neuroGPT-X: toward a clinic-ready large language model

OBJECTIVE

The objective was to assess the performance of a context-enriched large language model (LLM) compared with international neurosurgical experts on questions related to the management of vestibular schwannoma. Furthermore, another objective was to develop a chat-based platform incorporating in-text citations, references, and memory to enable accurate, relevant, and reliable information in real time.

METHODS

The analysis involved 1) creating a data set through web scraping, 2) developing a chat-based platform called neuroGPT-X, 3) enlisting 8 expert neurosurgeons across international centers to independently create questions (n = 1) and to answer (n = 4) and evaluate responses (n = 3) while blinded, and 4) analyzing the evaluation results on the management of vestibular schwannoma. In the blinded phase, all answers were assessed for accuracy, coherence, relevance, thoroughness, speed, and overall rating. All experts were unblinded and provided their thoughts on the utility and limitations of the tool. In the unblinded phase, all neurosurgeons provided answers to a Likert scale survey and long-answer questions regarding the clinical utility, likelihood of use, and limitations of the tool. The tool was then evaluated on the basis of a set of 103 consensus statements on vestibular schwannoma care from the 8th Quadrennial International Conference on Vestibular Schwannoma.

RESULTS

Responses from the naive and context-enriched Generative Pretrained Transformer (GPT) models were consistently rated not significantly different in terms of accuracy, coherence, relevance, thoroughness, and overall performance, and they were often rated significantly higher than expert responses. Both the naive and content-enriched GPT models provided faster responses to the standardized question set than expert neurosurgeon respondents (p < 0.01). The context-enriched GPT model agreed with 98 of the 103 (95%) consensus statements. Of interest, all expert surgeons expressed concerns about the reliability of GPT in accurately addressing the nuances and controversies surrounding the management of vestibular schwannoma. Furthermore, the authors developed neuroGPT-X, a chat-based platform designed to provide point-of-care clinical support and mitigate the limitations of human memory. neuroGPT-X incorporates features such as in-text citations and references to enable accurate, relevant, and reliable information in real time.

CONCLUSIONS

The present study, with its subspecialist-level performance in generating written responses to complex neurosurgical problems for which evidence-based consensus for management is lacking, suggests that context-enriched LLMs show promise as a point-of-care medical resource. The authors anticipate that this work will be a springboard for expansion into more medical specialties, incorporating evidence-based clinical information and developing expert-level dialogue surrounding LLMs in healthcare.

A Drug Repurposing Approach Reveals Targetable Epigenetic Pathways in Plasmodium vivax Hypnozoites

Radical cure of Plasmodium vivax malaria must include elimination of quiescent 'hypnozoite' forms in the liver; however, the only FDA-approved treatments are contraindicated in many vulnerable populations. To identify new drugs and drug targets for hypnozoites, we screened the Repurposing, Focused Rescue, and Accelerated Medchem (ReFRAME) library and a collection of epigenetic inhibitors against P. vivax liver stages. From both libraries, we identified inhibitors targeting epigenetics pathways as selectively active against P. vivax and P. cynomolgi hypnozoites. These include DNA methyltransferase (DNMT) inhibitors as well as several inhibitors targeting histone post-translational modifications. Immunofluorescence staining of Plasmodium liver forms showed strong nuclear 5-methylcystosine signal, indicating liver stage parasite DNA is methylated. Using bisulfite sequencing, we mapped genomic DNA methylation in sporozoites, revealing DNA methylation signals in most coding genes. We also demonstrated that methylation level in proximal promoter regions as well as in the first exon of the genes may affect, at least partially, gene expression in P. vivax. The importance of selective inhibitors targeting epigenetic features on hypnozoites was validated using MMV019721, an acetyl-CoA synthetase inhibitor that affects histone acetylation and was previously reported as active against P. falciparum blood stages. In summary, our data indicate that several epigenetic mechanisms are likely modulating hypnozoite formation or persistence and provide an avenue for the discovery and development of improved radical cure antimalarials.

Assessing the research landscape and clinical utility of large language models: a scoping review

IMPORTANCE

Large language models (LLMs) like OpenAI's ChatGPT are powerful generative systems that rapidly synthesize natural language responses. Research on LLMs has revealed their potential and pitfalls, especially in clinical settings. However, the evolving landscape of LLM research in medicine has left several gaps regarding their evaluation, application, and evidence base.

OBJECTIVE

This scoping review aims to (1) summarize current research evidence on the accuracy and efficacy of LLMs in medical applications, (2) discuss the ethical, legal, logistical, and socioeconomic implications of LLM use in clinical settings, (3) explore barriers and facilitators to LLM implementation in healthcare, (4) propose a standardized evaluation framework for assessing LLMs' clinical utility, and (5) identify evidence gaps and propose future research directions for LLMs in clinical applications.

EVIDENCE REVIEW

We screened 4,036 records from MEDLINE, EMBASE, CINAHL, medRxiv, bioRxiv, and arXiv from January 2023 (inception of the search) to June 26, 2023 for English-language papers and analyzed findings from 55 worldwide studies. Quality of evidence was reported based on the Oxford Centre for Evidence-based Medicine recommendations.

FINDINGS

Our results demonstrate that LLMs show promise in compiling patient notes, assisting patients in navigating the healthcare system, and to some extent, supporting clinical decision-making when combined with human oversight. However, their utilization is limited by biases in training data that may harm patients, the generation of inaccurate but convincing information, and ethical, legal, socioeconomic, and privacy concerns. We also identified a lack of standardized methods for evaluating LLMs' effectiveness and feasibility.

CONCLUSIONS AND RELEVANCE

This review thus highlights potential future directions and questions to address these limitations and to further explore LLMs' potential in enhancing healthcare delivery.

Automated Paper Screening for Clinical Reviews Using Large Language Models: Data Analysis Study

BACKGROUND

The systematic review of clinical research papers is a labor-intensive and time-consuming process that often involves the screening of thousands of titles and abstracts. The accuracy and efficiency of this process are critical for the quality of the review and subsequent health care decisions. Traditional methods rely heavily on human reviewers, often requiring a significant investment of time and resources.

OBJECTIVE

This study aims to assess the performance of the OpenAI generative pretrained transformer (GPT) and GPT-4 application programming interfaces (APIs) in accurately and efficiently identifying relevant titles and abstracts from real-world clinical review data sets and comparing their performance against ground truth labeling by 2 independent human reviewers.

