Standard prophylactic versus intermediate dose enoxaparin in adults with severe COVID-19: A multi-center, open-label, randomized controlled trial

American Society of Hematology living guidelines on use of anticoagulation for thromboprophylaxis for patients with COVID-19: executive summary

BACKGROUND

COVID-19-related critical and acute illness is associated with an increased risk of venous thromboembolism (VTE). These evidence-based recommendations of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in decisions about using anticoagulation for thromboprophylaxis for patients with COVID-19-related critical illness; patients with COVID-19-related acute illness; and those being discharged from the hospital, who do not have suspected or confirmed VTE.

METHODS

ASH formed a multidisciplinary panel, including patient representatives. The Michael G. DeGroote Cochrane Canada and MacGRADE Centres at McMaster University supported guideline development, including performing systematic reviews (up to June 2023). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess certainty in the evidence and make recommendations.

RESULTS

This is an executive summary of 3 updated recommendations that have been published, which concludes the living phase of the guidelines. For patients with COVID-19-related critical illness, the panel issued conditional recommendations suggesting (a) prophylactic-intensity over therapeutic-intensity anticoagulation and (b) prophylactic-intensity over intermediate-intensity anticoagulation. For patients with COVID-19-related acute illness, conditional recommendations were suggested (a) prophylactic-intensity over intermediate-intensity anticoagulation, and (b) therapeutic-intensity over prophylactic-intensity anticoagulation. The panel issued a conditional recommendation suggesting against the use of postdischarge anticoagulant thromboprophylaxis.

CONCLUSIONS

These conditional recommendations were made based on low or very low certainty in the evidence, underscoring the need for additional, high-quality, randomized controlled trials for patients with COVID-19.

Assessing differential application of thromboprophylaxis regimes related to risk of pulmonary embolism and mortality in COVID-19 patients through instrumental variable analysis

Thrombotic complications are common in Coronavirus disease 2019 (COVID-19) patients, with pulmonary embolism (PE) being the most frequent. Randomised trials have provided inconclusive results on the optimal dosage of thromboprophylaxis in critically ill COVID-19 patients. We utilized data from the multicentre CAPACITY-COVID patient registry to assess the effect of differential application of Low Molecular Weight Heparin (LMWH) dose protocols on PE and in-hospital mortality risk in critically ill COVID-19 patients. An instrumental variable analysis was performed to estimate the intention-to-treat effect, utilizing differences in thromboprophylaxis prescribing behaviour between hospitals. We included 939 patients with PCR confirmed SARS-CoV-2 infection from 34 hospitals. Two-hundred-and-one patients (21%) developed a PE. The adjusted cause-specific HR of PE was 0.92 (95% CI: 0.73-1.16) per doubling of LMWH dose. The adjusted cause-specific HR for in-hospital mortality was 0.82 (95% CI: 0.65-1.02) per doubling of LMWH dose. This dose-response relationship was shown to be non-linear. To conclude, this study did not find evidence for an effect of LMWH dose on the risk of PE, but suggested a non-linear decreased risk of in-hospital mortality for higher doses of LMWH. However, uncertainty remains, and the dose-response relationship between LMWH dose and in-hospital mortality needs further investigation in well-designed studies.

Severely Ill COVID-19 Patients May Exhibit Hypercoagulability Despite Escalated Anticoagulation

