bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nondifferential misclassification of outcome under (near)-perfect specificity: a simulation study
Authors: Ma Weida , MacLehose Richard F , Lash Timothy L , Collin Lindsay J , Tuo Ya , Ahern Thomas P 
Published: September 2024

Abstract
Mismeasurement of a dichotomous outcome yields an unbiased risk ratio estimate when there are no false positive cases (perfect specificity) and when sensitivity is nondifferential with respect to exposure status. In studies where these conditions are expected, quantitative bias analysis may be considered unnecessary. We conducted a simulation study to explore the robustness of this special case to small departures from perfect specificity and stochastic departures from nondifferential sensitivity. We observed substantial bias of the risk ratio with specificity values as high at 99.8%. The magnitude of bias increased directly with the true underlying risk ratio and was markedly stronger at lower baseline risk. Stochastic departure from nondifferential sensitivity also resulted in substantial bias in most simulated scenarios; downward bias prevailed when sensitivity was higher among unexposed compared with exposed, and upward bias prevailed when sensitivity was higher among exposed compared with unexposed. Our results show that seemingly innocuous departures from perfect specificity (eg, 0.2%) and from nondifferential sensitivity can yield substantial bias of the risk ratio under outcome misclassification. We present a web tool permitting easy exploration of this bias mechanism under user-specifiable study scenarios.
Task-Based Attentional Control: The Role of Anxiety and Age
Authors: Messerlie Amanda E , Guidotti Breting Leslie M , Calamari John E , Sweet Jerry J , Geary Elizabeth K , Axelrod Jenna , Neale Alec C , Waszczuk Monika A 
Published: September 2024

Abstract

Objective
Attentional Control Theory (ACT) posits that anxiety impacts cognitive functioning through interference in working memory and processing efficiency, resulting in performance deficits in set-shifting and inhibition. Few studies have examined the effects of anxiety on set-shifting and inhibition in clinical samples or how these relationships might be affected by age. The current study tested whether increased age, elevated anxiety, and their interaction were associated with reduced performance on measures of set-shifting and inhibition.

Method
Symptom and neuropsychological testing data were obtained from outpatient participants presenting at an academic medical center (N = 521; mean age = 50.39 years, SD = 22.35, range = 18–90; 47.4% female; 78.3% White). The Trail Making Test Difference score was used to assess set-shifting and the Stroop Color-Word Test Interference score was used to assess inhibition.

Results
After controlling for demographic variables, ADHD diagnosis, depression symptoms, and Mild Cognitive Impairment (MCI), both age and anxiety were significant predictors of set-shifting (β = 0.45 and β = 0.18, respectively, ps &lt; 0.001) and inhibition (β = −0.37, p &lt; 0.001 and β = −0.19, p = 0.001, respectively). No interaction was found between age and anxiety in the prediction of set-shifting or inhibition.

Conclusion
Congruent with ACT, anxiety was associated with worse performance on measures of set-shifting and inhibition. Older age was an independent predictor of worse set-shifting and inhibition but did not moderate the relationship between anxiety and attentional control, suggesting that anxiety adversely affected working memory and processing efficiency equivalently across the adult lifespan. The results highlight the importance of anxiety assessment in neuropsychological evaluation in patients of all ages.
Are weapon allometries steeper in major or minor males? A meta-analysis
Authors: Kochensparger Sydney K , Painting Christina J , Buzatto Bruno A , McCullough Erin L 
Published: September 2024

Abstract
Competition for mates can drive the evolution of exaggerated weaponry and male dimorphism associated with alternative reproductive tactics. In terrestrial arthropods, male dimorphism is often detected as non-linear allometries, where the scaling relationship between weapon size and body size differs in intercept and/or slope between morphs. Understanding the patterns of non-linear allometries is important as it can provide insights into threshold evolution and the strength of selection experienced by each morph. Numerous studies in male-dimorphic arthropods have reported that allometric slopes of weapons are shallower in large “major” males compared to small “minor” males. Because this pattern is common among beetles that undergo complete metamorphosis (holometabolous), researchers have hypothesized that the slope change reflects resource depletion during pupal development. However, no comprehensive survey has examined the generality of this trend. We systematically searched the literature for reports of weapon allometries in male dimorphic species and conducted a phylogenetically controlled meta-analysis to explore the factors influencing the difference in slopes between morphs. Our search identified 59 effect sizes from 19 studies, 50 species, and 5 orders of terrestrial arthropods. We found strong evidence that metamorphosis type influences the patterns of weapon allometries. Slopes were significantly steeper in minor males compared to major males in holometabolous species, but there was no difference in slopes between morphs in hemimetabolous species (i.e. those that undergo incomplete or no metamorphosis). These results support the hypothesis that holometabolous species face a resource ceiling during pupal development that limits the exaggeration of weapon size.
Visibility graph-based covariance functions for scalable spatial analysis in non-convex partially Euclidean domains
Authors: Gilbert Brian , Datta Abhirup 
Published: September 2024

