Longitudinal assessment of serum anticholinergic activity in delirium of the elderly

Differences of anticholinergic drug burden between older hospitalized patients with and without delirium: a systematic review and meta-analysis based on prospective cohort studies

OBJECTIVES

This review aims to comprehensively summarize the differences in anticholinergic drug burden (ADB) scores between older hospitalized patients with and without delirium.

METHODS

We searched PubMed, Embase, Web of Science, Cochrane Library and CINAHL EBSCOhost databases to identify prospective cohort studies exploring the relationship between ADB and the occurrence of delirium in older hospitalized patients. The primary outcome of the review was the mean ADB scores for the delirium and non-delirium groups, and the secondary outcome was the scores for the subsyndromal and non-delirium groups. The standardized mean difference (SMD) and corresponding 95% confidence intervals (95% CI) were incorporated using a fixed-effect method. Moreover, we performed subgroup analysis according to the admission type, age, the ADB scale type and the ADB classification.

RESULTS

Nine prospective cohort studies involving 3791 older patients with a median age of 75.1 (71.6-83.9) were included. The ADB score was significantly higher in the delirium group than in the non-delirium group (SMD = 0.21, 95%CI 0.13-0.28). In subgroup analysis, the age subgroup was split into < 75 and ≥ 75 according to the median age of the older people. There were significant differences in ADB scores between older people with delirium and those without delirium in various subgroups: surgical (SMD = 0.20, 95%CI 0.12-0.28), internal medicine (SMD = 0.64, 95%CI 0.25-1.02), age < 75 (SMD = 0.17, 95%CI 0.08-0.26), age ≥ 75 (SMD = 0.27, 95%CI 0.15-0.39), ADS scale (SMD = 0.13, 95%CI 0.13-0.40), ARS scale (SMD = 0.15, 95%CI 0.03-0.26), ACB scale (SMD = 0.13, 95%CI 0.01-0.25), pre-admission ADB (SMD = 0.24, 95%CI 0.05-0.43) and ADB during hospitalization (SMD = 0.20, 95%CI 0.12-0.27).

CONCLUSIONS

We found a quantitative relationship between ADB and delirium in older patients admitted for internal medicine and surgery. And this relationship remained significant in different age, ADB scale type and ADB classification subgroups. However, the actual difference in ADB scores between patients with delirium and without delirium was small. More high-quality observational studies should be conducted to explore the impact of ADB on delirium and subsyndromal delirium.

CLINICAL TRIAL REGISTRATION

The protocol was published in the International Prospective Register of Systematic Reviews (PROSPERO) [Ref: CRD42022353649].

Factors Associated With Delirium in Children: A Systematic Review and Meta-Analysis

OBJECTIVES

Pediatric delirium (PD) is a neuropsychiatric syndrome caused by a complex interplay between predisposing factors (e.g., age, cognitive impairment), acute illness, and environmental triggers. PD is associated with substantial morbidity and mortality. The objective of this study is to systematically review and evaluate factors associated with PD in hospitalized pediatric patients.

DATA SOURCES

A systematic search of PubMed, Embase, Ovid Medline, Web- of-Science, Cochrane, CIHNAL, and Google Scholar databases was conducted for relevant studies (1990-2022).

STUDY SELECTION

We included studies that compared pediatric patients with and without delirium. Reviews, editorials, congress abstracts, or studies that did not report factors for PD were excluded. No restrictions were imposed on language.

DATA EXTRACTION

Title and abstract were independently screened by two reviewers. Individual characteristics, study design, and outcomes were independently extracted.

DATA SYNTHESIS

Categorical dichotomous data were summarized across groups using Mantel-Haenszel odds ratios (ORs) with 95% 95% CIs. Either fixed-effect or random effects models were used as indicated by the results of a heterogeneity test. Of 1,846 abstracts, 24 studies were included. We identified 54 factors studied in univariate analyses, and 27 of these were associated with PD in multivariable analyses. In pooled analyses, greater odds of PD were associated with developmental delay (OR 3.98; 95% CI 1.54-10.26), need for mechanical ventilation (OR 6.02; 95% CI 4.43-8.19), use of physical restraints (OR 4.67; 95% CI 1.82-11.96), and receipt of either benzodiazepines (OR 4.10; 95% CI 2.48-6.80), opiates (OR 2.88; 95% CI 1.89-4.37), steroids (OR 2.02; 95% CI 1.47-2.77), or vasoactive medication (OR 3.68; 95% CI 1.17-11.60).