Introduction: Severely ill COVID-19 patients receiving prophylactic-dose anticoagulation exhibit high rates of thrombosis and mortality. The escalation of anticoagulation also does not reduce mortality and has an uncertain impact on thrombosis rates. The reasons why escalated doses fail to outperform prophylactic doses in reducing risks of thrombosis and death in severely ill COVID-19 patients remain unclear. We hypothesized that escalated anticoagulation would not effectively prevent hypercoagulability and, consequently, would not reduce the risk of thrombosis and death in some severely ill patients. Methods: We conducted a prospective multicenter study that enrolled 3860 COVID-19 patients, including 1654 severely ill. They received different doses of low-molecular-weight or unfractionated heparin, and their blood coagulation was monitored with activated partial thromboplastin time, D-dimer, and Thrombodynamics. A primary outcome was hypercoagulability detected by Thrombodynamics. Blood samples were collected at the trough level of anticoagulation. Results: We found that escalated anticoagulation did not prevent hypercoagulability in 28.3% of severely ill patients at the trough level of the pharmacological activity. Severely ill patients with such hypercoagulability had higher levels of inflammation markers and better creatinine clearance compared to severely ill patients without it. Hypercoagulability detected by Thrombodynamics was associated with a 1.68-fold higher hazard rate for death and a 3.19-fold higher hazard rate for thrombosis. Elevated D-dimer levels were also associated with higher hazard rates for thrombosis and death, while shortened APTTs were not. The simultaneous use of Thrombodynamics and D-dimer data enhanced the accuracy for predicting thrombotic events and fatal outcomes in severely ill patients. Conclusions: Thrombodynamics reliably detects hypercoagulability in COVID-19 patients and can be used in conjunction with D-dimer to assess the risk of thrombosis and death in severely ill patients. The pharmacological effect of LMWH at the trough level might be too low to prevent thrombosis in some severely ill patients with severe inflammation and better creatinine clearance, even if escalated doses are used.

Anticoagulation Among Patients Hospitalized for COVID-19 : A Systematic Review and Prospective Meta-analysis

BACKGROUND

Reported results of clinical trials assessing higher-dose anticoagulation in patients hospitalized for COVID-19 have been inconsistent.

PURPOSE

To estimate the association of higher- versus lower-dose anticoagulation with clinical outcomes.

DATA SOURCES

Randomized trials were identified from the World Health Organization's International Clinical Trials Registry Platform and ClinicalTrials.gov with no restriction by trial status or language.

STUDY SELECTION

Eligible randomized trials assigned patients hospitalized for COVID-19 to higher- versus lower-dose anticoagulation.

DATA EXTRACTION

20 eligible trials provided data in a prospectively agreed format. Two further studies were included based on published data. The primary outcome was all-cause mortality 28 days after randomization. Secondary outcomes were progression to invasive mechanical ventilation or death, thromboembolic events, and major bleeding.

DATA SYNTHESIS

Therapeutic- compared with prophylactic-dose anticoagulation with heparins reduced 28-day mortality (OR, 0.77 [95% CI, 0.64 to 0.93]; I 2 = 29%; 11 trials, 6297 patients, of whom 5456 required low or no oxygen at randomization). The ORs for 28-day mortality were 1.21 (CI, 0.93 to 1.58; I 2 = 0%) for therapeutic-dose compared with intermediate-dose anticoagulation (6 trials, 1803 patients, 843 receiving noninvasive ventilation at randomization) and 0.95 (CI, 0.76 to 1.19; I 2 = 0%; 10 trials, 3897 patients, 2935 receiving no or low oxygen at randomization) for intermediate- versus prophylactic-dose anticoagulation. Treatment effects appeared broadly consistent across predefined patient subgroups, although some analyses were limited in power. Higher- compared with lower-dose anticoagulation was associated with fewer thromboembolic events, but a greater risk for major bleeding.

CONCLUSION

Therapeutic-dose compared with prophylactic-dose anticoagulation reduced 28-day mortality. Mortality was similar for intermediate-dose compared with prophylactic-dose anticoagulation and higher for therapeutic-dose compared with intermediate-dose anticoagulation, although this comparison was not estimated precisely.

PRIMARY FUNDING SOURCE

No direct funding. (PROSPERO: CRD42020213461).

