Association of Depressive Symptoms With Postoperative Delirium and CSF Biomarkers for Alzheimer's Disease Among Hip Fracture Patients

The intersection of delirium and long-term cognition in older adults: the critical role of delirium prevention

Delirium, a neuropsychiatric syndrome characterized by an acute and usually reversible state of confusion, while dementia is a chronic, acquired cognitive impairment that significantly reduces a patient's ability to perform daily tasks, learn, work, and engage in social interactions. Previous studies indicates that individuals with dementia are more susceptible to delirium than the general population, and that delirium serves as an independent risk factor for the subsequent onset of dementia. However, a major controversy in this field concerns whether delirium is merely a marker of vulnerability to dementia, or whether delirium-induced adverse outcomes such as falls and functional decline contribute to dementia, or whether delirium directly causes permanent neuronal damage and lead to dementia. It is possible that all these hypotheses hold some truth. In this review, we examine the shared and distinct mechanisms of delirium and dementia by reviewing their clinical features, epidemiology, clinicopathological, biomarkers, neuroimaging, and recent experimental studies, and we discuss the importance of targeting delirium to explore new preventive and therapeutic strategies for reducing long-term cognitive impairment.

Global Research Trends in Postoperative Delirium and Its Risk Factors: A Bibliometric and Visual Analysis

PURPOSE

Postoperative delirium (POD) is one of the most frequent complications after surgery which is closely associated with many adverse outcomes, including high mortality and low quality of life. This study aims to carry out a bibliometric analysis of POD and its risk factors from 2012 to 2022 to reveal the research status and hot spots.

DESIGN

This study is a bibliometric and visualized analysis.

METHODS

Relevant publications between 2012 and 2022 were extracted from the Web of Science Core Collection database. CiteSpace software (v6.1. R2, Drexel University), VOSviewer software (v1.6.18, Leiden University), and the Online Analysis Platform of Literature Metrology were used to analyze research attributes. These publications were used to analyze research attributes, including countries, journals, institutions, authors, keywords, and burst detection, to predict trends and hot spots.

FINDINGS

We included a total of 1,324 related documents from 2012 to 2022. The literature on POD has increased significantly since 2016. The United States and Harvard University were the leading literature publishing country (436/1324, 32.9%) and institution (112/1324, 8.5%). Anesthesia and Analgesia was the most frequently published journal. Keywords analysis with VOSviewer revealed that the keywords could be divided into five clusters, including anesthesia techniques, cardiac surgery, risk factors, intraoperative anesthesia monitoring, and postoperative cognitive dysfunction. We included a total of 198 POD risk factors documents, and the literature on POD risk factors increased. The People's Republic of China and Harvard University were the leading literature publishing country (53/198, 26.8%) and institution (12/198, 6.1%). Elderly, hip surgery, frailty, postoperative pain, cardiac surgery, dementia, and depression are keywords that are risk factors for POD.

CONCLUSIONS

The number of literature on POD in the field of anesthesia has increased significantly. Risk factors and anesthesia techniques are still key areas of research. Encephalogram, the use of sedatives, and perioperative nursing may be the new research focus. Older adults, hip fractures, cardiac surgery, liver transplants, dementia, and depression are hot words in the field of POD risk factors.

Effect of esketamine on postoperative depression in women with breast cancer and preoperative depressive symptoms: The EASE randomized trial

STUDY OBJECTIVE

To determine whether intraoperative low-dose esketamine ameliorates depression in women having breast cancer surgery.

DESIGN

A prospective single-center double blind randomized placebo-controlled trial.

SETTING

Perioperative period, operating room, post anesthesia care unit and hospital ward.

PATIENTS

108 women 18-65 years old who were scheduled for elective breast cancer surgery. All had preoperative depressive symptoms as defined by Montgomery-Åsberg depression scores ≥12 (range, 0-60; higher scores indicate more severe depression).

INTERVENTIONS

Eligible participants were randomized to esketamine 0.25 mg/kg or saline placebo. Blinded trial drugs were given intravenously over the initial 40 min of anesthesia.

MEASUREMENTS

Our primary outcome was the fraction of patients who had at least a 50 % reduction in the Montgomery-Åsberg depression score within 3 postoperative days. Secondary outcomes included the fraction of patients with depression remission defined as Montgomery-Åsberg scores ≤10, the numeric value of the Montgomery-Åsberg depression scores, postoperative severe pain, and anxiety as determined by the Generalized Anxiety Disorder 7-item score. Adverse events were monitored for 72 postoperative hours.

MAIN RESULTS

54 women each were randomized to esketamine and saline, and 104 were available for our intent-to-treat analysis. The mean age was 50 years. Esketamine non-significantly doubled the fraction of patients who had a 50 % reduction in their depressions scores: 27 % vs 13 %, odds ratio 2.4, [95 % CI 0.9 to 6.6], P = 0.087. Montgomery-Åsberg depression scores were nearly a factor-of-two and significantly lower (better) on postoperative days 1 to 5 in patients given esketamine. Montgomery-Åsberg scores decreased significantly more from baseline in patients randomized to esketamine: mean difference - 2.5 [95 % CI -4.5 to -0.6], P = 0.010. Esketamine treatment had no significant effect on other secondary outcomes or on adverse events.

CONCLUSIONS

Intraoperative administration of 0.25 mg/kg esketamine did not significantly improve the fraction of depressed women having breast cancer patients who had a 50 % reduction in their depression scores at 3 days postoperatively. However, the observed factor-of-two treatment effect was clinically meaningful and esketamine significantly reduced short-term postoperative depression scores without provoking complications. Robust trials are warranted. Registration Trial registry:http://www.chictr.org.cn/; Identifier: ChiCTR2300071062.

