Risk factors for delirium in elderly patients after lumbar spinal fusion

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

PURPOSE

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

DESIGN

This study is a bibliometric and visualized analysis.

METHODS

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

FINDINGS

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

CONCLUSIONS

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

Preoperative anemia is associated with increased length of stay in adult spinal deformity surgery: evaluation of a large single-center patient cohort and future suggestions for patient optimization

PURPOSE

This study aimed to investigate the relationship of preoperative hemoglobin levels as an independent prognostic factor for hospital and intensive care unit (ICU) length of stay (LOS) in patients undergoing surgery for adult spinal deformity (ASD), with the intent of determining whether there exists a correlation and enhancing patient preoperative optimization protocols.

METHODS

The authors reviewed consecutive patients who underwent elective thoracolumbosacral posterior spinal fusion (PSF) involving six or more vertebrae for ASD from January 1, 2013, to December 13, 2021, with a minimum follow-up period of two years. This study primarily investigated the association of preoperative hemoglobin levels with hospital and ICU LOS. To analyze the data, both unadjusted and adjusted generalized linear models (GLM), incorporating cubic splines for non-linear variables, were applied.

RESULTS

A total of 598 patients were included. GLMs for hospital and ICU LOS demonstrated nonlinear relationships with preoperative hemoglobin levels. Specifically, hospital LOS decreased with increasing preoperative hemoglobin until a significance threshold of 13.5 g/dl. Similarly, ICU LOS significantly decreased with increasing preoperative hemoglobin until 13.0 g/dl. Lower preoperative hemoglobin was associated with more perioperative transfusions, less likely discharge to home, and greater risk of reoperation.

CONCLUSIONS

Preoperative anemia is an independent non-linear risk factor that significantly affects LOS, disposition, and outcomes after surgery for ASD. These findings advocate for a systemic preoperative approach and highlight the need for future research to improve postoperative outcomes and reduce hospital resource utilization.

LEVEL OF EVIDENCE

IV.

Postoperative delirium following total joint arthroplasty: epidemiology, risk factors, and associated complications

INTRODUCTION

Postoperative delirium (POD) is a feared complication following major surgery in elderly patients. Further investigation of the risk factors and consequences of POD following total joint arthroplasty is warranted.

METHODS

Patients who underwent total knee arthroplasty (TKA) or total hip arthroplasty (THA) were identified using PearlDiver. Patients were filtered into 2 cohorts based on the presence or absence of POD within 7 days of surgery. Epidemiological analyses were performed to examine trends in POD following TKA and THA by age group and year. Comparative analyses were performed on patient demographics and baseline cognitive status. After matching by age, sex, and comorbidities, electrolyte disturbances and 90-day postoperative complications were analysed.

RESULTS

Among 2,518,918 (99.7%) no POD and 7240 (0.3%) POD patients who underwent total knee or hip arthroplasty, mean age was 65.58 years, 60.2% were female, and mean CCI was 1.50 for the whole cohort. POD patients frequently had baseline cognitive impairment (P < 0.001). Incidence of POD decreased from 0.54% in 2010 to 0.10% in 2022 (P < 0.001) and increased with age (P < 0.001). POD patients had higher 90-day costs (TKA = $19,572 vs. $10,397, P < 0.001; THA = $18,496 vs. $9,877 P < 0.001). After matching, POD TKA patients had higher rates of hypernatraemia (6.1% vs 4.5%, P = 0.001) and POD THA patients had higher rates of hyponatraemia (26.5% vs 23.1%, P = 0.008). POD patients had higher rates of 90-day postoperative medical and surgical complications (P < 0.05) than no POD patients.

CONCLUSIONS

Nearly 0.3% of patients who underwent either TKA or THA between 2010 and 2022 developed transient delirium. POD was most common in elderly patients with baseline cognitive impairment undergoing revision surgery. POD patients had higher rates of 90-day postoperative surgical and joint-related complications. While POD rates have decreased, continued initiative to prevent POD in total joint arthroplasty patients is imperative.

