Differences in potential biomarkers of delirium between acutely ill medical and elective cardiac surgery patients

Meta-analysis of serological biomarkers at hospital admission for the likelihood of developing delirium during hospitalization

Importance

Identifying biomarkers that, at hospital admission, predict subsequent delirium will help to focus our clinical efforts on prevention and management.

Objective

The study aimed to investigate biomarkers at hospital admission that may be associated with delirium during hospitalization.

Data sources

A librarian at the Fraser Health Authority Health Sciences Library performed searches from 28 June 2021 to 9 July 2021, using the following sources: Medline, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Cochrane Methodology Register, and the Database of Abstracts of Reviews and Effects.

Study selection

The inclusion criteria were articles in English that investigated the link between serum concentration of biomarkers at hospital admission and delirium during hospitalization. Exclusion criteria were single case reports, case series, comments, editorials, letters to the editor, articles that were not relevant to the review objective, and articles concerning pediatrics. After excluding duplicates, 55 studies were included.

Data extraction and synthesis

This meta-analysis followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) protocol. Independent extraction, with the consensus of multiple reviewers, was used to determine the final studies included. The weight and heterogeneity of the manuscripts were calculated using inverse covariance with a random-effects model.

Main outcomes and measures

Differences in mean serum concentration of biomarkers at hospital admission between patients who did and did not develop delirium during hospitalization.

Results

Our search found evidence that patients who developed delirium during hospitalization had, at hospital admission, significantly greater concentrations of certain inflammatory biomarkers and one blood-brain barrier leakage marker than patients who did not develop delirium during hospitalization (differences in the mean: cortisol: 3.36 ng/ml, p < 0.0001; CRP: 41.39 mg/L, p < 0.00001; IL-6: 24.05 pg/ml, p < 0.00001; S100β 0.07 ng/ml, p < 0.00001). These differences were independent of other confounding variables such as the patient's severity of illness. A significantly lower serum concentration, at hospital admission, of acetylcholinesterase (difference in the means -0.86 U/ml, p = 0.004) was also associated with an increased vulnerability to developing delirium during hospitalization.

Conclusion and relevance

Our meta-analysis supports the hypothesis that patients with hypothalamic-pituitary axis dysfunction, increased blood-brain barrier permeability, and chronic overload of the cholinergic system, at hospital admission, are more vulnerable to developing delirium during hospitalization.

The C-reactive protein/albumin ratio predicts postoperative delirium in patients older than 60 years following total knee arthroplasty

Purpose

This study aimed to investigate the relationship between serum C-reactive protein (CRP)/Albumin ratio (CAR) and postoperative delirium (POD) in patients older than 60 years following total knee arthroplasty (TKA).

Methods

From January 2019 to January 2021, 268 patients were recruited in this prospective observational investigation. Patients with serum CRP, Alb, CAR, delirious status and delirious score were assessed. The effect of CRP, Alb, CAR on predicting delirium was assessed with the area under the receiver operating characteristic (ROC) curve (AUC).

Results

The study found that higher CRP level (P < 0.001), low Alb level (P < 0.001), and higher CAR (P < 0.001) were independently associated with POD. The AUC of CAR for POD was 0.782, with the cut-off value of 0.117, a sensitivity of 83.3% and a specificity of 65.9% respectively (P < 0.001), suggesting that CAR had moderate efficacy on predicting POD occurrence than CRP (AUC: 0.761) and Alb (AUC: 0.300). The results also showed that age, ASA and the operation time was an independent predictor for patients with POD.

Conclusions

Our findings demonstrated CAR may be an effective biomarker to predict postoperative delirium in patients over 60 years of age with TKA, which provides potential recommendations for early intervention in delirium care.

Validation of E-PRE-DELIRIC in cardiac surgical ICU delirium: A retrospective cohort study

BACKGROUND

The early prediction model for delirium in intensive care units (ICUs)-E-PRE-DELIRIC-has been created to predict delirium development during the length of stay in ICUs. However, there have been few early predictive models for delirium in the cardiac surgical ICU (CSICU), and the predictive ability of the E-PRE-DELIRIC among patients following cardiac surgeries is still unknown.

AIMS AND OBJECTIVES

To validate the performance of E-PRE-DELIRIC in CSICU.

DESIGN

A retrospective cohort study.

METHODS

Data were retrospectively extracted from the electronic records for patients admitted in CSICU from January 2018 to December 2018 in a tertiary teaching hospital in China. Adult patients were included following the criteria of the E-PRE-DELIRIC model. Predictors, including age, history of cognitive impairment, history of alcohol abuse, urgent admission, use of corticosteroids, respiratory failure, blood urea nitrogen, and mean arterial pressure, at the time of ICU admission were retrieved, and delirium was assessed twice a day using the Confusion Assessment Method for the ICU. The performance of the E-PRE-DELIRIC model was evaluated by area under receiver operator characteristic curve, precision-recall curve (AUPRC), Hosmer-Lemeshow (HL) test, and calibration belt.