METHODS

We introduce a novel workflow using the Chat GPT and GPT-4 APIs for screening titles and abstracts in clinical reviews. A Python script was created to make calls to the API with the screening criteria in natural language and a corpus of title and abstract data sets filtered by a minimum of 2 human reviewers. We compared the performance of our model against human-reviewed papers across 6 review papers, screening over 24,000 titles and abstracts.

RESULTS

Our results show an accuracy of 0.91, a macro F1-score of 0.60, a sensitivity of excluded papers of 0.91, and a sensitivity of included papers of 0.76. The interrater variability between 2 independent human screeners was κ=0.46, and the prevalence and bias-adjusted κ between our proposed methods and the consensus-based human decisions was κ=0.96. On a randomly selected subset of papers, the GPT models demonstrated the ability to provide reasoning for their decisions and corrected their initial decisions upon being asked to explain their reasoning for incorrect classifications.

CONCLUSIONS

Large language models have the potential to streamline the clinical review process, save valuable time and effort for researchers, and contribute to the overall quality of clinical reviews. By prioritizing the workflow and acting as an aid rather than a replacement for researchers and reviewers, models such as GPT-4 can enhance efficiency and lead to more accurate and reliable conclusions in medical research.

Outcomes of Laparoscopic Sleeve Gastrectomy (LSG) vs One-Anastomosis Gastric Bypass (OAGB) in Patients with Super-Super Obesity (BMI ≥ 60 kg/m2)

INTRODUCTION

The data comparing laparoscopic sleeve gastrectomy (LSG) and one-anastomosis gastric bypass (OAGB) in patients with BMI ≥ 60 kg/m2 is scarce.

METHODS

Prospectively collected data of patients with BMI ≥ 60 kg/m2 undergoing LSG or OAGB from January 2008 until June 2022 was analyzed retrospectively. Weight loss outcomes, impact on comorbidities, and complications were compared in both groups.

RESULTS

Fifty-six patients underwent LSG and 13 patients underwent OAGB. The median age and BMI were 37 (34-44) years and 63 (61.3-64.6) kg/m2 respectively. Both the groups had similar baseline demographic parameters. The percentage excess BMI loss (%EBMIL) was statistically similar in LSG and OAGB groups at 1 year (46.2% vs 46.1%), 3 years (52.9% vs 56.7%), and 5 years (51.1% vs 62.3%). The percentage excess BMI regain was lower (although statistically similar) following OAGB at 3 years (5.3% vs 0.1%) and 5 years (12.9% vs 4.4%). OAGB was found to correlate positively with weight loss and negatively with weight regain (p > 0.05). There was one 30-day mortality due to postoperative lower respiratory infection in the LSG group.

CONCLUSION

OAGB has a trend towards better weight loss outcomes as compared to LSG in patients with a BMI ≥ 60 kg/m2 with lesser complication rates and might be a preferred option. LSG also has acceptable weight loss and should be considered a standalone procedure if OAGB is not feasible technically.

ANXIETY SYNDROMES IN ADOLESCENTS WITH OPERATIONAL RESPIRATORY CONDITIONS: A PROSPECTIVE STUDY

Aim - determining the prevalence of anxiety disorders and their effect on disease progression and quality of life in adults with organic illnesses and functional disorders of the respiratory system treated in a pulmonology environment. A total of 135 young adults between the ages of 13 and 17 were analyzed. There were a total of 46 adolescents diagnosed with somatoform respiratory disorders (SRD), 45 adolescents diagnosed with bronchial asthma (BA), and 44 adolescents diagnosed with pneumonia. The Spielberger-Khanin anxiety questionnaire and the Nijmegen hyperventilation syndrome (HVS) scale were used for the research and diagnosis, respectively. The quality of life was measured using the asthma quality of life questionnaire (AQLQ). In comparison to adults with asthma (33.2%) and pneumonia (32.3%), adults with SRD (34.5%). There were mild immediate associations between the Spielberger scale and the Nijmegen HVS questionnaire for both trait and state anxiety, and mild inverse correlations between the Spielberger scale and the AQLQ for both state and trait anxiety. Adolescents with anxiety had a higher prevalence of trauma, pain, and social issues than their non-anxious counterparts who were referred to psychiatry. In adolescents, 5.1% had severe trait anxiety, and 19.3% had severe condition anxiety. Adolescents with SRD were twice as likely to suffer from extreme state and trait anxiety as the general population. It is hypothesized that anxiety problems are at the root of HVS and contribute to adults' dissatisfaction with their quality of life due to lung ailments. Although certain adolescents with anxiety disorders were referred for anxiety, this data nevertheless lends credence to the idea that using standardized and structured instruments regularly might help increase accuracy and detection rates in the clinic, regardless of the reason for referral. Complete evaluations are essential for this patient population due to the intricacy of their symptoms.

Single Institute Experience Treating Uterine Carcinosarcoma: Outcome Analysis

PURPOSE/OBJECTIVE(S)

Uterine carcinosarcoma (UCS) is rare with a poor prognosis. We report over 10 years' experience, reporting prognostic and predictive factors for overall survival (OS) and disease-free survival (DFS).

MATERIALS/METHODS

Patient, tumor, treatment and relapse characteristics of 168 women with stages I-IVB UCS treated at our institute between 2010 and 2020 were analyzed. OS and DFS at 2 and 5 years were the primary outcomes, estimated with Kaplan-Meier. The benefit of adjuvant chemotherapy and radiotherapy in the curative cohort was estimated using the log rank test.

RESULTS

Median follow up was 23 months (range 1-137 months). 34% had FIGO stage IA disease, 10% IB, 8% II. 16% IIIA-IIIC1, and 10% IIIC2 and 22% IVB. The overall 2-year OS was 52% and 5-year OS 30%. 2-year OS by FIGO stage were: IA 66%; IB 63%; II 54%; IIIA-IIIC1 54%; IIIC2 45%; IVB 26%. Within the curative cohort who were surgically staged, 2-year DFS was 47% and 5-year was 30%. 2-year DFS were 61% in IA disease, 53% IB, 12% II, 51% IIIA-IIIC1, and 45% IIIC2 and 4% IVB. A greater risk of death was conferred by lack of adjuvant treatment (lack of chemo > lack of radiotherapy). The most common chemotherapy regimen used was Carboplatin Paclitaxel and pelvic radiotherapy 45Gy 25F over 5 weeks. The combination of surgery and chemotherapy +/- radiotherapy significantly improved OS compared to surgery +/- radiotherapy (HR 0.5 with CI 0.3 - 0.9) p<0.05. Radiotherapy improved OS compared to surgery only (HR 0.4 with CI 0.2 - 1.1) p<0.05. Relapse rate in all patients following curative treatment is 72% within year 1 and 86% within year 2 from diagnosis. In 52 patients with stage 1A disease treated with surgery +/- radiotherapy only, 42.4% relapsed, median time to relapse was 8 months from diagnosis. Relapse occurred despite 69.2 % stage 1A patients receiving adjuvant pelvic EBRT and in these patients relapse within the pelvis occurred in 50%.

