery, hospitalization, acute illness, and delirium.

Delirium's Arousal Subtypes and Their Relationship with 6-Month Functional Status and Cognition

OBJECTIVE

We sought to determine how delirium subtyped by arousal affected 6-month function and cognition in acutely ill older patients.

METHODS

This was secondary analysis of a prospective cohort study which enrolled hospitalized patients ≥65 years old. Delirium and arousal were ascertained daily in the emergency department and the first 7 days of hospitalization using the modified Brief Confusion Assessment Method and Richmond Agitation Sedation Scale, respectively. For each day, patients were categorized as having no delirium, delirium with normal arousal, delirium with decreased arousal, or delirium with increased arousal. Preillness and 6-month functional status were determined using the Older American Resources and Services activities of daily living scale which ranges from 0 (completely dependent) to 28 (completely independent). Preillness and 6-month cognition were determined using the Informant Questionnaire on Cognitive Decline in the Elderly which ranges from 1 (markedly improved cognition) to 5 (severe cognitive impairment). Multiple linear regression was performed adjusted for preillness Older American Resources and Services activities of daily living and Informant Questionnaire on Cognitive Decline in the Elderly and other relevant confounders.

RESULTS

In 228 older patients, delirium with normal arousal was the only subtype independently associated with poorer 6-month function and cognition. For every day spent in this subtype, the 6-month Older American Resources and Services activities of daily living decreased by 0.84 points (95% confidence interval: -1.59 to -0.09) and the patient's 6-month Informant Questionnaire on Cognitive Decline in the Elderly significantly increased by 0.14 points (95% confidence interval: 0.06-0.23).

CONCLUSIONS

Delirium with normal arousal, as opposed to delirium with decreased or increased arousal, was the only arousal subtype significantly associated with worsening 6-month function and cognition. Subtyping delirium by arousal may have important prognostic value.

Delirium

Delirium is a common, often underdiagnosed, geriatric syndrome characterized by an acute change in attention and consciousness. As a neuropsychiatric disorder with an underlying organic cause, delirium has been considered a diagnosis reserved for the hospital setting. However, delirium is known to occur as both an acute and subacute condition that carries significant morbidity and mortality. Combined with its association with dementia and aging, this makes delirium an important topic for primary care providers to become more familiar with as they are tasked with caring for an aging population.

Delirium symptoms are associated with decline in cognitive function between ages 53 and 69 years: Findings from a British birth cohort study

INTRODUCTION

Few population studies have investigated whether longitudinal decline after delirium in mid-to-late life might affect specific cognitive domains.

METHODS

Participants from a birth cohort completing assessments of search speed, verbal memory, and the Addenbrooke's Cognitive Examination at age 69 were asked about delirium symptoms between ages 60 and 69 years. Linear regression models estimated associations between delirium symptoms and cognitive outcomes.

RESULTS

Period prevalence of delirium between 60 and 69 years was 4% (95% confidence interval 3.2%-4.9%). Self-reported symptoms of delirium over the seventh decade were associated with worse scores in the Addenbrooke's Cognitive Examination (-1.7 points; 95% confidence interval -3.2, -0.1; P = .04). In association with delirium symptoms, verbal memory scores were initially lower, with subsequent decline in search speed by the age of 69 years. These effects were independent of other Alzheimer's risk factors.

DISCUSSION

Delirium symptoms may be common even at relatively younger ages, and their presence may herald cognitive decline, particularly in search speed, over this time period.

The delirium and population health informatics cohort study protocol: ascertaining the determinants and outcomes from delirium in a whole population

BACKGROUND

Delirium affects 25% of older inpatients and is associated with long-term cognitive impairment and future dementia. However, no population studies have systematically ascertained cognitive function before, cognitive deficits during, and cognitive impairment after delirium. Therefore, there is a need to address the following question: does delirium, and its features (including severity, duration, and presumed aetiologies), predict long-term cognitive impairment, independent of cognitive impairment at baseline?

METHODS

The Delirium and Population Health Informatics Cohort (DELPHIC) study is an observational population-based cohort study based in the London Borough of Camden. It is recruiting 2000 individuals aged ≥70 years and prospectively following them for two years, including daily ascertainment of all inpatient episodes for delirium. Daily inpatient assessments include the Memorial Delirium Assessment Scale, the Observational Scale for Level of Arousal, and the Hierarchical Assessment of Balance and Mobility. Data on delirium aetiology is also collected. The primary outcome is the change in the modified Telephone Interview for Cognitive Status at two years.