Preoperative Neurofilament Light Associated With Postoperative Delirium in Hip Fracture Repair Patients Without Dementia

BACKGROUND

Delirium commonly occurs in older adults following surgery; although its pathophysiology is not fully understood, underlying neurodegeneration is a risk factor.

OBJECTIVE

Examine the association of preoperative levels of markers of neuronal damage, neurofilament light (NfL) and phosphorylated tau (p-tau)181, with postoperative delirium.

METHODS

Preoperative cerebrospinal fluid (CSF) and plasma were obtained from 158 patients undergoing hip fracture repair and enrolled in the clinical trial "A STrategy to Reduce the Incidence of Postoperative Delirium in Elderly Patients." Delirium diagnosis was adjudicated by a consensus panel. The association of plasma and CSF NfL and p-tau181 levels with delirium incidence and severity were examined for the overall cohort and for a subgroup (n = 134) of patients without dementia.

RESULTS

Patients who developed delirium were older, had lower Mini-Mental State Exam score, higher Clinical Dementia Rating and Geriatric Depression Scale scores at baseline; the overall incidence of delirium was 37.6% and 31.1% for the subgroup without dementia. Plasma and CSF p-tau181 levels were not associated with delirium incidence or severity. CSF NfL levels were significantly associated with delirium severity, but not with incidence in the overall cohort. In the subgroup of patients without dementia, CSF NfL levels were significantly associated with increased odds of delirium incidence (odds ratio 4.74, 95% confidence level 1.21-18.59, P = 0.03) adjusted for age, sex, and Clinical Dementia Rating.

CONCLUSIONS

CSF NfL was significantly associated with delirium incidence and severity in patients without dementia undergoing hip fracture repair. Results confirm prior studies suggesting NfL as an important marker of delirium risk and supports an association between pre-existing axonal injury and delirium. These results highlight delirium vulnerability in older hip fracture patients, even when clinical dementia is not identified.

Influence of cognitive, neuropsychiatric, and diagnostic factors on financial capacity: A longitudinal analysis of the ADNI cohort

Introduction

Financial capacity (FC) is the ability to independently manage finances in a manner consistent with one's self-interest. To investigate the relationship between FC, cognitive domains, neuropsychiatric symptoms, and transitions from normal cognition (cognitive normal [CN]) to mild cognitive impairment (MCI) or Alzheimer's disease (AD), we conducted a secondary analysis of the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort using the Financial Capacity Instrument short form (FCI-SF).

Methods

To examine these longitudinal relationships, we fit two models, a random effects (random intercept) "time-averaged" model and a "time since previous visit" model, where we regressed each of the five component financial scores on each of the cognitive composite scores. To examine the effect of baseline FCI-SF performance on conversion rates from normal to MCI or AD, we computed a survival model.

Results

A total of 874 participants (diagnostic group, N, mean age: CN: 501, 74.4; MCI: 319, 74.6; and AD 54, 74.9) were included in the analyses. In time since previous visit models, we found that lower executive function composite scores were related to decline in the complex checkbook score (ß = 1.35 (0.55), p = 0.016) and total completion time of the FCI-SF (ß = 1.85 (9.36), p = 0.025). In addition, lower composite visuospatial score was significantly related to poorer performance on financial conceptual knowledge, complex checkbook, and total completion time. Lower composite memory score was highly related to decline in financial conceptual knowledge, single checkbook, and bank statement subscale scores. ADNI participants in the lowest tertile of total completion time, at any point in time, were four times more likely to receive a diagnosis of MCI or AD compared to participants in the highest tertile with a hazard ratio of 4.22 ([2.29] p = 008).

Discussion

There is a multifaceted interaction between poorer cognition and everyday financial function where executive function, memory, and visuospatial cognition are related to FC. The strongest predictor of conversion from normal to either MCI or AD, appears to be time to completion.

Highlights

Decline in financial capacity (FC) is observed during transition to dementia and increases the risk of negative outcomes.Executive function, memory, and visuospatial cognition are related to FC.The strongest predictor of conversion from normal to either mild cognitive impairment (MCI) or Alzheimer's disease (AD) is time to completion or processing speed.

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.

Incidence and relative risk of delirium after major surgery for patients with pre-operative depression: a systematic review and meta-analysis

BACKGROUND

Delirium is a common and potentially serious complication after major surgery. A previous history of depression is a known risk factor for experiencing delirium in patients admitted to the hospital, but the generalised risk has not been estimated in surgical patients.

METHODS

We conducted a systematic review and meta-analysis of studies reporting the incidence or relative risk (or relative odds) of delirium in the immediate postoperative period for adults with pre-operative depression. We included studies that defined depression as either a formal pre-existing diagnosis or having clinically important depressive symptoms measured using a patient-reported instrument before surgery. Multilevel random effects meta-analyses were used to estimate the pooled incidences and pooled relative risks. We also conducted subgroup analyses by various study-level characteristics to identify important moderators of pooled estimates.

RESULTS

Forty-two studies (n = 4,664,051) from five continents were included. The pooled incidence of postoperative delirium for patients with pre-operative depression was 29% (95%CI 17-43%, I2 = 99.0%), compared with 15% (95%CI 6-28%, I2 = 99.8%) in patients without pre-operative depression and 21% (95% CI 11-33%, I2 = 99.8%) in the cohorts overall. For patients with pre-operative depression, the risk of delirium was 1.91 times greater (95%CI 1.68-2.17, I2 = 42.0%) compared with patients without pre-operative depression.

