Drug Treatment for Patients with Postoperative Delirium and Consultation-Liaison Psychiatry in Japan: A Retrospective Observational Study of a Nationwide Hospital Claims Database

Development and validation of a machine learning model to predict postoperative delirium using a nationwide database: A retrospective, observational study

STUDY OBJECTIVE

Postoperative delirium is a neuropsychological syndrome that typically occurs in surgical patients. Its onset can lead to prolonged hospitalization as well as increased morbidity and mortality. Therefore, it is important to promptly identify its signs. This study aimed to develop and validate a machine learning predictive model for postoperative delirium using extensive population data.

DESIGN

Retrospective observational study.

SETTING

Japanese Diagnosis Procedure Combination inpatient data. Data were used for internal (2016.4-2018.12) and temporal validation (2019.01-2019.10).

PATIENTS

Patients aged ≥65 years who underwent general anesthesia for surgical procedure.

MEASUREMENTS

The primary outcome was postoperative delirium, which was defined as a condition requiring newly prescribed antipsychotic drugs or assignment of the corresponding insurance claim code after the date of surgery. We trained and tuned the optimal machine-learning model through 10-fold cross-validation using the selected optimal area under the receiver operating characteristic curve (AUC) value. In the temporal validation, we measured the performance of our model.

MAIN RESULTS

The analysis included 557,990 patients. The light-gradient boosting machine models showed a higher AUC value (0.826 [95% confidence interval (CI): 0.822-0.829]) than the other models. Regarding performance, the model had a recall value of 0.124 (95% CI: 0.119-0.129) and precision value of 0.659 (95% CI: 0.641-0.677]). This performance was sustained in the temporal validation (AUC, 0.815 [95% CI: 0.811-0.818]). At a sensitivity of 0.80, the model achieved a specificity of 0.672 (95% CI: 0.670-0.674]), a negative predictive value of 0.975 (95% CI: 0.974-0.975), and a positive predictive value of 0.176 (95% CI: 0.176-0.179).

CONCLUSIONS

Using extensive Diagnostic Procedure Combination data, we successfully created and validated a machine learning model for predicting postoperative delirium. This model may facilitate prediction of postoperative delirium.

Association Between the Use of Midazolam During Cardiac Anesthesia and the Incidence of Postoperative Delirium: A Retrospective Cohort Study Using a Nationwide Database

OBJECTIVE

To evaluate the association between the intraoperative administration of midazolam and the incidence of postoperative delirium in patients undergoing cardiac surgery.

DESIGN

Retrospective observational cohort study.

SETTING

The Japanese Diagnosis Procedure Combination database.

PARTICIPANTS

Patients aged 65 years and older who underwent cardiovascular surgery (excluding transcatheter surgeries, multiple surgeries per admission, and preoperative delirium) between April 1, 2015, and October 31, 2019.

MEASUREMENTS AND MAIN RESULTS

Patients who received midazolam (midazolam group) were compared with those who did not receive midazolam (no midazolam group). The primary outcome was the incidence of postoperative delirium. The secondary outcomes were the incidence of postoperative nausea and vomiting, mortality, and duration of intensive care unit stay and hospitalization. Propensity scores were estimated using logistic regression based on the covariates. The outcomes were compared using stabilized inverse probability of treatment-weighting analyses. Among the 16,185 patients analyzed, 10,633 (65.7%) received midazolam. No significant differences were observed in the incidences of postoperative delirium (odds ratio [OR] 0.95; 95% CI 0.87-1.03; p = 0.21) and hospital mortality (OR 0.92; 95% CI 0.76-1.11; p = 0.39) between the groups; however, the midazolam group had slightly longer durations of intensive care unit stay (3.5 [3.5-3.6] v 3.3 [3.3-3.4] days, p < 0.001) and hospitalization (31.5 [31.1-31.9] v 29.4 [28.8-29.9] days, p < 0.001), and slightly lower incidences of postoperative nausea and vomiting (OR 0.92; 95% CI 0.85-0.99; p = 0.03). The sensitivity analyses supported these results.

CONCLUSIONS

Intraoperative administration of midazolam may not induce postoperative delirium in patients undergoing cardiac surgery.

Demographic and clinical characteristics of patients with delirium: analysis of a nationwide Japanese medical database

OBJECTIVES

Delirium commonly occurs during hospitalisation and is associated with increased mortality, especially in elderly patients. This study aimed to determine the demographic and clinical characteristics of patients with delirium in the Japanese real-world clinical setting using a nationwide database comprising claims and discharge abstract data.

DESIGN

This was an observational, cross-sectional, retrospective study in hospitalised patients with an incident delirium identified by a diagnosis based on International Classification of Diseases, 10th Revision codes or initiating antipsychotics recommended for delirium treatment in Japan during their hospitalisation.