CONCLUSION

This study constitutes the largest retrospective analyses of long-term mortality outcomes in UCS and confirms poor outcomes despite curative surgery and adjuvant therapy. Most patients relapse within the first year following curative treatment. The use of adjuvant chemotherapy improves OS in all stages. In stage 1A disease 42 % patients relapse locally and distantly. This is an area of controversy and this data would strongly suggest that the addition of adjuvant paclitaxel-carboplatin or cisplatin-doxorubicin chemotherapy to EBRT should be considered in all patients including earliest stage disease.

Single Institute Experience with MRI-Guided Adaptive Brachytherapy for Locally Advanced Cervix Cancer: Long Term Outcomes and Toxicity Analysis

PURPOSE/OBJECTIVE(S)

We report over 10 years' experience of MRI-guided adaptive brachytherapy (MRIGABT) in locally advanced cervix cancer (LACC).

MATERIALS/METHODS

A total of 162 patients with LACC FIGO stage IB-IVB were treated at our institute between 2010 and 2020. Treatment consisted of chemoradiotherapy (weekly intravenous cisplatin 40 mg/m², 5 cycles, 1 day per cycle, 45-50.4 Gy external beam radiotherapy (EBRT) in 1·8-2 Gy fractions, followed by MRIGABT. Target volume definition and dose reporting for MRIGABT was according to GEC-ESTRO recommendations. MRIGABT dose prescription was according to our institutional practice. Overall survival (OS) and disease-free survival (DFS) were the primary endpoints. Kaplan-Meier estimates were calculated for OS and DFS at 2, 5 and 10-years. Organ-specific late toxicity grade ≥3 (≥G3) (CTCAEv5.0) was reported, alongside rates of bowel fistula, stricture, and perforation. Using logistic regression, we explored the relationship between EQD2 D2cc bladder and ≥G3 genitourinary (GU) toxicity. We compared patient proportions developing ≥ G3 GU toxicity in those who received EQD2 ≥85 Gy versus <85 Gy. We examined the following predictors of ≥G3 gastrointestinal (GI) toxicity: EQD2 dose (≥65 Gy versus <65 Gy), pre-existing bowel conditions, nodal boost, and extended field EBRT.

RESULTS

Median follow up was 4.7 years (IQR 3.3-7.1 years). Median EBRT dose was 50.4 Gy (IQR 50.4-50.4 Gy); 91% received chemotherapy. Median high-risk clinical target volume (HRCTV) was 23.6 cm3 (IQR 16.6-31.3 cm3). Median doses were as follows; D90 HRCTV 88.9 Gy EQD210 (IQR 84.1-91.3 Gy), median D2cc bladder 81.6 (IQR 76.9-85.7 Gy), rectum 62.2 (IQR 57.9-65.3 Gy), sigmoid 67.4 (IQR 60.8-71.1 Gy), and bowel 55 (IQR 49.9-63.2 Gy), (all EQD23). The 2, 5 and-10-year OS were 98%, 80% and 75%. The 2, 5 and 10-year DFS were 98%, 75% and 60%. Late toxicity ≥G3 was 9% GU, 6% GI and 3% vaginal. There was a significant relationship between EQD2 and ≥G3 GU toxicity (OR: 1.11, 95% CI: 1.01-1.25; P = 0.04). When comparing those who received EQD2≥ 85Gy versus <85Gy, higher doses were associated with a greater proportion of ≥G3 GU toxicity (13% vs 6%). No significant predictors of ≥ G3 GI toxicity were observed.

CONCLUSION

We observed excellent LC and OS. A significant relationship was found between EQD2 >85 Gy and bladder toxicity, although ≥G3 toxicity was low. We did not identify predictors of bowel toxicity. New predictors of bowel toxicity are required. Mean EBRT dose, D1.0 cc rectum, sigmoid and bowel are being investigated further.

PfMORC protein regulates chromatin accessibility and transcriptional repression in the human malaria parasite, P. falciparum

The environmental challenges the human malaria parasite, Plasmodium falciparum, faces during its progression into its various lifecycle stages warrant the use of effective and highly regulated access to chromatin for transcriptional regulation. Microrchidia (MORC) proteins have been implicated in DNA compaction and gene silencing across plant and animal kingdoms. Accumulating evidence has shed light into the role MORC protein plays as a transcriptional switch in apicomplexan parasites. In this study, using CRISPR/Cas9 genome editing tool along with complementary molecular and genomics approaches, we demonstrate that PfMORC not only modulates chromatin structure and heterochromatin formation throughout the parasite erythrocytic cycle, but is also essential to the parasite survival. Chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) experiments suggest that PfMORC binds to not only sub-telomeric regions and genes involved in antigenic variation but is also most likely a key modulator of stage transition. Protein knockdown experiments followed by chromatin conformation capture (Hi-C) studies indicate that downregulation of PfMORC induces the collapse of the parasite heterochromatin structure leading to its death. All together these findings confirm that PfMORC plays a crucial role in chromatin structure and gene regulation, validating this factor as a strong candidate for novel antimalarial strategies.

Development and Validation of a Prognostic Risk Model for Patients with Advanced Melanoma Treated with Immune Checkpoint Inhibitors

BACKGROUND

Risk stratification tools for patients with advanced melanoma (AM) treated with immune checkpoint inhibitors (ICI) are lacking. We identified a new prognostic model associated with overall survival (OS).

PATIENTS AND METHODS

A total of 318 treatment naïve patients with AM receiving ICI were collected from a multi-centre retrospective cohort study. LASSO Cox regression identified independent prognostic factors associated with OS. Model validation was carried out on 500 iterations of bootstrapped samples. Harrel's C-index was calculated and internally validated to outline the model's discriminatory performance. External validation was carried out in 142 advanced melanoma patients receiving ICI in later lines.

RESULTS

High white blood cell count (WBC), high lactate dehydrogenase (LDH), low albumin, Eastern Cooperative Oncology Group (ECOG) performance status ≥1, and the presence of liver metastases were included in the model. Patients were parsed into 3 risk groups: favorable (0-1 factors) OS of 52.9 months, intermediate (2-3 factors) OS 13.0 months, and poor (≥4 factors) OS 2.7 months. The C-index of the model from the discovery cohort was 0.69. External validation in later-lines (N = 142) of therapy demonstrated a c-index of 0.65.