CONCLUSIONS

In this meta-analysis, we identified seven factors associated with greater odds of developing delirium during pediatric critical illness.

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.

Delirium in geriatric patients

Delirium is the most common acute disorder of cognitive function in older patients. Delirium is life threatening, often under-recognized, serious, and costly. The causes are multifactorial, with old age and neurocognitive disorders as the main risk factors. Etiologies are various and multifactorial, and often related to acute medical illness, adverse drug reactions, or medical complications. To date, diagnosis is clinically based, depending on the presence or absence of certain features. In view of the multifactorial etiology, multicomponent approaches seem most promising for facing patients’ needs. Pharmacological intervention, neither for prevention nor for treatment, has been proven effective unanimously. This article reviews the current clinical practice for delirium in geriatric patients, including etiology, pathophysiology, diagnosis, prognosis, treatment, prevention, and outcomes.

Biomarkers in delirium: A systematic review

BACKGROUND

Delirium is a common neuropsychiatric disorder associated with prolonged hospital stays, and increased morbidity and mortality. Diagnosis is frequently missed due to varying disease presentation and lack of standardized testing. We examined biomarkers as diagnostic or prognostic indicators of delirium, and provide a rational basis for future studies.

METHOD

Systematic review of literature published between Jan 2000 and June 2019. Searches included: PubMed; Web of Science; CINAHL; EMBASE; COCHRANE and Medline. Additional studies were identified by searching bibliographies of eligible articles.

RESULTS

2082 relevant papers were identified from all sources. Seventy-three met the inclusion criteria, all of which were observational. These assessed a range of fourteen biomarkers. All papers included were in the English language. Assessment methods varied between studies, including: DSM criteria; Confusion Assessment Method (CAM) or CAM-Intensive Care Unit (ICU). Delirium severity was measured using the Delirium Rating Scale (DRS). Delirium was secondary to post-operative dysfunction or acute medical conditions.

CONCLUSION

Evidence does not currently support the use of any one biomarker. However, certain markers were associated with promising results and may warrant evaluation in future studies. Heterogeneity across study methods may have contributed to inconclusive results, and more clarity may arise from standardization of methods of clinical assessment. Adjusting for comorbidities may improve understanding of the pathophysiology of delirium, in particular the role of confounders such as inflammation, cognitive disorders and surgical trauma. Future research may also benefit from inclusion of other diagnostic modalities such as EEG as well as analysis of genetic or epigenetic factors.

Melatonin to prevent delirium in patients with advanced cancer: a double blind, parallel, randomized, controlled, feasibility trial

BACKGROUND

Delirium is highly problematic in palliative care (PC). Preliminary data indicate a potential role for melatonin to prevent delirium, but no randomized controlled trials (RCTs) are reported in PC.

METHODS

Patients aged ≥18 years, with advanced cancer, admitted to an inpatient Palliative Care Unit (PCU), having a Palliative Performance Scale rating ≥ 30%, and for whom consent was obtained, were included in the study. Patients with delirium on admission were excluded. The main study objectives were to assess the feasibility issues of conducting a double-blind RCT of exogenous melatonin to prevent delirium in PC: recruitment, retention, procedural acceptability, appropriateness of outcome measures, and preliminary efficacy and safety data. Study participants were randomized in a double-blind, parallel designed study to receive daily melatonin 3 mg or placebo orally at 21:00 over 28 days or less if incident delirium, death, discharge or withdrawal occurred earlier. Delirium was diagnosed using the Confusion Assessment Method. Efficacy endpoints in the melatonin and placebo groups were compared using time-to-event analysis: days from study entry to onset of incident delirium.

RESULTS

Over 16 months, 60/616 (9.7%; 95% CI: 7.5-12.4%) screened subjects were enrolled. The respective melatonin (n = 30) vs placebo (n = 30) outcomes were: incident delirium in 11/30 (36.7%; 95%CI: 19.9-56.1%) vs 10/30 (33%; 95% CI: 17.3-52.8%); early discharge (6 vs 5); withdrawal (6 vs 3); death (0 vs 1); and 7 (23%) vs 11 (37%) reached the 28-day end point. The 25th percentile time-to-event were 9 and 18 days (log rank, χ² = 0.62, p = 0.43) in melatonin and placebo groups, respectively. No serious trial medication-related adverse effects occurred and the core study procedures were acceptable. Compared to those who remained delirium-free during their study participation, those who developed delirium (n = 21) had poorer functional (p = 0.036) and cognitive performance (p = 0.013), and in particular, poorer attentional capacity (p = 0.003) at study entry.

