Anticoagulants for people hospitalised with COVID-19.

BACKGROUND: The primary manifestation of coronavirus disease 2019 (COVID-19) is respiratory insufficiency that can also be related to diffuse pulmonary microthrombosis and thromboembolic events, such as pulmonary embolism, deep vein thrombosis, or arterial thrombosis. People with COVID-19 who develop thromboembolism have a worse prognosis. Anticoagulants such as heparinoids (heparins or pentasaccharides), vitamin K antagonists and direct anticoagulants are used for the prevention and treatment of venous or arterial thromboembolism. Besides their anticoagulant properties, heparinoids have an additional anti-inflammatory potential. However, the benefit of anticoagulants for people with COVID-19 is still under debate. OBJECTIVES: To assess the benefits and harms of anticoagulants versus active comparator, placebo or no intervention in people hospitalised with COVID-19. SEARCH METHODS: We searched the CENTRAL, MEDLINE, Embase, LILACS and IBECS databases, the Cochrane COVID-19 Study Register and medRxiv preprint database from their inception to 14 April 2021. We also checked the reference lists of any relevant systematic reviews identified, and contacted specialists in the field for additional references to trials. SELECTION CRITERIA: Eligible studies were randomised controlled trials (RCTs), quasi-RCTs, cluster-RCTs and cohort studies that compared prophylactic anticoagulants versus active comparator, placebo or no intervention for the management of people hospitalised with COVID-19. We excluded studies without a comparator group and with a retrospective design (all previously included studies) as we were able to include better study designs. Primary outcomes were all-cause mortality and necessity for additional respiratory support. Secondary outcomes were mortality related to COVID-19, deep vein thrombosis, pulmonary embolism, major bleeding, adverse events, length of hospital stay and quality of life. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures. We used Cochrane RoB 1 to assess the risk of bias for RCTs, ROBINS-I to assess risk of bias for non-randomised studies (NRS) and GRADE to assess the certainty of evidence. We meta-analysed data when appropriate. MAIN RESULTS: We included seven studies (16,185 participants) with participants hospitalised with COVID-19, in either intensive care units, hospital wards or emergency departments. Studies were from Brazil (2), Iran (1), Italy (1), and the USA (1), and two involved more than country. The mean age of participants was 55 to 68 years and the follow-up period ranged from 15 to 90 days. The studies assessed the effects of heparinoids, direct anticoagulants or vitamin K antagonists, and reported sparse data or did not report some of our outcomes of interest: necessity for additional respiratory support, mortality related to COVID-19, and quality of life. Higher-dose versus lower-dose anticoagulants (4 RCTs, 4647 participants) Higher-dose anticoagulants result in little or no difference in all-cause mortality (risk ratio (RR) 1.03, 95% CI 0.92 to 1.16, 4489 participants; 4 RCTs) and increase minor bleeding (RR 3.28, 95% CI 1.75 to 6.14, 1196 participants; 3 RCTs) compared to lower-dose anticoagulants up to 30 days (high-certainty evidence). Higher-dose anticoagulants probably reduce pulmonary embolism (RR 0.46, 95% CI 0.31 to 0.70, 4360 participants; 4 RCTs), and slightly increase major bleeding (RR 1.78, 95% CI 1.13 to 2.80, 4400 participants; 4 RCTs) compared to lower-dose anticoagulants up to 30 days (moderate-certainty evidence). Higher-dose anticoagulants may result in little or no difference in deep vein thrombosis (RR 1.08, 95% CI 0.57 to 2.03, 3422 participants; 4 RCTs), stroke (RR 0.91, 95% CI 0.40 to 2.03, 4349 participants; 3 RCTs), major adverse limb events (RR 0.33, 95% CI 0.01 to 7.99, 1176 participants; 2 RCTs), myocardial infarction (RR 0.86, 95% CI 0.48 to 1.55, 4349 participants; 3 RCTs), atrial fibrillation (RR 0.35, 95% CI 0.07 to 1.70, 562 participants; 1 study), or thrombocytopenia (RR 0.94, 95% CI 0.71 to 1.24, 2789 participants; 2 RCTs) compared to lower-dose anticoagulants up to 30 days (low-certainty evidence). It is unclear whether higher-dose anticoagulants have any effect on necessity for additional respiratory support, mortality related to COVID-19, and quality of life (very low-certainty evidence or no data). Anticoagulants versus no treatment (3 prospective NRS, 11,538 participants) Anticoagulants may reduce all-cause mortality but the evidence is very uncertain due to two study results being at critical and serious risk of bias (RR 0.64, 95% CI 0.55 to 0.74, 8395 participants; 3 NRS; very low-certainty evidence). It is uncertain if anticoagulants have any effect on necessity for additional respiratory support, mortality related to COVID-19, deep vein thrombosis, pulmonary embolism, major bleeding, stroke, myocardial infarction and quality of life (very low-certainty evidence or no data). Ongoing studies We found 62 ongoing studies in hospital settings (60 RCTs, 35,470 participants; 2 prospective NRS, 120 participants) in 20 different countries. Thirty-five ongoing studies plan to report mortality and 26 plan to report necessity for additional respiratory support. We expect 58 studies to be completed in December 2021, and four in July 2022. From 60 RCTs, 28 are comparing different doses of anticoagulants, 24 are comparing anticoagulants versus no anticoagulants, seven are comparing different types of anticoagulants, and one did not report detail of the comparator group. AUTHORS' CONCLUSIONS: When compared to a lower-dose regimen, higher-dose anticoagulants result in little to no difference in all-cause mortality and increase minor bleeding in people hospitalised with COVID-19 up to 30 days. Higher-dose anticoagulants possibly reduce pulmonary embolism, slightly increase major bleeding, may result in little to no difference in hospitalisation time, and may result in little to no difference in deep vein thrombosis, stroke, major adverse limb events, myocardial infarction, atrial fibrillation, or thrombocytopenia.  Compared with no treatment, anticoagulants may reduce all-cause mortality but the evidence comes from non-randomised studies and is very uncertain. It is unclear whether anticoagulants have any effect on the remaining outcomes compared to no anticoagulants (very low-certainty evidence or no data). Although we are very confident that new RCTs will not change the effects of different doses of anticoagulants on mortality and minor bleeding, high-quality RCTs are still needed, mainly for the other primary outcome (necessity for additional respiratory support), the comparison with no anticoagulation, when comparing the types of anticoagulants and giving anticoagulants for a prolonged period of time.

