Preventive Effects of Suvorexant on Delirium: A Randomized Placebo-Controlled Trial

Pharmacological Management of Sleep-Wake Disturbances in Delirium

Delirium is a heterogeneous syndrome primarily characterized by fluctuations in attention and awareness. Sleep-wake disturbances are a common and significant feature of delirium and can manifest as circadian rhythm inversion, sleep fragmentation, and reduced rapid eye movement (REM) and slow-wave sleep. Some literature suggests that the relationship between sleep disruption and delirium is reciprocal wherein the two reinforce one another and may share an underlying etiology. As there are no FDA-approved medications for delirium or delirium-related sleep disturbances, management is primarily focused on addressing underlying medical concerns and promoting physiologic circadian patterns with non-pharmacological behavioral interventions. In practice, however, medications are often used, albeit with limited evidence to support their use. This literature review explores the pharmacology and pharmacokinetics of several medications with literature investigating their use in delirium: melatonin, ramelteon, dual orexin receptor antagonists (DORAs), and dexmedetomidine. Current evidence suggests a possible benefit of ramelteon or melatonin, dexmedetomidine for patients in the ICU setting, and DORAs as therapeutic options for the re-regulation of sleep-wake cycle disruption in delirium. We discuss pertinent pharmacokinetic and pharmacodynamic factors that may influence clinical decision-making regarding these interventions.

The association between salivary IL-6 and poor sleep quality assessed using Apple watches in stressed workers in Japan

Insomnia is a major concern among stressed workers worldwide. Although stress generally has a detrimental effect on sleep quality, the impact of biological stress, especially the immunological stress response, on sleep quality is not yet fully understood. Stressed workers were recruited through a screening process using a Brief Job Stress Questionnaire. The participants were asked to complete various occupation-related questionnaires. Additionally, saliva samples were collected to assess interleukin-6 (IL-6) levels as an immunological stress response. Subsequently, they were asked to wear an Apple Watch to record their sleep pattern for one week. Their sleep architecture was estimated using a previously published and validated method. Finally, data from 73 participants were analyzed. Our multivariable analysis revealed that shorter durations of slow-wave sleep (non-rapid eye movement sleep stage 3) were significantly associated with elevated IL-6 levels (p = 0.005) and greater daytime sleepiness (p = 0.002) after controlling for total sleep time. Our finding that a higher immunological stress response is associated with poor sleep quality contributes to a better understanding of insomnia in stressed workers and emphasizes the importance of stress management in this population.

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

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

Intensive care unit interventions to promote sleep and circadian biology in reducing incident delirium: a scoping review

RATIONALE/OBJECTIVES

Despite plausible pathophysiological mechanisms, research is needed to confirm the relationship between sleep, circadian rhythm and delirium in patients admitted to the intensive care unit (ICU). The objective of this review is to summarise existing studies promoting, in whole or in part, the normalisation of sleep and circadian biology and their impact on the incidence, prevalence, duration and/or severity of delirium in ICU.

METHODS

A sensitive search of electronic databases and conference proceedings was completed in March 2023. Inclusion criteria were English-language studies of any design that evaluated in-ICU non-pharmacological, pharmacological or mixed intervention strategies for promoting sleep or circadian biology and their association with delirium, as assessed at least daily. Data were extracted and independently verified.

RESULTS

Of 7886 citations, we included 50 articles. Commonly evaluated interventions include care bundles (n=20), regulation or administration of light therapy (n=5), eye masks and/or earplugs (n=5), one nursing care-focused intervention and pharmacological intervention (eg, melatonin and ramelteon; n=19). The association between these interventions and incident delirium or severity of delirium was mixed. As multiple interventions were incorporated in included studies of care bundles and given that there was variable reporting of compliance with individual elements, identifying which components might have an impact on delirium is challenging.

CONCLUSIONS

This scoping review summarises the existing literature as it relates to ICU sleep and circadian disruption (SCD) and delirium in ICU. Further studies are needed to better understand the role of ICU SCD promotion interventions in delirium mitigation.

Prevalence and risk factors of postoperative delirium in tumor patients after free flap reconstruction: A systematic review and meta-analysis of case-control studies

BACKGROUND

Postoperative delirium is a severe complication of flap transplantation surgery, adversely affecting surgical prognoses. The intricate pathophysiology of postoperative delirium renders the elucidation of its risk factors challenging. This research aims to delineate the prevalence and the specific risk factors of postoperative delirium in patients with cancer undergoing free flap reconstruction through a systematic review and meta-analysis to enlighten proactive prevention measures.

METHODS

The researchers systematically queried both the international and Chinese databases. Searches were performed for publications from inception until September 14, 2023, using the terms "free tissue flaps," "delirium," "neoplasms," and "risk factors." Data synthesis and statistical analysis were conducted using Stata SE (version 15.0) to calculate the combined effect size for identified risk factors. Reported outcomes included weighted mean differences or odds ratios with their respective 95% confidence intervals.

RESULTS

Twelve case-control studies were included (ntotal = 3,256). Among them, 515 patients developed postoperative delirium after free flap surgery, compared with 2,741 patients who did not. The outcomes suggest that the risk factors include but are not limited to age, male, late neoplasm staging, use of hypnotic or antipsychotic, history of background diseases, psychiatric review, tracheotomy, and impaired wound healing. In contrast, early neoplasm staging and others are the protective factors with statistical significance. Multivariate analysis further identified significant correlations between preoperative albumin, perioperative blood transfusion, sleep disturbance, postoperative visual analog scale, postoperative albumin, smoking, and the appearance of postoperative delirium.

CONCLUSION

The determined risk factors were grouped into preoperative, intraoperative, and postoperative categories substantiated by current data to present instructions for postoperative delirium prevention.

Suvorexant for Reduction of Delirium in Older Adults After Hospitalization: A Randomized Clinical Trial

Importance

Delirium is common among older hospitalized adults. In addition to presenting immediate management issues, delirium can increase the long-term risk of dementia, institutionalization, and mortality. Delirium is associated with disrupted sleep, and prior studies suggest that some specific sleep-promoting agents may reduce delirium.

Objective

To evaluate the orexin receptor antagonist suvorexant for reducing delirium in older adults at high risk for delirium after hospitalization.

Design, Setting, and Participants

This double-blind, placebo-controlled, phase 3 randomized clinical trial was conducted at 50 hospitals in Japan between October 22, 2020, and December 23, 2022. The study population included Japanese adults aged 65 to 90 years who were at high risk for delirium (mild cognitive impairment or mild dementia, history of delirium at prior hospitalization, or both) and had been hospitalized for acute disease or elective surgery. Data analysis was performed between January 23 and March 13, 2023.

Intervention

Participants were randomized 1:1 to suvorexant (15 mg) or placebo taken at bedtime for up to 7 days while in the hospital.

Main Outcomes and Measures

Delirium, the primary end point, was diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria while participants were hospitalized. The treatment difference in the proportion of participants with delirium was analyzed.

Results

This study included 203 participants: 101 were treated with suvorexant (mean [SD] age, 81.5 [4.5]; years; 52 men [51.5%] and 49 women [48.5%]) and 102 received placebo (mean [SD] age, 82.0 [4.9] years; 45 men [44.1%] and 57 women [55.9%]). There were 17 participants with delirium (16.8%) in the suvorexant group compared with 27 (26.5%) in the placebo group (difference, -8.7% [95% CI, -20.1% to 2.6%]; P = .13). Adverse events were similar between the 2 groups.

Conclusions and Relevance

In this randomized clinical trial of suvorexant in older adults at high risk for delirium after hospitalization, fewer participants taking suvorexant had delirium compared with placebo, but the difference was not statistically significant. Further studies are needed to determine whether suvorexant may be useful for reducing delirium, particularly delirium with a hyperactive component, in this population.

Trial Registration

ClinicalTrials.gov Identifier: NCT04571944.

Preventive Effects of Ramelteon, Suvorexant, and Lemborexant on Delirium in Hospitalized Patients With Physical Disease: A Retrospective Cohort Study

BACKGROUND

New sleep-inducing drugs (eg, ramelteon, suvorexant, and lemborexant) have been shown to prevent delirium in high-risk groups. However, no single study has simultaneously evaluated the delirium-preventing effects of all novel sleep-inducing drugs in hospitalized patients. Therefore, this study aimed to clarify the relationship between sleep-inducing drugs and delirium prevention in patients hospitalized in general medical-surgical settings for nonpsychiatric conditions who underwent liaison interventions for insomnia.