CONCLUSIONS

Patients with a previous diagnosis of depression or clinically important depressive symptoms before surgery have substantially greater risk of experiencing delirium after surgery. Clinicians and patients should be informed of these increased risks. Robust screening and other risk mitigation strategies for postoperative delirium are warranted, especially for patients with pre-operative depression.

Management of Depression and Anxiety in Perioperative Medicine

This Clinical Focus Review summarizes contemporary best practices, recent clinically relevant research, and pertinent unanswered questions related to perioperative screening and treatment of anxiety and depression.

Association between pre-hip fracture depression and days at home after fracture and assessing sex differences

BACKGROUND

Hip fracture and depression are important public health issues among older adults, but how pre-fracture depression impacts recovery after hip fracture is unknown, especially among males who often experience greater depression severity. Days at home (DAH), or the days spent outside a hospital or healthcare facility, is a novel, patient-centered outcome that can capture meaningful aspects of fracture recovery. How pre-fracture depression impacts DAH after fracture, and related sex differences, remains unclear.

METHODS

Participants included 63,618 Medicare fee-for-service beneficiaries aged 65+ years, with a hospitalization claim for hip fracture surgery between 2010 and 2017. The primary exposure was a diagnosis of depression at hospital admission, and the primary outcome was total DAH over 12 months post-discharge. Longitudinal associations between pre-fracture depression and the count of DAH among beneficiaries were estimated using Poisson regression models after adjustment for covariates; sex-by-depression interactions were also assessed. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) reflecting relative differences were estimated from these models.

RESULTS

Overall, beneficiaries with depression were younger, White females, and spent 11 fewer average DAH compared to counterparts without depression when demographic factors (age and sex) (IRR = 0.91; 95% CI = 0.90, 0.92; p < 0.0001) and social determinants of health (race, Medicaid dual eligibility, and poverty) were adjusted for (IRR = 0.92; 95% CI = 0.91, 0.93; p < 0.0001), but this association attenuated after adjusting for medical complexities (IRR = 0.99; 95% CI = 0.98, 1.01; p = 0.41) and facility and geographical factors (IRR = 1.0037; 95% CI = 0.99, 1.02; p = 0.66). There was no evidence of effect modification by sex.

CONCLUSIONS

The comorbidity burden of preexisting depression may impact DAH among both male and female Medicare beneficiaries with hip fracture. Results suggest a holistic health approach and secondary prevention of depressive symptoms after hip fracture.

Prevalence of preoperative depression and adverse outcomes in older patients undergoing elective surgery: A systematic review and meta-analysis

STUDY OBJECTIVE

Depression is a common cause of long-lasting disability and preoperative mental health state that has important implications for optimizing recovery in the perioperative period. In older elective surgical patients, the prevalence of preoperative depression and associated adverse pre- and postoperative outcomes are unknown. This systematic review and meta-analysis aimed to determine the prevalence of preoperative depression and the associated adverse outcomes in the older surgical population.

DESIGN

Systematic review and meta-analysis.

SETTING

MEDLINE, MEDLINE Epub Ahead of Print and In-Process, In-Data-Review & Other Non-Indexed Citations, Embase/Embase Classic, Cochrane CENTRAL, and Cochrane Database of Systematic Reviews, ClinicalTrials.Gov, the WHO ICTRP (International Clinical Trials Registry Platform) for relevant articles from 2000 to present.

PATIENTS

Patients aged ≥65 years old undergoing non-cardiac elective surgery with preoperative depression assessed by tools validated in older adults. These validated tools include the Geriatric Depression Scale (GDS), Hospital Depression and Anxiety Scale (HADS), Beck Depression Inventory-II (BDI), Patient Health Questionnaire-9 (PHQ-9), and the Centre for Epidemiological Studies Depression Scale (CESD).

INTERVENTIONS

Preoperative assessment.

MEASUREMENT

The primary outcome was the prevalence of preoperative depression. Additional outcomes included preoperative cognitive impairment, and postoperative outcomes such as delirium, functional decline, discharge disposition, readmission, length of stay, and postoperative complications.

MAIN RESULTS

Thirteen studies (n = 2824) were included. Preoperative depression was most assessed using the Geriatric Depression Scale-15 (GDS-15) (n = 12). The overall prevalence of preoperative depression was 23% (95% CI: 15%, 30%). Within non-cancer non-cardiac mixed surgery, the pooled prevalence was 19% (95% CI: 11%, 27%). The prevalence in orthopedic surgery was 17% (95% CI: 9%, 24%). In spine surgery, the prevalence was higher at 46% (95% CI: 28%, 64%). Meta-analysis showed that preoperative depression was associated with a two-fold increased risk of postoperative delirium than those without depression (32% vs 23%, OR: 2.25; 95% CI: 1.67, 3.03; I2: 0%; P ≤0.00001).

CONCLUSIONS

The overall prevalence of older surgical patients who suffered from depression was 23%. Preoperative depression was associated with a two-fold higher risk of postoperative delirium. Further work is needed to determine the need for depression screening and treatment preoperatively.

