Severe ARDS Secondary to Legionella Pneumonia Requiring VV ECMO in the Setting of Newly Diagnosed Hairy Cell Leukemia

Venovenous (VV) extracorporeal membrane oxygenation (ECMO) for severe acute respiratory distress syndrome (ARDS) is initiated in patients with high mortality as a potential lifesaving intervention. Hematologic malignancy (HM) is considered a relative exclusion criterion by the Extracorporeal Life Support Organization (ELSO). This case examines the relative contraindication and presents a successful outcome. A healthy 59-year-old male presented with respiratory distress. On arrival his SpO₂ on room air was 82%, chest x-ray revealed a lobar infiltrate, complete blood count demonstrated severe leukopenia, and a peripheral blood smear demonstrated cytoplasmic inclusions concerning for hairy cells. He was intubated and decision was made to initiate VV-ECMO during hospital day (HD) 1. Cytometry later confirmed a diagnosis of hairy cell leukemia (HCL). A diagnosis of Legionella was confirmed on HD 5. Initial hospitalization was complicated by progression to complete bilateral lung involvement, pulmonary hemorrhage, recurrent tachyarrhythmias, hemodynamic instability, and acute renal failure. Respiratory status stabilized and eventually began to improve. On HD 27, he was decannulated and later discharged to rehabilitation. Four months later he received inpatient chemotherapy and is currently in full remission. This is a successful outcome in a patient with severe ARDS requiring VV-ECMO in the setting of newly diagnosed HCL. The 10-year survival for treated HCL is near 100%. Due to favorable prognosis, HCL should not be considered a relative contraindication to VV-ECMO. While HM remains a relative exclusion criterion by the ELSO, it is important to analyze each patient individually and make decisions based on evolving bodies of evidence.

Understanding Pneumomediastinum as a Complication in Patients With COVID-19: A Case Series

Pneumomediastinum is a rare complication among non-coronavirus patients but has been published with increased incidence in patients positive for SARS-CoV-2 infection. Most of these studies report patients on mechanical ventilation and an understanding of mechanisms causing this remains limited. We aim to use an increasing occurrence in patients not on mechanical ventilation to further explore mechanisms that predispose patients to pneumomediastinum and to assess characteristics potentially related to poor outcomes. We report a case series of 37 patients diagnosed with COVID-19 and pneumomediastinum at a 2-hospital institution between January 1, 2020 and April 30, 2021. At 28 days after diagnosis of pneumomediastinum, 19 (51.4%) were dead and mortality was significantly higher among those who were older (t = 2.147, P = .039), female (χ2 = 10.431, P = .015), body mass index ≥30 (χ2 = 6.0598, P = .01), intubated (χ2 = 4.937, P = .026), and had pre-existing lung disease (χ2 = 4.081, P = .043). Twenty-three patients (62.2%) were identified to have pneumomediastinum without receiving invasive mechanical ventilation, of which 11 (47.8%) were diagnosed without receiving noninvasive ventilation. The increased diagnosis of pneumomediastinum in patients with COVID-19 while not on mechanical ventilation, in this case series and in comparable studies, may attribute to mechanisms aside from positive pressure ventilation such as patient self-induced lung injury and pulmonary frailty.

The Scottish Brain Health Service Model: Rationale and Scientific Basis for a National Care Pathway of Brain Health Services in Scotland

In order to address the oft-cited societal, economic, and health and social care impacts of neurodegenerative diseases, such as Alzheimer's disease, we must move decisively from reactive to proactive clinical practice and to embed evidence-based brain health education throughout society. Most disease processes can be at least partially prevented, slowed, or reversed. We have long neglected to intervene in neurodegenerative disease processes, largely due to a misconception that their predominant symptom - cognitive decline - is a normal, age-related process, but also due to a lack of multi-disciplinary collaboration. We now understand that there are modifiable risk factors for neurodegenerative diseases, that successful management of common comorbidities (such as diabetes and hypertension) can reduce the incidence of neurodegenerative disease, and that disease processes begin (and, crucially, can be detected, reduced, and delayed, prevented, or treated) decades earlier in life than had previously been appreciated. Brain Health Scotland, established by Scottish Government and working in partnership with Alzheimer Scotland, propose far-reaching public health and clinical practice approaches to reduce neurodegenerative disease incidence. Focusing here on Brain Health Scotland's clinical offerings, we present the Scottish Model for Brain Health Services. To our knowledge, the Scottish Model for Brain Health, built on foundations of personalised risk profiling, targeted risk reduction and prevention, early disease detection, equity of access, and harnessing comprehensive data to assist in clinical decision-making, marks the first example of a nationwide approach to overhauling clinical, societal, and political approaches to the prevention, assessment, and treatment of neurodegenerative disease.