CONCLUSIONS

Liver metastases, low albumin, high LDH, high WBC, and ECOG≥1 can be combined into a prognostic model for AM patients treated with ICI.

Development and validation of a 21-gene prognostic signature in neuroblastoma

Survival outcomes for patients with neuroblastoma vary markedly and reliable prognostic markers and risk stratification tools are lacking. We sought to identify and validate a transcriptomic signature capable of predicting risk of mortality in patients with neuroblastoma. The TARGET NBL dataset (n = 243) was used to develop the model and two independent cohorts, E-MTAB-179 (n = 478) and GSE85047 (n = 240) were used as validation sets. EFS was the primary outcome and OS was the secondary outcome of interest for all analysis. We identified a 21-gene signature capable of stratifying neuroblastoma patients into high and low risk groups in the E-MTAB-179 (HR 5.87 [3.83-9.01], p < 0.0001, 5 year AUC 0.827) and GSE85047 (HR 3.74 [2.36-5.92], p < 0.0001, 5 year AUC 0.815) validation cohorts. Moreover, the signature remained independent of known clinicopathological variables, and remained prognostic within clinically important subgroups. Further, the signature was effectively incorporated into a risk model with clinicopathological variables to improve prognostic performance across validation cohorts (Pooled Validation HR 6.93 [4.89-9.83], p < 0.0001, 5 year AUC 0.839). Similar prognostic utility was also demonstrated with OS. The identified signature is a robust independent predictor of EFS and OS outcomes in neuroblastoma patients and can be combined with clinically utilized clinicopathological variables to improve prognostic performance.

THE IMPACT OF CLIMATE CHANGE ON INFECTIOUS DISEASES: A COMPREHENSIVE ANALYSIS OF VECTOR-BORNE DISEASES, WATER-BORNE DISEASES, AND PUBLIC HEALTH STRATEGIES

Climate change is long-term modifications to weather patterns and a rise in extreme weather events. It might modify the hazard to human health and exacerbate current problems. The article explores the scientific data in a description of the effects of Infectious diseases in humans and climate change. It identifies scientific advancements and gaps in potential responses from human civilization and how it might prepare for the changes that come with it by adjusting to them. The impact reflects three aspects, such as climate variables, selected infectious diseases, and infectious disease components. This study demonstrates how vulnerable people are to any ill consequences that climate change may have on their health. Humans can actively influence controllable correlated health impacts by taking proactive measures, such as increasing our understanding of the detrimental effects associated with specific diseases and the patterns in climate change. We can also carefully distribute technology and resources, encouraging exercise and public awareness. It is advised to take the following adaption measures: Considering how infectious diseases and climate change are not the only things that science has discovered and create locally efficient early warning systems for those effects to produce more scientific justifications and go beyond scientific reports. Improve prediction of the spatiotemporal processes behind climate change and changes in infectious illnesses connected at different temporal and spatial scales.

Mechanisms and clinical implications in renal carcinoma resistance: narrative review of immune checkpoint inhibitors

Clear cell renal cell carcinoma (ccRCC) is the most common histological subtype of renal cell carcinoma. The prognosis for patients with ccRCC has improved over recent years with the use of combination therapies with an anti-programmed death-1 (PD-1) backbone. This has enhanced the quality of life and life expectancy of patients with this disease. Unfortunately, not all patients benefit; eventually, most patients will develop resistance to therapy and progress. Recent molecular, biochemical, and immunological research has extensively researched anti-angiogenic and immune-based treatment resistance mechanisms. This analysis offers an overview of the principles underpinning the resistance pathways related to immune checkpoint inhibitors (ICIs). Additionally, novel approaches to overcome resistance that may be considered for the trial context are discussed.

Treatment-Free Survival After Nivolumab vs Pembrolizumab vs Nivolumab-Ipilimumab for Advanced Melanoma

Importance

Treatment-free survival (TFS) represents an alternative time-to-event end point, accurately characterizing time spent free of systemic therapy, providing a more patient-centric view of immune checkpoint inhibitor (ICI) therapy regimens. There remains a lack of studies evaluating TFS outcomes among patients with advanced melanoma who are receiving immunotherapy, especially outside of the clinical trial setting.

Objective

To evaluate TFS outcomes for patients with advanced melanoma receiving first-line ICI therapy outside of a clinical trial setting.

Design, Setting, and Participants

This multicenter cohort study of patients with advanced melanoma receiving first-line ICI therapy between August 1, 2013, and May 31, 2020, was conducted in Alberta, Canada. Data analysis was performed in August 2022.

Exposures

Patients received standard-of-care, first-line ICI therapy treatment regimens including single-agent nivolumab, single-agent pembrolizumab, or ipilimumab-nivolumab.

Main Outcomes and Measures

Treatment-free survival was defined as the difference in the 36-month restricted mean survival time between 2 conventional survival end points: (1) time from treatment initiation to ICI cessation, death, or censoring at last follow-up and (2) time from treatment initiation to subsequent systemic anticancer therapy, death, or censoring at last follow-up.

Results

A total of 316 patients with advanced melanoma receiving first-line nivolumab (n = 51; median age, 66 years [IQR, 56-78 years]; 31 men [60.8%]), pembrolizumab (n = 158; median age, 69 years [IQR, 60-78 years]; 112 men [70.9%]), or combination nivolumab-ipilimumab (n = 107; median age, 53 years [IQR, 42-60 years]; 72 men [67.3%]) were included. Treatment groups were similar with regard to sex, primary tumor location, and presence of metastasis, although patients receiving combination nivolumab-ipilimumab had a lower Eastern Cooperative Oncology Group status, were younger, and were more likely to be BRAF V600E positive than those receiving anti-programmed cell death protein 1 (anti-PD-1) monotherapy. The restricted mean TFS was longer for nivolumab-ipilimumab (12.4 months [95% CI, 8.8-16.0 months]) compared with nivolumab (8.9 months [95% CI, 4.4-13.5 months]) and pembrolizumab (11.1 months [95% CI, 8.5-13.8 months]). During the 36-month follow-up interval, patients treated with nivolumab-ipilimumab spent 34.4% of their time (12.4 of 36 months) not receiving systemic anticancer treatments compared with 30.8% (11.1 of 36 months) and 24.7% (8.9 of 36 months) of the time for the pembrolizumab and nivolumab treatment groups, respectively.

