Bayesian emulation and history matching of JUNE

We analyze JUNE: a detailed model of COVID-19 transmission with high spatial and demographic resolution, developed as part of the RAMP initiative. JUNE requires substantial computational resources to evaluate, making model calibration and general uncertainty analysis extremely challenging. We describe and employ the uncertainty quantification approaches of Bayes linear emulation and history matching to mimic JUNE and to perform a global parameter search, hence identifying regions of parameter space that produce acceptable matches to observed data, and demonstrating the capability of such methods. This article is part of the theme issue 'Technical challenges of modelling real-life epidemics and examples of overcoming these'.

Bayesian emulation and history matching of JUNE

We analyze JUNE: a detailed model of COVID-19 transmission with high spatial and demographic resolution, developed as part of the RAMP initiative. JUNE requires substantial computational resources to evaluate, making model calibration and general uncertainty analysis extremely challenging. We describe and employ the uncertainty quantification approaches of Bayes linear emulation and history matching to mimic JUNE and to perform a global parameter search, hence identifying regions of parameter space that produce acceptable matches to observed data, and demonstrating the capability of such methods. This article is part of the theme issue 'Technical challenges of modelling real-life epidemics and examples of overcoming these'.

P-280 Potential for improvement and current limitations of Artificial Intelligence (AI) for embryo selection: analysis of external validation data

Study question

What are the prospects of improvement and the limitations of an AI system for embryo selection?

Summary answer

The predictive performance of AI can be enhanced by including additional factors, on top of embryo images, and by assessing images with centered blastocysts.

What is known already

We previously reported the external validation of IVFvision.ai, an AI algorithm that differentiates between Day-5 blastocysts with a positive or negative implantation outcome. IVFvision.ai had higher AUC and overall accuracy in predicting implantation compared to KIDScoreD5 and senior embryologists. Here we report a secondary analysis of external validation data, focusing on a) the improvement of the predictive ability of IVFvision.ai by incorporating data from additional sources, and b) the impact of the blastocyst image quality on the performance of IVFvision.ai.

Study design, size, duration

This is a secondary analysis of external validation data. External validation of IVFvision.ai was performed at a University IVF Clinic using 113 anonymised Embryoscope images of single D5 blastocyst transfers with known implantation outcome.

Participants/materials, setting, methods

The performance of IVFvision.ai and three senior Embryologists to correctly classify blastocysts according to implantation outcome were compared in images in which the whole blastocyst was visible (centred blastocysts, n = 62) vs images in which part of the blastocyst was not visible (off-centred blastocysts, n = 51). Logistic regression models were created: a) IVFvision alone, b) IVFvision+age, c) IVFvision+fertilisation_method, d) IVFvision+KIDScoreD5, e) IVFvision+age+Fertilisation_method+KIDScoreD5. The AUC of each model in predicting implantation was estimated using ROC curve analysis.

Main results and the role of chance

The AUC of IVFVision.ai (0.675 vs 0.432), Embryologist 1 (0.570 vs 0.390), Embryologist 2 (0.663 vs 0.448) and Embryologist 3 (0.628 vs 0.485) were higher for images with centered blastocysts compared to non-centered blastocysts, respectively. There was a progressive increase of AUC with the addition of more factors in the predictive models. a) IVFvision alone: AUC=0.675, b) IVFvision+age: AUC=0.675 c) IVFvision+KIDScoreD5: AUC=0.721 d) IVFvision+fertilisation_method=0.740, e) IVFvision+age+Fertilisation_method+KIDScoreD5=0.768.

Limitations, reasons for caution

The retrospective nature of the study and the small sample of the study raise the need for further prospective studies with a larger number of embryos.

Wider implications of the findings

The highest performance of IVFvision.ai is achieved in images with centred blastocysts, suggesting that implantation cannot be predicted accurately in images with non-centred blastocysts. In addition, we provide provide proof of concept that training AI systems using data from different sources, in addition to embryo images, may increase overall accuracy.

Trial registration number

not applicable

066 Utilising optical coherence tomography measures as surrogates for raised intracranial pressure in idiopathic intracranial hypertension

Aim

To determine whether Optical Coherence Tomography (OCT) of the optic nerve head in papil- loedema could act as a surrogate measure of intracranial pressure (ICP).