Cryotherapy: A Safe Approach to Pulmonary Hemorrhage During VV-ECMO

The number of hospitals with veno-venous extracorporeal membrane oxygenation (VV-ECMO) capabilities is expanding. To support an ECMO program, centers must be equipped to handle associated complications such as pulmonary hemorrhage. We describe a case series of 4 patients with life-threatening pulmonary bleeding and central airway obstruction. A therapeutic approach of anticoagulation cessation coupled with cryoextraction via flexible bronchoscopy led to successful restoration of airway patency without any adverse events. A low threshold to stop anticoagulation with a strong consideration of bronchoscopy with cryotherapy for pulmonary toilet should be done in patients with pulmonary hemorrhage during VV-ECMO.

Polyarticular Haemophilus Influenza Septic Arthritis in an HIV Patient

Haemophilus influenzae is an opportunistic gram-negative bacterium most commonly found in the upper respiratory tract of humans. With the advent of vaccines, most infections caused by these bacteria have been suppressed. However, in the immunocompromised host, an invasive infection may occur, particularly within the musculoskeletal system. In this paper, we present the case of a 55-year-old male with septic shock secondary to polyarticular Haemophilus influenza infection. The patient was successfully treated with surgical irrigation and debridement, and antibiotics. Haemophilus infections should be part of the differential in patients with musculoskeletal pain and immunocompromise to avoid potential delays in surgical management.

A broad-scale spatial analysis of the environmental benefits of fertiliser closed periods implemented under the Nitrates Directive in Europe

Nutrient pollution from agriculture has been an ongoing challenge for decades, contributing to numerous negative environmental impacts. In the European Union policies have been developed to address nutrient pollution, including Nitrate Action Programmes under Council Directive 91/676/EEC. Although Member States report on progress on implementation, there have been few studies that explore how measures have been implemented; the environmental implications of any differences; and how they vary spatially on a European scale. This study aims to address this gap with respect to fertiliser closed periods (1155 different closed periods across 69 Nitrate Action Programmes). This included the development of an approach that can be applied using readily available spatial data. Each closed period was scored for its coverage of risk periods for losses of nitrate; organic material; nitrous oxide and ammonia. Closed periods were then matched to relevant combinations of spatial data for each environmental zone and fertiliser type. The scores for each combination were used to create maps and calculate spatial statistics. The results show that in addition to nitrate, closed periods also reduce the risk of organic material run-off, emissions of nitrous oxide and to a lesser extent ammonia. However, risk reduction is spatially variable across all the impacts and the scope for synergy is also variable (e.g. nitrate loss does not always correlate with nitrous oxide or ammonia risk reduction). Regions in the Atlantic, Lustanian and some areas within the Mediterranean zones appear to provide the greatest combined risk reduction, with other zones, especially in eastern Europe, having a lower combined risk reduction (due to a combination of different risk periods coupled with lower coverage of individual risks). The spatial analysis within this study is relatively simple; is based on a snapshot of closed periods during 2019-2020; and only explores one measure. However, it does provide some useful data and insights that could support policy development in the future. This includes scope for Member States and regions to learn from others where greater coverage of risk periods has been achieved; and highlighting how a more holistic perspective can be taken to the environmental management of nutrients. As we strive towards developing sustainable production systems, farmers and policy makers need to take a more integrated approach to incorporate additional environmental objectives; which increases the complexity of the challenge. Consequently, the demand for pragmatic approaches that take a more holistic approach is likely to increase in the future.

ReIMAGINE: a prostate cancer research consortium with added value through its patient and public involvement and engagement

BACKGROUND

ReIMAGINE aims to improve the current prostate specific antigen (PSA)/biopsy risk stratification for prostate cancer (PCa) and develop a new image-based method (with biomarkers) for diagnosing high/low risk PCa in men. ReIMAGINE's varied patient and public involvement (PPI) and engagement (PE) strategy maximises the impact of its scientific output by informing and shaping the different stages of research.