Efficacy of COVID-19 Treatments in Intensive Care Unit: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objectives: Examining the cumulative evidence from randomized controlled trials (RCTs), evaluating the use of pharmacological agents for the treatment of COVID-19 infections in patients with critical illness. Data Sources: Databases Medline, Embase, Web of Science, Scopus, CINAHL, and Cochrane. Study Selection: Inclusion criteria were RCTs that enrolled patients with confirmed or suspected COVID-19 infection who are critically ill. Only RCTs that examined therapeutic agents against one another or no intervention, placebo, or standard of care, were included. Data Extraction: Pairs of reviewers extracted data independently. Outcomes of interest included the overall reported mortality defined as either the ICU mortality, hospital mortality, mortality within 28 days or mortality within 90 days. Data Synthesis: A total of 40 studies (11,613 patients) evaluated 50 therapeutic intervention arms divided into five main therapy categories; steroids, antiviral medications, immunomodulators, plasma therapies [intravenous immunoglobulins (IVIG), convalescent plasma and/or, therapeutic plasma exchange], and therapeutic anticoagulation. Immunomodulators was the only group with possible mortality benefit, risk ratio (RR) 0.83 (95% CI 0.73; 0.95), with nonsignificant heterogeneity (I 2 = 8%, p=0.36). In contrast, the other therapy groups showed no significant impact on mortality, as indicated by their respective pooled RRs: steroids [RR 0.91 (95% CI 0.82; 1.01), I 2 = 31%], antiviral medications [RR 1.11 (95% CI 0.82; 1.49), I 2 = 57%], plasma therapies [RR 0.77 (95% CI 0.58; 1.01), I 2 = 36%], and anticoagulation [RR 1.06 (95% CI 0.95; 1.18), I 2 = 0%]. Conclusions: This meta-analysis highlights both the heterogeneity and a lack of benefit from therapies evaluated during the COVID-19 pandemic. Many of the RCTs were developed based on limited observational data. Future RCTs investigating pharmaceutical interventions in critically ill patients during pandemics need to be designed based on better evidence.

Impact of antiplatelets, anticoagulants and cyclic nucleotide stimulators on neutrophil extracellular traps (NETs) and inflammatory markers during COVID-19

While the association between coronavirus disease-19 (COVID-19) and neutrophils extracellular traps (NETs) is recognized, uncertainties remain regarding its precise onset, timing of resolution and target therapy. To assess changes in inflammatory and NET markers during the first week of COVID-19 hospitalization, and the association with disease severity. "In vitro" experiments investigated the effect of antiplatelets, anticoagulants, and cyclic nucleotide stimulators on NETs release. Prospective cohort study, changes in interleukin (IL)-6, IL-8, IL-17, TNF-α, RANTES, PF4, and citrullinated-H3 (citH3) levels within each outcome group was evaluated using ANOVA. Differences between moderately ill, critically ill, and non-survivors were determined using Kruskal-Wallis and logistic regression. Healthy neutrophils were stimulated with phorbol-12-myristate-13-acetate (PMA) or COVID-19 sera and treated with unfractionated heparin (UFH), low molecular weight heparin (LMWH), aspirin (ASA), ticagrelor, cinaciguat, sildenafil, and milrinone. The proportion of NETosis was assessed using IncuCyte Cell Imager. Of the 125 patients, 40.8% had moderate COVID-19, 40.8% had critical COVID-19 but recovered, and 18.4% died. From admission to hospitalization day 8, IL-6 levels decreased in moderately and critically ill, but not in non-survivors, while citH3 levels increased in critically ill and non-survivors. IL-6, IL-8, and TNF-α levels were associated with critical and fatal COVID-19. The release of NETs by neutrophils stimulated with PMA or COVID-19 sera was decreased in the presence of ASA, UFH, LMWH and cyclic nucleotide stimulators in a dose-dependent manner. In the first week of hospitalization, NET markers rose later than inflammatory markers in severe COVID-19 cases. Cyclic nucleotide stimulators, ASA and heparin may emerge as treatment approaches as they may modulate NETosis.