METHODS

This retrospective cohort study included patients treated in general medical-surgical settings for nonpsychiatric conditions with consultation-liaison psychiatry consult for insomnia. Delirium was diagnosed by fully certified psychiatrists using the Diagnostic and Statistical Manual of Mental Disorders 5 th edition. The following items were retrospectively examined from medical records as factors related to delirium development: type of sleep-inducing drugs, age, sex, and delirium risk factors. The risk factors of delirium development were calculated using adjusted odds ratios (aORs) via multivariate logistic regression analysis.

RESULTS

Among the 710 patients analyzed, 257 (36.2%) developed delirium. Suvorexant (aOR, 0.61; 95% confidence interval [CI], 0.40-0.94; P = 0.02) and lemborexant (aOR, 0.23; 95% CI, 0.14-0.39; P < 0.0001) significantly reduced the risk of developing delirium. Benzodiazepines (aOR, 1.90; 95% CI, 1.15-3.13; P = 0.01) significantly increased this risk. Ramelteon (aOR, 1.30; 95% CI, 0.84-2.01; P = 0.24) and Z-drugs (aOR, 1.27; 95% CI, 0.81-1.98; P = 0.30) were not significantly associated with delirium development.

CONCLUSIONS

The use of suvorexant and lemborexant may prevent delirium in patients with a wide range of medical conditions.

Pharmacologic Sleep Aids in the Intensive Care Unit: A Systematic Review

Background: Patients in the intensive care unit (ICU) often experience poor sleep quality. Pharmacologic sleep aids are frequently used as primary or adjunctive therapy to improve sleep, although their benefits in the ICU remain uncertain. This review aims to provide a comprehensive assessment of the objective and subjective effects of medications used for sleep in the ICU, as well as their adverse effects. Methods: PubMed, Web of Science, Scopus, Embase, and Cochrane Central Register of Controlled Trials were systematically searched from their inception until June 2023 for comparative studies assessing the effects of pharmacologic sleep aids on objective and subjective metrics of sleep. Results: Thirty-four studies with 3498 participants were included. Medications evaluated were melatonin, ramelteon, suvorexant, propofol, and dexmedetomidine. The majority of studies were randomized controlled trials. Melatonin and dexmedetomidine were the best studied agents. Objective sleep metrics included polysomnography (PSG), electroencephalography (EEG), bispectral index, and actigraphy. Subjective outcome measures included patient questionnaires and nursing observations. Evidence for melatonin as a sleep aid in the ICU was mixed but largely not supportive for improving sleep. Evidence for ramelteon, suvorexant, and propofol was too limited to offer definitive recommendations. Both objective and subjective data supported dexmedetomidine as an effective sleep aid in the ICU, with PSG/EEG in 303 ICU patients demonstrating increased sleep duration and efficiency, decreased arousal index, decreased percentage of stage N1 sleep, and increased absolute and percentage of stage N2 sleep. Mild bradycardia and hypotension were reported as side effects of dexmedetomidine, whereas the other medications were reported to be safe. Several ongoing studies have not yet been published, mostly on melatonin and dexmedetomidine. Conclusions: While definitive conclusions cannot be made for most medications, dexmedetomidine improved sleep quantity and quality in the ICU. These benefits need to be balanced with possible hemodynamic side effects.

The influence of sleep disorders on perioperative neurocognitive disorders among the elderly: A narrative review

This review comprehensively assesses the epidemiology, interaction, and impact on patient outcomes of perioperative sleep disorders (SD) and perioperative neurocognitive disorders (PND) in the elderly. The incidence of SD and PND during the perioperative period in older adults is alarmingly high, with SD significantly contributing to the occurrence of postoperative delirium. However, the clinical evidence linking SD to PND remains insufficient, despite substantial preclinical data. Therefore, this study focuses on the underlying mechanisms between SD and PND, underscoring that potential mechanisms driving SD-induced PND include uncontrolled central nervous inflammation, blood-brain barrier disruption, circadian rhythm disturbances, glial cell dysfunction, neuronal and synaptic abnormalities, impaired central metabolic waste clearance, gut microbiome dysbiosis, hippocampal oxidative stress, and altered brain network connectivity. Additionally, the review also evaluates the effectiveness of various sleep interventions, both pharmacological and nonpharmacological, in mitigating PND. Strategies such as earplugs, eye masks, restoring circadian rhythms, physical exercise, noninvasive brain stimulation, dexmedetomidine, and melatonin receptor agonists have shown efficacy in reducing PND incidence. The impact of other sleep-improvement drugs (e.g., orexin receptor antagonists) and methods (e.g., cognitive-behavioral therapy for insomnia) on PND is still unclear. However, certain drugs used for treating SD (e.g., antidepressants and first-generation antihistamines) may potentially aggravate PND. By providing valuable insights and references, this review aimed to enhance the understanding and management of PND in older adults based on SD.

Association Between Antidiabetic Drugs and Delirium: A Study Based on the Adverse Drug Event Reporting Database in Japan

BACKGROUND AND OBJECTIVE

Several associations between diabetes mellitus and delirium have been reported; however, they have been inconsistent, and evidence on the effects of antidiabetic medications on delirium is also limited. This study aimed to investigate whether the use of antidiabetic drugs is a risk factor for delirium development.

METHODS

Using the Japanese Adverse Event Reporting Database, we analyzed 662,899 reports between 2004 and 2022. Reporting odds ratios (RORs) and 95% confidence intervals (CIs) for delirium associated with diabetes and using each antidiabetic medication were calculated after adjusting for potential confounders.

RESULTS

Overall, 8892 of the reports analyzed were associated with delirium. A comparison of the incidence of delirium between patients with and without diabetes showed no significant difference, with 1.34% in patients without diabetes and 1.37% in those with diabetes. In each antidiabetic medication, signals for delirium were detected for sulfonylurea (crude ROR, 1.35; 95% CI 1.21-1.51) and insulin (crude ROR, 1.28; 95% CI 1.13-1.44). These results were maintained even after adjusting for factors with potential confounders (sulfonylurea: adjusted ROR, 1.75; 95% CI 1.54-2.00, insulin: adjusted ROR, 1.35; 95% CI 1.20-1.54).

CONCLUSIONS

Our results suggest no association between diabetes and delirium; however, using sulfonylurea and insulin may be associated with delirium development. Nonetheless, these findings should be validated in future studies.

Orexin Receptor Antagonism: Normalizing Sleep Architecture in Old Age and Disease

Sleep is essential for human well-being, yet the quality and quantity of sleep reduce as age advances. Older persons (>65 years old) are more at risk of disorders accompanied and/or exacerbated by poor sleep. Furthermore, evidence supports a bidirectional relationship between disrupted sleep and Alzheimer's disease (AD) or related dementias. Orexin/hypocretin neuropeptides stabilize wakefulness, and several orexin receptor antagonists (ORAs) are approved for the treatment of insomnia in adults. Dysregulation of the orexin system occurs in aging and AD, positioning ORAs as advantageous for these populations. Indeed, several clinical studies indicate that ORAs are efficacious hypnotics in older persons and dementia patients and, as in adults, are generally well tolerated. ORAs are likely to be more effective when administered early in sleep/wake dysregulation to reestablish good sleep/wake-related behaviors and reduce the accumulation of dementia-associated proteinopathic substrates. Improving sleep in aging and dementia represents a tremendous opportunity to benefit patients, caregivers, and health systems.

Efficacy of combined use of Suvorexant and Ramelteon in preventing postoperative delirium: a retrospective comparative study

BACKGROUND

Suvorexant and ramelteon have been presented as useful for preventing postoperative delirium. Previous studies reported on the comparison with benzodiazepine hypnotics which have been known for the risk for inducing delirium, but the comparison with patients not taking any hypnotics has not been reported yet. Therefore, we assessed the incidence rates for postoperative delirium comparing cancer patients who received preoperative combined administration with suvorexant and ramelteon and those not taking any hypnotics.

METHODS

Among 110 cancer patients who underwent surgeries at the Division of Hepato-Biliary-Pancreatic Surgery at the Shizuoka Cancer Center between April 1, 2017 and June 30, 2020, 50 patients who received combined administration with suvorexant and ramelteon from 7 days prior to their surgeries and 60 patients who did not take any hypnotics including suvorexant and ramelteon were classified. They were retrospectively observed during the 7 days from their surgeries onward to compare the cumulative incidence rates for postoperative delirium.

RESULTS

The cumulative incidence rate for postoperative delirium during the 7 days in the combined-administration group was 14.0% (7/50), while that for the no-hypnotic group was 36.7% (22/60), which proved that the incidence rate for the former was significantly low (OR: 0.28, 95%CI: 0.11-0.73, P = 0.009).