Longitudinal Trends in the Incidence of Hyperactive Delirium and Its Causes of Change After Surgery for Degenerative Lumbar Disease: A Population-Based Study of 7250 Surgical Patients Over 11 Years

OBJECTIVES

Delirium is one of the common complications in elderly patients after spinal surgery. Severe delirium can lead to a series of adverse consequences such as drainage tube removal, wound rupture, patient falls, and severe adverse effects. The current research on POD is mostly small sample studies. This study aimed to investigate longitudinal changes in the incidence of hyper-postoperative delirium in patients with lumbar degenerative disease at our institution over the past 11 years and to identify the potential causes of these changes.

METHODS

This is a retrospective cohort study included 7250 patients who underwent surgical treatment for lumbar degenerative diseases at a single center from 2011 to 2021. These patients were diagnosed with delirium through the Confusion Assessment Method and then diagnosed with high activity delirium through the Richmond Agitation-Sedation Scale, totaling 130 cases. According to the incidence rate of hyper-postoperative delirium within 11 years, the trend test is divided into three groups: S1 upward trend (2011-2014), S2 downward trend (2015-2016) and S3 upward trend (2016-2021). The study collected variables from patients before, during, and after surgery, including gender, age, laboratory tests, anesthesia risk score, New York Heart Association cardiac function grading, number of surgical segments, surgical time, estimated intraoperative blood loss, anesthesia medication, and supplementary analgesic medication in the ward within 3 days after surgery. Kruskal Wallis one-way ANOVA test, Kruskal-Wallis H test, or chi-square test are used to evaluate inter group differences. p < 0.05 is considered statistically significant.

RESULTS

The pooled incidence of hyper-postoperative delirium over the past 11 years was 1.79% (130/7250). The average age of 7250 patients was 54.5 ± 13 years, with a male/female ratio close to 1:1. We statistically analyzed the relevant influencing factors before, during, and after surgery of S1 and S3 in the incidence rate increase group and found no statistical difference between the two groups. Our research results show that the incidence of high activity delirium is correlated with age, number of surgical segments, surgical duration, use of dexmedetomidine, remifentanil, and benzodiazepines, with p < 0.05.

CONCLUSIONS

The reduced use of dexmedetomidine, increased use of benzodiazepines, and prolonged surgical time are the reasons for the increased incidence of hyper-postoperative delirium. The joint management of orthopedic surgeons and anesthesiologists during the perioperative period is of great significance in reducing the incidence of hyper-postoperative delirium in patients undergoing lumbar spine surgery.

The Role of Stress Hyperglycemia on Delirium Onset

Delirium is an acute neuropsychiatric syndrome that recognizes one or more underlying causal medical conditions. Stress hyperglycemia usually refers to transient hyperglycemia associated with stress conditions such as stroke, myocardial infarction, and major surgery. Both delirium and stress hyperglycemia share common pathways, such as activation of inflammation. Stress hyperglycemia has been associated with negative outcomes, and recent studies suggested that there is an increased risk of delirium onset in patients with stress hyperglycemia. The purpose of this review is to illustrate the relationship between stress hyperglycemia and delirium. Initially, we illustrate the role of diabetes on delirium onset, summarize the criteria used for the diagnosis of stress hyperglycemia, discuss the impact of stress hyperglycemia on outcome, and focus on the evidence about the relationship between stress hyperglycemia and delirium.

Postoperative pain and neurocognitive outcomes after noncardiac surgery: a systematic review and dose-response meta-analysis

BACKGROUND

Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are common after noncardiac surgery. Postsurgical pain is frequent and can persist as chronic postsurgical pain (CPSP). The association between postsurgical pain and POD or POCD is biologically plausible. We conducted this systematic review to evaluate the association between acute postsurgical pain or CPSP and POD or POCD in adults undergoing noncardiac surgery.

METHODS

We followed Preferred Reporting Items for Systematic Review and Meta-Analyses. We searched MEDLINE, EMBASE, Cochrane, CINAHL and PSYCHINFO up to May 2023. We included cohort, case-control, and cross-sectional studies of any language. Pairs of reviewers independently screened studies, extracted data and assessed the risk of bias using the CLARITY tool and the Joanna Briggs Institute checklist. We assessed the certainty of evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. Where possible, we conducted random-effects meta-analyses to summarise our findings.