CONCLUSIONS

A larger double-blind RCT is feasible, but both subject accrual and withdrawal rates signal a need for multisite collaboration. The apparent trend for shorter time to incident delirium in the melatonin group bodes for careful monitoring in a larger trial.

TRIAL REGISTRATION

Registered on July 21st 2014 with ClinicalTrials.gov : NCT02200172 .

Haloperidol versus placebo for delirium prevention in acutely hospitalised older at risk patients: a multi-centre double-blind randomised controlled clinical trial

Background

because the few randomised placebo-controlled trials investigating the potential role for prophylactic haloperidol in delirium prevention have focused on specific surgical populations, we investigated its efficacy and safety in acutely hospitalised older patients.

Methods

this multi-centre, double-blind, stratified, block randomised, placebo-controlled trial was conducted at six Dutch hospitals. Patients age ≥70 years, acutely admitted through the emergency department for general medicine or surgical specialties and at risk for delirium were randomised (n = 245) to haloperidol or placebo 1 mg orally twice-daily (maximum of 14 doses) on top of standard nonpharmacological prevention strategies. The primary outcome was delirium incidence. Other endpoints included delirium severity and duration, drug safety and clinical outcomes.

Results

intention-to-treat analysis included 242 participants (calculated sample size n = 390, statistical power of current sample 59%) allocated to haloperidol (n = 118) or placebo (n = 124). In the haloperidol and placebo group, delirium incidence was 19.5 versus 14.5% (OR 1.43, 95% CI 0.72 to 2.78); median (IQR) delirium duration 4 (2, 5) versus 3 (1, 6) days (P = 0.366); maximum DRS-R-98 score 16 (9.8, 19.5) versus 10 (5.5, 22.5) (P = 0.549; 53.7% missing data); hospital LOS 7 (4, 10.3) versus 7 (5, 11.8) days (P = 0.343); 3-month mortality 9.9 versus 12.5% (OR 0.77, 95% CI 0.34 to 1.75), respectively. No treatment-limiting side effects were noted.

Conclusions

prophylactic low-dose oral haloperidol did not reduce delirium incidence in acutely hospitalised older patients. Therefore, prophylactic use of haloperidol in this population is not recommended.

A Systematic Review and Meta-analysis Examining the Impact of Incident Postoperative Delirium on Mortality

Background

Delirium is an acute and reversible geriatric syndrome that represents a decompensation of cerebral function. Delirium is associated with adverse postoperative outcomes, but controversy exists regarding whether delirium is an independent predictor of mortality. Thus, we assessed the association between incident postoperative delirium and mortality in adult noncardiac surgery patients.

Methods

A systematic search was conducted using Cochrane, MEDLINE/PubMed, Cumulative Index to Nursing and Allied Health Literature, and Embase. Screening and data extraction were conducted by two independent reviewers. Pooled-effect estimates calculated with a random-effects model were expressed as odds ratios with 95% CIs. Risk of bias was assessed using the Cochrane Risk of Bias Tool for Non-Randomized Studies.

Results

A total of 34 of 4,968 screened citations met inclusion criteria. Risk of bias ranged from moderate to critical. Pooled analysis of unadjusted event rates (5,545 patients) suggested that delirium was associated with a four-fold increase in the odds of death (odds ratio = 4.12 [95% CI, 3.29 to 5.17]; I2 = 24.9%). A formal pooled analysis of adjusted outcomes was not possible due to heterogeneity of effect measures reported. However, in studies that controlled for prespecified confounders, none found a statistically significant association between incident postoperative delirium and mortality (two studies in hip fractures; n = 729) after an average follow-up of 21 months. Overall, as study risk of bias decreased, the association between delirium and mortality decreased.

Conclusions

Few high-quality studies are available to estimate the impact of incident postoperative delirium on mortality. Studies that controlled for prespecified confounders did not demonstrate significant independent associations of delirium with mortality.