Effects of adjunctive esketamine on depression in elderly patients undergoing hip fracture surgery: a randomized controlled trial

BACKGROUND

Depression is a prevalent perioperative psychiatric complication among elderly hip fracture patients. Esketamine has rapid and robust antidepressant effects. However, it is unknown whether it can alleviate depressive symptoms in elderly patients who undergo hip fracture surgery. This study aimed to explore whether the adjunctive esketamine in patient-controlled intravenous analgesia (PCIA) could improve depressive symptoms in elderly patients undergoing hip fracture surgery.

METHODS

A single-center, prospective, double-blind and randomized controlled clinical trial was carried out from July 2022 to August 2023 at the Wenzhou People's Hospital among 90 patients, aged ≥ 65 years with hip fracture undergoing elective surgery. Participants were randomly allocated to either the esketamine group (group S) or the control group (group C). In Group S, patients were administered 0.5 mg/kg of esketamine as a PCIA adjuvant for 48 h, while the control group received saline. The primary outcome was the assessment of depressive symptoms using the Geriatric Depression Scale-15 (GDS-15) on postoperative day 2. The secondary outcomes were assessments of depressive symptoms on postoperative day 7 and postoperative day 30, serum levels of brain-derived neurotrophic factor (BDNF) and 5-hydroxytryptamine (5-HT), postoperative pain intensity, the number of effective PCIA presses, sufentanil consumption, and adverse events.

RESULTS

The prevalence and GDS-15 scores of depression were significantly lower in group S on postoperative day 2 (28.6% vs. 53.5%; 3.5 ± 1.8 vs. 4.3 ± 1.7, P < 0.05). In group S, the number of effective PCIA presses was significantly lower on postoperative day 2 than that in group C [2(1-4) vs. 1(0-2), P<0.05]. Higher levels of BDNF (23.8 ± 1.7 ng/mL vs. 25.3 ± 2.0 ng/mL, P < 0.05) and 5-HT (219.5 ± 19.5 ng/mL vs. 217.0 ± 22.2 ng/mL, P < 0.05) in the blood were observed on postoperative day 2 in group S.

CONCLUSION

In elderly patients aged ≥ 65 years undergoing hip fracture surgery, the administration of adjunctive esketamine in PCIA could improve depressive symptoms and increase levels of BDNF and 5-HT in the blood.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2200061956 (Date: 13/07/2022).

Insulin resistance and osteocalcin associate with the incidence and severity of postoperative delirium in elderly patients undergoing joint replacement

AIM

While insulin sensitivity plays an important role in maintaining glucose metabolic homeostasis and cognitive function, its impact on postoperative delirium (POD) remains unclear. This study aimed to investigate the association between POD and indicators of insulin sensitivity, including insulin resistance and osteocalcin.

METHODS

A total of 120 elderly patients undergoing joint replacement were recruited and divided into delirium and non-delirium groups. Plasma and cerebrospinal fluid (CSF) samples were collected for the analysis of biomarkers, including insulin, uncarboxylated osteocalcin (ucOC), total osteocalcin (tOC), and glucose. Insulin resistance was assessed through the homeostatic model assessment of insulin resistance (HOMA-IR).

MAIN RESULTS

Out of the total, 28 patients (23.3%) experienced POD within 5 days after surgery. Patients with delirium exhibited higher levels of preoperative HOMA-IR and ucOC in CSF and plasma, and of tOC in CSF (P = 0.028, P < 0.001, P = 0.005, P = 0.019). After adjusting for variables, including age, Mini-Mental State Examination score, surgical site and preoperative fracture, only preoperative ucOC in CSF and HOMA-IR were significantly linked to the incidence of delirium (OR = 5.940, P = 0.008; OR = 1.208, P = 0.046, respectively), both of which also correlated with the severity of delirium (P = 0.007, P < 0.001). Receiver operating curve analysis indicated that preoperative HOMA-IR and ucOC in CSF might partly predict POD (area under the curve [AUC] = 0.697, 95% confidence interval [CI] = 0.501-0.775, AUC = 0.745, 95% CI = 0.659-0.860).

CONCLUSIONS

We observed that preoperative elevated HOMA-IR and ucOC in CSF were associated with the incidence and severity of POD. While these preliminary results need confirmation, they suggest a potential involvement of insulin resistance and osteocalcin in the pathological mechanism of POD. Geriatr Gerontol Int 2024; 24: 421-429.

Tau and delirium superimposed on dementia: A case report

We present a case involving a 60-year-old man with subacute delirium characterized by challenging attention shifts and obstinate behavior, contrasting with his usual mild-mannered personality. The patient developed pneumonia and a urinary tract infection following the onset of subacute delirium. Despite exhaustive investigations, the cause remained elusive until cerebrospinal fluid analysis revealed Tau positivity. Our overview suggests neurodegenerative diseases as the primary cause, rather than infectious or autoimmune factors. The case underscores a significant association between Tau and delirium superimposed on dementia, offering guidance to clinicians managing such patients.

Sleep and APOE-ε4 have a synergistic effect on plasma biomarkers and longitudinal cognitive decline in older adults

BACKGROUND

Sleep disorders are prevalent among patients with Alzheimer's disease (AD), and the APOE ε4 genotype is a key genetic risk factor for sporadic AD. However, the combined effect of the genotype and sleep disorders on cognitive decline remains uncertain.

METHODS

A total of 972 participants were drawn from the SILCODE cohort, comprising 655 without the ε4 allele (APOE-) and 317 with ε4 allele (APOE+). Data were collected, including neuropsychological assessments, sleep measurements, plasma biomarkers, and PET imaging. A Sleep Composite Index (SCI) was created, categorizing participants into high risk (Sleep+) and low risk (Sleep-).