Anticoagulant therapy in adult with COVID-19: a systematic review and meta-analysis of randomized controlled trial

Background

Blood coagulation dysfunction is a risk factor for adverse outcomes in patients with coronavirus disease 2019 (COVID-19), especially in severe cases. The evidence for the effects of anticoagulation therapy on prognosis of COVID-19 patients and its risk of causing bleeding events is accumulating. Here we conducted a meta-analysis to assess the efficacy and safety of anticoagulants in COVID-19 patients of different severity.

Methods

We searched PubMed, Embase databases, Cochrane Trials, OVID MEDLINE from December 2019 to April 2023. We included randomized controlled trials (RCTs) involving COVID-19 patients over 18 years of age, which explored the effect of anticoagulant and its dose on outcomes including all-cause mortality, bleeding events or thrombotic events. We calculated the risk ratio (RR) and its 95% confidence interval (CI) for each outcome. We also performed subgroup analyses to assess the impact of disease severity, using a fixed-effect model to test for heterogeneity. The risk of bias, publication bias, and the quality of evidence were also evaluated.

Results

A total of 20 RCTs were included for final analysis. When compared with standard care, anticoagulation treatment reduced all-cause mortality (RR 0.47, 95% CI: 0.29-0.76) and thrombotic events (RR 0.35, 95% CI: 0.15-0.83) in the whole population with COVID-19 (n=2,365), without increase in bleeding events (total: RR 1.47, 95% CI: 0.54-4.00). Most of the studies only enrolled non-severe patients (n=2,329), while the number of severe patients (n=36) was scarce. In RCTs compared therapeutical and prophylactic doses of anticoagulants, no significant difference in on all-cause mortality was found in the whole population and non-severe and severe subgroups (total: RR 1.01, 95% CI: 0.92-1.10; non-severe: RR 1.03, 95% CI: 0.81-1.32; severe: RR 1.00, 95% CI: 0.91-1.11). Therapeutical dose reduced risk of thrombotic events (total: RR 0.59, 95% CI: 0.48-0.73; subtotal of non-severe: RR 0.57, 95% CI: 0.39-0.84; Subtotal of severe: RR 0.61, 95% CI: 0.47-0.78), while risk of bleeding was increased (total: RR 1.98, 95% CI: 1.47-2.66; non-severe: RR 2.38, 95% CI: 1.56-3.62; severe: RR 1.63, 95% CI: 1.07-2.47). Study heterogeneity was found only in the analysis of effects of anticoagulants on risk of thrombotic events.

Conclusions

Anticoagulant therapy reduces all-cause mortality and risk of thrombosis in non-severe COVID-19 patients. Therapeutic dose of anticoagulant therapy can be considered in both non-severe and severe COVID-19 patients to reduce thrombosis, but may be associated with increased bleeding events.

Hemorrhages and risk factors in patients undergoing thromboprophylaxis in a respiratory critical care unit: a secondary data analysis of a cohort study

OBJECTIVE

To verify whether the bleeding risk assessment guidelines from the 9th American College of Chest Physicians (ACCP) are prognostic for respiratory intensive care unit (RICU) patients and to explore risk factors for hemorrhages, we conducted a secondary data analysis based on our previously published cohort study of venous thromboembolism.

PATIENTS AND METHODS

We performed a secondary data analysis on the single-center prospective cohort from our previous study. Patients admitted to the RICU at Beijing Chao-Yang Hospital from August 1, 2014 to December 31, 2020 were included and followed up until discharge.

RESULTS

The study enrolled 931 patients, of which 715 (76.8%) were at high risk of bleeding, while the remaining were at low risk. Of the total, 9.2% (86/931) suffered major bleeding, and no significant difference was found between the two risk groups (p = 0.601). High-risk patients had poor outcomes, including higher mortality and longer stays. Independent risk factors for major bleeding were APACHE II score ≥ 15; invasive pulmonary aspergillosis; therapeutic dose of anticoagulants; extracorporeal membrane oxygenation; and continuous renal replacement therapy. Blood transfusion not related to bleeding appeared to be an independent protective factor for major bleeding (OR 0.099, 95% CI 0.045-0.218, p < 0.001).