RESULTS

We analysed 30 studies (>9000 participants) that assessed the association between acute postoperative pain and POD/POCD. Dose-response meta-analyses found that postoperative pain intensity was associated with occurrence of POD (adjusted relative risk [aRR]/unit of pain intensity: 1.26; 95% confidence interval [CI]: 1.17-1.35; low certainty of evidence) and risk of developing POD (aRR/unit of pain intensity: 1.18; 95% CI: 1.08-1.30; low certainty of evidence). There was very low certainty of evidence regarding the association between postoperative pain and POCD. No studies assessed the association between CPSP and POCD. Residual confounding and substantial methodological variability between studies prevented pooling data from many of the included studies and lowered certainty of evidence.

CONCLUSIONS

Dose-response meta-analyses found that postoperative pain intensity was associated with occurrence of and risk of developing POD.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO-CRD42021192105.

Clinical Application of Different Doses of Hydromorphone Slow-Release Analgesia in Lumbar Fusion in Elderly Patients

INTRODUCTION

The aim of this study is to examine the analgesic efficacy of varying doses of hydromorphone hydrochloride in conjunction with absorbable gelatin sponge for postoperative pain management in elderly individuals undergoing lumbar fusion surgery. Additionally, the study aims to assess the sustained release analgesic properties of this combination and to determine the optimal dosage of hydromorphone hydrochloride for effective pain relief.

METHODS

A total of 113 elderly patients (aged ≥ 65 years old) meeting the criteria for 1-2-level posterior lumbar fusion surgery at Ganzhou City People's Hospital between July 2022 and August 2023 were randomly assigned to four groups: group A (0.2 mg hydromorphone hydrochloride 1 ml), group B (0.3 mg hydromorphone hydrochloride 1.5 ml), group C (0.4 mg hydromorphone hydrochloride 2 ml), and group D (0.9% normal saline 2 ml) for standard anesthesia induction and maintenance. Prior to suturing the incision, gelfoam was utilized to administer epidural analgesia to each group. Following the surgical procedure, an intravenous analgesia pump was utilized for pain management. The baseline infusion rate was set at 0.5 ml/h. Patient-controlled analgesia (PCA) was administered at a dose of 2 ml, with a lockout interval of 20 min, allowing the patient to self-administer as needed. Pain relief was assessed using the visual analogue scale (VAS) prior to surgery, as well as at 1 day and 3 days post-operation. The frequency of PCA requests within the initial 48-h postoperative period, the remedial analgesia with dezocine, postoperative adverse reactions, and duration of hospitalization were documented for analysis.

RESULTS

The VAS scores of groups B and C were found to be significantly lower than those of group D 1 day after the operation. Additionally, VAS scores at 3 days post-operation, remedial rate of dezocine and PCA follow-up times at 48 h in groups A, B, and C were significantly lower compared to group D (P < 0.001). There was no statistically significant difference between group B and group C in VAS scores at 1 day and 3 days post-operation, as well as PCA follow-up times at 48 h post-operation (P < 0.001). Furthermore, the VAS scores of groups B and C were lower than those of group A at 1 day and 3 days post-operation (P < 0.05). The PCA frequency of group C was also lower than that of group A at 48 h post-operation (P < 0.05).

CONCLUSION

The combination of hydromorphone hydrochloride and absorbable gelatin sponge epidural analgesia has been shown to enhance postoperative pain management. A dosage of 0.4 mg of hydromorphone hydrochloride may be considered an appropriate analgesic dose, as it can provide effective pain relief without eliciting adverse reactions.

TRIAL REGISTRATION

ChiCTR.org.cn(ChiCTR2200064863). Registered on October 20, 2022.

Sex-stratified analyses of comorbidities associated with an inpatient delirium diagnosis using real world data

Delirium is a detrimental mental condition often seen in older, hospitalized patients and is currently hard to predict. In this study, we leverage electronic health records (EHR) to identify 7,492 UCSF patients and 19,417 UC health system patients with an inpatient delirium diagnosis and the same number of control patients without delirium. We found significant associations between comorbidities or laboratory values and an inpatient delirium diagnosis, including metabolic abnormalities and psychiatric diagnoses. Some associations were sex-specific, including dementia subtypes and infections. We further explored the associations with anemia and bipolar disorder by conducting longitudinal analyses from the time of first diagnosis to development of delirium, demonstrating a significant relationship across time. Finally, we show that an inpatient delirium diagnosis leads to increased risk of mortality. These results demonstrate the powerful application of the EHR to shed insights into prior diagnoses and laboratory values that could help predict development of inpatient delirium and the importance of sex when making these assessments.