CONCLUSIONS

The present study suggests that the preventive combined administration with suvorexant and ramelteon starting from the preoperative period for cancer patients can be effective in lowering the incidence rate for postoperative delirium.

TRIAL REGISTRATION

Retrospectively registered.

Development of postoperative delirium prediction models in patients undergoing cardiovascular surgery using machine learning algorithms

Associations between delirium and postoperative adverse events in cardiovascular surgery have been reported and the preoperative identification of high-risk patients of delirium is needed to implement focused interventions. We aimed to develop and validate machine learning models to predict post-cardiovascular surgery delirium. Patients aged ≥ 40 years who underwent cardiovascular surgery at a single hospital were prospectively enrolled. Preoperative and intraoperative factors were assessed. Each patient was evaluated for postoperative delirium 7 days after surgery. We developed machine learning models using the Bernoulli naive Bayes, Support vector machine, Random forest, Extra-trees, and XGBoost algorithms. Stratified fivefold cross-validation was performed for each developed model. Of the 87 patients, 24 (27.6%) developed postoperative delirium. Age, use of psychotropic drugs, cognitive function (Mini-Cog < 4), index of activities of daily living (Barthel Index < 100), history of stroke or cerebral hemorrhage, and eGFR (estimated glomerular filtration rate) < 60 were selected to develop delirium prediction models. The Extra-trees model had the best area under the receiver operating characteristic curve (0.76 [standard deviation 0.11]; sensitivity: 0.63; specificity: 0.78). XGBoost showed the highest sensitivity (AUROC, 0.75 [0.07]; sensitivity: 0.67; specificity: 0.79). Machine learning algorithms could predict post-cardiovascular delirium using preoperative data.Trial registration: UMIN-CTR (ID; UMIN000049390).

Ramelteon and suvorexant for postoperative delirium in elderly patients with esophageal cancer

BACKGROUND

There is no clear evidence on the prevention of postoperative delirium with pharmacotherapy in elderly patients with esophageal cancer. This retrospective study aimed to evaluate the efficacy of ramelteon and suvorexant in preventing postoperative delirium in this patient group.

METHODS

Data on 251 patients who received radical esophagectomy for thoracic esophageal cancer were collected from January 2010 to September 2021. In total, 74 patients did not receive preventive intervention, and 177 received ramelteon and suvorexant. After propensity score matching, the rate of postoperative delirium was compared between the two groups.

RESULTS

Seventy-two well-balanced patients in each group demonstrated similar clinical and pathological characteristics. The mean ages of the intervention and control groups were 70.8 and 70.3 years, respectively. All the patients underwent McKeown esophagectomy, and in the volume of intraoperative blood loss or operative time did not significantly differ between the two groups. The incidence rates of postoperative hyperactive delirium were 7% (5/72) in the intervention group and 32% (23/72) in the control group (p < 0.001). No severe adverse event potentially attributable to the intervention drug was observed. The multivariate analysis showed that the use of ramelteon and suvorexant was the only independent protective factor against postoperative delirium (hazard ratio 0.157, 95% CI 0.055-0.448, p < 0.001).

CONCLUSIONS

Ramelteon and suvorexant may play an important role in reducing postoperative delirium in elderly patients with esophageal cancer.

Orexin receptor antagonists versus antipsychotics for the management of delirium in intensive care unit patients with cardiovascular disease: A retrospective observational study

OBJECTIVE

Although antipsychotics are often used in the pharmacological treatment of delirium, recent reports suggest the efficacy of orexin receptor antagonists. This study investigated whether orexin receptor antagonists could be a possible treatment option for delirium.

METHOD

A nonblinded nonrandomized routine clinical treatment was performed. Patients treated in intensive care units (ICU) for cardiovascular disease and receiving psychiatric intervention were studied retrospectively. The scores from the Intensive Care Delirium Screening Checklist (ICDSC) were compared between patients treated with orexin receptor antagonists and those treated with antipsychotics.

RESULTS

The mean (standard deviation) ICDSC scores were 4.5 (1.8) at day -1 and 2.6 (2.6) at day 7 for orexin receptor antagonist group (n = 25) and 4.6 (2.4) at day -1 and 4.1 (2.2) at day 7 for antipsychotic group (n = 28). The orexin receptor antagonist group showed significantly lower ICDSC scores than the antipsychotic group (p = 0.021).

CONCLUSION

While precise efficacy cannot be determined from our retrospective, observational, and uncontrolled pilot study, this analysis encourages a future double-blind randomized placebo-controlled trial of orexin-antagonists for delirium treatment.

Data-driven categorization of postoperative delirium symptoms using unsupervised machine learning

Background

Phenotyping analysis that includes time course is useful for understanding the mechanisms and clinical management of postoperative delirium. However, postoperative delirium has not been fully phenotyped. Hypothesis-free categorization of heterogeneous symptoms may be useful for understanding the mechanisms underlying delirium, although evidence is currently lacking. Therefore, we aimed to explore the phenotypes of postoperative delirium following invasive cancer surgery using a data-driven approach with minimal prior knowledge.

Methods

We recruited patients who underwent elective invasive cancer resection. After surgery, participants completed 5 consecutive days of delirium assessments using the Delirium Rating Scale-Revised-98 (DRS-R-98) severity scale. We categorized 65 (13 questionnaire items/day × 5 days) dimensional DRS-R-98 scores using unsupervised machine learning (K-means clustering) to derive a small set of grouped features representing distinct symptoms across all participants. We then reapplied K-means clustering to this set of grouped features to delineate multiple clusters of delirium symptoms.

Results

Participants were 286 patients, of whom 91 developed delirium defined according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, criteria. Following the first K-means clustering, we derived four grouped symptom features: (1) mixed motor, (2) cognitive and higher-order thinking domain with perceptual disturbance and thought content abnormalities, (3) acute and temporal response, and (4) sleep-wake cycle disturbance. Subsequent K-means clustering permitted classification of participants into seven subgroups: (i) cognitive and higher-order thinking domain dominant delirium, (ii) prolonged delirium, (iii) acute and brief delirium, (iv) subsyndromal delirium-enriched, (v) subsyndromal delirium-enriched with insomnia, (vi) insomnia, and (vii) fit.

Conclusion

We found that patients who have undergone invasive cancer resection can be delineated using unsupervised machine learning into three delirium clusters, two subsyndromal delirium clusters, and an insomnia cluster. Validation of clusters and research into the pathophysiology underlying each cluster will help to elucidate the mechanisms of postoperative delirium after invasive cancer surgery.

Sleep during and following critical illness: A narrative review

Sleep is a complex process influenced by biological and environmental factors. Disturbances of sleep quantity and quality occur frequently in the critically ill and remain prevalent in survivors for at least 12 mo. Sleep disturbances are associated with adverse outcomes across multiple organ systems but are most strongly linked to delirium and cognitive impairment. This review will outline the predisposing and precipitating factors for sleep disturbance, categorised into patient, environmental and treatment-related factors. The objective and subjective methodologies used to quantify sleep during critical illness will be reviewed. While polysomnography remains the gold-standard, its use in the critical care setting still presents many barriers. Other methodologies are needed to better understand the pathophysiology, epidemiology and treatment of sleep disturbance in this population. Subjective outcome measures, including the Richards-Campbell Sleep Questionnaire, are still required for trials involving a greater number of patients and provide valuable insight into patients’ experiences of disturbed sleep. Finally, sleep optimisation strategies are reviewed, including intervention bundles, ambient noise and light reduction, quiet time, and the use of ear plugs and eye masks. While drugs to improve sleep are frequently prescribed to patients in the ICU, evidence supporting their effectiveness is lacking.

COVID-19 delirium and encephalopathy: Pathophysiology assumed in the first 3 years of the ongoing pandemic

Background

The coronavirus disease (COVID-19) continues to spread worldwide. It has a high rate of delirium, even in young patients without comorbidities. Infected patients required isolation because of the high infectivity and virulence of COVID-19. The high prevalence of delirium in COVID-19 primarily results from encephalopathy and neuroinflammation caused by acute respiratory distress syndrome (ARDS)-associated cytokine storm. Acute respiratory distress syndrome has been linked to delirium and psychotic symptoms in the subacute phase (4 to 12 weeks), termed post-acute COVID-19 syndrome (PACS), and to brain fog, cognitive dysfunction, and fatigue, termed "long COVID," which persists beyond 12 weeks. However, no review article that mentions "COVID-19 delirium" have never been reported.