CONCLUSION

Bleeding risk assessment models from the 9th ACCP guidelines may not be suitable for patients in RICU. Building a bleeding risk assessment model that is suitable for patients in all RICUs remains a challenge. Trial registration ClinicalTrials.gov: NCT02213978.

Extracellular histones: a unifying mechanism driving platelet-dependent extracellular vesicle release and thrombus formation in COVID-19

BACKGROUND

COVID-19 can cause profound inflammation and coagulopathy, and while many mechanisms have been proposed, there is no known common pathway leading to a prothrombotic state.

OBJECTIVES

From the beginning of the COVID-19 pandemic, elevated levels of extracellular histones have been found in plasma of patients infected with SARS-CoV-2. We hypothesized that platelet activation triggered by extracellular histones might represent a unifying mechanism leading to increased thrombin generation and thrombosis.

METHODS

We utilized blood samples collected from an early clinical trial of hospitalized COVID-19 patients (NCT04360824) and recruited healthy subjects as controls. Using plasma samples, we measured the procoagulant and prothrombotic potential of circulating extracellular histones and extracellular vesicles (EVs). Platelet prothrombotic activity was assessed via thrombin generation potential and platelet thrombus growth. Circulating EVs were assessed for thrombin generation potential in vitro in plasma and enhancement of thrombotic susceptibility in vivo in mice.

RESULTS

Compared with controls, COVID-19 patients had elevated plasma levels of citrullinated histone H3, cell-free DNA, nucleosomes, and EVs. Plasma from COVID-19 patients promoted platelet activation, platelet-dependent thrombin generation, thrombus growth under venous shear stress, and release of platelet-derived EVs. These prothrombotic effects of COVID-19 plasma were inhibited by an RNA aptamer that neutralizes both free and DNA-bound histones. EVs isolated from COVID-19 plasma enhanced thrombin generation in vitro and potentiated venous thrombosis in mice in vivo.

CONCLUSION

We conclude that extracellular histones and procoagulant EVs drive the prothrombotic state in COVID-19 and that histone-targeted therapy may prove beneficial.

Challenges of consolidating evidence collected during a pandemic and lessons for the future

OBJECTIVE

To illustrate the challenges encountered when gathering rapidly synthesized evidence in response to the coronavirus disease 2019 (COVID-19) pandemic.

METHODS

In this article, we describe the challenges encountered when we performed a systematic literature review (SLR) of randomized controlled trials (RCTs) on the efficacy and safety of treatments for severe COVID-19. The methods of the SLR are described in full, to show the context of our objectives. Then we use the results of the SLR to demonstrate the problems of producing synthesized evidence in this setting.

RESULTS

Various challenges were identified during this SLR. These were primarily a result of heterogeneity in the study methodology of eligible studies. Definitions of the patient populations and outcome measurements were highly variable and the majority of studies demonstrated a high risk of bias, preventing quantitative synthesis of the collated evidence.

CONCLUSION

Consolidating evidence from RCTs evaluating COVID-19 interventions was problematic. Guidance is needed for scenarios with high rapid output in primary research.

Anticoagulation in COVID-19 patients - An updated systematic review and meta-analysis

BACKGROUND

Thromboembolic events are common complications of COVID-19. Clinical study results on safety and efficacy of anticoagulation in COVID-19 are controversial.

MATERIAL AND METHODS

This report is the second update of our systematic review with meta-analysis on randomized controlled trials (RCTs) comparing standard thromboprophylaxis, intermediate or therapeutic dose anticoagulation or no anticoagulation in COVID-19 in- and outpatients. We searched eligible studies up to 5 October 2023. Certainty of evidence was assessed using GRADE.