SETTING

Patients from the Medical Data Vision database including more than 400 acute care hospitals in Japan were evaluated from admission to discharge.

PARTICIPANTS

Of the 32 910 227 patients who were included in the database between April 2012 and September 2020, a total of 145 219 patients met the criteria for delirium.

PRIMARY AND SECONDARY OUTCOME MEASURES

Demographic and baseline characteristics, comorbidities, clinical profiles and pharmacological treatments were evaluated in patients with delirium.

RESULTS

The mean (SD) patient age was 76.5 (13.8) years. More than half of the patients (n=82 159; 56.6%) were male. The most frequent comorbidities were circulatory system diseases, observed in 81 954 (56.4%) patients. Potentially inappropriate medications (PIMs) with risk of delirium including benzodiazepines and opioids were prescribed to 76 798 (52.9%) patients. Approximately three-fourths of these patients (56 949; 74.2%) were prescribed ≥4 PIMs. The most prescribed treatment for delirium was injectable haloperidol (n=82 490; 56.8%). Mean (SD) length of hospitalisation was 16.0 (12.1) days.

CONCLUSIONS

The study results provide comprehensive details of the clinical characteristics of patients with delirium and treatment patterns with antipsychotics in the Japanese acute care setting. In this patient population, the prescription rate of injectable haloperidol and PIMs was high, suggesting the need for improved understanding among healthcare providers about the appropriate management of delirium, which may benefit patients.

Comparison of total intravenous with inhalational anesthesia in terms of postoperative delirium and complications in older patients: a nationwide population-based study

PURPOSE

Postoperative delirium incidences are increasing in older adults. A Cochrane Review found no significant difference in the incidence of postoperative delirium between total intravenous anesthesia (TIVA) and inhalational anesthesia (IA). This study evaluated the differences in postoperative delirium and morbidity between patients who underwent either TIVA or IA.

METHODS

A nationwide Japanese inpatient database was used to retrospectively compare differences in postoperative delirium and composite morbidity between patients older than 65 years, who underwent general anesthesia (TIVA or IA). The primary outcome was postoperative delirium. The secondary outcomes were: morbidity incidence, length of hospital stay, and mortality. A 1:3 propensity score analysis of patients who underwent all surgical procedures was conducted according to covariates, to calculate odds ratios and their 95% confidence intervals (CIs). Sensitivity analyses were conducted using an instrumental variable analysis of the proportion of TIVA by hospital scale, stabilized inverse probability of treatment weighting analyses, limiting the definitions of postoperative delirium, and subgroup analysis.

RESULTS

Of 738,600 patients, 149,540 received TIVA and 589,060 received IA. After 1:3 propensity score matching, the adjusted odds ratios for postoperative delirium and composite morbidity were 0.93 (95% CI 0.91-0.95) and 0.94 (95% CI 0.90-0.97), respectively, for TIVA concerning IA. There were no differences in the length of the intensive care unit and hospital stay, or hospital mortality. The findings were consistent with the sensitivity analyses.

CONCLUSIONS

This study demonstrated that TIVA was related to a slightly decreased postoperative delirium and incidence of morbidity compared to IA.

Comparing the effects of peripheral nerve block and general anesthesia with general anesthesia alone on postoperative delirium and complications in elderly patients: a retrospective cohort study using a nationwide database

INTRODUCTION

The difference between the effects of peripheral nerve block (PNB) with general anesthesia (GA) and GA alone on the patients' postoperative clinical outcomes remains unknown. We assessed whether there is a difference in postoperative delirium and composite morbidity between patients receiving GA with PNB and GA alone using a national clinical database in Japan.

METHODS

We compared the outcomes of patients receiving GA with PNB and GA alone from April 2016 to October 2019. The primary outcome was postoperative delirium, defined as a status requiring newly prescribed antipsychotic drugs or that given the code of a reimbursable disease after the surgery date. The secondary outcome was morbidity incidence as the occurrence of at least one of any of the following life-threatening complications. We conducted propensity score-matched analyses using covariates for patients who underwent any surgical procedure. We used instrumental variables and restricted the definition of postoperative delirium and subgroup for sensitivity analyses.

RESULTS

Of 653,759 patients, 90,358 received GA-PNB and 563,401 received only GA. After 1:4 propensity score matching, 89,754 patients were included in the GA-PNB and 359,015 in the GA. The adjusted ORs for postoperative delirium and composite morbidity were 0.96 (95% CIs 0.94 to 0.99; p<0.01), 0.80 (95% CIs 0.76 to 0.83; p<0.001), respectively, for the GA-PNB concerning the GA. For sensitivity analyses, findings were also consistent with instrumental variables and subgroup analyses.

DISCUSSION

This retrospective, nationwide cohort study demonstrated that GA-PNB was associated with a small reduction in the likelihood of postoperative delirium and a moderate reduction in the likelihood of composite morbidity.