Care for adults with COVID-19: living guidelines from the National COVID-19 Clinical Evidence Taskforce.

INTRODUCTION: The Australian National COVID-19 Clinical Evidence Taskforce was established in March 2020 to maintain up-to-date recommendations for the treatment of people with coronavirus disease 2019 (COVID-19). The original guideline (April 2020) has been continuously updated and expanded from nine to 176 recommendations, facilitated by the rapid identification, appraisal, and analysis of clinical trial findings and subsequent review by expert panels. MAIN RECOMMENDATIONS: In this article, we describe the recommendations for treating non-pregnant adults with COVID-19, as current on 1 August 2022 (version 61.0). The Taskforce has made specific recommendations for adults with severe/critical or mild disease, including definitions of disease severity, recommendations for therapy, COVID-19 prophylaxis, respiratory support, and supportive care. CHANGES IN MANAGEMENT AS A RESULT OF THE GUIDELINE: The Taskforce currently recommends eight drug treatments for people with COVID-19 who do not require supplemental oxygen (inhaled corticosteroids, casirivimab/imdevimab, molnupiravir, nirmatrelvir/ritonavir, regdanvimab, remdesivir, sotrovimab, tixagevimab/cilgavimab) and six for those who require supplemental oxygen (systemic corticosteroids, remdesivir, tocilizumab, sarilumab, baricitinib, casirivimab/imdevimab). Based on evidence of their achieving no or only limited benefit, ten drug treatments or treatment combinations are not recommended; an additional 42 drug treatments should only be used in the context of randomised trials. Additional recommendations include support for the use of continuous positive airway pressure, prone positioning, and endotracheal intubation in patients whose condition is deteriorating, and prophylactic anticoagulation for preventing venous thromboembolism. The latest updates and full recommendations are available at www.covid19evidence.net.au.

The Australian living guidelines for the clinical care of people with COVID-19: What worked, what didn't and why, a mixed methods process evaluation.