Conclusions and Relevance

This cohort study of patients with advanced melanoma receiving first-line ICI therapy suggests that TFS represents a patient-centric, informative end point. Patients treated with combination nivolumab-ipilimumab spent more time alive and free from systemic anticancer therapy than those treated with anti-PD-1 monotherapy alone.

Trends in health care spending on kidney cancer in the United States, 1996-2016

BACKGROUND

Paradigm shifts in kidney cancer management have led to higher health care spending. Here, total and per capita health care spending and primary drivers of change in health expenditures for kidney cancer in the United States between 1996 and 2016 are estimated.

METHODS

Public databases developed by the Institute for Health Metrics and Evaluation for the Disease Expenditure Project were used. The prevalence of kidney cancer was estimated from the Global Burden of Disease Study. Changes in health care spending on kidney cancer were assessed by joinpoint regression and expressed as annual percent changes (APCs).

RESULTS

In 2016, total health care spending on kidney cancer was $3.42 billion (95% CI, $2.91 billion to $3.89 billion) compared with $1.18 billion (95% CI, $1.07 billion to $1.31 billion) in 1996. Per capita spending had two inflection points in 2005 and 2008, close to the approval years of targeted therapies, which corresponded to APCs of +2.9% (95% CI, +2.3% to +3.6%; p < .001) per year, 1996-2005; +9.2% (95% CI, +3.4% to +15.2%; p = .004) per year, 2005-2008; and +3.1% (95% CI, +2.2% to +3.9%; p < .001) per year, 2008-2016. Inpatient care was the largest contributor to health expenditures, which accounted for $1.56 billion (95% CI, $1.19 billion to $1.95 billion) in 2016. Price and intensity of care was the primary driver of increased health expenditures, whereas service utilization was the primary driver of reduced health expenditures.

CONCLUSIONS

Prevalence-adjusted health care spending on kidney cancer continues to rise in the United States, which is primarily attributable to inpatient care and driven by the price and intensity of care over time.

A142 APPROPRIATENESS OF POST-ENDOSCOPY CARE IN PATIENTS PRESENTING WITH FOOD BOLUS IMPACTIONS OVERNIGHT: A POPULATION-BASED MULTICENTER COHORT STUDY

Background

Appropriate management of esophageal food bolus impactions includes endoscopic evaluation and follow-up for potential underlying esophageal pathology. Patients who present with impactions at night may not receive optimal long-term post-endoscopy care due to patient-, physician-, or system-related factors.

Purpose

We aimed to evaluate the appropriateness of care for patients who present with food bolus impactions after regular daytime hours.

Method

We conducted a retrospective, population-based, multi-center cohort study of adult patients undergoing endoscopy for food impaction between 19:00-06:59 from 2016-2018 in the Calgary Health Zone, Canada. Appropriate post-endoscopy care was defined by a composite of a follow-up clinic visit, repeat endoscopy, other appropriate investigations (e.g., manometry), or appropriate medical treatment (e.g., proton pump inhibitor). Predictors of inappropriate care were assessed using multivariable logistic regression, expressed as adjusted odds ratios (aOR) with 95% confidence intervals (CI).

Result(s)

A total of 323 patients underwent an after-hours or overnight endoscopy for food bolus impaction. 25.4% (82/323) of patients did not receive appropriate post-endoscopy care. Predictors of inappropriate care included rural residence (aOR 2.66 [95% CI: 1.18-6.01], p=0.02), first food bolus presentation (aOR 2.38 [95% CI: 1.04-5.44], p=0.04), and absence of a specific pathology during the index procedure (aOR 3.01 [95% CI: 0.97-9.29], p=0.05), suggesting a potential association with clinician cognitive bias. Among patients who were followed, 18.9% (35/185) had a change in the original diagnosis.

Image

Conclusion(s)

One quarter of patients presenting with a food bolus impaction at night do not receive appropriate post-endoscopy care. System-based interventions should target this high-risk population as the diagnosis and management may change with follow-up.

Please acknowledge all funding agencies by checking the applicable boxes below

None

Disclosure of Interest

None Declared

The effectiveness of prenatal and postnatal home visits by paramedical professionals and women's group meetings in improving maternal and child health outcomes in low and middle-income countries: a systematic review and meta-analysis

OBJECTIVE

To assess the effectiveness of prenatal and postnatal home visits (HVs) and women group meetings (WGMs) by paramedical professionals to improve maternal and child health outcomes in low- and middle-income countries (LMICs).

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

We conducted a systematic review of trials published till December 2020, as per registered protocol in The International Prospective Register of Systematic Reviews (PROSPERO) (CRD42018091968). Outcomes were neonatal mortality rate (NMR), maternal mortality ratio (MMR), the incidence of low birth weight, and still birth rate (SBR). The Cochrane Pregnancy and Childbirth Group's Trials Register, Cochrane Central Register of Controlled Trials, PubMed, and Excerpta Medica Database (EMBASE) were searched. Pooled results were estimated using random-effects meta-analysis in RevMan version 5.2.

RESULTS

Twenty-five trials met the inclusion criteria. HVs were the key intervention in 12, WGMs in 11, and both interventions in 2 trials. The pooled estimates have shown that NMR was significantly reduced by HVs (OR 0.77, confidence interval [CI]: 0.67-0.90, P = 0.0007, I² = 77%) and WGMs (OR 0.76, CI: 0.65-0.90, P = 0.001, I² = 71%). SBR was significantly reduced by HVs (OR 0.77, CI: 0.70-0.85; P < 0.001, I² = 0%). Subgroup analysis of studies in which more than 10% of pregnant women participated in the WGMs showed significant reduction in NMR (OR 0.67, CI 0.58-0.77, P = 0.00001, I² = 31%) and MMR (OR 0.55, CI 0.36-0.84, P = 0.005, I² = 27%). Two studies reported improvement in birth weight by HVs.

CONCLUSIONS

HVs and WGMs (with >10% pregnant women) by paramedical professionals are effective strategies in reducing the NMR and MMR in LMICs. HVs were also effective in reducing SBR.

LDL cholesterol an unmet target in diabetic, hypertensive population pan India exposing susceptive cardiovascular disorder risk

Funding Acknowledgements

Type of funding sources: None.

Background

Management and pathophysiology of diabetes and hypertension has always been the centre of research, with new insights being found consistently. CVD is the major cause of mortality in patients with type 2 diabetes and affects approximately 32.2% of people with type 2 diabetes. Southeast Asia stands out with a higher prevalence of CAD (29.4%) compared with other regions.

Purpose

The purpose of this EHR based real world study was to identify the proportion of patients with LDL-C out of control in people living with diabetes and hypertension who were under regular care of physicians. Specialized clinical care by super-specialists ensures management of specific disorders, yet risk factors for overall cardiovascular health continue to be expressed uncontrolled.