RESULTS

Of the 725 patients included, 120 (16.6%) developed delirium. The AUROC was 0.54 (95% confidence interval [CI], 0.48-0.59), and the AUPRC was 0.18 (95% CI, 0.12-0.20). The HL test showed a significant difference between predicted probability and delirium occurrence (χ² = 17.326, P = .027), and the overestimation chance of the E-PRE-DELIRIC score was 0.24 to 0.43.

CONCLUSION

The E-PRE-DELIRIC model has poor-to-fair predictive value in this study; thus, its application among the CSICU patients is limited. Development of reliable and validated tools for early prediction of delirium in CSICU is required.

RELEVANCE TO CLINICAL PRACTICE

Early prediction of delirium risk at CSICU admission is of vital importance and could provide timely information to caregivers. However, the E-PRE-DELIRIC model should be applied cautiously in the CSICU because of the significant probability of over-estimating the risk of developing delirium.

Characteristics, Risk Factors And Outcome Of Early-Onset Delirium In Elderly Patients With First Ever Acute Ischemic Stroke - A Prospective Observational Cohort Study

Introduction

Post-stroke delirium is a common clinical problem, occurring in 10% to 48% of patients. It has been associated with longer hospitalization times, increased mortality and worse functional outcome. In early phase of stroke, it may be regarded as particularly difficult to differentiate from other neurological symptoms. For practical purposes, there is a need to identify simple pre-operative laboratory parameters that may aid delirium diagnosis early after stroke. Our aim was to identify the incidence of early-onset (first 24 hrs) post-stroke delirium, its risk factors and outcomes (complications and mortality) in patients with first-ever acute ischemic stroke (AIS).

Material and methods

A retrospective analysis of a prospective observational study (NCT03944694) was performed. Patients were screened for delirium using CAM-ICU method. Clinical and laboratory data were collected, including baseline inflammatory parameters.

Results

Final analysis included 760 patients, 121 (15.9%) developed delirium. Patients with delirium were older (75.9±13.5 years, p<0.001). Most common complications in the delirium group were pulmonary (57.8% vs 21.4%, p<0.001), cardiac (38.8% vs 13.6%, p<0.001) and renal (13.2% vs 7.5%, p=0.038). Neutrophil-to-lymphocyte ratio (NLR) (6.71±9.65 vs 4.55±5.51, p<0.001), C-reactive protein level (32.59±65.94 vs 15.70±38.56, p<0.001) and troponin T level (72.59±180.15 vs 26.85±77.62, p<0.001) were higher in delirious patients and platelet-to white blood cell count ratio (PWR) (23.42±9.51 vs 27.13±10.58, p<0.001) was lower. Multivariable logistic regression showed that atrial fibrillation (OR 1.651, p=0.049), higher Rankin score on admission (OR 1.689, p<0.001), hemianopia (OR 2.422, p=0.003) and PWR <20.22 (OR 2.197, p=0.002) were independently associated with delirium. Kaplan–Meier curves indicated that mortality increased for patients with delirium at 3 months (p<0.001) and 1 year (p<0.001) after AIS.

Conclusion

Atrial fibrillation, higher Rankin score, hemianopia and lower PWR were independently associated with early onset delirium in patients with first ever AIS. This confirms that deprivation of senses and early generalized inflammatory response are critical for delirium development.

Serum biomarkers of delirium in the elderly: a narrative review

Delirium after surgery and in the intensive care unit (ICU) remains a challenge for patients, families, and caregivers. Over the years, many promising biomarkers have been investigated as potential instruments for risk stratification of delirium. This review aimed to identify and assess the clinical usefulness of candidate serum biomarkers associated with hospital delirium in patients aged 60 years and older. We performed a time-unlimited review of publications indexed in PubMed, Cochrane, Embase, and MEDLINE databases until June 2019 that evaluated baseline and/or longitudinal biomarker measurements in patients suffering from delirium at some point during their hospital stay. A total of 32 studies were included in this review reporting information on 7610 patients. Of these 32 studies, twenty-four studies reported data from surgical patients including four studies in ICU cohorts, five studies reported data from medical patients (1026 patients), and three studies reported data from a mixed cohort (1086 patients), including one study in an ICU cohort. Findings confirm restricted clinical usefulness to predict or diagnose delirium due to limited evidence on which biomarkers can be used and limited availability due to non-routine use.