Introducing a machine learning algorithm for delirium prediction-the Supporting SURgery with GEriatric Co-Management and AI project (SURGE-Ahead)

INTRODUCTION

Post-operative delirium (POD) is a common complication in older patients, with an incidence of 14-56%. To implement preventative procedures, it is necessary to identify patients at risk for POD. In the present study, we aimed to develop a machine learning (ML) model for POD prediction in older patients, in close cooperation with the PAWEL (patient safety, cost-effectiveness and quality of life in elective surgery) project.

METHODS

The model was trained on the PAWEL study's dataset of 878 patients (no intervention, age ≥ 70, 209 with POD). Presence of POD was determined by the Confusion Assessment Method and a chart review. We selected 15 features based on domain knowledge, ethical considerations and a recursive feature elimination. A logistic regression and a linear support vector machine (SVM) were trained, and evaluated using receiver operator characteristics (ROC).

RESULTS

The selected features were American Society of Anesthesiologists score, multimorbidity, cut-to-suture time, estimated glomerular filtration rate, polypharmacy, use of cardio-pulmonary bypass, the Montreal cognitive assessment subscores 'memory', 'orientation' and 'verbal fluency', pre-existing dementia, clinical frailty scale, age, recent falls, post-operative isolation and pre-operative benzodiazepines. The linear SVM performed best, with an ROC area under the curve of 0.82 [95% CI 0.78-0.85] in the training set, 0.81 [95% CI 0.71-0.88] in the test set and 0.76 [95% CI 0.71-0.79] in a cross-centre validation.

CONCLUSION

We present a clinically useful and explainable ML model for POD prediction. The model will be deployed in the Supporting SURgery with GEriatric Co-Management and AI project.

The Association of Preoperative Diabetes With Postoperative Delirium in Older Patients Undergoing Major Orthopedic Surgery: A Prospective Matched Cohort Study

BACKGROUND

Postoperative delirium (POD) is a common form of postoperative brain dysfunction, especially in the elderly. However, its risk factors remain largely to be determined. This study aimed to investigate whether (1) preoperative diabetes is associated with POD after elective orthopedic surgery and (2) intraoperative frontal alpha power is a mediator of the association between preoperative diabetes and POD.

METHODS

This was a prospective matched cohort study of patients aged 60 years or more, with a preoperative diabetes who underwent elective orthopedic surgery. Nondiabetic patients were matched 1:1 to diabetic patients in terms of age, sex, and type of surgery. Primary outcome was occurrence of POD, assessed using the 3-minute Diagnostic Confusion Assessment Method (3D-CAM) once daily from 6 pm to 8 pm during the postoperative days 1-7 or until discharge. Secondary outcome was the severity of POD which was assessed for all participants using the short form of the CAM-Severity. Frontal electroencephalogram (EEG) was recorded starting before induction of anesthesia and lasting until discharge from the operating room. Intraoperative alpha power was calculated using multitaper spectral analyses. Mediation analysis was used to estimate the proportion of the association between preoperative diabetes and POD that could be explained by intraoperative alpha power.

RESULTS

A total of 138 pairs of eligible patients successfully matched 1:1. After enrollment, 6 patients in the diabetes group and 4 patients in the nondiabetes group were excluded due to unavailability of raw EEG data. The final analysis included 132 participants with preoperative diabetes and 134 participants without preoperative diabetes, with a median age of 68 years and 72.6% of patients were female. The incidence of POD was 16.7% (22/132) in patients with preoperative diabetes vs 6.0% (8/134) in patients without preoperative diabetes. Preoperative diabetes was associated with increased odds of POD after adjustment of age, sex, body mass index, education level, hypertension, arrhythmia, coronary heart disease, and history of stroke (odds ratio, 3.2; 95% confidence interval [CI], 1.4-8.0; P = .009). The intraoperative alpha power accounted for an estimated 20% (95% CI, 2.6-60%; P = .021) of the association between diabetes and POD.