Methods

Patients reporting for routine care in 14 centers across the country were eligible to participate in the study. Patient recruitment at each site required informed consent signature, history of at least 6 months of diabetes mellitus type 2, was sequential and independent of other sites. An EMR (Medeva) integrated research proforma was created only for this study which collected data on medical history, comorbidities, diabetic complications, medications and laboratory values of relevance to the study. The recruitment started in March 2022 and ended in August 2022 (6 months).

Results

Average age of these patients was 54.36 years, and 1238 were male and 964 were female patients. Out of this sample, 1388 patients were only diabetic and 814 patients had diabetes as well as hypertension. 256 patients 44.8% patients had LDL-C within acceptable limits and the remaining 51.2% had hyperdyslipidemia. Average LDL-C value for all patients was 107.07, average LDL-C levels in only diabetic patients was 116.51, and LDL in patients with diabetes and hypertension is 90.97. In diabetes only patients, 37% patients had LDL-C under control whereas in diabetes and hypertension group 58% patients had LDL-C under control.

Conclusion

Although diabetic patients are under regular clinical care, their LDL-C values were higher in 55.2% of the patients. This is an alarming signal that calls all the stakeholders - diabetologists, researchers, educators, dieticians, policymakers, government agencies and people with diabetes must contribute towards the management of lipid profile for prevention of cardiovascular events. Also, the proportion of patients with LDL-C under control is lesser in patients who are only diabetic as compared to patients who are both diabetic and hypertensive. This finding suggests that there is either lesser focus or inadequate on lipid profile of patients who are only diabetic; more holistic management is an unprecedented requirement. More research is needed in this direction to recognize the loopholes, manage them and prevent them adequately.

Expression of risk genes linked to vitamin D receptor super-enhancer regions and their association with phenotype severity in multiple sclerosis

Multiple sclerosis (MS) is a chronic debilitating neurological condition with a wide range of phenotype variability. A complex interplay of genetic and environmental factors contributes to disease onset and progression in MS patients. Vitamin D deficiency is a known susceptibility factor for MS, however the underlying mechanism of vitamin D-gene interactions in MS etiology is still poorly understood. Vitamin D receptor super-enhancers (VSEs) are enriched in MS risk variants and may modulate these environment-gene interactions. mRNA expression in total of 64 patients with contrasting MS severity was quantified in select genes. First, RNA-seq was performed on a discovery cohort (10 mild, 10 severe MS phenotype) and ten genes regulated by VSEs that have been linked to MS risk were analyzed. Four candidates showed a significant positive association (GRINA, PLEC, PARP10, and LRG1) in the discovery cohort and were then quantified using digital droplet PCR (ddPCR) in a validation cohort (33 mild, 11 severe MS phenotype). A significant differential expression persisted in the validation cohort for three of the VSE-MS genes: GRINA (p = 0.0138), LRG1 (p = 0.0157), and PLEC (p = 0.0391). In summary, genes regulated by VSE regions that contain known MS risk variants were shown to have differential expression based on disease severity (p<0.05). The findings implicate a role for vitamin D super-enhancers in modulating disease activity. In addition, expression levels may have some utility as prognostic biomarkers in the future.

Awareness of lipid guideline recommendations for high-risk patients amongst primary care physicians in Canada

Background

Lipid guidelines for cardiovascular (CV) risk reduction have evolved in recent years, particularly since the introduction of PCSK9 inhibitors. In many jurisdictions, CV risk management is provided by primary care physicians (PCPs). We surveyed Canadian PCPs regarding their awareness and implementation of the 2021 Canadian Cardiovascular Society (CCS) lipid guideline recommendations for patients following an acute coronary syndrome (ACS) or for those with diabetes but without CV disease.

Methods and results

From a national database of PCPs with interest and/or experience in CV medicine, we invited PCPs to complete a survey regarding lipid management in high-risk patients. A committee of PCPs and specialists with lipid expertise including several co-authors of the 2021 CCS lipid guidelines had designed the survey to probe awareness and practice patterns. A total of 203 PCPs from across Canada completed the survey between January and March 2022. 23.6% of respondents had previously prescribed a PCSK9 inhibitor. Almost all (96.5%) PCPs concurred that a post-ACS patient should be seen by their PCP within 4 weeks of hospital discharge (79.3% within 2 weeks). Almost half (45.3%) responded that discharge summaries provided inadequate information relevant for PCPs, and 43% felt that lipid management post-ACS was the primary responsibility of specialists. More than half (56%) articulated challenges when seeing a post-ACS patient, related to inadequate discharge information, complexities of polypharmacy and duration of therapies, and managing perceived or real statin intolerance. 62% correctly identified the LDL-C intensification threshold of 1.8 mmol/L in post-ACS patients, while 79% considered that PCSK9 inhibitors were indicated only for those patients who were already receiving statins plus ezetimibe or had substantially elevated LDL-C levels. 55.2% were able to correctly identify clinical features associated with greatest absolute benefit of PCSK9 inhibitors in post-ACS patients. For patients with diabetes but without ASCVD, 80% of PCPs incorrectly believed that PCSK9 inhibitors were indicated for LDL-C levels above threshold despite statin therapy, and only 42% correctly identified the LDL-C threshold for treatment intensification of 2.0 mmol/L.

Conclusion

While PCPs are aware of the urgency regarding lipid management in post-ACS patients, many encounter challenges after hospital discharge, frequently deferring lipid management to specialists. Thus, almost one year following publication of the 2021 CCS lipid guidelines, substantial knowledge gaps remain regarding intensification thresholds and treatment options for patients post-ACS or for those with diabetes. Innovative and effective knowledge translation programs are urgently required.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Amgen Canada

Banded Sleeve Gastrectomy vs Non-banded Sleeve Gastrectomy: a Systematic review and Meta-analysis

Banded sleeve gastrectomy (BSG) was developed to restrict progressive dilation of the gastric sleeve, which remains a commonly implicated reason for weight regain following SG. The present study attempted to perform a systematic review and meta-analysis comparing the two procedures. Literature search was performed across PubMed and Google Scholar, using the keywords "Banded Sleeve Gastrectomy", "Sleeve gastrectomy", "Banded", "BSG" and "LSG". It yielded 4267 articles, six of which have been included in this review. Better weight loss outcomes at 3 and 5 years are noted following BSG, with a margin of 6.39% and 9.97% in %TWL at respective time points. No difference in impact on co-morbidities was noted. A revision rate of 7.1% was seen after BSG, with increased regurgitation as the most common indication.