Basic Procedures

This narrative review summarizes data on delirium associated with acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and related neurological symptoms of persistent post-infection illness (PACS or long COVID) after persistence of cognitive dysfunction. Thus, we describe the pathophysiological hypothesis of COVID-19 delirium and its continuation as long COVID. This review also describes the treatment of delirium complicated by COVID-19 pneumonia.

Main Findings

SARS-CoV-2 infection is associated with encephalopathy and delirium. An association between COVID-19 infection and Alzheimer's disease has been suggested, and studies are being conducted from multiple facets including genetics, cytology, and postmortem study.

Principal Conclusions

This review suggests that COVID-19 has important short and long-term neuropsychiatric effects. Several hypotheses have been proposed that highlight potential neurobiological mechanisms as causal factors, including neuronal-inflammatory pathways by cytokine storm and cellular senescence, and chronic inflammation.

Association between nocturnal falls and hypnotic drug use in older patients at acute care hospitals

PURPOSE

Although hypnotic drug use is a known risk factor for falls, few reports have analyzed fall risk associated with individual hypnotic drugs after adjusting for confounding factors. While it is recommended that benzodiazepine receptor agonists not be prescribed for older adults, it is unknown whether melatonin receptor agonists and orexin receptor antagonists are safe in this population. Here, we aimed to assess the influence of various hypnotic drugs on fall risk in older patients admitted to acute care hospitals.

METHODS

We investigated the relationship between nocturnal falls and sleeping pill use in 8,044 hospitalized patients aged > 65 years. We used a propensity score matching method to homogenize characteristics of patients with and without nocturnal falls (n = 145 patients per group) using 24 extracted factors (excluding hypnotic drugs) as covariates.

RESULTS

Our analysis of fall risk for each hypnotic drug revealed that benzodiazepine receptor agonists were the only drugs significantly associated with falls, suggesting that use of the drugs is a risk factor for falls in older adults (p = 0.003). In addition, a multivariate analysis of 24 selected factors, excluding hypnotic drugs, revealed that patients with advanced recurrent malignancies were at greatest risk of experiencing falls (OR: 2.62; 95% CI: 1.23-5.60; p = 0.013).

CONCLUSION

Benzodiazepine receptor agonists should be avoided in older hospitalized patients since they increase fall risk, with melatonin receptor agonists and orexin receptor antagonists used instead. Particularly, fall risk associated with hypnotic drugs should be considered in patients with advanced recurrent malignancies.

Evaluation of the delirium preventive effect of dual orexin receptor antagonist (DORA) in critically ill adult patients requiring ventilation with tracheal intubation at an advanced emergency center: A single-center, retrospective, observational study

OBJECTIVE

ICU delirium reportedly contributes to increased mortality attributed to underlying diseases, long-term cognitive decline, and increased healthcare costs. Dual orexin receptor antagonists (DORAs), suvorexant and lemborexant, have been suggested for preventing ICU delirium. Although ventilator management is a risk factor for delirium, no study has examined the efficacy of suvorexant and lemborexant in preventing delirium in critically ill patients requiring ventilation. Thus, we retrospectively evaluated the efficacy of DORA in preventing delirium in critically ill adult patients requiring ventilatory management in the emergency room.

METHOD

This retrospective study included patients aged ≥18 years who were admitted to the emergency room and received ventilator support between January 2015 and April 2022. The HR (95% CI) for delirium development in patients taking DORA was estimated using a Cox proportional hazards model, which was adjusted for the patient background and concomitant medications. HRs were calculated for patients taking suvorexant and those taking lemborexant using a stratified analysis.

RESULTS

Of the 297 patients included in the study, 67 were in the DORA group; 50 were on suvorexant and 17 were on lemborexant. The DORA group had a lower incidence of delirium than the control group (p < 0.0001). The risk of delirium was lower in the DORA group compared the control group (HR, 0.22; 95% CI 0.12-0.40).The risk of developing delirium was lower with suvorexant (HR 0.22; 95% CI 0.11-0.41) and lemborexant (HR 0.25; 95% CI 0.08-0.81).

CONCLUSION

DORA is a promising drug that could have the potential to prevent delirium, and its efficacy in preventing delirium should be tested in randomized controlled trials in the future.

Anti-inflammatory medication use associated with reduced delirium risk and all-cause mortality: A retrospective cohort study

OBJECTIVE

To investigate the relationship between history of anti-inflammatory medication use and delirium risk, as well as long-term mortality.

METHODS

In this retrospective cohort study, subjects recruited between January 2016 and March 2020 were analyzed. Information about anti-inflammatory medication use history including aspirin, NSAIDs, glucosamine, and other anti-inflammatory drugs, was collected. Logistic regression analysis investigated the relationship between anti-inflammatory medications and delirium. Log-rank analysis and cox proportional hazards model investigated the relationship between anti-inflammatory medications and one-year mortality.

RESULTS

The data from 1274 subjects were analyzed. The prevalence of delirium was significantly lower in subjects with NSAIDs usage (23.0%) than in those without NSAIDs usage (35.0%) (p < 0.001). Logistic regression analysis controlling for age, sex, dementia status, and hospitalization department showed that the risk of delirium tended to be reduced by a history of NSAIDs use (OR, 0.76 [95% CI, 0.55 to 1.03]). The one-year mortality in the subjects with NSAIDs (survival rate, 0.879 [95% CI, 0.845 to 0.906]) was significantly higher than in the subjects without NSAIDs (survival rate, 0.776 [95% CI, 0.746 to 0.803]) (p < 0.001). A history of NSAIDs use associated with the decreased risk of one-year mortality even after adjustment for age, sex, Charlson Comorbidity Index, delirium status, and hospitalization department (HR, 0.70 [95% CI, 0.51 to 0.96]).

CONCLUSION

This study suggested that NSAIDs usage was associated with decreased delirium prevalence and lower one-year mortality. The potential benefit of NSAIDs on delirium risk and mortality were shown.

Acceptability of transdermal antipsychotic patches by patients who refuse oral medication and their effectiveness in preventing recurrence of delirium: a retrospective observational study

Injectable antipsychotics had been used for patients who refuse oral medications in delirium practice. The objectives were to investigate acceptability of transdermal antipsychotic patches by patients who refuse oral medications and their effectiveness in preventing recurrence of delirium. In this retrospective observational study, data were collected between October 2019 and December 2021. The sample was represented by patients hospitalized because of acute diseases or elective surgery who had delirium on the night before the consultation and had refused oral therapy after consultation. Delirium has been diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Instead, a transdermal patch of blonanserin, a second-generation antipsychotic drug, was tried. The primary outcome was the rate of patients who accepted it. The secondary outcome was recurrence rates of delirium. As much as 95.1% of patients who refused oral medications (98/103 patients) accepted to receive the transdermal patch. Of these, 24 patients developed delirium again, whereas all five patients who refused it developed delirium again [24.5% (24/98) vs. 100% (5/5); P = 0.0014]. The present findings suggest that transdermal antipsychotic patches are more likely to be accepted by patients who refuse oral medications. Prospective studies are needed.

Effectiveness of suvorexant versus benzodiazepine receptor agonist sleep drugs in reducing the risk of hip fracture: Findings from a regional population-based cohort study

Sleep drugs are often necessary to treat insomnia in older patients. Benzodiazepine receptor agonists (BZRAs) are primarily used for insomnia in these patients, but there are concerns regarding their association with delirium and bone fractures. Among sleep drugs, orexin receptor antagonists such as suvorexant have a lower risk of delirium than BZRAs, but their effectiveness in preventing hip fractures is unknown. Hip fracture is a life-threatening trauma in advanced-age patients and a social problem. Therefore, we investigated the relationship between suvorexant and hip fracture. The Shizuoka Kokuho Database was used to compare the time to hip fracture in patients who had been newly taking suvorexant and other sleep drugs such as benzodiazepines since November 2014. A proportional hazards model for hip fracture as an outcome was used to estimate the hazard ratio. Propensity scores were estimated using a logistic regression model, and the confounding factors were age, sex, several comorbidities, and each oral medication. The suvorexant group comprised 6860 patients (110 with hip fracture), and the BZRA group (benzodiazepines and Z-drugs) comprised 50,203 patients (1487 with hip fracture). In the matched cohort (6855:6855 patients), 259 and 249 patients in the suvorexant and BZRA group developed hip fractures during the observational period, respectively. The hazard ratio of the suvorexant group compared with the BZRA group was 1.48 (95% confidence interval, 1.20-1.82). In the subgroup analysis, patients in the suvorexant group had a higher risk of hip fracture if they were aged >75 years, had no diabetes, had no neurological disease, had no renal failure, had liver disease, had hypertension, were not taking alpha 1 blockers, and were not taking oral steroids. Among people in the Japanese regional population who use sleep drugs, patients taking suvorexant can be at higher risk of hip fracture than patients taking BZRAs.