Abstract
We present a new method for constructing valid covariance functions of Gaussian processes for spatial analysis in irregular, non-convex domains such as bodies of water. Standard covariance functions based on geodesic distances are not guaranteed to be positive definite on such domains, while existing non-Euclidean approaches fail to respect the partially Euclidean nature of these domains where the geodesic distance agrees with the Euclidean distances for some pairs of points. Using a visibility graph on the domain, we propose a class of covariance functions that preserve Euclidean-based covariances between points that are connected in the domain while incorporating the non-convex geometry of the domain via conditional independence relationships. We show that the proposed method preserves the partially Euclidean nature of the intrinsic geometry on the domain while maintaining validity (positive definiteness) and marginal stationarity of the covariance function over the entire parameter space, properties which are not always fulfilled by existing approaches to construct covariance functions on non-convex domains. We provide useful approximations to improve computational efficiency, resulting in a scalable algorithm. We compare the performance of our method with those of competing state-of-the-art methods using simulation studies on synthetic non-convex domains. The method is applied to data regarding acidity levels in the Chesapeake Bay, showing its potential for ecological monitoring in real-world spatial applications on irregular domains.
Unit information Dirichlet process prior
Authors: Gu Jiaqi , Yin Guosheng 
Published: September 2024

ABSTRACT
Prior distributions, which represent one’s belief in the distributions of unknown parameters before observing the data, impact Bayesian inference in a critical and fundamental way. With the ability to incorporate external information from expert opinions or historical datasets, the priors, if specified appropriately, can improve the statistical efficiency of Bayesian inference. In survival analysis, based on the concept of unit information (UI) under parametric models, we propose the unit information Dirichlet process (UIDP) as a new class of nonparametric priors for the underlying distribution of time-to-event data. By deriving the Fisher information in terms of the differential of the cumulative hazard function, the UIDP prior is formulated to match its prior UI with the weighted average of UI in historical datasets and thus can utilize both parametric and nonparametric information provided by historical datasets. With a Markov chain Monte Carlo algorithm, simulations and real data analysis demonstrate that the UIDP prior can adaptively borrow historical information and improve statistical efficiency in survival analysis.
MOY 3 - Development and external validation of the “Global Surgical-Site Infection” (GloSSI) predictive model in adult patients undergoing abdominal surgery
Authors:   NIHR Global Research Health Unit on Global Surgery and GlobalSurg Collaborative
Published: September 2024

Abstract

Aims
Identification of patients at high-risk of surgical-site infections (SSI) may allow surgeons to minimise associated morbidity. However, there are significant concerns with the methodological quality and transportability of models previously developed. We aimed to develop a novel score to predict 30-day SSI risk following gastrointestinal surgery across a global context, and externally validate against existing models.

Methods
This was a secondary analysis of 2 prospective international cohort studies: GlobalSurg-1 (July-November 2014) and GlobalSurg-2 (January-July 2016). Consecutive adults undergoing gastrointestinal surgery were eligible. Model development was performed in GlobalSurg-2 data, with novel and previous scores externally validated in GlobalSurg-1. The primary outcome was 30-day SSI, with two predictive techniques explored: penalised regression (LASSO) and machine learning (XGBOOST). Final model selection based on prognostic accuracy and clinical utility.

Results
There were 14,019 patients (SSI=12.3%) for derivation, and 8,464 (SSI=11.4%) for external validation. The LASSO model was selected due to similar discrimination to XGBoost (AUC: 0.738, 0.725-0.750 versus 0.737, 0.709-0.765), but greater explainability. The final score included six variables: country income, ASA grade, diabetes, and operative contamination, approach, and duration. Model performance remained good on external validation (AUC: 0.730, 0.715-0.744; calibration-in-the-large: -0.098, slope: 1.008), and demonstrated superior performance to external validation of all previous models.