Methods

This is a longitudinal cohort study using data collected from three randomised controlled trials, between from April 1st, 2014 to August, 1st 2019. OCT imaging and automated perimetry was followed immediately by ICP measurement on the same day. Cohort 1 utilised continuous sitting telemetric ICP monitoring (Raumedic Neurovent P-tel device) on one visit. Cohort 2 were evaluated at baseline, 3, 12 and 24 months and underwent lumbar puncture assessment of ICP.

Results

104 patients were recruited. Amongst cohort 1 (n=15), the range of OCT protocols were evaluated and optic nerve head central thickness was found to be most closely associated with ICP (right eye: p=0.017, r = 0.60; left eye: p = 0.002; r = 0.73). Subsequently, cohort 2 (n=89) confirmed the correlation between central thickness and ICP longitudinally (12 and 24 months). Finally, bootstrap surrogacy analysis noted a positive association between central thickness and ICP treatment effects at all time points (e.g. at 12 months, an decrease in central thickness of 50µm predicted a decrease in ICP of 5 cmCSF).

Conclusion

OCT optic nerve head volume measures reproducibly correlates with ICP and surrogacy analysis demonstrated its ability to inform ICP changes. This data suggests that OCT can non-invasively predict ICP.

soozmollan@doctors.org.uk

58

A randomised controlled, trial of the GLP-1 receptor agonist exenatide in idiopathic intracranial hypertension

Background

Pre-clinical data demonstrates the ability of Exenatide, a GLP-1R agonist, to reduce CSF secretion and ICP.1 Existing GLP-1R agonists are widely used to treat obesity and diabetes (but do not cause hypoglycaemia).

Methods

Randomised, placebo controlled, double-blind trial of Exenatide in women with active IIH. Participants were randomised 1:1 to Exenatide (10mcg twice daily sub-cutaneous) or placebo for 12 weeks. Telemetric, intraparenchymal ICP monitors (Raumedic) recorded ICP over 12 weeks. Analysis was by hierarchical regression, significance level set at p <0.1

Results

16 participants were recruited, 15 completed the study: BMI 38.1(6.2) kg/m2, ICP 30.6(5.1) cmCSF. ICP, the primary endpoint, fell significantly (2.5 hours -5.7(2.9) cmCSF (p=0.048), 24 hours -6.4 (2.9) cmCSF (p=0.030) and 12 weeks -5.6 (3.0) cmCSF (p=0.058)). Monthly headache days fell in the Exenatide treated cohort (-7.7 (9.2) p=0.069) and vision improved (logMar acuity -0.1 (0.04) p=0.004).

Conclusions

Exenatide reduced ICP acutely and after chronic dosing. GLP-1R agonists represent a new approach to treat IIH.

1. Botfield HF, Uldall MS, Westgate CSJ, Mitchell JL, Hagen SM, Gonzalez AM, Hodson DJ, Jensen RH, Sinclair AJ. A glucagon-like peptide-1 receptor agonist reduces intracranial pressure in a rat model of hydro- cephalus. Sci Transl Med. 2017 Aug 23;9(404):eaan0972. doi: 10.1126/scitranslmed.aan0972.

jamesmitchell4@nhs.net

20

Micron-sized biogenic and synthetic hollow mineral spheres occlude additives within single crystals

Incorporating additives within host single crystals is an effective strategy for producing composite materials with tunable mechanical, magnetic and optical properties. The type of guest materials that can be occluded can be limited, however, as incorporation is a complex process depending on many factors including binding of the additive to the crystal surface, the rate of crystal growth and the stability of the additives in the crystallisation solution. In particular, the size of occluded guests has been restricted to a few angstroms – as for single molecules – to a few hundred nanometers – as for polymer vesicles and particles. Here, we present a synthetic approach for occluding micrometer-scale objects, including high-complexity unicellular organisms and synthetic hollow calcite spheres within calcite single crystals. Both of these objects can transport functional additives, including organic molecules and nanoparticles that would not otherwise occlude within calcite. Therefore, this method constitutes a generic approach using calcite as a delivery system for active compounds, while providing them with effective protection against environmental factors that could cause degradation.

Occlusion of micron-sized algae cells and calcitic hollow spheres within calcite single crystals, mediated by the positively charged polymer poly(allylamine hydrochloride). Both objects are used to transport functional additives to the host lattice.