AIMS

Through including the voice of patients and the public, the ReIMAGINE Consortium aims to translate these different perspectives into the design and implementation process. This will improve the overall quality of the research by: reflecting the needs and priorities of patients and the public, ensuring methods and procedures are feasible and appropriate ensuring information is relevant and accessible to those being recruited to the study identifying dissemination channels relevant to patients/the public and developing outputs that are accessible to a lay audience With support from our patient/user groups, the ReIMAGINE Consortium aims to improve our ability to derive prognostic information and allocate men to the most appropriate and effective therapies, using a novel image-based risk stratification with investigation of non-imaging biomarkers.

FINDINGS

We have been working with patients and the public from initiation of the project to ensure that the research is relevant to men and their families. Our PPI Sub-Committee, led by a PCa patient, has been involved in our dissemination strategy, outreach activities, and study design recommendations. For example, the sub-committee have developed a variety of informative videos relevant and accessible to those being recruited, and organised multiple online research engagement events that are accessible to a lay audience. As quoted by one of the study participants, "the more we present the benefits and opportunities to patients and the public, the more research commitment we obtain, and the sooner critical clinical questions such as PCa diagnostics will be addressed".

Utility of polygenic embryo screening for disease depends on the selection strategy

Polygenic risk scores (PRSs) have been offered since 2019 to screen in vitro fertilization embryos for genetic liability to adult diseases, despite a lack of comprehensive modeling of expected outcomes. Here we predict, based on the liability threshold model, the expected reduction in complex disease risk following polygenic embryo screening for a single disease. A strong determinant of the potential utility of such screening is the selection strategy, a factor that has not been previously studied. When only embryos with a very high PRS are excluded, the achieved risk reduction is minimal. In contrast, selecting the embryo with the lowest PRS can lead to substantial relative risk reductions, given a sufficient number of viable embryos. We systematically examine the impact of several factors on the utility of screening, including: variance explained by the PRS, number of embryos, disease prevalence, parental PRSs, and parental disease status. We consider both relative and absolute risk reductions, as well as population-averaged and per-couple risk reductions, and also examine the risk of pleiotropic effects. Finally, we confirm our theoretical predictions by simulating 'virtual' couples and offspring based on real genomes from schizophrenia and Crohn's disease case-control studies. We discuss the assumptions and limitations of our model, as well as the potential emerging ethical concerns.

1426 Assessing the Impact Of COVID-19 On ENT Referrals at A West London General Practice

Aim

The COVID-19 pandemic has resulted in initial GP consultations being conducted via telephone. This quality improvement initiative quantified this impact on ENT referrals conducted at a West London GP, using education to improve awareness of the relevant NICE guidance to reduce inappropriate referrals.

Method

An initial retrospective audit comparing number and urgency of ENT referrals and the appropriateness of ENT referrals (using NICE guidance) during the face to face (F2F) period (August 2019 – February 2020) and telephone period (March – September 2020) was performed. Results were presented locally to GPs, with education measures on relevant NICE guidance implemented. Further PDSA cycles occurred during October and November 2020.

Results

In total, 16 ENT referrals were made during the F2F period (routine n = 15; urgent n = 1); 3 were inappropriate. 31 referrals were made between March and September 2020 (routine n = 27, urgent n = 2, 2WW n = 2); 4 were inappropriate. Further cycles in October 2020, and November 2020 identified 13 referrals (routine n = 10, 2WW n = 3), and 2 referrals (routine n = 2) respectively. 1 inappropriate referral was made during October and none in November.

Conclusions

Locally, it appears that the number of routine referrals has increased since the advent of the initial lockdown. This may be partially explained by the practice losing the ability to perform some ENT services, such as ear wax micro-suctioning. Education to increase awareness of relevant guidance has been shown to reduce the number of inappropriate referrals to ENT services.

Intraoperative Tibia Fractures During Primary Total Knee Arthroplasty

Intraoperative tibia fractures during primary total knee arthroplasty (TKA) are a known complication, however, the management options and outcome are poorly represented in the orthopedic literature. We performed a thorough literature review and detailed two cases of intraoperative tibia fractures during primary TKA at our institution to determine the mechanism behind these injuries and the optimal treatment strategy. We describe one case of intraoperative tibia fracture during primary posterior stabilized (PS) TKA and one case during primary cruciate retaining TKA. Open reduction and internal fixation with plate and screws, lag screws alone, suture anchors, or tension wiring were the most common treatment options reported in the literature. Although there was no consensus on the optimal postoperative protocol, in our series, both cases achieved satisfactory clinical outcomes with and without further fixation of the fracture. Intraoperative tibia fractures are unforeseeable complications during routine primary TKA and the operating surgeon should be aware of the different strategies in managing these complications.