Conclusion
The GloSSI score allowed accurate prediction of the risk of SSI with 6 simple variables which are routinely available at the time of surgery across global settings. This can inform use of intraoperative and postoperative interventions to modify the risk of SSI and minimise associated harm.
SP1.1 - The effect of mesh fixation on post-operative pain and recurrence in laparoscopic inguinal hernia repair
Authors: Jones Stacey , Davies Elin , Fatima Sabiha , May Thomas , Papakonstantinou Dimitrios , Sheredi Mohamed 
Published: September 2024

Abstract

Aims
To evaluate post-operative pain and inguinal hernia recurrence following laparoscopic totally extraperitoneal (TEP) or transabdominal preperitoneal (TAPP) techniques. Secondly, in TAPP approach to compare outcomes with method of mesh fixation.

Methods
545 patients underwent elective laparoscopic inguinal hernia repair in a single centre, between October 2015 and April 2023. Surgical approach and method of mesh fixation was obtained from operation note. Patients were contacted retrospectively via telephone call. Post-operative pain was assessed using a scale (1-10). Chronic pain defined as pain persisting beyond 3 months. Hernia recurrence defined as new groin lump at site of previous repair.

Results
545 patients underwent surgery. 212 did not answer follow-up call, 43 declined to take part in study and 22 had died. 268 analysed; 167 underwent TEP and 101 TAPP inguinal hernia repair. Groups were similar in age and gender. Initial post-operative pain score in TEP group was 4.7 (range 1-10) as compared with 4.5 (range 1-10) in TAPP group.13.8% experienced chronic pain, score of 2.9 (range 2-5) in TEP group compared with 16.8%, score of 2.7 (range 2-5) in TAPP group. Hernia recurrences were similar between groups; 4.8% and 4% respectfully. Neither mesh-fixation or non-fixation techniques were found to affect post-operative chronic pain (p=0.8). Patients undergoing tacker fixation reported less hernia recurrence, 1.7% and 5.1% respectfully. No significant difference noted between absorbable and metallic tackers in terms of chronic post-operative pain and recurrence.

Conclusion
Mesh placement without fixation produced similar post-operative pain but a higher hernia recurrence than mesh-fixation techniques.
SP2.8 - The undifferentiated general surgical take over 10 years: emergency operating
Authors: Hale Emily , Bowling Kirk 
Published: September 2024

Abstract

Aims
The aim of this study is to further understand the specific pressures on the department’s operating theatres and capacity, and to identify areas in which we could adapt to facilitate these demands, by reviewing the undifferentiated general surgical admissions in a District General Hospital in July 2013 and July 2023.

Methods
All patients seen by the emergency general surgical team in July 2013 and July 2023 were identified retrospectively. Data was gathered using electronic notes, to analyse admissions and surgeries within 30 days. Patients were excluded if there was insufficient information available.

Results
26% (n=102/395) of all patients treated by emergency general surgical teams in July 2013 had surgery within 30 days. This proportion reduced to 23% (134/594) in July 2023, however overall volume has increased by 31%. The proportion of procedures performed on the day of admission has decreased from 10% to 7%. 3% of procedures were performed under local anaesthetic both in 2013 and 2023. Wait from admission to surgery has decreased from 2.84 days (+/-0.6, p=0.02) in 2013, to 1.9 days in 2023 (+/-0.83, p=0.02).

Conclusions
Although volume of procedures within the same 31-day period has increased throughout the 10 years, the proportion of patients that proceed to intervention has reduced marginally. This is reflected in the increasingly busy emergency operating lists throughout the country, with little change in resources to account for increasing volume. The rising proportion of patients managed conservatively may represent improving medical management of conditions, or more pragmatic management of frail patients.
SP2.9 - National Emergency Laparotomy Audit (NELA) and American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) risk prediction calculators are not accurate in predicting 30-day mortality in patients aged 80 and above
Authors: Moscalu Andrei , Timofeiov Sergiu , Saravanan Balakrishnan , Sinclair Martin 
Published: September 2024

Abstract

Background
30- to 50000 Emergency Laparotomies (EL) are performed annually in the UK. More than half of patients are aged 70 or over and have a high post-operative complication rate along with a 16-20% risk of 30-day mortality (30-dm). To date, the literature lacks a dedicated risk prediction tool for mortality and morbidity following EL in the elderly population.