RESULTS

Significant predictions of dementia risk associated with plasma p-tau181, neurofilament light chain (NfL), and SCI. Individuals with both Sleep+ and APOE+ had a higher risk of dementia compared to those with Sleep-. The Sleep+/APOE+ group had higher plasma NfL levels than the Sleep-/APOE- group. Similar trends emerged in plasma NfL levels among the Aβ PET-positive subgroup. Plasma NfL levels explained 23% of the relationship between SCI and cognitive impairment.

CONCLUSION

Our study highlights sleep disorder was associated with cognitive decline, with plasma NfL playing a partial mediating role. These findings explain how sleep disorders affect cognitive function and emphasize the importance of healthy sleep for older adults.

Bibliometric Analysis of Alzheimer's Disease and Depression

BACKGROUND

The link between Alzheimer's disease and depression has been confirmed by clinical and epidemiological research. Therefore, our study examined the literary landscape and prevalent themes in depression-related research works on Alzheimer's disease through bibliometric analysis.

METHODS

Relevant literature was identified from the Web of Science core collection. Bibliometric parameters were extracted, and the major contributors were defined in terms of countries, institutions, authors, and articles using Microsoft Excel 2019 and VOSviewer. VOSviewer and CiteSpace were employed to visualize the scientific networks and seminal topics.

RESULTS

The analysis of literature utilised 10,553 articles published from 1991 until 2023. The three countries or regions with the most publications were spread across the United States, China, and England. The University of Toronto and the University of Pittsburgh were the major contributors to the institutions. Lyketsos, Constantine G., Cummings, JL were found to make outstanding contributions. Journal of Alzheimer's Disease was identified as the most productive journal. Furthermore, "Alzheimer's", "depression", "dementia", and "mild cognitive decline" were the main topics of discussion during this period.

LIMITATIONS

Data were searched from a single database to become compatible with VOSviewer and CiteSpace, leading to a selection bias. Manuscripts in English were considered, leading to a language bias.

CONCLUSION

Articles on "Alzheimer's" and "depression" displayed an upward trend. The prevalent themes addressed were the mechanisms of depression-associated Alzheimer's disease, the identification of depression and cognitive decline in the early stages of Alzheimer's, alleviating depression and improving life quality in Alzheimer's patients and their caregivers, and diagnosing and treating neuropsychiatric symptoms in Alzheimer. Future research on these hot topics would promote understanding in this field.

Biomarkers of neurodegeneration and neural injury as potential predictors for delirium

OBJECTIVES

Determine if biomarkers of Alzheimer's disease and neural injury may play a role in the prediction of delirium risk.

METHODS

In a cohort of older adults who underwent elective surgery, delirium case-no delirium control pairs (N = 70, or 35 matched pairs) were matched by age, sex and vascular comorbidities. Biomarkers from CSF and plasma samples collected prior to surgery, including amyloid beta (Aβ)42 , Aβ40 , total (t)-Tau, phosphorylated (p)-Tau181 , neurofilament-light (NfL), and glial fibrillary acid protein (GFAP) were measured in cerebrospinal fluid (CSF) and plasma using sandwich enzyme-linked immunosorbent assays (ELISAs) or ultrasensitive single molecule array (Simoa) immunoassays.

RESULTS

Plasma GFAP correlated significantly with CSF GFAP and both plasma and CSF GFAP values were nearly two-fold higher in delirium cases. The median paired difference between delirium case and control without delirium for plasma GFAP was not significant (p = 0.074) but higher levels were associated with a greater risk for delirium (odds ratio 1.52, 95% confidence interval 0.85, 2.72 per standard deviation increase in plasma GFAP concentration) in this small study. No matched pair differences or associations with delirium were observed for NfL, p-Tau 181, Aβ40 and Aβ42 .

CONCLUSIONS

These preliminary findings suggest that plasma GFAP, a marker of astroglial activation, may be worth further investigation as a predictive risk marker for delirium.

Relationship between preoperative neutrophil-to-lymphocyte ratio and postoperative delirium: The PNDABLE and the PNDRFAP cohort studies

OBJECTIVES

In this study, the relationship between preoperative neutrophil-to-lymphocyte ratio (NLR) and Alzheimer-related biomarkers in cerebrospinal fluid (CSF) was investigated to determine whether high NLR is a potential risk factor for postoperative delirium (POD) and to evaluate its predictive efficacy.

METHODS

We selected 1000 patients from the perioperative neurocognitive disorder risk factor and prognosis (PNDRFAP) database and 999 patients from the perioperative neurocognitive disorder and biomarker lifestyle (PNDABLE) database. Patients in the PNDABLE database have been measured for Alzheimer-related biomarkers in CSF (Aβ40 , Aβ42 , P-tau, and tau protein). Mini-mental state examination was used to assess the preoperative mental status of patients. POD was diagnosed using the confusion assessment method and assessed for severity using the memorial delirium assessment scale. Logistic regression analysis was utilized to explore the association of preoperative NLR with POD. What's more, we also performed sensitivity analysis by adding corrected confounders, and the results were almost unchanged. Spearman's rank correlation was used to determine the associations between NLR and Alzheimer-related biomarkers. Mediation analyses with 10,000 bootstrapped iterations were used to explore the mediation effects. Finally, we use decision curves and the nomogram model to evaluate the efficacy of preoperative NLR in predicting POD; we also performed external validation using data from Qilu Hospital.