Can Lemborexant for Insomnia Prevent Delirium in High-Risk Patients with Pancreato-Biliary Disease after Endoscopic Procedures under Deep Sedation?

Background and aim: Pancreato-biliary patients who undergo endoscopic procedures have high potential risk of delirium. Although benzodiazepine has traditionally been used to treat insomnia, this drug might increase delirium. Lemborexant may be useful for patients with insomnia, without worsening delirium, although there is no evidence for high-risk patients with pancreato-biliary disease. The aim of this pilot study was to evaluate the safety and efficacy of lemborexant for insomnia and the frequency of delirium after endoscopic procedures under deep sedation in patients with pancreato-biliary disease. Method: This retrospective study included consecutive patients who were administered lemborexant after endoscopic procedures for pancreato-biliary disease between September 2020 and June 2022. The primary outcome of this study was evaluation of the safety and efficacy of lemborexant for insomnia. Frequency of delirium was the secondary outcome. Result: In total, 64 patients who had the complication of insomnia after an endoscopic procedure were included in the study. Risk factors for delirium were advanced age (n = 36, 56.3%), dementia (n = 10, 15.6%), and regular alcohol use (n = 13, 20.3%), as well as the sedatives midazolam and pentazocine that were administered to all patients at the time of the endoscopic procedure. Successful asleep was achieved by 61/64 patients (95.3%). No fall event was observed during the night following the procedure in any patient. However, mild consciousness transformation was observed in one patient. Conclusions: In conclusion, lemborexant use may be effective and safe for use after endoscopic procedures in pancreato-biliary patients, without increasing the risk of delirium.

Delusions and Hallucinations Are Associated With Greater Severity of Delirium

BACKGROUND

The 3 core domains of delirium (cognitive, higher level thinking, circadian) do not include the less common noncore psychotic symptoms. However, psychosis might inform about perturbations of neural circuitry, outcomes, or suggest tailored clinical management.

OBJECTIVE

We assessed for the first time the relationships between psychosis and other characteristics of delirium in patients without confounders for delirium phenotype, such as dementia or antipsychotics treatment.

METHODS

Cross-sectional analysis of 366 adults with delirium per the Delirium Rating Scale Revised-98, whose items distinguish hallucinations and delusions from other types of misperceptions and abnormal thought content, assessed during the preceding 24 hours to capture symptom severity fluctuation. The relationship of psychosis with other delirium characteristics was assessed using bivariate comparisons and analysis of variance as appropriate for groups with no psychosis and any psychosis (hallucinations and/or delusions), and subgroups with only hallucinations, only delusions, or both. A discriminant logistic model assessed variables associated with presence of any psychotic features versus none.

RESULTS

Delirium with any psychotic features occurred in 44.5% (163 of 366). Of the 366, 119 (32.5%) had only hallucinations (Hall), 14 (3.8%) had only delusions (Del), and 30 (8.2%) had both (Both). In the psychotic group (n = 163), 73.0% were Hall, 8.6% Del, and 18.4% Both. All psychotic patient groupings had significantly greater delirium severity on the Delirium Rating Scale Revised-98. Delusions and hallucinations were discordant for occurring together. The discriminant model found increased odds of having psychosis as 3 symptom severities increased (visuospatial ability, thought process, and sleep-wake cycle) where these each represented a delirium core domain. The noncore symptom of lability of affect had high odds ratio for psychosis, while motor retardation reduced odds of psychosis in this model.

CONCLUSIONS

Consistent with prior reports, psychosis occurred in less than half of delirious patients with delusions being infrequent, and an association with affective lability was found. We are the first to report that psychotic features are a marker for more severe delirium affecting all core domains. Given that previous functional magnetic resonance imaging research found a correlation between neural network dysconnectivity with greater severity of delirium, psychotic symptoms might be a clinical marker for greater underlying cerebral cortical neural circuitry dysfunction.

Reducing the effect of immortal time bias affects the analysis of prevention of delirium by suvorexant in critically ill patients: A retrospective cohort study

BACKGROUND

Studies assessing the effect of suvorexant on delirium prevention included patients treated before development of delirium, which can introduce immortal time bias. The objective of the present study was to evaluate the effect of suvorexant on delirium, comparing patients treated before the onset of delirium with patients treated within 72h of admission using the same dataset.

METHODS

Data from adult patients admitted to the ICU from August 2018 to July 2021 were retrospectively analyzed. In "any time before" analysis, the incidence of delirium was compared for patients who received suvorexant at any time during their ICU stay (suvorexant) (unless delirium developed before treatment) with patients who either did not receive suvorexant or received suvorexant after development of delirium (control). This design was used in previously published studies. In "within 72h" analysis, the incidence of delirium was compared for patients who received suvorexant within 72 hours of admission (suvorexant) and patients who did not receive suvorexant or received it more than 72 hours after admission (control). Patients who developed delirium during the initial 72 hours were excluded from "within 72h" analysis (N = 799).

RESULTS

"Within 72h" analysis included 1,255 patients, and "any time before" analysis included 2,054 patients (of 6599 admissions). The unadjusted hazard ratio of "any time before" analysis was 0.16 and the 95% confidence interval was 0.13-0.21 (p<0.01). The adjusted hazard ratio was 0.21, and the 95% confidence interval was 0.16-0.27 (p<0.01). "Within 72h" analysis had an unadjusted hazard ratio of 0.54 and the 95% confidence interval was 0.36-0.82 (p<0.01). However, this association lost statistical significance after adjustment for potential confounders (adjusted hazard ratio 1.02, 95% confidence interval 0.65-1.59, p = 0.93).

CONCLUSION

Reducing the effect of immortal time bias led to a significantly reduced effect of suvorexant for the prevention of delirium.

Sleep Spindles and K-Complexes Are Favorable Prognostic Biomarkers in Critically Ill Patients

SUMMARY

In this narrative review, we summarize recent research on the prognostic significance of biomarkers of sleep in continuous EEG and polysomnographic recordings in intensive care unit patients. Recent studies show the EEG biosignatures of non-rapid eye movement 2 sleep (sleep spindles and K-complexes) on continuous EEG in critically ill patients better predict functional outcomes and mortality than the ictal-interictal continuum patterns. Emergence of more complex and better organized sleep architecture has been shown to parallel neurocognitive recovery and correlate with functional outcomes in traumatic brain injury and strokes. Particularly interesting are studies which suggest intravenous dexmedetomidine may induce a more biomimetic non-rapid eye movement sleep state than intravenous propofol, potentially providing more restorative sleep and lessening delirium. Protocols to improve intensive care unit sleep and neurophysiological studies evaluating the effect of these on sleep and sleep architecture are here reviewed.

Pharmacotherapy for elderly patients with delirium in a general ward setting: A retrospective study

Antipsychotic medications are widely used in patients with delirium. However, antipsychotics may lead to various adverse events including cardiac arrythmias, extrapyramidal side effects, and oversedation. This study aimed to investigate whether non-antipsychotic medications including ramelteon, suvorexant, and trazodone are useful for the treatment of elderly inpatients with delirium in a general ward setting. This was a retrospective cohort study using medical chart reviews of all consecutive inpatients with hyperactive forms of delirium who were admitted to a regional general hospital. The primary outcome of this study was to evaluate whether non-antipsychotic medication (ramelteon, suvorexant, and trazodone) is inferior, in terms of efficacy and safety, to antipsychotic medication in delirium treatment. Of 154 patients who consulted psychiatrists during the study period, 33 patients were diagnosed with hyperactive delirium. Of these patients, 21 were categorized into the antipsychotic medication group, and 12 were categorized into the non-antipsychotic medication group. The duration of delirium after pharmacological treatments was not statistically different between the two groups. However, the rates of adverse events related to psychotropic medications in the antipsychotic medication group were significantly higher than that in the non-antipsychotic medication group. This study demonstrated that, in the treatment of elderly patients with delirium, non-antipsychotic drugs, such as suvorexant, ramelteon, and trazodone, could be more useful than antipsychotics in terms of efficacy and safety.