Gastrointestinal Quality of Life in Morbidly Obese Patients Undergoing One Anastomosis Gastric Bypass (OAGB): Derivation of a "Mini GIQLI" Score

BACKGROUND

One anastomosis gastric bypass (OAGB) is now one of the mainstream bariatric surgical procedures with proven safety and efficacy. However, data on the gastrointestinal quality of life following OAGB is lacking.

METHODS

This is a retrospective analysis of a prospectively collected database, performed at a single tertiary care teaching hospital from January 2016 until March 2021. All patients undertook the Gastrointestinal Quality of Life Index (GIQLI) questionnaire. GIQLI was correlated with various parameters. Principal component analysis (PCA) was used to assess the importance of each question in the questionnaire and devise a "Mini GIQLI score".

RESULTS

A total of 60 patients were included. The %TWL at 3 and 5 years was 26.2 ± 11.9%, 31.7 ± 11 respectively. The mean weight regain was 5.6 ± 8.5 kg. The mean GIQLI score was 125 ± 13.1. The mean scores for questions pertaining to gastrointestinal, social, psychological, and physical domains were 3.49, 3.7, 3.45, and 3.27 respectively. Scree plot of principal component analysis showed that a new score ("Mini GIQLI") combining only 5 questions had good correlation with the overall GIQOL score (r = 0.842). The five questions related to anxiety, fatigue, feeling unwell, loss of endurance, and feeling unfit.

CONCLUSIONS

Patients report a good score on GIQLI assessment following OAGB. The Mini GIQLI score is a quicker tool with good correlation to the full-length GIQLI score.

Impact of tele rehabilitation on clinical outcomes in patients recovering from COVID-19: a preliminary investigation

Pulmonary rehabilitation has proven to be an effective therapeutic intervention for people with chronic respiratory disease. Considering the highly contagious nature of coronavirus disease (COVID-19), it becomes imperative to develop a method which can effectively improve clinical disease outcomes of these patients without any physical contact. The purpose of the study was to investigate the impact of tele rehabilitation on dyspnoea, endurance and quality-of-life in patients recovering from COVID 19. Thirty-two participants (age: 42.5±13.94, height: 165.8±10.06, weight: 68.5±9.63, body mass index: 25.0±3.61) who are recovering from COVID-19 were recruited as per the eligibility criteria. They were randomly allocated into two groups, Tele rehabilitation (n=16) and Control (n=16) by lottery method. All the selected participants were assessed at baseline for perceived dyspnoea, endurance and quality-of-life. Patients in the Tele rehabilitation group received 14 sessions of rehabilitation on alternate days online via google meet over a period of 28 days. Control group received usual care during the study period. Standard statistical tests were employed to test the study hypothesis. Results suggested a significant improvement in both dyspnoea (P=0.001) and endurance (P<0.001) in response to tele rehabilitation. Domains of quality-of-life such as physical role (P=0.02), vitality (P=0.04), emotional role (P=0.03), mental health (P=0.02) and physical components score (P=0.007) also showed significant improvement with tele rehabilitation in patients recovering from COVID-19. Findings of this preliminary study concludes that tele rehabilitation may be considered a treatment of choice in patients recovering from COVID-19 for improving outcomes of dyspnoea, endurance and quality-of-life.

Interface morphology driven exchange interaction and magnetization reversal in a Gd/Co multilayer

Rare-earth (RE)/transition metal (TM) ferromagnetic heterostructures with competing interfacial coupling and Zeeman energy provide a rich ground to study different phase states as a function of magnetic field and temperature. The interface morphology as a knob in these RE/TM heterostructures provides an excellent opportunity to engineer the macroscopic magnetic response by tuning the interface dependent microscopic interactions between the layers. We have investigated the interface morphology driven structure and magnetic properties of a Gd/Co multilayer. The interface morphology of the multilayer was controlled by annealing the multilayer at a relatively low temperature of 573 K under vacuum conditions. Combining the different experimental techniques and a simple one-dimensional spin-based model calculation, we studied the detailed magnetic structure and magnetization reversal mechanism in this system across compensation temperature (T_comp), which suggested a strong interface dependent coupling in the system. We showed that changes in the interface morphology of the Gd/Co multilayer strongly influence the macroscopic magnetic properties of the system. The calculation also confirms the formation of a helical magnetic structure with a 2π domain wall in this system below T_comp. The experimental finding and the simulation of this technologically important system will help to understand the physics of all-optical switching and related applications.

Optimization of a Flat Die Including Elongational Viscosity Effects

A software package for optimization of polymer extrusion dies is developed. Die geometry is optimized such that a uniform velocity distribution is obtained at the die exit without excessively increasing the pressure drop in the die. The software uses the BFGS optimization algorithm, and employs the adjoint method to obtain the design sensitivities. The optimization software is successfully used to optimize the geometry of a flat die for polymer sheet extrusion such that a uniform velocity distribution is obtained at the die exit, without increasing the pressure drop in the die.

A134 UES MANOMETRIC PARAMETERS IN ESOPHAGEAL MOTILITY DISORDERS

Background

Upper esophageal sphincter (UES) function may be evaluated manometrically using a solid-state high-resolution manometry (HRM) system, which allows for the measurement of manometric parameters specific to the UES. While many of these parameters have yet to be validated for use in clinical practice, there is some suggestion that there may be an association between esophageal motility and UES function.

Aims

We aimed to identify the relationship between UES manometric variables and high-resolution esophageal manometry (HREM) diagnoses.

Methods

A retrospective analysis of HREM studies was performed between 2019 and 2021. Extraction of esophageal and UES manometric variables were performed. UES manometric values of interest included: mean basal pressure (mmHg), mean residual pressure (mmHg), relaxation time-to-nadir (ms), relaxation duration (ms), and recovery time (ms). Relationships between manometric diagnosis (Chicago Classification version 3) and UES manometric variables were explored. All values are expressed a medians and group means were compared with the non-parametric Mann-Whitney U test.

Results

2119 symptomatic patients underwent HREM over the study period. Manometric diagnoses were achalasia (72 patients), esophagogastric junction outflow obstruction (286), absent contractility (108), distal esophageal spasm (53), jackhammer esophagus (32), and ineffective esophageal motility (694). 886 patients had no specific motility disorder; 643 of whom had ≤ 20% ineffective swallows and were considered symptomatic controls.