RESULT

Logistic regression results showed that an elevated preoperative NLR was a risk factor for the development of POD in patients (PNDRFAP: OR = 1.067, 95% CI 1.020-1.116; PNDABLE: OR = 1.182, 95% CI 1.048-1.335, p < .05). Spearman's rank correlation analysis showed a positive but weak correlation between NLR and P-tau/T-tau (R = .065). The mediating effect results indicate that NLR likely mediates the occurrence of POD through elevated tau protein levels (proportion: 47.47%). The results of the box plots showed statistically significant NLR and CSF biomarkers between the POD and non-POD (NPOD) groups (p < .05), with higher NLR, P-tau, and T-tau in the POD group than in the NPOD group. In contrast, the NPOD group had higher Aβ42 levels compared to the POD group. In addition, we used R package to plot the decision curve and nomogram both suggesting a good predictive effect of preoperative NLR on the occurrence of POD.

CONCLUSION

Elevated preoperative NLR levels may be a risk factor for POD and likely mediate the development of POD through elevated P-tau/T-tau levels.

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.

Assessment of Risk Factors for Postoperative Delirium in Older Adults Who Underwent Spinal Surgery and Identifying Associated Biomarkers Using Exosomal Protein

PURPOSE

With an increase in the aging population, the number of patients with degenerative spinal diseases undergoing surgery has risen, as has the incidence of postoperative delirium. This study aimed to investigate the risk factors affecting postoperative delirium in older adults who had undergone spine surgery and to identify the associated biomarkers.

METHODS

This study is a prospective study. Data of 100 patients aged ≥ 70 years who underwent spinal surgery were analyzed. Demographic data, medical history, clinical characteristics, cognitive function, depression symptoms, functional status, frailty, and nutritional status were investigated to identify the risk factors for delirium. The Confusion Assessment Method, Delirium Rating Scale-R-98, and Nursing Delirium Scale were also used for diagnosing delirium. To discover the biomarkers, urine extracellular vesicles (EVs) were analyzed for tau, ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), neurofilament light, and glial fibrillary acidic protein using digital immunoassay technology.

RESULTS

Nine patients were excluded, and data obtained from the remaining 91 were analyzed. Among them, 18 (19.8%) developed delirium. Differences were observed between participants with and without delirium in the contexts of a history of mental disorder and use of benzodiazepines (p = .005 and p = .026, respectively). Tau and UCH-L1-concentrations of urine EVs-were comparatively higher in participants with severe delirium than that in participants without delirium (p = .002 and p = .001, respectively).

CONCLUSION

These findings can assist clinicians in accurately identifying the risk factors before surgery, classifying high-risk patients, and predicting and detecting delirium in older patients. Moreover, urine EV analysis revealed that postoperative delirium following spinal surgery is most likely associated with brain damage.

Predicting postoperative delirium after hip arthroplasty for elderly patients using machine learning

BACKGROUND

Postoperative delirium (POD) is a common and severe complication in elderly hip-arthroplasty patients.

AIM

This study aims to develop and validate a machine learning (ML) model that determines essential features related to POD and predicts POD for elderly hip-arthroplasty patients.

METHODS

The electronic record data of elderly patients who received hip-arthroplasty surgery between January 2017 and April 2021 were enrolled as the dataset. The Confusion Assessment Method (CAM) was administered to the patients during their perioperative period. The feature section method was employed as a filter to determine leading features. The classical machine learning algorithms were trained in cross-validation processing, and the model with the best performance was built in predicting the POD. Metrics of the area under the curve (AUC), accuracy (ACC), sensitivity, specificity, and F1-score were calculated to evaluate the predictive performance.

RESULTS

476 Arthroplasty elderly patients with general anesthesia were included in this study, and the final model combined feature selection method mutual information (MI) and linear binary classifier using logistic regression (LR) achieved an encouraging performance (AUC = 0.94, ACC = 0.88, sensitivity = 0.85, specificity = 0.90, F1-score = 0.87) on a balanced test dataset.

CONCLUSION

The model could predict POD with satisfying accuracy and reveal important features of suffering POD such as age, Cystatin C, GFR, CHE, CRP, LDH, monocyte count, history of mental illness or psychotropic drug use and intraoperative blood loss. Proper preoperative interventions for these factors could reduce the incidence of POD among elderly patients.

Predisposing and Precipitating Factors Associated With Delirium: A Systematic Review

Importance

Despite discrete etiologies leading to delirium, it is treated as a common end point in hospital and in clinical trials, and delirium research may be hampered by the attempt to treat all instances of delirium similarly, leaving delirium management as an unmet need. An individualized approach based on unique patterns of delirium pathophysiology, as reflected in predisposing factors and precipitants, may be necessary, but there exists no accepted method of grouping delirium into distinct etiologic subgroups.

Objective

To conduct a systematic review to identify potential predisposing and precipitating factors associated with delirium in adult patients agnostic to setting.

Evidence Review

A literature search was performed of PubMed, Embase, Web of Science, and PsycINFO from database inception to December 2021 using search Medical Subject Headings (MeSH) terms consciousness disorders, confusion, causality, and disease susceptibility, with constraints of cohort or case-control studies. Two reviewers selected studies that met the following criteria for inclusion: published in English, prospective cohort or case-control study, at least 50 participants, delirium assessment in person by a physician or trained research personnel using a reference standard, and results including a multivariable model to identify independent factors associated with delirium.

Findings

A total of 315 studies were included with a mean (SD) Newcastle-Ottawa Scale score of 8.3 (0.8) out of 9. Across 101 144 patients (50 006 [50.0%] male and 49 766 [49.1%] female patients) represented (24 015 with delirium), studies reported 33 predisposing and 112 precipitating factors associated with delirium. There was a diversity of factors associated with delirium, with substantial physiological heterogeneity.