Serum Anticholinergic Activity and Cognitive and Functional Adverse Outcomes in Older People: A Systematic Review and Meta-Analysis of the Literature

INTRODUCTION

Studies have reported associations between serum anticholinergic activity (SAA) and decline in cognitive performance, delirium, and functional impairment. The aim of this meta-analysis was to explore and quantify associations between SAA and adverse cognitive and functional outcomes in older people.

MATERIALS AND METHODS

A literature search in Ovid MEDLINE, EMBASE, PsycINFO and IPA from 1946-2014 was completed. The primary outcomes of interest were cognitive and functional adverse outcomes associated with SAA in older people aged 55 years and above. The Cochrane Risk-Bias assessment tool was used to assess bias in randomised controlled trials (RCTs). The Newcastle-Ottawa Scale was used to assess the quality of non-RCTs. Meta-analyses were conducted for RCTs and cohort studies separately. Heterogeneity was assessed using I2 tests.

RESULTS

The primary electronic literature search identified a total of 1559 records in the 4 different databases. On the basis of full-text analysis, 33 studies that met the inclusion criteria. The review included 4 RCTs, 5 prospective cohort studies, 3 longitudinal cohort studies, 17 cross-sectional studies, and 4 case-control studies. Twenty-four of the retrieved studies examined an association between SAA and cognitive outcomes, 2 studies examined an association with SAA and functional outcomes and 8 studies examined associations between SAA and both cognitive, and functional outcomes. The meta-analysis on 4 RCTs showed no association with higher SAA and cognitive performance (I2 = 89.38%, H2 = 25.53 and p-value = <0.05) however, the pooled data from 4 observational studies showed elevated SAA was associated with reduced cognitive performance (I2 = 0.00%, H2 = 3.37 and p-value = 0.34).

CONCLUSION

This systematic review summarises the limitations of the SAA on predicting cognitive and functional outcomes in older people. SAA measured by receptor bioassay is flawed and its use in older people with multimorbidity and polypharmacy is questionable.

Anticholinergic drugs and negative outcomes in the older population: from biological plausibility to clinical evidence

The use of medication with anticholinergic properties is widespread among older subjects. Many drugs of common use such as antispasmodics, bronchodilators, antiarrhythmics, antihistamines, anti-hypertensive drugs, antiparkinson agents, skeletal muscle relaxants, and psychotropic drugs have been demonstrated to have an anticholinergic activity. The most frequent adverse effects are dry mouth, nausea, vomiting, constipation, abdominal pain, urinary retention, blurred vision, tachycardia and neurologic impairment such as confusion, agitation and coma. A growing evidence from experimental studies and clinical observations suggests that drugs with anticholinergic properties can cause physical and mental impairment in the elderly population. However, the morbidity and management issues associated with unwanted anticholinergic activity are underestimated and frequently overlooked. Moreover, their possible relation with specific negative outcome in the elderly population is still not firmly established. The aim of the present review was to evaluate the relationship between the use of drugs with anticholinergic activity and negative outcomes in older persons. We searched PubMed and Cochrane combining the search terms "anticholinergic", "delirium", "cognitive impairment", "falls", "mortality" and "discontinuation". Medicines with anticholinergic properties may increase the risks of functional and cognitive decline, morbidity, institutionalization and mortality in older people. However, such evidences are still not conclusive probably due to possible confounding factors. In particular, more studies are needed to investigate the effects of discontinuation of drug with anticholinergic properties. Overall, minimizing anticholinergic burden should always be encouraged in clinical practice to improve short-term memory, confusion and delirium, quality of life and daily functioning.

Efficacy and safety of haloperidol for in-hospital delirium prevention and treatment: A systematic review of current evidence

OBJECTIVE

Haloperidol is generally considered the drug of choice for in-hospital delirium management. We conducted a systematic review to evaluate the evidence for the efficacy and safety of haloperidol for the prevention and treatment of delirium in hospitalized patients.

METHODS

PubMed, Embase, Cumulative Index to Nursing and Allied Health (CINAHL), PsycINFO, and the Cochrane Library were systematically searched up to April 21, 2015. We included English full-text randomized controlled trials using haloperidol for the prevention or treatment of delirium in adult hospitalized patients reporting on delirium incidence, duration, or severity as primary outcome. Quality of evidence was graded. Meta-analysis was not conducted because of between-study heterogeneity.