Suvorexant with or without ramelteon to prevent delirium: a systematic review and meta-analysis

Delirium is a common and serious neurobehavioral syndrome, associated with prolonged hospital stays, and increased morbidity and mortality. As it remains unclear whether suvorexant with or without ramelteon prevents delirium in elderly hospitalized patients, we conducted a systematic review and meta-analysis to evaluate, searching the PubMed, Cochrane Library, Web of Science, EMBASE, and EBSCOhost databases for all randomized controlled trials (RCTs), case-control studies, and cohort studies that investigated the effects of suvorexant with or without ramelteon on delirium in adult hospitalized patients. The primary outcome was the incidence of delirium. Two randomized controlled trials, 7 cohort studies and 2 case-control studies involving 2594 patients were included in this meta-analysis. The results showed that both suvorexant alone (odds ratio (OR) = 0.30, 95% confidence interval (CI): 0.14-0.65, P = 0.002) and suvorexant with ramelteon (OR = 0.39, 95% CI 0.23-0.65, P = 0.0003) reduced the incidence of delirium in adult hospitalized patients. Six studies involved the use of benzodiazepines; subgroup analysis performed separately in the suvorexant alone and suvorexant with ramelteon groups indicated that when benzodiazepine was administered, suvorexant with ramelteon was effective at reducing the incidence of delirium (OR = 0.53, 95% CI 0.37-0.74, P = 0.0002), but no significant difference was observed for suvorexant alone (OR = 0.40, 95% CI 0.11-1.53, P = 0.18). The current literature thus supports the effectiveness of suvorexant with or without ramelteon for delirium prevention, although suvorexant alone failed to significantly reduce the incidence of delirium when benzodiazepine was administered. The present study was limited by the significant heterogeneity among the included studies, and caution should be exercised when interpreting the results. This study was registered in the PROSPERO database (CRD4202017964).

Prevention of Delirium Via Melatonin and Orexin Neurotransmission

The fundamental conception of delirium is altered arousal. In addition, sleep-wake cycle isturbances including insomnia, excessive daytime napping, and disintegration of the xpected circadian patterns have been described as a characteristic component of delirium or decades, and demonstrated to be a core symptom domain of delirium. Although on-pharmacological interventions are successful to some extent, they have limitations due o various biological etiologies for delirium. Among pharmacological interventions, ntipsychotics seem to be effective, but they are not suitable for preventive use because f relatively frequent side-effects such as extrapyramidal symptoms. Recently, new type of rugs for insomnia have been focused with respect to delirium prevention. Recent eta-analyses show effectiveness of melatonin receptor agonists and orexin receptor ntagonists for delirium prevention, and real-world data support them.

Effect of enterally administered sleep-promoting medication on the intravenous sedative dose and its safety and cost profile in mechanically ventilated patients: A retrospective cohort study

BACKGROUND

The clinical effect of enteral administration of sleep-promoting medication (SPM) in mechanically ventilated patients remains unclear. This study aimed to investigate the relationship between enteral SPM administration and the intravenous sedative dose and examine the safety and cost of enteral SPM administration.

METHODS

This single-center retrospective cohort study was conducted in a Japanese tertiary hospital intensive care unit (ICU). The exposure was enteral SPM administration during mechanical ventilation. The outcome was the average daily propofol dose per body weight administered as a continuous sedative during mechanical ventilation. Patients were divided into three groups based on the timing of SPM administration at ICU admission: "administration within 48 hours (early administration [EA])," "administration after 48 hours (late administration [LA])," and "no administration (NA)." We used multiple linear regression models.

RESULTS

Of 123 included patients, 37, 50, and 36 patients were assigned to the EA, LA, and NA groups, respectively. The average daily propofol dose per body weight was significantly lower in the EA group than in the LA and NA groups (β -5.13 [95% confidence interval (CI) -8.93 to -1.33] and β -4.51 [95% CI -8.59 to -0.43], respectively). Regarding safety, enteral SPM administration did not increase adverse events, including self-extubation. The total cost of neuroactive drugs tended to be lower in the EA group than in the LA and NA groups.

CONCLUSIONS

Early enteral SPM administration reduced the average daily propofol dose per body weight without increasing adverse events.

Predictors of postoperative delirium in elderly patients following total hip and knee arthroplasty: a systematic review and meta-analysis

BACKGROUND

Postoperative delirium (POD) is widely reported as a common postoperative complication following total joint arthroplasty (TJA) of the hip and knee in elderly patients, leading to many adverse effects. We sought to investigate predictors of delirium after TJA.

METHODS

PubMed, EMBASE, Cochrane Library and Web of Science were searched up to 2020 for studies examining POD following TJA in elderly patients. Pooled odds ratio (OR) and mean difference (MD) of those who experienced delirium compared to those who did not were calculated for each variable. The Newcastle-Ottawa Scale (NOS) was used for the study quality evaluation.

RESULTS

Fifteen studies with 31 potential factors were included. In the primary analysis, 9 factors were associated with POD, comprising advanced age (MD 3.81; 95% confidence interval (CI) 1.80-5.83), dementia (OR 24.85; 95% CI 7.26-85.02), hypertension (OR 2.26; 95% CI 1.31-3.89), diabetes (OR 2.02; 95% CI 1.15-3.55), stroke (OR 14.61; 95% CI 5.26-40.55), psychiatric illness (OR 2.72; 95% CI 1.45-5.08), use of sedative-hypnotics (OR 6.42; 95% CI 2.53-16.27), lower preoperative levels of hemoglobin (MD - 0.56; 95% CI - 0.89-- 0.22), and lower preoperative mini-mental state examination score (MD - 0.40; 95% CI - 0.69-- 0.12). Twelve studies were included in the systematic review, of which 24 factors were additionally correlated with POD using single studies.

CONCLUSIONS

Strategies and interventions should be implemented for the elderly patients receiving TJA surgeries with potential predictors identified in this meta-analysis.

The assessment of risk factors for postoperative delirium using cubic spline curves in gastroenterological surgery

PURPOSE

Delirium is associated with longer hospital stays and increased medical costs and mortality. This study explored the risk factors for postoperative delirium in gastroenterological surgery and investigated the association between qualitative changes in risk factors and the incidence of postoperative delirium.

METHODS

A total of 418 patients > 18 years old who underwent gastroenterological surgery at our department between April 2018 and September 2019 were included. Risk factors were identified by comparing patients with and without postoperative delirium. Continuous variables were evaluated graphically using cubic spline curves. A logistic regression analysis was performed to assess independent risk factors.

RESULTS

The incidence of postoperative delirium was 6.9%. The cubic spline curve showed that the incidence of postoperative delirium began to increase at 50 years old and increased sharply at 70 years old. A multiple logistic regression analysis of patients > 50 years old identified 5 risk factors: age ≥ 70 years, preoperative serum albumin ≤ 3.8 g/dL, psychosis, sedative-hypnotics, and intensive-care unit admission.

CONCLUSION

The risk of postoperative delirium increases progressively at 50 years old and sharply at 70 years old. Advanced age, preoperative hypoalbuminemia, psychosis, sedative-hypnotics, and intensive-care unit admission are risk factors for postoperative delirium in patients > 50 years old undergoing gastroenterological surgery.

Evidence-based insomnia treatment strategy using novel orexin antagonists: A review

Most conventional insomnia medications are gamma‐aminobutylic acid receptor agonists. However, physical dependence is a concern and one of the major limiting factors for long‐term treatment. The dual orexin receptor antagonists, suvorexant and lemborexant, were recently approved for treating chronic insomnia, giving a novel pharmacotherapeutic option. Because there are no comparative studies on these drugs, a network meta‐analysis was conducted, which is suitable for comparing interventions. According to this analysis, 5‐ and 10‐mg lemborexant were superior to 20‐mg suvorexant because of the greater improvement in initiating sleep after 1‐week administration. Furthermore, 5‐mg lemborexant (not 10 mg) and suvorexant were similarly well tolerated, without requiring discontinuation due to adverse events. We also overviewed the pharmacological and pharmacokinetic properties of lemborexant and suvorexant that may support these clinical outcomes. When compared to suvorexant, lemborexant quickly binds to the orexin receptors. The time to reach the maximum concentration after multiple administrations is shorter for lemborexant than for suvorexant. Considering these results, we recommend 5‐mg lemborexant as an initial treatment for insomnia, followed by 10‐mg lemborexant or suvorexant.

A network meta‐analysis of the dual orexin receptor antagonists, suvorexant, and lemborexant, showed that 5‐ and 10‐mg lemborexant were superior to 20‐mg suvorexant, with greater improvement in sleep onset after 1 week of treatment. In addition, 5‐mg (but not 10‐mg) lemborexant and suvorexant were similarly well tolerated. We have overviewed the pharmacological and pharmacokinetic properties of lemborexant and suvorexant that may support these clinical results, and recommended 5‐mg lemborexant as initial treatment for insomnia, followed by 10‐mg lemborexant or suvorexant.

