How distant? An experimental analysis of students' COVID-19 exposure and physical distancing in university buildings

Closed university buildings proved to be one of the main hot spots for virus transmission during pandemics. As shown during the COVID-19 pandemic, physical distancing is one of the most effective measures to limit such transmission. As universities prepare to manage in-class activities, students' adherence to physical distancing requirements is a priority topic. Unfortunately, while physical distancing in classrooms can be easily managed, the movement of students inside common spaces can pose high risk of close proximity. This paper provides an experimental analysis of unidirectional student movement inside a case-study university building to investigate how physical distancing requirements impact student movement and grouping behaviour. Results show general adherence with the minimum required physical distancing guidance, but spaces such as corridors pose higher risk of exposure than doorways. Doorway width, in combination with group behaviour, affect the students' capacity to keep the recommended physical distance. Furthermore, questionnaire results show that students report higher perceived vulnerability while moving along corridors. Evidence-based results can support decision-makers in understanding individuals' exposure to COVID-19 in universities and researchers in developing behavioural models in preparation of future outbreaks and pandemics.

Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

Abstract P2-08-05: Association between the neutrophil-to-lymphocyte ratio (NLR) and the 21-gene recurrence score

Introduction: A high neutrophil-to-lymphocyte ratio (NLR) has been reported to be a poor prognostic indicator in several malignancies including breast cancer. It is unknown whether the prognosis associated with high NLR can be explained by other prognostic factors such as proliferation or estrogen receptor signalling. Here we explore the association between NLR and the 21-gene recurrence score (RS).

Methods: The associations between RS, NLR, tumor size, histologic grade, and estrogen receptor (ER) and progesterone receptor (PgR) expression (assessed by immunohistochemistry) were explored in sequential women with early-stage, lymph node-negative (or with lymph node micrometastases), ER-positive and HER2-negative breast cancer treated at Princess Margaret Cancer Centre in Toronto, Canada and in whom results of the RS were available. NLR was measured prior to surgery. Patients with a documented history of pre-existing infectious/inflammatory condition were excluded. Associations were explored using simple linear regression and statistical significance was defined as p<0.05.

Results: A total of 130 women diagnosed between January 2006 and April 2015 were included in the analysis. Median age was 55 (range 32-79), 87% were lymph node negative and 13% had nodal micrometastases. The median NLR was 2.2 (range 0.9-9.1) and was collected at a median of 12 days prior to surgery (range 0-60). The median RS was 18 (range 0-41). There was no association between RS and NLR (R=-0.10, p=0.31), grade (R=0.13, p=0.15), age (R=-0.05, p=0.58) or tumor size (R=0.06, p=0.48). RS was negatively associated with the magnitude of expression of both ER (R=-0.22, p=0.01) and PgR (R=-0.44, p<0.001). There was no association between NLR and grade (R=0.20, p=0.15), age (R=-0.13, p=0.17), tumor size (R=0.14, p=0.93), ER (R=0.01, p=0.94) or PgR (R=0.13, p=0.23)

Conclusion: The poor outcomes associated with high NLR are unlikely explained by proliferation of estrogen receptor signalling.

Citation Format: Srikanthan A, Bedard PL, Goldstein S, Templeton A, Amir E. Association between the neutrophil-to-lymphocyte ratio (NLR) and the 21-gene recurrence score. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-08-05.