INTRODUCTION: The Australian National COVID-19 Clinical Evidence Taskforce is producing living, evidence-based, national guidelines for treatment of people with COVID-19 which are updated each week. To continually improve the process and outputs of the Taskforce, and inform future living guideline development, we undertook a concurrent process evaluation examining Taskforce activities and experience of team members and stakeholders during the first 5 months of the project. METHODS: The mixed-methods process evaluation consisted of activity and progress audits, an online survey of all Taskforce participants; and semi-structured interviews with key contributors. Data were collected through five, prospective 4-weekly timepoints (beginning first week of May 2020) and three, fortnightly retrospective timepoints (March 23, April 6 and 20). We collected and analysed quantitative and qualitative data. RESULTS: An updated version of the guidelines was successfully published every week during the process evaluation. The Taskforce formed in March 2020, with a nominal start date of March 23. The first version of the guideline was published two weeks later and included 10 recommendations. By August 24, in the final round of the process evaluation, the team of 11 staff, working with seven guideline panels and over 200 health decision-makers, had developed 66 recommendations addressing 58 topics. The Taskforce website had received over 200,000 page views. Satisfaction with the work of the Taskforce remained very high (>90% extremely or somewhat satisfied) throughout. Several key strengths, challenges and methods questions for the work of the Taskforce were identified. CONCLUSIONS: In just over 5 months of activity, the National COVID-19 Clinical Evidence Taskforce published 20 weekly updates to the evidence-based national treatment guidelines for COVID-19. This process evaluation identified several factors that enabled this achievement (e.g. an extant skill base in evidence review and convening), along with challenges that needed to be overcome (e.g. managing workloads, structure and governance) and methods questions (pace of updating, and thresholds for inclusion of evidence) which may be useful considerations for other living guidelines projects. An impact evaluation is also being conducted separately to examine awareness, acceptance and use of the guidelines.

Care of older people and people requiring palliative care with COVID-19: guidance from the Australian National COVID-19 Clinical Evidence Taskforce.

INTRODUCTION: Older people living with frailty and/or cognitive impairment who have coronavirus disease 2019 (COVID-19) experience higher rates of critical illness. There are also people who become critically ill with COVID-19 for whom a decision is made to take a palliative approach to their care. The need for clinical guidance in these two populations resulted in the formation of the Care of Older People and Palliative Care Panel of the National COVID-19 Clinical Evidence Taskforce in June 2020. This specialist panel consists of nursing, medical, pharmacy and allied health experts in geriatrics and palliative care from across Australia. MAIN RECOMMENDATIONS: The panel was tasked with developing two clinical flow charts for the management of people with COVID-19 who are i) older and living with frailty and/or cognitive impairment, and ii) receiving palliative care for COVID-19 or other underlying illnesses. The flow charts focus on goals of care, communication, medication management, escalation of care, active disease-directed care, and managing symptoms such as delirium, anxiety, agitation, breathlessness or cough. The Taskforce also developed living guideline recommendations for the care of adults with COVID-19, including a commentary to discuss special considerations when caring for older people and those requiring palliative care. CHANGES IN MANAGEMENT AS RESULT OF THE GUIDELINE: The practice points in the flow charts emphasise quality clinical care, with a focus on addressing the most important challenges when caring for older individuals and people with COVID-19 requiring palliative care. The adult recommendations contain additional considerations for the care of older people and those requiring palliative care.

Awareness, value and use of the Australian living guidelines for the clinical care of people with COVID-19: an impact evaluation.

BACKGROUND AND OBJECTIVE: The Australian National COVID-19 Clinical Evidence Taskforce is developing living, evidence-based, national guidelines for treatment of people with COVID-19. These living guidelines are updated each week. We undertook an impact evaluation to understand the extent to which health professionals providing treatment to people with COVID 19 were aware of, valued and used the guidelines, and the factors that enabled or hampered this. METHODS: A mixed methods approach was used for the evaluation. Surveys were conducted to collect both quantitative and qualitative data and were supplemented with qualitative interviews. Australian healthcare practitioners potentially providing care to individuals with suspected or confirmed COVID-19 were invited to participate. Data were collected on guideline awareness, relevance, ease of use, trustworthiness, value, importance of updating, use, and strengths and opportunities for improvement. RESULTS: A total of 287 people completed the surveys and 10 interviews were conducted during November 2020. Awareness of the work of the Taskforce was high and the vast majority of respondents reported that the guidelines were very or extremely relevant, easy to use, trustworthy and valuable. More than 50% of respondents had used the guidelines to support their own clinical decision-making; and 30% were aware of other examples of the guidelines being used. Qualitative data revealed that amongst an overwhelming morass of evidence and opinions during the COVID-19 pandemic, the guidelines have been a reliable, united source of evidence-based advice; participants felt the guidelines built confidence and provided reassurance in clinical decision-making. Opportunities to improve awareness and accessibility to the guidelines were also explored. CONCLUSIONS: As of June 2021, the guidelines have been published and updated more than 40 times, include more than 140 recommendations and are being used to inform clinical decisions. The findings of this impact evaluation will be used to improve processes and outputs of the Taskforce and guidelines project, and to inform future living guideline projects.