Prevention of postoperative delirium after cardiovascular surgery: A team-based approach

OBJECTIVE

We investigated the efficacy of the Delirium Team Approach program for delirium prevention after cardiovascular surgery.

METHODS

We retrospectively investigated 256 patients who underwent cardiac or thoracic vascular surgery between May 2017 and May 2020. We compared the outcomes before and after implementation of the Delirium Team Approach program in December 2018. The program included the following components: (a) educational sessions for the medical team regarding delirium and its management, (b) review of preprinted physician orders for insomnia and agitation, and (c) routine screening for delirium. We investigated the early outcomes and effects of the Delirium Team Approach program on postoperative delirium.

RESULTS

The incidence of postoperative delirium significantly decreased from 53.3% to 37.0% after implementation of the Delirium Team Approach program (P = .008). Although no intergroup differences were observed in the rates of stroke and reexploration for bleeding, the length of intensive care unit stay and the overall length of postoperative hospital stay were shorter in the postintervention group. Hospital costs, excluding surgery, and the cost during intensive care unit stay were lower in the postintervention group. Multivariable analysis showed that the Delirium Team Approach program was associated with a reduction in postoperative delirium (odds ratio, 0.38; 95% confidence interval, 0.21-0.67; P = .001). Other predictors of delirium included age, dementia, chronic kidney disease, and intubation time. After risk adjustment using propensity score matching, the rate of postoperative delirium was lower in the postintervention group.

CONCLUSIONS

Implementation of the Delirium Team Approach program was associated with a lower incidence of postoperative delirium in patients who underwent cardiovascular surgery.

[Standardization of Hypnotic Agents for Prevention of Falls: A Pharmacoeconomic Study]

To reduce the number of falls caused by hypnotic agents, the standardization of insomnia treatment was carried out at Yamaguchi University Hospital from April 2019. There were concerns that medical costs would increase due to the selected medicines-suvorexant and eszopiclone-being more expensive than conventional benzodiazepines. In this study, the standardization of insomnia treatment was evaluated by pharmacoeconomics. The costs of the hypnotic agents was considered, as was the cost of examination/treatment following falls. Effectiveness was evaluated as the incidence of falls within 24 hours of taking hypnotic agents. This analysis took the public healthcare payer's perspective. Propensity score matching based on patient background, showed that, per hospitalization the medicine costs of the recommended group increased by 1,020 yen, however, the examination/treatment costs following falls decreased by 487 yen when compared with the non-recommended group. Overall, the recommended group incurred costs of 533 yen more per hospitalization for patients prescribed hypnotic agents compared to the non-recommended group, but the incidence of falls for the recommended group was significantly lower than that in the non-recommended group (1.9% vs. 6.3%; p<0.01). These results suggest that in order to prevent the incidence of falls by 1 case, it is necessary to increase costs by 12,086 yen which is the subthreshold cost for switching to the recommended medicine as standardization. The selection of recommended medicines may be a cost-effectiveness option compared with non-recommended medicines.

Significant decrease in delirium referrals after changing hypnotic from benzodiazepine to suvorexant

BACKGROUND

The use of benzodiazepines (BZDs) causes delirium, especially in elderly people. For this reason, suvorexant has been recommended as the first-line hypnotic in elderly patients. The aim of this study was to determine whether the first-line use of suvorexant, instead of BZDs, decreases referrals for delirium in elderly patients.

METHODS

Since May 2016 at Nagoya Ekisaikai Hospital, suvorexant has been recommended as the first-line hypnotic instead of BZDs. In May 2017, suvorexant was adopted as the first-line hypnotic. The number of delirium cases referred to psychiatry was compared among three consecutive periods: period A (May 2015-April 2016), during which BZDs were mainly used for insomnia; period B (May 2016-April 2017), during which the use of suvorexant was recommended instead of BZDs; and period C (May 2017-April 2018), during which suvorexant was principally adopted as the first-line hypnotic for insomnia. Potential confounding factors that may affect the development of delirium were also examined during the three periods.

RESULTS

The number of delirium referral cases in elderly patients in each period decreased, from 133 in period A to 86 in period B and 53 in period C. The rate of delirium referral cases decreased significantly every year (P = 9.02 × 10^-10 ). Almost no significant confounding factors other than hypnotics were detected during the three periods.

CONCLUSION

The referrals for delirium in elderly patients decreased significantly after the hypnotic was changed from BZDs to suvorexant.

Delirium: A Marker of Vulnerability in Older People

Delirium is an acute neuropsychiatric syndrome and one of the most common presenting symptoms of acute medical illnesses in older people. Delirium can be triggered by a single cause, but in most cases, it is multifactorial as it depends on the interaction between predisposing and precipitating factors. Delirium is highly prevalent in older patients across various settings of care and correlates with an increased risk of adverse clinical outcomes. Several pathophysiological mechanisms may contribute to its onset, including neurotransmitter imbalance, neuroinflammation, altered brain metabolism, and impaired neuronal network connectivity. Several screening and diagnostic tools for delirium exist, but they are unfortunately underutilized. Additionally, the diagnosis of delirium superimposed on dementia poses a formidable challenge - especially if dementia is severe. Non-pharmacological approaches for the prevention and multidomain interventions for the treatment of delirium are recommended, given that there is currently no robust evidence of drugs that can prevent or resolve delirium. This article aims to review the current understanding about delirium in older people. To achieve this goal, we will describe the epidemiology and outcomes of the syndrome, the pathophysiological mechanisms that are supposed to be involved, the most commonly used tools for screening and diagnosis, and prevention strategies and treatments recommended. This review is intended as a brief guide for clinicians in hospital wards to improve their knowledge and practice. At the end of the article, we propose an approach to improve the quality of care provided to older patients throughout a systematic detection of delirium.

A retrospective study of factors associated with persistent delirium

BACKGROUND

It has been reported that delirium causes various problems. Many researchers have reported the risk factors associated with the onset of delirium; however, there are few reports focused on persistent delirium. This study aimed to identify the risk factors associated with persistent delirium.

METHODS

A total of 573 patients hospitalised in Nara Prefecture General Medical Centre from October 2014 through September 2017 who were referred to the psychiatry consultation service were included in this study. Persistent delirium was defined as delirium lasting for 14 days or more. A retrospective study was carried out based on the patients' records. The relationship between various background factors and persistent delirium was statistically analysed.

RESULTS

Of the 573 hospitalised patients, 295 were diagnosed as having delirium. Forty-six patients with persistent delirium and 181 patients with nonpersistent delirium were included in this study. Multivariable logistic regression analyses revealed that male gender, opioid analgesics use, non-opioid analgesics use, and low serum sodium were significantly and independently associated with persistent delirium. Ramelteon or trazodone was used significantly more in persistent delirium, although each use was not significant.

CONCLUSION

This is the first study to reveal that male gender and use of analgesics were associated with persistent delirium in general hospital. However, as this is a case-control study and may contain bias, future cohort studies and intervention studies are needed. It is also necessary to investigate the relevance of the 'degree of pain' behind the use of analgesics.

Bispectral EEG (BSEEG) quantifying neuro-inflammation in mice induced by systemic inflammation: A potential mouse model of delirium

Most of the animal studies using inflammation-induced cognitive change have relied on behavioral testing without objective and biologically solid methods to quantify the severity of cognitive disturbances. We have developed a bispectral EEG (BSEEG) method using a novel algorithm in clinical study. This method effectively differentiates between patients with and without delirium, and predict long-term mortality. In the present study, we aimed to apply our bispectral EEG (BSEEG) method, which can detect patients with delirium, to a mouse model of delirium with systemic inflammation induced by lipopolysaccharides (LPS) injection. We recorded EEG after LPS injection using wildtype early adulthood mice (2~3-month-old) and aged mice (18-19-month-old). Animal EEG recordings were converted for power spectral density to calculate BSEEG score using the similar BSEEG algorithm previously developed for our human study. The BSEEG score was relatively stable and slightly high during the day. Alternatively, the BSEEG score was erratic and low in average during the night. LPS injection increased the BSEEG score dose-dependently and diminished the diurnal changes. The mean BSEEG score increased much more in the aged mice group as dosage increased. Our results suggest that BSEEG method can objectively "quantify" level of neuro-Inflammation induced by systemic inflammation (LPS), and that this BSEEG method can be useful as a model of delirium in mice.