Patients with achalasia had significantly higher mean basal pressures (63.2 vs. 54.4, p = .001), mean residual pressure (3.8 vs. -1.9, p < .001), relaxation-time-to-nadir (182.0 vs. 142.0, p = .005), relaxation duration (820.5 vs. 708.0, p < .001) and recovery time (623.0 vs. 562, p < .001) compared to control patients. Among patients with achalasia, the presence of panesophageal pressurization correlated weakly with recovery time (R² .3, p = .03). Patients with ineffective esophageal motility had significantly higher mean basal pressures (61.7 vs. 54.0, p < .001).

Among all patients, patients with incomplete bolus clearance (≥ 30%) had significantly higher UES mean basal pressure (58.9 vs. 54.6, p = .004), mean residual pressure (-.62 vs. -2, p < .001), relaxation duration (724.0 vs. 707.0, p = .014) and recovery time (580 vs. 558.0, p < .001).

Conclusions

Patients with achalasia may have higher basal and residual UES pressures, and slower relaxation compared to patients with normal esophageal motility. This may reflect dynamic changes of the UES in response to obstruction at the esophagogastric junction. Elevated UES pressures are also seen in patients with ineffective esophageal motility, potentially reflecting a response to poor bolus clearance. More work needs to be done to validate these parameters in clinical practice.

Funding Agencies

None

Subclinical left and right ventricular dysfunction in COVID-19 recovered patients using speckle tracking echocardiography

Funding Acknowledgements

Type of funding sources: None.

Introduction

Myocardial injury during acute COVID-19 infection is well characterised however, its persistence during recovery is unclear.

Purpose

We assessed left ventricle (LV) global longitudinal strain (GLS) and right ventricular (RV) free wall longitudinal strain and RV global longitudinal strain (RV-GLS) using speckle tracking echocardiography (STE) in COVID-19 recovered patients (30-45 days post recovery) and studied its correlation with various parameters.

Methods

Of the 245 subjects screened, a total of 53 subjects recovered from COVID-19 infection and normal LV ejection fraction were enrolled. Routine blood investigations, inflammatory markers (on admission) and comprehensive echocardiography including STE were done for all.

Results

All the 53 subjects were symptomatic during COVID-19 illness and were categorized as mild: 27 (50.9%), moderate: 20 (37.7%) and severe: 6 (11.4%) COVID-19 illness. Reduced LV GLS was reported in 22 (41.5%), reduced RV-GLS in 23 (43.4%) and reduced RVFWS in 22 (41.5%) patients respectively. LVGLS was significantly lower in patients recovered from severe illness (mild: -20.3 ± 1.7%; moderate: -15.3 ± 3.4%; severe: -10.7 ± 5.1%; P < 0.0001). Similarly, RVGLS (mild: -21.8 ± 2.8%; moderate: -16.8 ± 4.8%; severe: -9.7 ± 4.6%; P < 0.0001) and RVFWS (mild: -23.0 ± 4.1%; moderate: -18.1 ± 5.5%; severe: -9.3 ± 4.4%; P < 0.0001) were significantly lower in subjects with severe COVID-19. Subjects with reduced LVGLS as well as RVGLS and RVFWS had significantly higher interleukin-6, C-reactive protein, lactate dehydrogenase and serum ferritin levels during index admission.

Conclusions

Subclinical LV and RV dysfunction was seen in majority of  COVID-19 recovered patients. Patients with severe disease during index admission had far lower LV and RVGLS as compared to mild and moderate cases. Our study highlights the need for close follow-up of COVID-19 recovered subjects in order to determine the long-term cardiovascular outcomes.

Asymptomatic infection and transmission of COVID-19 among clusters: systematic review and meta-analysis

OBJECTIVES

Countries throughout the world are experiencing COVID-19 viral load in their populations, leading to potential transmission and infectivity of asymptomatic COVID-19 cases. The current systematic review and meta-analysis aims to investigate the role of asymptomatic infection and transmission reported in family clusters, adults, children and health care workers, globally.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

An online literature search of PubMed, Google Scholar, medRixv and BioRixv was performed using standard Boolean operators and included studies published up to 17 August 2021. For the systematic review, case reports, short communications and retrospective studies were included to ensure sufficient asymptomatic COVID-19 transmission data were reported. For the quantitative synthesis (meta-analysis), participant data from a collection of cohort studies focusing on groups of familial clusters, adults, children and health care workers were included. Inconsistency among studies was assessed using I² statistics. The data synthesis was computed using the STATA 16.0 software.

RESULTS

This study showed asymptomatic transmission among familial clusters, adults, children and health care workers of 15.72%, 29.48%, 24.09% and 0%, respectively. Overall, asymptomatic transmission was 24.51% (95% confidence interval [CI]: 14.38, 36.02) among all studied population groups, with a heterogeneity of I² = 95.30% (P < 0.001). No heterogeneity was seen in the population subgroups of children and health care workers. The risk of bias in all included studies was assessed using the Newcastle Ottawa Scale.

CONCLUSIONS

For minimising the spread of COVID-19 within the community, this study found that following the screening of asymptomatic cases and their close contacts for chest CT scan (for symptomatic patients), even after negative nucleic acid testing, it is essential to perform a rigorous epidemiological history, early isolation, social distancing and an increased quarantine period (a minimum of 14-28 days). This systematic review and meta-analysis supports the notion of asymptomatic COVID-19 infection and person-to-person transmission and suggests that this is dependent on the varying viral incubation period among individuals. Children, especially those of school age (i.e. <18 years), need to be monitored carefully and follow mitigation strategies (e.g. social distancing, hand hygiene, wearing face masks) to prevent asymptomatic community transmission of COVID-19.

Phylogenetic and Ancestral Sequence Reconstruction of SARS-CoV-2 Reveals Latent Capacity to Bind Human ACE2 Receptor

SARS-CoV-2 is a unique event, having emerged suddenly as a highly infectious viral pathogen for human populations. Previous phylogenetic analyses show its closest known evolutionary relative to be a virus detected in bats (RaTG13), with a common assumption that SARS-CoV-2 evolved from a zoonotic ancestor via recent genetic changes (likely in the Spike protein receptor-binding domain or RBD) that enabled it to infect humans. We used detailed phylogenetic analysis, ancestral sequence reconstruction, and in situ molecular dynamics simulations to examine the Spike-RBD's functional evolution, finding that the common ancestral virus with RaTG13, dating to no later than 2013, possessed high binding affinity to the human ACE2 receptor. This suggests that SARS-CoV-2 likely possessed a latent capacity to bind to human cellular targets (though this may not have been sufficient for successful infection) and emphasizes the importance of expanding efforts to catalog and monitor viruses circulating in both human and non-human populations.