Clinical care of children and adolescents with COVID-19: recommendations from the National COVID-19 Clinical Evidence Taskforce.

INTRODUCTION: The epidemiology and clinical manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are different in children and adolescents compared with adults. Although coronavirus disease 2019 (COVID-19) appears to be less common in children, with milder disease overall, severe complications may occur, including paediatric inflammatory multisystem syndrome (PIMS-TS). Recognising the distinct needs of this population, the National COVID-19 Clinical Evidence Taskforce formed a Paediatric and Adolescent Care Panel to provide living guidelines for Australian clinicians to manage children and adolescents with COVID-19 and COVID-19 complications. Living guidelines mean that these evidence-based recommendations are updated in near real time to give reliable, contemporaneous advice to Australian clinicians providing paediatric care. MAIN RECOMMENDATIONS: To date, the Taskforce has made 20 specific recommendations for children and adolescents, including definitions of disease severity, recommendations for therapy, respiratory support, and venous thromboembolism prophylaxis for COVID-19 and for the management of PIMS-TS. CHANGES IN MANAGEMENT AS A RESULT OF THE GUIDELINES: The Taskforce currently recommends corticosteroids as first line treatment for acute COVID-19 in children and adolescents who require oxygen. Tocilizumab could be considered, and remdesivir should not be administered routinely in this population. Non-invasive ventilation or high flow nasal cannulae should be considered in children and adolescents with hypoxaemia or respiratory distress unresponsive to low flow oxygen if appropriate infection control measures can be used. Children and adolescents with PIMS-TS should be managed by a multidisciplinary team. Intravenous immunoglobulin and corticosteroids, with concomitant aspirin and thromboprophylaxis, should be considered for the treatment of PIMS-TS. The latest updates and full recommendations are available at www.covid19evidence.net.au.

Prophylaxis against covid-19: living systematic review and network meta-analysis.

OBJECTIVE: To determine and compare the effects of drug prophylaxis on SARS-CoV-2 infection and covid-19. DESIGN: Living systematic review and network meta-analysis. DATA SOURCES: World Health Organization covid-19 database, a comprehensive multilingual source of global covid-19 literature to 25 March 2021, and six additional Chinese databases to 20 February 2021. STUDY SELECTION: Randomised trials of people at risk of covid-19 who were assigned to receive prophylaxis or no prophylaxis (standard care or placebo). Pairs of reviewers independently screened potentially eligible articles. METHODS: Random effects bayesian network meta-analysis was performed after duplicate data abstraction. Included studies were assessed for risk of bias using a modification of the Cochrane risk of bias 2.0 tool, and certainty of evidence was assessed using the grading of recommendations assessment, development, and evaluation (GRADE) approach. RESULTS: The first iteration of this living network meta-analysis includes nine randomised trials-six of hydroxychloroquine (n=6059 participants), one of ivermectin combined with iota-carrageenan (n=234), and two of ivermectin alone (n=540), all compared with standard care or placebo. Two trials (one of ramipril and one of bromhexine hydrochloride) did not meet the sample size requirements for network meta-analysis. Hydroxychloroquine has trivial to no effect on admission to hospital (risk difference 1 fewer per 1000 participants, 95% credible interval 3 fewer to 4 more; high certainty evidence) or mortality (1 fewer per 1000, 2 fewer to 3 more; high certainty). Hydroxychloroquine probably does not reduce the risk of laboratory confirmed SARS-CoV-2 infection (2 more per 1000, 18 fewer to 28 more; moderate certainty), probably increases adverse effects leading to drug discontinuation (19 more per 1000, 1 fewer to 70 more; moderate certainty), and may have trivial to no effect on suspected, probable, or laboratory confirmed SARS-CoV-2 infection (15 fewer per 1000, 64 fewer to 41 more; low certainty). Owing to serious risk of bias and very serious imprecision, and thus very low certainty of evidence, the effects of ivermectin combined with iota-carrageenan on laboratory confirmed covid-19 (52 fewer per 1000, 58 fewer to 37 fewer), ivermectin alone on laboratory confirmed infection (50 fewer per 1000, 59 fewer to 16 fewer) and suspected, probable, or laboratory confirmed infection (159 fewer per 1000, 165 fewer to 144 fewer) remain very uncertain. CONCLUSIONS: Hydroxychloroquine prophylaxis has trivial to no effect on hospital admission and mortality, probably increases adverse effects, and probably does not reduce the risk of SARS-CoV-2 infection. Because of serious risk of bias and very serious imprecision, it is highly uncertain whether ivermectin combined with iota-carrageenan and ivermectin alone reduce the risk of SARS-CoV-2 infection. SYSTEMATIC REVIEW REGISTRATION: This review was not registered. The protocol established a priori is included as a supplement. READERS' NOTE: This article is a living systematic review that will be updated to reflect emerging evidence. Updates may occur for up to two years from the date of original publication.