Mortality and morbidity following postoperative use of short-term, low-dose quetiapine vs risperidone in patients with diabetes: Analysis using a national inpatient database

PURPOSE

Short-term, low-dose quetiapine is used to treat postoperative delirium and insomnia. Quetiapine is contraindicated for patients with diabetes in Japan because there have been several case reports of diabetic ketoacidosis (DKA) in patients receiving long-term, high-dose quetiapine. However, because safety of short-term, low-dose quetiapine remains controversial, it is prescribed for patients with diabetes in real-world clinical practice. The present study aimed to compare in-hospital mortality and morbidity between short-term, low-dose quetiapine and risperidone in postoperative patients with diabetes.

METHODS

We used a national inpatient database in Japan to perform a retrospective cohort study. We identified hospitalized patients with diabetes who underwent scheduled elective surgery and received oral quetiapine 200 mg/d or less or oral risperidone 4 mg/d or less within 7 days of surgery between July 2010 and March 2018. We performed one-to-one propensity score-matched analyses to compare outcomes between patients with quetiapine and risperidone. The primary outcome was in-hospital mortality. The secondary outcome was infectious complications (pneumonia, urinary tract infection, surgical site infection, and sepsis).

RESULTS

Propensity score matching created 665 pairs of patients who received quetiapine or risperidone. The primary outcome was observed in 19 (2.9%) of the quetiapine group and 11 (1.7%) of the risperidone group (relative risk, 1.27; 95% confidence interval, 0.97-1.68; P = .14). The secondary outcome did not differ significantly between the groups.

CONCLUSION

In terms of mortality and infectious outcomes, safety of quetiapine and risperidone may be comparable.

Melatonin, Ramelteon, Suvorexant, and Dexmedetomidine to Promote Sleep and Prevent Delirium in Critically Ill Patients: A Narrative Review With Practical Applications

Sleep plays an important role in the recovery of critically ill patients. However, patients in the intensive care unit (ICU) often suffer sleep disturbances and abnormal circadian rhythms, which may increase delirium and lengthen ICU stay. Nonpharmacologic strategies for preventing and treating sleep disturbances and delirium, such as overnight eye masks and ear plugs, are usually employed first, given the lack of adverse effects. However, a multimodal approach to care including pharmacotherapy may be necessary. Despite the limited available data supporting their use, medications such as melatonin, ramelteon, suvorexant, and dexmedetomidine may promote sleep and improve a variety of patient-centric outcomes such as delirium. This narrative review focuses on these nonbenzodiazepine agents used for sleep in the ICU. Practical application of each of these agents is described for when providers choose to utilize one of these pharmacotherapies to promote sleep or prevent delirium.

New Cutoff Scores for Delirium Screening Tools to Predict Patient Mortality

BACKGROUND/OBJECTIVES

Detecting delirium is important to identify patients with a high risk of poor outcomes. Although many different kinds of screening instruments for delirium exist, there is no solid consensus about which methods are the most effective. In addition, it is important to find the most useful tools in predicting outcomes such as mortality.

DESIGN

Retrospective cohort study.

SETTING

University of Iowa Hospitals and Clinics.

PARTICIPANTS

A total of 1,125 adult inpatients (mean age = 67.7; median age = 69).

MEASUREMENTS

Post hoc analyses were performed based on existing data from the Confusion Assessment Method for Intensive Care Unit (CAM-ICU), Delirium Rating Scale-Revised-98 (DRS), and the Delirium Observation Screening Scale (DOSS). Correlation among these scales and relationships between 365-day mortality and each scale were evaluated.

RESULTS

A positive result on the CAM-ICU ("CAM-ICU positive") was associated with higher DRS and DOSS scores. A DRS score = 9/10 was the best cutoff to detect CAM-ICU positive, and DOSS = 2/3 was the best cutoff to detect CAM-ICU positive. CAM-ICU positive was associated with high 365-day mortality. DRS score = 9/10 and DOSS score = 0/1 were found to differentiate mortality risk the most significantly. Higher DRS and DOSS scores significantly coincided with a decrease in a patient's survival rate at 365 days.

CONCLUSION

The best DRS and DOSS cutoff scores to differentiate 365-day mortality risk were lower than those commonly used to detect delirium in the literature. New cutoff scores for the DRS and DOSS might be useful in differentiating risk of mortality among hospital patients.

[Association Suvorexant and Ramelteon Use with the Risk of Falling: A Retrospective Case-control Study]

Sedative hypnotics are among the classes of drugs reported to influence falls. However, the effects of the sedative hypnotic drugs, suvorexant and ramelteon, on falls are not well known. Therefore, we conducted this retrospective case-control study to examine the association of the use of these two sedative hypnotics with the risk of falls. Conducted at the Sapporo Medical University Hospital in Japan, our study included 360 patients with fall incidents and 819 randomly selected control patients. Patients in the fall group were significantly older with a lower body mass index, and had a history of falls, disabilities in activities of daily living, cognitive impairment, and delirium. Monovariate analysis revealed that patients in the fall group frequently used ramelteon [odds ratio (OR) 2.38, 95% confidence interval (CI): 1.49-3.81, p<0.001], but rarely used suvorexant (OR 0.66, 95% CI: 0.29-1.39, p=0.317), compared with control patients. Furthermore, multivariate analysis revealed that ramelteon use did not increase the risk of falls (adjusted OR 1.43, 95% CI: 0.82-2.48, p=0.207), whereas suvorexant use significantly decreased the risk of falls (adjusted OR 0.32, 95% CI: 0.13-0.76, p=0.009). Although ramelteon tends to be used in patients at a high risk of falls, it may not increase the risk of falls. In contrast, the use of suvorexant may reduce the risk of falls.

Suvorexant for the prevention of delirium: A meta-analysis

BACKGROUND

Delirium is a frequently encountered complication, which is associated with increased mortality. Suvorexant, an approved agent for the treatment of insomnia, is recently suggested to be also effective for prevention of delirium by some authors. However, a consensus has yet to be reached. The goal of this study was to perform a meta-analysis to overall estimate the effectiveness of suvorexant in preventing delirium and its related consequences.

METHODS

Eligible studies were identified by searching online databases of PubMed, EMBASE, and Cochrane Library. The pooled OR was calculated for binary outcomes (e.g., the incidence of delirium, mortality, or adverse events), while standardized mean difference (SMD) were expressed for continuous outcomes (e.g., time to delirium onset, length of stay in hospital and ICU, time on ventilation).

RESULTS

Seven studies which comprised 402 suvorexant treatment patients and 487 patients with control treatment were included in this meta-analysis. Overall, pooled analysis indicated the incidence of delirium could be significantly reduced (OR, 0.30; P < .001) and time to delirium onset was significantly lengthened (SMD, 0.44; P = .006) in patients undergoing suvorexant treatment compared with controls. Suvorexant had no beneficial effects on the secondary outcomes [length of stay in hospital (SMD, -0.65; P = .161) and ICU (SMD, 0.34; P = .297), time on ventilation (SMD, 1.09; P = .318), drug-related adverse events (OR, drug-related adverse events (OR, 1.66; P = .319) and mortality (OR, 2.21; P = .261)]. Subgroup analysis also confirmed the benefit of suvorexant on the development of delirium, which was significant in any subgroup.

CONCLUSION

Suvorexant should be recommended for the prevention of delirium in clinic.

A phase II study of ramelteon for the prevention of postoperative delirium in elderly patients undergoing gastrectomy

PURPOSE

The growing number of cases of gastric cancer being diagnosed in elderly patients highlights the importance of preventing postoperative delirium. This phase II study aimed to evaluate the efficacy of perioperative treatment with ramelteon for preventing postoperative delirium in elderly patients undergoing gastrectomy.

METHODS

This study was designed as a single-institute prospective phase II study. Patients ≥ 75 years old were eligible. Ramelteon 8 mg/day was administered from 8 days before the operation until discharge. Postoperative delirium was evaluated using the Confusion Assessment Method-Intensive Care Unit flow sheet.

RESULTS

Between September 2015 and July 2017, a total of 83 patients were enrolled, 76 of whom were eligible and included in the analysis. Postoperative delirium was observed in four patients (5%) (60% confidence interval: 3.0-8.7). The upper margin of the confidence interval was lower than the prespecified threshold of 13%; therefore, the null hypothesis was rejected.

CONCLUSION

This phase II study suggested that the perioperative administration of ramelteon is safe and feasible for preventing postoperative delirium in elderly patients undergoing gastrectomy. Trial registration This study was registered at UMIN (UMIN 000018697).