Conclusions and Relevance

In this systematic review, a comprehensive list of potential predisposing and precipitating factors associated with delirium was found across all clinical settings. These findings may be used to inform more precise study of delirium's heterogeneous pathophysiology and treatment.

Effect of Repeated Intranasal Administration of Different Doses of Insulin on Postoperative Delirium, Serum τ and Aβ Protein in Elderly Patients Undergoing Radical Esophageal Cancer Surgery

Objective

Postoperative delirium is common after general anesthesia in older patients. However, there are currently no effective preventive measures. This study investigated the effect of repeated intranasal administration of different insulin doses before surgery on postoperative delirium in older patients with esophageal cancer, and the possible mechanism for its efficacy.

Methods

In this randomized, placebo-controlled, double-blind, parallel-group study, 90 older patients were randomly assigned to either a Control (normal saline), Insulin 1 (20 U/0.5 mL intranasal insulin), or Insulin 2 (30 U/0.75 mL intranasal insulin) group. Delirium was assessed on postoperative days 1 (T2), 2 (T3), and 3 (T4) using the Confusion Assessment Method for the Intensive Care Unit. Serum τ and Aβ protein levels were measured at T0 (before insulin/saline administration), T1 (end of surgery), T2, T3 and T4.

Results

The Insulin 2 group had a significantly lower prevalence of delirium compared to the Control and Insulin 1 groups three days after surgery. Compared to baseline, τ and Aβ protein levels increased significantly at T1-T4. Compared to the Control group, the Insulin 1 and 2 groups had significantly lower τ and Aβ protein levels at T1-T4, and the Insulin 2 group had significantly lower levels than the Insulin 1 group at T1-T2.

Conclusion

The administration of 30 U of intranasal insulin twice daily, from 2 days preoperatively until 10 minutes preanesthesia on the day of surgery, can significantly reduce postoperative delirium in older patients undergoing radical esophagectomy. It can also decrease postoperative τ and Aβ protein expression without causing hypoglycemia.

Clinical Trial Registration

This study was registered at the Chinese Clinical Trial Registry (www.chictr.org.cn, with the unique identifier: ChiCTR2100054245; December 11, 2021).

The inter-relationship between delirium and dementia: the importance of delirium prevention

Delirium and dementia are two frequent causes of cognitive impairment among older adults and have a distinct, complex and interconnected relationship. Delirium is an acute confusional state characterized by inattention, cognitive dysfunction and an altered level of consciousness, whereas dementia is an insidious, chronic and progressive loss of a previously acquired cognitive ability. People with dementia have a higher risk of developing delirium than the general population, and the occurrence of delirium is an independent risk factor for subsequent development of dementia. Furthermore, delirium in individuals with dementia can accelerate the trajectory of the underlying cognitive decline. Delirium prevention strategies can reduce the incidence of delirium and associated adverse outcomes, including falls and functional decline. Therefore, delirium might represent a modifiable risk factor for dementia, and interventions that prevent or minimize delirium might also reduce or prevent long-term cognitive impairment. Additionally, understanding the pathophysiology of delirium and the connection between delirium and dementia might ultimately lead to additional treatments for both conditions. In this Review, we explore mechanisms that might be common to both delirium and dementia by reviewing evidence on shared biomarkers, and we discuss the importance of delirium recognition and prevention in people with dementia.

In this Review, Fong and Inouye explore mechanisms that might be common to both delirium and dementia. They present delirium as a possible modifiable risk factor for dementia and discuss the importance of delirium prevention strategies in reducing this risk.

Delirium and dementia are frequent causes of cognitive impairment among older adults and have a distinct, complex and interconnected relationship.

Delirium prevention strategies have been shown to reduce not only the incidence of delirium but also the incidence of adverse outcomes associated with delirium such as falls and functional decline.

Adverse outcomes associated with delirium, such as the onset of dementia symptoms in individuals with preclinical dementia, and/or the acceleration of cognitive decline in individuals with dementia might also be delayed by the implementation of delirium prevention strategies.

Evidence regarding the association of systemic inflammatory and neuroinflammatory biomarkers with delirium is variable, possibly as a result of co-occurring dementia pathology or disruption of the blood–brain barrier.

Alzheimer disease pathology, even prior to the onset of symptoms, might have an effect on delirium risk, with potential mechanisms including neuroinflammation and gene–protein interactions with the APOE ε4 allele.

Novel strategies, including proteomics, multi-omics, neuroimaging, transcranial magnetic stimulation and EEG, are beginning to reveal how changes in cerebral blood flow, spectral power and connectivity can be associated with delirium; further work is needed to expand these findings to patients with delirium superimposed upon dementia.

Potential Value of Serum Uric Acid in the Identification of Postoperative Delirium in Geriatric Patients Undergoing Knee Replacement

Objectives

The relationship between preoperative serum uric acid (SUA) and cerebrospinal fluid (CSF) Alzheimer-related biomarkers were investigated to determine whether high SUA is a potential risk factor for postoperative delirium (POD) and to evaluate its predictive efficacy.