Social determinants of health influence disease activity and functional disability in Polyarticular Juvenile Idiopathic Arthritis

BACKGROUND

Social determinants of health (SDH) greatly influence outcomes during the first year of treatment in rheumatoid arthritis, a disease similar to polyarticular juvenile idiopathic arthritis (pJIA). We investigated the correlation of community poverty level and other SDH with the persistence of moderate to severe disease activity and functional disability over the first year of treatment in pJIA patients enrolled in the Childhood Arthritis and Rheumatology Research Alliance Registry.

METHODS

In this cohort study, unadjusted and adjusted generalized linear mixed effects models analyzed the effect of community poverty and other SDH on disease activity, using the clinical Juvenile Arthritis Disease Activity Score-10, and disability, using the Child Health Assessment Questionnaire, measured at baseline, 6, and 12 months.

RESULTS

One thousand six hundred eighty-four patients were identified. High community poverty (≥20% living below the federal poverty level) was associated with increased odds of functional disability (OR 1.82, 95% CI 1.28-2.60) but was not statistically significant after adjustment (aOR 1.23, 95% CI 0.81-1.86) and was not associated with increased disease activity. Non-white race/ethnicity was associated with higher disease activity (aOR 2.48, 95% CI: 1.41-4.36). Lower self-reported household income was associated with higher disease activity and persistent functional disability. Public insurance (aOR 1.56, 95% CI 1.06-2.29) and low family education (aOR 1.89, 95% CI 1.14-3.12) was associated with persistent functional disability.

CONCLUSION

High community poverty level was associated with persistent functional disability in unadjusted analysis but not with persistent moderate to high disease activity. Race/ethnicity and other SDH were associated with persistent disease activity and functional disability.

VA Problem-Solving Training During COVID-19 for Clinicians of Patients With Complex Comorbidities

To address the shortage of mental health providers in geriatrics, VA has implemented clinician training in a VA Problem Solving Training (PST) protocol adapted to the needs of mostly older patients with complex comorbidities. This presentation will summarize PST implementation adaptations during COVID-19, and compare Veteran treatment outcomes before (2019) and during COVID-19 (2020). Sixty-one clinicians attended a workshop and small-group consultation for two training cases. Consultants provided ongoing feedback to program leadership about pandemic-related implementation challenges. Program adaptations during COVID-19 addressed challenges related to delivering treatment by telephone, video, or in-person and recruitment barriers. Veterans in both cohorts (N = 122) had significant reductions in mental health symptoms from baseline to posttreatment in paired t-test comparisons (ps &lt; .01). Flexibilities afforded to clinicians in the training during the pandemic did not diminish the effectiveness of the intervention, thus supporting continued implementation of the training program with added flexibility.

Oral vaccination of dogs with a monovalent live-avirulent vaccine confers 1 year of immunity against Bordetella bronchiseptica challenge

This experimental challenge study assessed immune protection 1 year after a single dose of live-attenuated oral Bordetella bronchiseptica (Bb) vaccine in dogs. Forty Bb-seronegative 7-9-week-old puppies were randomly assigned at Day 0 to receive a single oral dose of either Bb vaccine (n = 20; vaccinated group) or sterile water (n = 20; control group). Groups were housed separately until comingling 1 day pre-challenge (Day 365). Challenge with virulent aerosolized Bb occurred at Day 366. Clinical scores were obtained at Days 1-7, and 366-380. Bb microagglutination test (MAT) titers were obtained at Days -7, 0, monthly post-vaccination, and Days 358, 365, and 380. Nasal swabs were collected for microbiological assessment at Days -7, 0, 365, and 367-380. Oral Bb vaccination was not associated with side effects. Pre-challenge, vaccinated dogs developed persistent Bb MAT titers and control dogs remained seronegative. Post-challenge, duration of cough was longer in control dogs (least square means [LSM], 8.6 days) than vaccinated dogs (LSM, 1.5 days; P < 0.0001), with more control dogs having cough on 2 or more consecutive days (control group, n = 17/19, 89.5%; vaccinated group, n = 3/19, 15.8%; P = 0.0011). Post-challenge, Bb shedding occurred in all control dogs and 5/19 (26%) vaccinated dogs. Average duration of Bb shedding was longer in the control group (11.9 days vs. 0.6 days; P < 0.0001) and nasal Bb loads were higher in the control group (P < 0.00001). Orally administered Bb vaccine stimulated immunity that was still protective against virulent Bb challenge after 1 year.