Machine Learning Prediction of Death in Critically Ill Patients With Coronavirus Disease 2019

OBJECTIVES

Critically ill patients with coronavirus disease 2019 have variable mortality. Risk scores could improve care and be used for prognostic enrichment in trials. We aimed to compare machine learning algorithms and develop a simple tool for predicting 28-day mortality in ICU patients with coronavirus disease 2019.

DESIGN

This was an observational study of adult patients with coronavirus disease 2019. The primary outcome was 28-day inhospital mortality. Machine learning models and a simple tool were derived using variables from the first 48 hours of ICU admission and validated externally in independent sites and temporally with more recent admissions. Models were compared with a modified Sequential Organ Failure Assessment score, National Early Warning Score, and CURB-65 using the area under the receiver operating characteristic curve and calibration.

SETTING

Sixty-eight U.S. ICUs.

PATIENTS

Adults with coronavirus disease 2019 admitted to 68 ICUs in the United States between March 4, 2020, and June 29, 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The study included 5,075 patients, 1,846 (36.4%) of whom died by day 28. eXtreme Gradient Boosting had the highest area under the receiver operating characteristic curve in external validation (0.81) and was well-calibrated, while k-nearest neighbors were the lowest performing machine learning algorithm (area under the receiver operating characteristic curve 0.69). Findings were similar with temporal validation. The simple tool, which was created using the most important features from the eXtreme Gradient Boosting model, had a significantly higher area under the receiver operating characteristic curve in external validation (0.78) than the Sequential Organ Failure Assessment score (0.69), National Early Warning Score (0.60), and CURB-65 (0.65; p < 0.05 for all comparisons). Age, number of ICU beds, creatinine, lactate, arterial pH, and Pao2/Fio2 ratio were the most important predictors in the eXtreme Gradient Boosting model.

CONCLUSIONS

eXtreme Gradient Boosting had the highest discrimination overall, and our simple tool had higher discrimination than a modified Sequential Organ Failure Assessment score, National Early Warning Score, and CURB-65 on external validation. These models could be used to improve triage decisions and clinical trial enrichment.

LGG-13. PILOCYTIC ASTROCYTOMAS WITH NOVEL BRAF FUSIONS DEMONSTRATE MAPK PATHWAY ACTIVATION

Background

Pilocytic astrocytomas (PAs) are the most common pediatric low-grade glioma subtype. Oftentimes, PAs demonstrate somatic genetic alterations, the most common being the BRAF-KIAA1549 fusion, which results in constitutive activation of the MAPK pathway. Better understanding of the effects of other RAF fusions is necessary to determine the potential utility of MAPK-targeting therapies.

Methods

Three patients presented to Children’s Hospital Colorado and were ultimately diagnosed with PAs harboring previously unreported gene fusions identified as FYCO-RAF1, CCTTNNBP2-BRAF, and SLC44A1-BRAF. Utilizing immunohistochemistry, we stained novel samples and controls for ERK and pERK (phosphorylated ERK) to assess the activation of the MAPK pathway. PAs with known BRAF-KIAA1549 fusions (4 samples) and normal brain tissue (5 samples) were used as positive and negative controls, respectively. We additionally performed RNA sequencing to better understand expression changes associated with these fusions, utilizing Metascape and GSEA (Gene Set Enrichment Analysis) for analysis.

Results

Immunohistochemistry of negative control samples demonstrated less p-ERK than ERK (ratios of 0.6–0.9, mean 0.8). All samples with novel fusions demonstrated statistically significantly higher p-ERK expression compared to negative controls (ratios of 1.3–1.7, mean 1.4). These experimental samples also all fell within the p-ERK to ERK expression range of the positive control samples, which demonstrated the widest range of expression (ratios of 1.1–4.5, mean 2.2). Our molecular analysis further confirmed these results, with GSEA demonstrating positively upregulated MAPK and ERK pathways in 2 positive controls and 1 novel fusion sample. Metascape analysis emphasized overall similar gene expression between these samples, demonstrating many shared genes and functional pathways.