Methods

The participants were selected from the Perioperative Neurocognitive Disorder Risk Factor and Prognosis (PNDRFAP) study and the Perioperative Neurocognitive Disorder and Biomarker Lifestyle (PNDABLE) study. The logistic regression equation was used to analyze the risk factors and protective factors of POD. The interaction term (SUA × Sex) was introduced into the linear model to explore the potential modification effects of sex on the identified correlations. We analyzed the mediating effects of Alzheimer-related biomarkers. Finally, we constructed the receiver operating characteristic (ROC) curve and the nomogram model to evaluate the efficacy of SUA and Alzheimer-related biomarkers in predicting POD.

Results

Patients with POD had elevated SUA level (PNDRFAP: p = 0.002, PNDABLE: p < 0.001). Preoperative SUA level was positively correlated with CSF phosphorylated tau (P-tau) (p = 0.027) and β-amyloid42 (Aβ₄₂)/P-tau (p = 0.023). Interaction analysis did not find any modification effect of sex. The relationship between SUA and POD was partially mediated by CSF P-tau (15.3%). ROC curve showed that the model combining SUA and Alzheimer-related biomarkers had better performance in predicting POD [area under the curve (AUC) = 0.880; p < 0.001], and the predictive model is accurate.

Conclusions

High SUA may enhance CSF P-tau level, thus increasing the risk of POD, and the model combining SUA and Alzheimer-related biomarkers can accurately predict the occurrence of POD.

Comorbidity of osteoporosis and Alzheimer's disease: Is `AKT `-ing on cellular glucose uptake the missing link?

Osteoporosis and Alzheimer's disease (AD) are both degenerative diseases. Osteoporosis often proceeds cognitive deficits, and multiple studies have revealed common triggers that lead to energy deficits in brain and bone. Risk factors for osteoporosis and AD, such as obesity, type 2 diabetes, aging, chemotherapy, vitamin deficiency, alcohol abuse, and apolipoprotein Eε4 and/or Il-6 gene variants, reduce cellular glucose uptake, and protective factors, such as estrogen, insulin, exercise, mammalian target of rapamycin inhibitors, hydrogen sulfide, and most phytochemicals, increase uptake. Glucose uptake is a fine-tuned process that depends on an abundance of glucose transporters (Gluts) on the cell surface. Gluts are stored in vesicles under the plasma membrane, and protective factors cause these vesicles to fuse with the membrane, resulting in presentation of Gluts on the cell surface. This translocation depends mainly on AKT kinase signaling and can be affected by a range of factors. Reduced AKT kinase signaling results in intracellular glucose deprivation, which causes endoplasmic reticulum stress and iron depletion, leading to activation of HIF-1α, the transcription factor necessary for higher Glut expression. The link between diseases and aging is a topic of growing interest. Here, we show that diseases that affect the same biochemical pathways tend to co-occur, which may explain why osteoporosis and/or diabetes are often associated with AD.

Potential value of preoperative fasting blood glucose levels in the identification of postoperative delirium in non-diabetic older patients undergoing total hip replacement: The perioperative neurocognitive disorder and biomarker lifestyle study

BACKGROUND

Postoperative delirium (POD) is a common complication after total hip replacement. This study aims to explore the relationship between preoperative fasting blood glucose (FBG) levels and POD in non-diabetic older patients undergoing total hip replacement.

MATERIALS AND METHODS

This study included a total of 625 patients undergoing elective total hip replacement under combined spinal and epidural anesthesia from the PNDABLE study. The relationship between POD and preoperative FBG was analyzed by using the logistic regression model. The associations of FBG with individual cerebrospinal fluid (CSF) biomarkers were detected by using the multivariable linear regression model controlling for age, gender, and education level. The mediation effects were explored by mediation analyses with 5,000 bootstrap iterations, while sensitivity analysis was used to test the reliability and stability of the results. The receiver operating characteristic (ROC) curve and the nomogram model were applied to evaluate the efficacy of FBG and POD-related CSF biomarkers in predicting POD. POD assessment was performed two times daily by a trained anesthesiologist at 9:00-10:00 am and 2:00-3:00 pm on postoperative days 1-7 or before the patients were discharged from the hospital. POD was defined by the Confusion Assessment Method (CAM), and POD severity was measured using the Memorial Delirium Assessment Scale (MDAS). Enzyme-linked immunosorbent assay (ELISA) was used to measure CSF Aβ₄₀, Aβ₄₂, T-tau, and P-tau levels.

RESULTS

POD was detected in 10.2% (60/588) of the patients. Logistic regression analysis showed that after adjusting for age and education level, the increased levels of FBG (OR 1.427, 95% CI 1.117-1.824, P = 0.004), CSF P-tau (OR 1.039, 95% CI 1.019-1.060, P < 0.001), and CSF T-tau (OR 1.013, 95% CI 1.009-1.018, P < 0.001) were risk factors for POD, and the increased level of CSF Aβ₄₂ (OR 0.996, 95% CI 0.994-0.998, P = 0.001) was a protective factor for POD. Multivariable linear regression models showed that when adjusting for age, gender, and education level, in the POD group, higher preoperative FBG levels were negatively correlated with the CSF Aβ42 level (β = -0.290, P = 0.028) and positively correlated with CSF P-tau (β = 0.384, P = 0.004) and T-tau (β = 0.447, P < 0.001). In the non-POD group, a higher preoperative FBG was not related to CSF biomarkers. Mediated effect analysis showed that CSF T-tau (proportion = 17.1%) had an apparent mediation effect on the relationship between FBG and POD. Sensitivity analysis revealed that the results from the logistic regression and multivariable linear regression models were consistent with previous results.

CONCLUSION

Increased preoperative FBG was a risk factor for POD in older patients without T₂DM, and T-tau might mediate the relationship between FBG and POD.