RESULTS

Twelve studies met our inclusion criteria, four prevention and eight treatment trials. Methodological limitations decreased the graded quality of included studies. Results from placebo-controlled prevention studies suggest a haloperidol-induced protective effect for delirium in older patients scheduled for surgery: two studies reported a significant reduction in ICU delirium incidence and one study found a significant reduction in delirium severity and duration. Although placebo-controlled trials are missing, pharmacological treatment of established delirium reduced symptom severity. Haloperidol administration was not associated with treatment-limiting side-effects, but few studies used a systematic approach to identify adverse events.

CONCLUSION

Although results on haloperidol for delirium management seem promising, current prevention trials lack external validity and treatment trials did not include a placebo arm on top of standard nonpharmacological care. We therefore conclude that the current use of haloperidol for in-hospital delirium is not based on robust and generalizable evidence.

Biomarkers of postoperative delirium and cognitive dysfunction

Elderly surgical patients frequently experience postoperative delirium (POD) and the subsequent development of postoperative cognitive dysfunction (POCD). Clinical features include deterioration in cognition, disturbance in attention and reduced awareness of the environment and result in higher morbidity, mortality and greater utilization of social financial assistance. The aging Western societies can expect an increase in the incidence of POD and POCD. The underlying pathophysiological mechanisms have been studied on the molecular level albeit with unsatisfying small research efforts given their societal burden. Here, we review the known physiological and immunological changes and genetic risk factors, identify candidates for further studies and integrate the information into a draft network for exploration on a systems level. The pathogenesis of these postoperative cognitive impairments is multifactorial; application of integrated systems biology has the potential to reconstruct the underlying network of molecular mechanisms and help in the identification of prognostic and diagnostic biomarkers.

Increasing anticholinergic burden and delirium in palliative care inpatients

BACKGROUND

Delirium may complicate the hospital course and adversely impact remaining quality of life for palliative care inpatients. Medications with anticholinergic properties have been linked to delirium within elderly populations via serum anticholinergic assays.

AIM

The aim of this study is to determine whether increasing anticholinergic burden, as measured using a clinical assessment tool, is associated with an increase in delirium among palliative care inpatients.

DESIGN

This study was completed as a retrospective, case-control study.

SETTING/PARTICIPANTS

Veterans admitted to the Veterans Affairs Boston Healthcare System and consulted to the palliative care service were considered for inclusion. Increase in anticholinergic burden from admission through hospital day 14 was assessed using the Anticholinergic Risk Scale. Presence of delirium was determined by use of a validated chart review instrument.

RESULTS

A total of 217 patients were analyzed, with a mean age of 72.9 (±12.8) years. The overall delirium rate was 31% (n = 67). Patients with an increase in Anticholinergic Risk Scale (n = 72 (33%)) were 40% more likely to experience delirium (odds ratio = 1.44, 95% confidence interval = 1.07-1.94) compared to those without increase (n = 145 (67%)). After adjustment for age, brain metastasis, intensive care unit admission, illness severity, opiate use, and admission Anticholinergic Risk Scale using multivariable modeling, delirium risk remained significantly higher in patients with an Anticholinergic Risk Scale increase compared to those without increase (adjusted odds ratio = 1.43, 95% confidence interval = 1.04-1.94).

CONCLUSION

An increase in Anticholinergic Risk Scale from admission was associated with delirium in palliative care inpatients. While additional study is needed, anticholinergic burden should be increased cautiously in palliative inpatients, and those with increases should be closely followed for delirium.

Serum anticholinergic activity: a possible peripheral marker of the anticholinergic burden in the central nervous system in Alzheimer's disease

We review the utility of serum anticholinergic activity (SAA) as a peripheral marker of anticholinergic activity (AA) in the central nervous system (CAA). We hypothesize that the compensatory mechanisms of the cholinergic system do not contribute to SAA if their system is intact and that if central cholinergic system deteriorates alone in conditions such as Alzheimer's disease or Lewy body dementia, CAA and SAA are caused by way of hyperactivity of inflammatory system and SAA is a marker of the anticholinergic burden in CNS. Taking into account the diurnal variations in the plasma levels of corticosteroids, which are thought to affect SAA, it should be measured at noon or just afterward.