Clinical care of pregnant and postpartum women with COVID-19: Living recommendations from the National COVID-19 Clinical Evidence Taskforce.

To date, 18 living recommendations for the clinical care of pregnant and postpartum women with COVID-19 have been issued by the National COVID-19 Clinical Evidence Taskforce. This includes recommendations on mode of birth, delayed umbilical cord clamping, skin-to-skin contact, breastfeeding, rooming-in, antenatal corticosteroids, angiotensin-converting enzyme inhibitors, disease-modifying treatments (including dexamethasone, remdesivir and hydroxychloroquine), venous thromboembolism prophylaxis and advanced respiratory support interventions (prone positioning and extracorporeal membrane oxygenation). Through continuous evidence surveillance, these living recommendations are updated in near real-time to ensure clinicians in Australia have reliable, evidence-based guidelines for clinical decision-making. Please visit https://covid19evidence.net.au/ for the latest recommendation updates.

Weekly updates of national living evidence-based guidelines: methods for the Australian living guidelines for care of people with COVID-19.

BACKGROUND AND OBJECTIVES: The Australian National COVID-19 Clinical Evidence Taskforce is a consortium of 31 Australian health professional organisations developing living, evidence-based guidelines for care of people with COVID-19, which are updated weekly. This article describes the methods used to develop and maintain the guidelines. METHODS: The guidelines use the GRADE methods and are designed to meet Australian NHMRC standards. Each week, new evidence is reviewed, current recommendations are revised, and new recommendations made. These are published in MAGIC and disseminated through traditional and social media. Relevant new questions to be addressed are continually sought from stakeholders and practitioners. For prioritized questions, the evidence is actively monitored and updated. Evidence surveillance combines horizon scans and targeted searches. An evidence team appraises and synthesizes evidence and prepares evidence-to-decision frameworks to inform development of recommendations. A guidelines leadership group oversees the development of recommendations by multidisciplinary guidelines panels and is advised by a consumer panel. RESULTS: The Taskforce formed in March 2020, and the first recommendations were published 2 weeks later. The guidelines have been revised and republished on a weekly basis for 24 weeks, and as of October 2020, contain over 90 treatment recommendations, suggesting that living methods are feasible in this context. CONCLUSIONS: The Australian guidelines for care of people with COVID-19 provide an example of the feasibility of living guidelines and an opportunity to test and improve living evidence methods.