CONCLUSIONS

This study suggests that preoperative diabetes is associated with an increased risk of POD in older patients undergoing major orthopedic surgery, and that low intraoperative alpha power partially mediates such association.

Preoperative geriatric nutritional risk index is useful factor for predicting postoperative delirium among elderly patients with degenerative lumbar diseases

PURPOSE

It is the first study to evaluate the predictive value of the geriatric nutritional risk index (GNRI) on postoperative delirium (POD) after transforaminal lumber interbody fusion (TLIF) in elderly patients with degenerative lumbar diseases.

METHODS

A retrospective study was conducted to assess the outcomes of TLIF surgery in elderly patients with lumbar degenerative disease between the years 2016 and 2022. Delirium was diagnosed by reviewing postoperative medical records during hospitalization, utilizing the Confusion Assessment Method. The geriatric nutritional risk index was calculated using the baseline serum albumin level and body weight. Multivariate logistic regression analysis was employed to identify the association between preoperative GNRI and postoperative delirium (POD). Additionally, a receiver operating characteristic curve was utilized to determine the optimal GNRI cutoff for predicting POD.

RESULTS

POD was observed in 50 of the 324 patients. The GNRI was visibly reduced in the delirium group. The mean GNRI was 93.0 ± 9.1 in non-delirium group and 101.2 ± 8.2 in delirium group. On multivariate logistic regression, Risk of POD increases significantly with low GNRI and was an independent factor in predicting POD following TLIF (OR 0.714; 95% CI 0.540-0.944; p = 0.018). On receiver operating characteristic curve, the area under curve (AUC) for GNRI was 0.738 (95% CI 0.660-0.817). The cutoff value for GNRI according to the Youden index was 96.370 (sensitivity: 66.0%, specificity: 70.4%).

CONCLUSION

Our study indicated that lower GNRI correlated significantly with POD after TLIF. Performing GNRI evaluation prior to TLIF may be an effective approach of predicting the risk for POD among elderly patients with degenerative lumbar diseases.

Thoracic delirium index for predicting postoperative delirium in elderly patients following thoracic surgery: A retrospective case-control study

BACKGROUND

Postoperative delirium (POD) is an acute neurological complication in the elderly undergoing thoracic surgery and can result in serious adverse consequences.

AIMS

This study aimed to identify the related risk factors for POD following thoracic surgery, primarily focusing on preoperative serum biomarkers, and further to establish a novel delirium index to better predict POD.

METHODS

A total of 279 patients aged ≥60 years who underwent elective thoracic surgery from August 2021 to August 2022 were enrolled in this observational study. The platelet-to-white blood cell ratio (PWR) was calculated as number the of platelets divided by the number of white blood cells. POD was defined by the confusion assessment method twice daily during the postoperative first 3 days. Multivariate regression analysis was performed to identify all potential variables for POD. Moreover, a novel thoracic delirium index (TDI) was developed based on the related risk factors. The accuracy of TDI and its component factors in predicting POD was determined by the curve of receiver operating characteristic (ROC).

RESULTS

In total, 25 of 279 patients developed POD (8.96%). Age, PWR, and average pain scores within the first 3 days after surgery were regarded as the independent risk factors for POD. Moreover, the ROC analysis showed the TDI, including age, PWR, and average pain scores within the first 3 days after surgery, can more accurately predict POD with the largest area under the curve of 0.790 and the optimal cutoff value of 9.072, respectively.

CONCLUSION

The TDI can scientifically and effectively predict POD to provide optimal clinical guidance for older patients after thoracic surgery.

Sex-stratified phenotyping of comorbidities associated with an inpatient delirium diagnosis using real world data

Delirium is a heterogeneous and detrimental mental condition often seen in older, hospitalized patients and is currently hard to predict. In this study, we leverage large-scale, real- world data using the electronic health records (EHR) to identify two cohorts comprised of 7,492 UCSF patients and 19,417 UC health system patients (excluding UCSF patients) with an inpatient delirium diagnosis and the same number of propensity score-matched control patients without delirium. We found significant associations between comorbidities or laboratory test values and an inpatient delirium diagnosis which were validated independently. Most of these associations were those previously-identified as risk factors for delirium, including metabolic abnormalities, mental health diagnoses, and infections. Some of the associations were sex- specific, including those related to dementia subtypes and infections. We further explored the diagnostic associations with anemia and bipolar disorder by conducting longitudinal analyses from the time of first diagnosis of the risk factor to development of delirium demonstrating a significant relationship across time. Finally, we show that an inpatient delirium diagnosis leads to dramatic increases in mortality outcome across both cohorts. These results demonstrate the powerful application of leveraging EHR data to shed insights into prior diagnoses and laboratory test values that could help predict development of inpatient delirium and emphasize the importance of considering patient demographic characteristics including documented sex when making these assessments.