DISCUSSION

DELPHIC is the first population sample to assess older persons before, during and after hospitalisation. The cumulative incidence of delirium in the general population aged ≥70 will be described. DELPHIC offers the opportunity to quantify the impact of delirium on cognitive and functional outcomes. Overall, DELPHIC will provide a real-time public health observatory whereby information from primary, secondary, intermediate and social care can be integrated to understand how acute illness is linked to health and social care outcomes.

Key components of the delirium syndrome and mortality: greater impact of acute change and disorganised thinking in a prospective cohort study

BACKGROUND

Delirium increases the risk of mortality during an acute hospital admission. Full syndromal delirium (FSD) is associated with greatest risk and subsyndromal delirium (SSD) is associated with intermediate risk, compared to patients with no delirium - suggesting a dose-response relationship. It is not clear how individual diagnostic symptoms of delirium influence the association with mortality. Our objectives were to measure the prevalence of FSD and SSD, and assess the effect that FSD, SSD and individual symptoms of delirium (from the Confusion Assessment Method-short version (s-CAM)) have on mortality rates.

METHODS

Exploratory analysis of a prospective cohort (aged ≥70 years) with acute (unplanned) medical admission (4/6/2007-4/11/2007). The outcome was mortality (data censored 6/10/2011). The principal exposures were FSD and SSD compared to no delirium (as measured by the CAM), along with individual delirium symptoms on the CAM. Cox regression was used to estimate the impact FSD and SSD and individual CAM items had on mortality.

RESULTS

The cohort (n = 610) mean age was 83 (SD 7); 59% were female. On admission, 11% had FSD and 33% had SSD. Of the key diagnostic symptoms for delirium, 17% acute onset, 19% inattention, 17% disorganised thinking and 17% altered level of consciousness. Unadjusted analysis found FSD had an increased hazard ratio (HR) of 2.31 (95% CI 1.71, 3.12), for SSD the HR was 1.26 (1.00, 1.59). Adjusted analysis remained significant for FSD (1.55 95% CI 1.10, 2.18) but nonsignificant for SSD (HR = 0.92 95% CI 0.70, 1.19). Two CAM items were significantly associated with mortality following adjustment: acute onset and disorganised thinking.

CONCLUSION

We observed a dose-response relationship between mortality and delirium, FSD had the greatest risk and SSD having intermediate risk. The CAM items "acute-onset" and "disorganised thinking" drove the associations observed. Clinically, this highlights the necessity of identifying individual symptoms of delirium.

A prospective observational study to investigate utility of the Delirium Observational Screening Scale (DOSS) to detect delirium in care home residents

Background

care home residents are particularly at risk of delirium due to high prevalence of dementia. The Delirium Observation Screening Scale (DOSS) identifies behavioural changes associated delirium onset that nursing staff are uniquely placed to recognise. We tested the psychometric properties of the DOSS in UK care homes compared with the Confusion Assessment Method (CAM).

Design

prospective observational cohort study performed between 1 March 2015 and 30 June 2016.

Setting

nine UK residential and nursing care homes.

Subjects

residents over 65 years except those approaching end of life or unable to complete delirium assessments.

Methods

the 25-item DOSS was completed daily by care home staff and compared with the temporally closest CAM performed twice per week by trained researchers. Sensitivity, specificity, positive and negative predictive values, diagnostic odds and likelihood ratios were calculated.

Results

216 residents participated; mean age 84.9 (SD 7.9); 50% had cognitive impairment (median AMTS 7 (IQR 3-9)). Half of all expected DOSS assessments occurred (30,201); of these, 11,659 (39%) were complete. 78 positive CAM measurements were made during 71 delirium episodes in 45 residents over 70 weeks. Sensitivity and specificity for delirium detection were optimised at a DOSS cut point of ≥5 (sensitivity 0.61 (95% CI: 0.39-0.80) and specificity (0.71 95% CI: 0.70-0.73)). Positive and negative predictive values were 1.6 and 99.5%, respectively.

Conclusions

the low sensitivity of the DOSS limits clinical utility for detection of delirium as part of routine care for care home residents, although a negative DOSS affords confidence that delirium is not present.