Conclusions

We identified 3 previously unreported RAF fusions in PA that demonstrate activation of the MAPK pathway, although not as extensively as seen in some positive control samples with BRAF-KIAA1549 fusions. MEK inhibition may be a useful therapeutic strategy in these tumors if targeted therapy is indicated.

HGG-26. SINGLE-CELL RNA-SEQ OF PEDIATRIC HIGH-GRADE GLIOMAS IDENTIFIES COMMON ONCOGENIC PROCESSES AMONG DISTINCT TUMOR HISTOLOGIES

Background

Pediatric high-grade glioma (PHGG) is a deadly childhood brain tumor that responds poorly to treatment. PHGG comprises two major subtypes: cortical tumors with wild-type H3K27 and diffuse midline gliomas (DMG) that occur in the midline and have characteristic H3K27M mutations. Cortical PHGG is heterogeneous with multiple molecular subtypes. In order to identify underlying commonalities in cortical PHGG that might lead to better treatment modalities, we performed molecular profiling, including single-cell RNA-Seq (scRNA-Seq), on PHGG samples from Children’s Hospital Colorado.

Methods

Nineteen cortical PHGG tumor samples, one DMG and one normal margin sample obtained at biopsy were disaggregated to isolate viable cells. Fifteen were glioblastomas (GBM), including five with epithelioid and/or giant cell features and five radiation-induced glioblastomas (RIG). There were also four non-GBM PHGG. We performed scRNA-Seq using 10X Genomics v.3 library preparation to enable capture of infiltrating immune cells. We also performed bulk RNA-Seq and DNA methylation profiling.

Results

After eliminating patient-specific and cell-cycle effects, RIG, epithelioid GBM, and other GBM each formed identifiable subgroups in bulk RNA-Seq and scRNA-Seq datasets. In the scRNA-Seq data, clusters with cells from multiple tumor samples included a PDGFRA-positive population expressing oligodendrocyte progenitor markers, astrocytic, mesenchymal and stemlike populations, macrophage/monocyte immune cells, and a smaller T-cell population. Analyses of DNA methylation data showed PDGFRA and CDK4 amplification and CDKN2A deletion are common alterations among PHGG. Inferred copy number variation analysis of the single-cell data confirmed that individual tumors include populations that both include and lack the molecular alterations identified in the methylation data. RNA velocity studies to define tumor cells of origin and further analyses of the immune cell populations are underway.

Conclusions

Single-cell analysis of PHGG confirms a large degree of tumor heterogeneity but also shows that PHGG have stemlike, mesenchymal and immune cell populations with common characteristics.

HGG-25. PRMT5 PROMOTES TUMOR GROWTH BY MAINTAINING STEMNESS OF PEDIATRIC HIGH-GRADE GLIOMA CELLS

Background

Pediatric high-grade gliomas (pHGG) are aggressive tumors that together constitute the most common cause of childhood cancer mortality. Tumor stem cells that drive proliferation of pHGG resist chemotherapy and radiation, complicating treatment. The arginine methyltransferase PRMT5 maintains self-renewal in neural stem cells through epigenetic modifications. We hypothesized that PRMT5, which we identified as a potential driver of diffuse midline glioma (DMG) through an shRNA screen, plays a similar role in pHGG.

Methods

Using lentiviral delivery of shRNA, we knocked down (KD) PRMT5 in cortical pHGG and DMG cell lines and performed phenotypic, mechanistic and self-renewal assays. We irradiated PRMT5 KD and control cells to study sensitization. We orthotopically injected mice with PRMT5 KD pHGG cells, and with DMG cells in which PRMT5 was knocked out (KO) using CRISPR-Cas.

Results

In cellular models of cortical pHGG and DMG, PRMT5 KD significantly reduced proliferation, inhibited cell cycle progression, increased apoptosis resistance, and decreased self-renewing cell frequency. A relative shift of PRMT5 from the cytoplasm to the nucleus accompanied differentiation induced by PRMT5 KD. Epigenetic changes accompanying PRMT5 KD included increased H3K27me3, a global transcription inhibitor, and decreased H3K27M expression in DMG. PRMT5 KD sensitized pHGG cells to radiation, increasing cell death 17–30%. PRMT5 KD/KO significantly increased survival in mice and decreased tumor aggressiveness and proliferation, but mice still died of tumor-related effects.