One Sentence Summary

Longitudinal analysis of electronic health record data reveals associations between inpatient delirium, comorbidities, and mortality.

Surgeon-Specific Treatment Selection Bias and Heterogeneous Perioperative Practices in an Observational Spine Surgery Study. A Statistical Tutorial with Implications for Analysis of Observational Studies of Perioperative Interventions

BACKGROUND

It is essential that treatment effects reported from retrospective observational studies are as reliable as possible. In a retrospective analysis of spine surgery patients, we obtained a spurious result: tranexamic acid (TXA) had no effect on intraoperative blood loss. This statistical tutorial explains how this result occurred and why statistical analyses of observational studies must consider the effects of individual surgeons.

METHODS

We used an observational database of 580 elective adult spine surgery patients, supplemented with a review of perioperative medication records. We tested whether common statistical methods (multivariable regression or propensity score-based methods) could adjust for surgeons' selection bias in TXA administration.

RESULTS

Because TXA administration (frequency, timing, and dose) and surgeon were linked (collinear), estimating and testing the independent effect of TXA on outcome using multivariable regression without including surgeon as a variable would provide biased (spurious) results. Likewise, because of surgeon/TXA linkage, assumptions of propensity score-based analysis were violated, statistical methods to improve comparability between groups failed, and spurious blood loss results were worsened. Others numerous differences among surgeons existed in intraoperative and postoperative practices and outcomes.

CONCLUSIONS

In observational studies in which individual surgeons determine whether their patients receive the treatment of interest, consideration must be given to inclusion of surgeon as an independent variable in all analyses. Failure to include the surgeon in an analysis of observational data carries a substantial risk of obtaining spurious results, either creating a spurious treatment effect or failing to detect a true treatment effect.

High ASA Physical Status and Low Serum Uric Acid to Creatinine Ratio are Independent Risk Factors for Postoperative Delirium Among Older Adults Undergoing Urinary Calculi Surgery

Purpose

This study was to investigate the incidence and potential predictive factors for postoperative delirium (POD) in older people following urinary calculi surgery, and to establish the corresponding risk stratification score by the significant factors to predict the risk of POD.

Patients and Methods

We retrospectively analyzed the perioperative data of 195 patients aged 65 or older who underwent elective urinary calculi surgery between September 2020 and September 2022. POD was defined by chart-based method, and the serum uric acid to creatinine (SUA/Cr) ratio as well as neutrophil-to-lymphocyte ratio (NLR) were calculated, respectively. Identification of the risk factors for POD was performed by univariate and multivariate logistic regression analysis. Moreover, the risk stratification score was developed based on the regression coefficients of the associated variables.

Results

In 195 eligible patients following urinary calculi surgery, the median age was 69 (66-72) and 19 patients ultimately developed POD (9.7%). The results by univariate analysis showed that patients with advanced age, high American Society of Anesthesiologists (ASA) physical status (≥3) and low SUA/Cr ratio (≤3.3) were more likely to develop POD, but dexmedetomidine can significantly decrease the risk of the occurrence of POD. The multivariate analysis further indicated that high ASA physical status (≥3) and low SUA/Cr ratio (≤3.3) were independently associated with POD, and the POD incidence could obviously be elevated with the increase of risk stratification score. Moreover, patients with delirium had longer hospital stays.

Conclusion

POD is frequent in geriatric patients following urinary calculi surgery (9.7%). The high ASA physical status (≥3) and low SUA/Cr ratio (≤3.3) were effective predictors of POD. The corresponding risk stratification based on these factors could be beneficial to determining patients who are susceptible to POD, and thus better preventing and reducing the occurrence of POD. However, large prospective studies are needed to confirm this finding.