Methods
A multi-center, retrospective study of patients aged ≥80 undergoing EL examined the correlation between predicted 30-dm using NELA and ACS-NSQIP and actual 30-dm. This occurred in two UK centers over a 2-year period. The primary outcome was defined as the correlation between actual 30-dm and NELA or ACS-NSQIP predicted 30-dm. GraphPad Prism 10.1.1. was used for statistical analysis.

Results
141 cases were included in the final analysis (Table 1). The actual 30-dm was 17.73%, NELA predicted 30-dm 13.07% (7.21;27.84), and ACS-NSQIP 9.4% (3.8;20.6). NELA correlated positively with ACS-NSQIP predicted 30-dm (R²=0.79; p&lt;0.0001). No association was found between actual 30-dm and predicted NELA 30-dm, R²=0.01; p&lt;0.0001 or ACS-NSQIP, R²=0.01; p&lt;0.0001. All data is expressed as Median + IQR.

Conclusion
In octo- and nonagenarians, following an emergency laparotomy, both NELA and ACS-NSQIP are not accurate in predicting 30-day mortality.Table 1Male/female ratio0.63Age (years)84 (81;87)BMI (kg/m²)24.27 (21.43;27)Lactate (most recent preoperative value) mmol/L1.7 mmol/L (1.14;3.01)ASA grade3 (2;4)Clinical frailty score3 (3;5)Charlson Comorbidity Index4 (2;5)
SP3.3 - Real World Experience of 600+ Minimally Invasive Abdominoperineal Resections (APR) Done for Low Rectal Cancers in Tertiary Cancer Care Center
Authors: Vispute Tejas , Bansod Yogesh , Sharma Ankit , Kazi Mufaddal , Desouza Ashwin , Saklani Avanish , Singh Sanjay 
Published: September 2024

Abstract

Introduction
APR is standard of care surgery for low rectal cancers involving sphincter. Surgery is commonly done in minimally invasive way. Robotic surgery has recently gained popularity due to ease of procedure. Margin positivity and local recurrence still remain a challenge.

Methods
It is a retrospective study from prospectively maintained database from Aug 2013 to Aug 2023. Surgical and oncological outcome were analyzed using SPSS version 25 software.

Results
Total 657 minimally invasive APRs were done. All were done in supine lithotomy position. 570 were laparoscopic and 87 robotic. Mean age was 48.4 years. 6 cases were converted to open (5 lap and 1 robotic). Mean BMI was 22.3. Mean distance from anal verge was 3 cm. Majority patients were cT3 (74%). Median blood loss was 150 ml. Clavien Dindo grade III and beyond complications were seen in 11.2%. Mean hospital stay was 7 days. Mean nodes harvested were 13. Mean no of positive nodes were 1.22. Extended resections (extended TME) were 25% in lap and 42% in robotic. Poorly differentiated and signet histology was seen in 27%. CRM positivity was 6.9%. It increases to 15.5% in signet ring histology. Median follow up achieved was 46 months. Local recurrence was 5.5%. Distant recurrence was 20%. 3-year OS and DFS were 73% and 63% respectively.

Conclusion
In high volume minimally invasive surgery centre, MIS abdominoperineal resection - both laparoscopic and robotic has acceptable surgical and oncological outcomes.
SP4.3 - Pancreatoduodenectomy for malignancy with concomitant arterial resection: results from the Recurrence After Whipple’s (RAW) study
Authors: Abdelmohsin Omar , Russell Thomas B , Labib Peter L ,   RAW Study Collaborators, Aroori Somaiah 
Published: September 2024

Abstract

Background
Most centres are reluctant to perform pancreatoduodenectomy (PD) with concomitant arterial resection (AR) in patients with a cancer affecting the pancreatic head. This is because outcomes are poor and the potential benefits of an aggressive resection are unlikely to outweigh the potential risks, particularly in a patient with an aggressive tumour and limited life expectance. AR has been shown to correlate with higher rates of morbidity, reoperation and mortality, and reduced overall survival. However, AR may be justified in selected patients in specialist centres. This study aimed to compare the outcomes of PD patients who underwent AR to those who did not.