Conclusions

PRMT5 maintains self-renewal and drives proliferation in preclinical pHGG models. In cellular and in vivo models, PRMT5 KD/KO produces epigenetic changes, including increased H3K27me3 levels and diminished H3K27M, that may reduce proliferation and self-renewal. Future work includes elucidation of the mechanisms by which PRMT5 produces the observed changes. Because PRMT5 KD/KO does not eliminate tumor growth, we plan to further study combining PRMT5 KD/KO and clinical-grade small molecule PRMT5 inhibitors with radiation and chemotherapeutic agents.

An evaluation of MR based deep learning auto-contouring for planning head and neck radiotherapy

INTRODUCTION

Auto contouring models help consistently define volumes and reduce clinical workload. This study aimed to evaluate the cross acquisition of a Magnetic Resonance (MR) deep learning auto contouring model for organ at risk (OAR) delineation in head and neck radiotherapy.

METHODS

Two auto contouring models were evaluated using deep learning contouring expert (DLCExpert) for OAR delineation: a CT model (modelCT) and an MR model (modelMRI). Models were trained to generate auto contours for the bilateral parotid glands and submandibular glands. Auto-contours for modelMRI were trained on diagnostic images and tested on 10 diagnostic, 10 MR radiotherapy planning (RTP), eight MR-Linac (MRL) scans and, by modelCT, on 10 CT planning scans. Goodness of fit scores, dice similarity coefficient (DSC) and distance to agreement (DTA) were calculated for comparison.

RESULTS

ModelMRI contours improved the mean DSC and DTA compared with manual contours for the bilateral parotid glands and submandibular glands on the diagnostic and RTP MRs compared with the MRL sequence. There were statistically significant differences seen for modelMRI compared to modelCT for the left parotid (mean DTA 2.3 v 2.8 mm), right parotid (mean DTA 1.9 v 2.7 mm), left submandibular gland (mean DTA 2.2 v 2.4 mm) and right submandibular gland (mean DTA 1.6 v 3.2 mm).

CONCLUSION

A deep learning MR auto-contouring model shows promise for OAR auto-contouring with statistically improved performance vs a CT based model. Performance is affected by the method of MR acquisition and further work is needed to improve its use with MRL images.

Thrombosis, Bleeding, and the Observational Effect of Early Therapeutic Anticoagulation on Survival in Critically Ill Patients With COVID-19

BACKGROUND

Hypercoagulability may be a key mechanism of death in patients with coronavirus disease 2019 (COVID-19).

OBJECTIVE

To evaluate the incidence of venous thromboembolism (VTE) and major bleeding in critically ill patients with COVID-19 and examine the observational effect of early therapeutic anticoagulation on survival.

DESIGN

In a multicenter cohort study of 3239 critically ill adults with COVID-19, the incidence of VTE and major bleeding within 14 days after intensive care unit (ICU) admission was evaluated. A target trial emulation in which patients were categorized according to receipt or no receipt of therapeutic anticoagulation in the first 2 days of ICU admission was done to examine the observational effect of early therapeutic anticoagulation on survival. A Cox model with inverse probability weighting to adjust for confounding was used.

SETTING

67 hospitals in the United States.

PARTICIPANTS

Adults with COVID-19 admitted to a participating ICU.

MEASUREMENTS

Time to death, censored at hospital discharge, or date of last follow-up.

RESULTS

Among the 3239 patients included, the median age was 61 years (interquartile range, 53 to 71 years), and 2088 (64.5%) were men. A total of 204 patients (6.3%) developed VTE, and 90 patients (2.8%) developed a major bleeding event. Independent predictors of VTE were male sex and higher D-dimer level on ICU admission. Among the 2809 patients included in the target trial emulation, 384 (11.9%) received early therapeutic anticoagulation. In the primary analysis, during a median follow-up of 27 days, patients who received early therapeutic anticoagulation had a similar risk for death as those who did not (hazard ratio, 1.12 [95% CI, 0.92 to 1.35]).

LIMITATION

Observational design.

CONCLUSION

Among critically ill adults with COVID-19, early therapeutic anticoagulation did not affect survival in the target trial emulation.

PRIMARY FUNDING SOURCE

None.