Tumor and serum levels of per- and polyfluoroalkyl (PFAS) in hepatobiliary and gastrointestinal malignancy

BACKGROUND

There has been significant controversy over the carcinogenic potential of per- and polyfluoroalkyl substances (PFAS).

STUDY DESIGN

A total of 37 serum and tumor samples from patients with hepatobiliary and gastrointestinal malignancy were tested for 24 analytes of PFAS.

RESULTS

At least one PFAS analyte was found in 97% (36/37) of the serum samples and 41% (15/37) of the tumor samples. The serum Perfluorooctanesulfonic acid (PFOS) levels were significantly higher than the national levels (6.77 ng/mL vs. 5.20 ng/mL; p = 0.038). Patients with PFOS in tumor samples had significantly higher levels in serum when compared to tumor samples without PFOS (9.4 ng/mL vs 5.5 ng/mL; p = 0.015).

CONCLUSIONS

Patients were found to have significantly higher levels of PFOS when compared to the reported national levels. Additionally, the patients with higher serum levels of PFOS also had tumor positive samples.

Recurrence and survival after curative-intent treatment for colorectal liver metastases: Implications for adjuvant liver-directed regional chemotherapy

BACKGROUND

This study investigates tumor recurrence patterns and their effect on postrecurrence survival following curative-intent treatment of colorectal liver metastases (CRLM) to identify those who stand to benefit the most from adjuvant liver-directed therapy.

METHODS

This is a retrospective analysis of all patients that underwent liver resection and/or ablation for CRLM between 2007 and 2019. Postrecurrence survival was compared between recurrence locations. Risk factors for liver recurrence were sought.

RESULTS

The study included 227 patients. Majority were treated with resection (71.0%) while combination resection/ablation (18.9%) and ablation alone (11.0%), were less common. At a median follow-up of 3.0 years, recurrence was observed in 151 (66.5%) patients. Of those, liver, lung, and peritoneal recurrence were most common at 66.9%, 49.6%, and 9.2%, respectively. Median postrecurrence survival after liver, lung, and multisite recurrence was 39.6-, 68.4-, and 33.6 months, respectively. High tumor grade (p < 0.014), perineural invasion (p = 0.002), and N0 node status (p = 0.017) of primary tumor correlated with liver recurrence on multivariate analysis.

CONCLUSIONS

Tumor grade, perineural invasion, and N0 node status of the primary tumor are associated with increased risk of liver recurrence after CRLM resection and represent a target population that may benefit the most from adjuvant liver-directed regional chemotherapy.

Bone turnover markers as determinants of bone density and fracture in men with distal forearm fractures: the pathogenesis examined in the Mr F study

The pathogenesis for low-trauma wrist fractures in men is not fully understood. This study found that these men had evidence of significantly higher bone turnover compared with control subjects. Bone turnover markers were negative predictors of bone mineral density and were a predictor of fracture.

INTRODUCTION

Men with distal forearm fractures have reduced bone density, an increased risk of osteoporosis and of further fractures. The aim of this study was to investigate whether or not men with distal forearm fractures had evidence of altered bone turnover activity.

METHODS

Fifty eight men with low-trauma distal forearm fracture and 58 age-matched healthy control subjects were recruited. All subjects underwent a DXA scan of the forearm, both hips, and lumbar spine, biochemical investigations, and health questionnaires. Measurements of beta crosslaps (βCTX), procollagen type I N-terminal propeptide (PINP), sclerostin, Dickkopf-1 (Dkk1), and fibroblast growth factor 23 (FGF 23) were made.

RESULTS

Men with fracture had significantly higher PINP than controls at 39.2 ng/ml (SD 19.5) versus 33.4 ng/ml (SD13.1) (p<0.001). They also had significantly higher βCTX at 0.45 ng/ml (SD 0.21) versus 0.37 ng/ml (SD 0.17) (p= 0.037). Fracture subjects had significantly lower aBMD and PINP was a negative predictor of aBMD at the total hip and βCTX a negative predictor of forearm aBMD. Sclerostin was a positive predictor of aBMD at the lumbar spine and hip sites. Sex hormone binding globulin (SHBG) at 37nmol/L (SD 15.0) was lower in fracture cohort compared to 47.9 nmol/L (SD 19.2) (p=0.001) in control. Multiple regression revealed that the best model for prediction of fracture included SHBG, P1NP, and ultra-distal forearm aBMD. The likelihood of distal forearm fracture was decreased by 5.1% for each nmol/L increase in SHBH and by 1.4% for every mg/cm² increase in ultra-distal forearm aBMD, but increased by 6.1 % for every ng/ml increase in P1NP. Men in the highest quartile of PINP had a significantly greater likelihood of distal forearm fracture than those in the lowest quartile.