Methods
Data were extracted from the Recurrence After Whipple’s (RAW) study, a multicentre retrospective cohort study of outcomes of PD performed for pancreatic head malignancy (29 centres from eight countries, n=1484). Patients who underwent AR were identified and compared to those who did not undergo AR using the chi-squared test. The following were compared: length of stay (LoS), incidence of postpancreatectomy haemorrhage (PPH), and rates of unplanned return to theatre, 30-day readmission, 90-day mortality, and five-year survival.

Results
Out of 1484 patients, 8.8% did not have data regarding their AR status recorded so they were excluded. Of the rest, 25 (1.8%) underwent AR. Despite the small sample size, these patients had significantly higher rates of PPH (20.0 vs 5.9%, p=0.0004) and reduced five-year survival (12.0% vs 33.1%, p=0.03).

Conclusion
AR should be reserved for selected PD patients in specialist units. Despite our small sample size, our multicentre study demonstrated that these patients have higher incidence of PPH and reduced long-term survival
SP4.5 - Cost estimates of intra-operative cell salvage in patients undergoing major liver surgery: a retrospective cohort study
Authors: Lakha Adil Siraj , Nibber Anjan , Barbosa Antonio , von-Kier Stephen , Gordon-Weeks Alex , Landeiro Filipa 
Published: September 2024

Abstract

Aims
Major liver surgery is associated with a high risk of blood loss. Autologous transfusion of blood salvaged intra-operatively (cell salvage) reduces the requirement for post-operative allogenic transfusion. Allogenic transfusion is associated with risks, and blood is a scarce and costly resource. However, the cost of cell salvage in liver resection has not been previously estimated.

Objective
To estimate the cost of cell salvage in patients undergoing major liver surgery.

Methods
We analysed a cohort of 243 patients who underwent major liver surgery between 2015 and 2022 at a large tertiary referral hospital in England. Cost of cell salvage was calculated as an average price for consumables and operator time. Cost of admission including cell salvage was assessed per year.

Results
The average cost of cell salvage per patient was £433. On average, consumables costed £240 and costs associated with operating cell salvage machinery were £193. The average cost for an index admission for this cohort of patients undergoing major liver surgery with cell salvage was £24,694. When comparing the required units of allogeneic blood required to replace the red cells lost during surgery, cell salvage led to cost-savings in one of the years under analysis.

Conclusions
Our findings suggest that cell salvage has the potential to be cost-effective in patients undergoing major liver surgery. These findings should be assessed in an economic evaluation conducted alongside a randomised controlled trial.
SP4.9 - Relationship Between Classifications for Cancer Cachexia and Overall Survival in Patients with Oesophagogastric Cancer
Authors: Brown Leo R , Soupashi Maria , Yule Michael S , Laird Barry J A , Wigmore Stephen J , Skipworth Richard J E 
Published: September 2024

Abstract

Aim
Classifications for cancer cachexia remain heterogenous within the existing literature. The aim of this study is to compare prognostication using three established descriptors: the Fearon et al. consensus definition, Martin et al.’s weight loss grading system and the Global Leadership Initiative on Malnutrition (GLIM) criteria, in patients with oesophagogastric cancer.

Methods
Consecutive patients with newly diagnosed oesophagogastric cancer between 2019-2020 were identified from a prospectively maintained regional database. Data were retrieved regarding involuntary weight loss, body mass index, CT body composition analyses and neutrophil-lymphocyte-ratio at the time of clinical staging. This allowed comparison based on Fearon, Martin and GLIM classifications. The primary outcome of interest was overall survival.

Results
Overall, 465 patients (66.9% male, median 71 years) were diagnosed with oesophageal (72.0%) or gastric cancer (28.0%). Greater proportions of advanced stage disease were associated with Fearon (p=0.019), Martin (p=0.004) and GLIM (p&lt;0.001) defined cachexia. Patients who met the GLIM criteria were also older and had poorer ECOG performance status (both p&lt;0001). Each cachexia classifier was associated with worsened overall survival (all p&lt;0.001). Following adjustment for clinicopathological confounders, Fearon (aHR: 1.54 (95%CI:1.24-1.92) and GLIM defined cachexia (aHR: 1.74 (95%CI:1.40-2.17) were both adversely associated with overall survival. Grade 4 weight-loss, as per Martin et al., had the greatest prognostic effect (aHR: 2.11 (95%CI:1.52-2.93).

Conclusion
Cancer cachexia is strongly associated with poorer survival in oesophagogastric cancer. The GLIM criteria and high Martin et al. weight loss grade appear to have the greatest prognostic value.