Prophylactic anticoagulants for people hospitalised with COVID-19.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a serious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The primary manifestation is respiratory insufficiency that can also be related to diffuse pulmonary microthrombosis in people with COVID-19. This disease also causes thromboembolic events, such as pulmonary embolism, deep venous thrombosis, arterial thrombosis, catheter thrombosis, and disseminated intravascular coagulopathy. Recent studies have indicated a worse prognosis for people with COVID-19 who developed thromboembolism. Anticoagulants are medications used in the prevention and treatment of venous or arterial thromboembolic events. Several drugs are used in the prophylaxis and treatment of thromboembolic events, such as heparinoids (heparins or pentasaccharides), vitamin K antagonists and direct anticoagulants. Besides their anticoagulant properties, heparinoids have an additional anti-inflammatory potential, that may affect the clinical evolution of people with COVID-19. Some practical guidelines address the use of anticoagulants for thromboprophylaxis in people with COVID-19, however, the benefit of anticoagulants for people with COVID-19 is still under debate. OBJECTIVES: To assess the effects of prophylactic anticoagulants versus active comparator, placebo or no intervention, on mortality and the need for respiratory support in people hospitalised with COVID-19. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, LILACS and IBECS databases, the Cochrane COVID-19 Study Register and medRxiv preprint database from their inception to 20 June 2020. We also checked reference lists of any relevant systematic reviews identified and contacted specialists in the field for additional references to trials. SELECTION CRITERIA: Randomised controlled trials (RCTs), quasi-RCTs, cluster-RCTs and cohort studies that compared prophylactic anticoagulants (heparin, vitamin K antagonists, direct anticoagulants, and pentasaccharides) versus active comparator, placebo or no intervention for the management of people hospitalised with COVID-19. We excluded studies without a comparator group. Primary outcomes were all-cause mortality and need for additional respiratory support. Secondary outcomes were mortality related to COVID-19, deep vein thrombosis (DVT), pulmonary embolism, major bleeding, adverse events, length of hospital stay and quality of life. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures. We used ROBINS-I to assess risk of bias for non-randomised studies (NRS) and GRADE to assess the certainty of evidence. We reported results narratively. MAIN RESULTS: We identified no RCTs or quasi-RCTs that met the inclusion criteria. We included seven retrospective NRS (5929 participants), three of which were available as preprints. Studies were conducted in China, Italy, Spain and the USA. All of the studies included people hospitalised with COVID-19, in either intensive care units, hospital wards or emergency departments. The mean age of participants (reported in 6 studies) ranged from 59 to 72 years. Only three included studies reported the follow-up period, which varied from 8 to 35 days. The studies did not report on most of our outcomes of interest: need for additional respiratory support, mortality related to COVID-19, DVT, pulmonary embolism, adverse events, and quality of life. Anticoagulants (all types) versus no treatment (6 retrospective NRS, 5685 participants) One study reported a reduction in all-cause mortality (adjusted odds ratio (OR) 0.42, 95% confidence interval (CI) 0.26 to 0.66; 2075 participants). One study reported a reduction in mortality only in a subgroup of 395 people who required mechanical ventilation (hazard ratio (HR) 0.86, 95% CI 0.82 to 0.89). Three studies reported no differences in mortality (adjusted OR 1.64, 95% CI 0.92 to 2.92; 449 participants; unadjusted OR 1.66, 95% CI 0.76 to 3.64; 154 participants and adjusted risk ratio (RR) 1.15, 95% CI 0.29 to 2.57; 192 participants). One study reported zero events in both intervention groups (42 participants). The overall risk of bias for all-cause mortality was critical and the certainty of the evidence was very low. One NRS reported bleeding events in 3% of the intervention group and 1.9% of the control group (OR 1.62, 95% CI 0.96 to 2.71; 2773 participants; low-certainty evidence). Therapeutic-dose anticoagulants versus prophylactic-dose anticoagulants (1 retrospective NRS, 244 participants) The study reported a reduction in all-cause mortality (adjusted HR 0.21, 95% CI 0.10 to 0.46) and a lower absolute rate of death in the therapeutic group (34.2% versus 53%). The overall risk of bias for all-cause mortality was serious and the certainty of the evidence was low. The study also reported bleeding events in 31.7% of the intervention group and 20.5% of the control group (OR 1.8, 95% CI 0.96 to 3.37; low-certainty evidence). Ongoing studies We found 22 ongoing studies in hospital settings (20 RCTs, 14,730 participants; 2 NRS, 997 participants) in 10 different countries (Australia (1), Brazil (1), Canada (2), China (3), France (2), Germany (1), Italy (4), Switzerland (1), UK (1) and USA (6)). Twelve ongoing studies plan to report mortality and six plan to report additional respiratory support. Thirteen studies are expected to be completed in December 2020 (6959 participants), eight in July 2021 (8512 participants), and one in December 2021 (256 participants). Four of the studies plan to include 1000 participants or more. AUTHORS' CONCLUSIONS: There is currently insufficient evidence to determine the risks and benefits of prophylactic anticoagulants for people hospitalised with COVID-19. Since there are 22 ongoing studies that plan to evaluate more than 15,000 participants in this setting, we will add more robust evidence to this review in future updates.