CONCLUSION

The fracture group had significantly higher PINP and βCTX compared with the control group, and these markers were negative predictors of aBMD at the total hip and forearm sites, respectively. Sclerostin was a positive predictor of the variance of spinal and hip aBMD. Likelihood of forearm fracture was best predicted by a combination of SHBG, PINP, and ultra-distal forearm aBMD. Findings of such cross-sectional data should be treated with caution, as longitudinal studies would be required to confirm or refute them.

1037 Early Detection and Management of Preoperative Anaemia in An Elective Vascular Surgery Cohort

Introduction

Iron deficiency anaemia is the most common cause of anaemia in the surgical population. Patients receiving transfusions during major surgery encounter more adverse outcomes compared to those that do not, indicating the early management of pre-operative anemia is likely to reduce major surgical patient morbidity and mortality. Previous studies have demonstrated that 33% of patients undergoing major vascular surgery operations are anaemic (haemaglobin, Hb, &lt;130g/L).

Aim

We aim to reduce the proportion of anaemic patients undergoing major vascular surgery by 50%.

Method

A point-of-care HemoCue machine was used to measure Hb in patients who were referred for elective major surgery in 11 vascular clinics. Patients with Hb &lt; 130g/L were prescribed a 1-month course of Ferrous Sulfate (200mg TDS), and a letter was sent to their GP requesting iron function tests. Post-intervention Hb levels were rechecked following the preoperative anaesthetics review.

Results

11 patients were referred for major surgery, of which 4 were identified as anaemic (36%). The mean Hb concentration was 121.3g/L, which increased to 137.3g/L following oral iron therapy. The mean duration of follow up was 36 days (range 0-94 days).

Conclusions

The implementation of a HemoCue machine to identify and manage preoperative anaemia was successful in our pilot study. Further work should include full integration of our pathway into current vascular clinics without student support. This will enable evaluation of the impact of our intervention on a wider scale.

423 Patient Perspective on the Use of the Independent Sector to Maintain Elective NHS Services During the COVID-19 Pandemic

Introduction

COVID-19 resulted in the suspension of planned treatments for patients worldwide leaving millions suffering the physical and mental effects of delay. Reports indicate that when services have been re-established, patients have been afraid to take up appointments. Hospitals put processes in place to counter this, notably separating emergency and elective patient cohorts. Most notably seen by the co-operation between the NHS and independent private healthcare providers in March 2020 at the height of the pandemic. We undertook a study to ascertain the perceptions of NHS patients who underwent elective treatment at independent ‘cold’ sites during the COVID-19 pandemic.

Method

A cross-sectional study with structured telephone interviews of patients who had planned elective treatments at ‘cold’ independent hospitals between March and September 2020. 1150 patients were identified, and a 20% sample formed a 230 patient study group, with 158 (70%) agreeing to participate.

Results

30% of patients delayed their treatment due to COVID related concerns, with 76% of these only accepting treatment because this was at a ‘cold’ site. 46% of patients perceived treatment at a ‘cold’ site as the most important factor contributing to their safety. 153 patients (97%) supported the paid arrangement between the NHS and the independent sector to provide separate ‘cold’ sites for elective treatments.

Discussion

Safely restarting elective services to allow important planned treatments to take place, as was the pandemic continues, is a priority. Our study indicates that physical separation of patient pathways impacted most on patient confidence, and that the use of ‘cold’ sites is a viable option.

Showcasing Nursing Leadership and Contributions to a University's COVID-19 Student Contact Tracing Process

The COVID-19 pandemic was an unprecedented event that impacted every segment of healthcare, including universities preparing healthcare professionals. Instituting processes to coordinate student return to campus and ongoing COVID-19 testing and contract tracing challenged university campuses, but also brought opportunities for collaboration. This article reports on the experiences of one nonprofit private higher education university in management of the COVID-19 testing and contact tracing that were led by school of nursing faculty and nursing leadership.