RESULTS

For this update we included fourteen new RCTs and a total of 27 RCTs with 16,789 patients. Certainty of evidence ranged from very low to high depending on outcome and comparison. Standard thromboprophylaxis with low dose anticoagulation may have little or no effect for COVID-19 outpatients compared to no anticoagulation. In inpatients with moderate or severe COVID-19, intermediate dose anticoagulation may decrease any thrombotic events or death, but may increase major bleeding compared to standard thromboprophylaxis. Therapeutic dose anticoagulation decreases thrombotic events or deaths in inpatients with moderate COVID-19, but probably has little or no effect in patients with severe COVID-19 compared to standard thromboprophylaxis with low or intermediate dose anticoagulation. With therapeutic dose anticoagulation, the risk of major bleeding probably increases regardless of COVID-19 severity. We are uncertain on the effect of thromboprophylaxis with low dose anticoagulation compared to no anticoagulation in the post-discharge setting.

CONCLUSIONS

Hospitalized, moderately-ill COVID-19 patients may benefit from intermediate or therapeutic dose anticoagulation, while critically ill patients may not. Risk of major bleeding must be considered.

Pulmonary thrombosis associated with COVID-19 pneumonia: Beyond classical pulmonary thromboembolism

BACKGROUND

Classical pulmonary thromboembolism (TE) and local pulmonary thrombosis (PT) have been suggested as mechanisms of thrombosis in COVID-19. However, robust evidence is still lacking because this was mainly based on retrospective studies, in which patients were included when TE was suspected.

METHODS

All patients with COVID-19 pneumonia underwent computed tomography and pulmonary angiography in a prospective study. The main objective was to determine the number and percentage of thrombi surrounded by lung opacification (TSO) in each patient, as well as their relationship with percentage of lung involvement (TLI), to distinguish classical TE (with a random location of thrombi that should correspond to a percentage of TSO equivalent to the TLI) from PT. We determined TLI by artificial intelligence. Analyses at patient level (TLI and percentage of TSO) and at thrombi level (TLI and TSO) were performed.

RESULTS

We diagnosed TE in 70 out of 184 patients. Three (2-8) thrombi/patient were detected. The percentage of TSO was 100% (75-100) per patient, and TLI was 19.9% (4.6-35.2). Sixty-five patients (92.9%) were above the random scenario with higher percentage of TSO than TLI. Most thrombi were TSO (n = 299, 75.1%). When evaluating by TLI (<10%, 10%-20%, 20%-30% and >30%), percentage of TSO was higher in most groups. Thrombi were mainly in subsegmental/segmental arteries, and percentage of TSO was higher in all locations.

CONCLUSIONS

Thrombi in COVID-19 were found within lung opacities in a higher percentage than lung involvement, regardless of TLI and clot location, supporting the hypothesis of local PT rather than "classic TE".

Appropriate thromboprophylaxis strategy for COVID-19 patients on dosage, antiplatelet therapy, outpatient, and postdischarge prophylaxis: a meta-analysis of randomized controlled trials

BACKGROUND

There was controversy surrounding the optimal thromboprophylaxis strategy for coronavirus disease 2019 (COVID-19) patients. This included debates on the dosage of anticoagulants for thromboembolism prophylaxis, the requirement for additional antiplatelet therapy, and the necessity of prophylaxis for outpatients and postdischarge. To explore this, the authors performed a meta-analysis of randomized controlled trials.

METHODS

PubMed, Cochrane Library, Embase, and Web of Science were last searched on 26 July 2023 for studies comparing the effect of different dose of anticoagulation, additional antiplatelet, and postdischarge prophylaxis for COVID-19 patients. The results of eligible studies were analyzed in terms of thromboembolism events, major bleeding and all-cause mortality during follow-up.

RESULTS

Our study included a total of 25 randomized controlled trials, involving 17 911 patients. Our results revealed that, compared to prophylactic dose, therapeutic dose showed lower thrombotic risk (RR, 0.66; 95% CI: 0.45-0.96) but had similar major bleeding risk for critically ill patients with COVID-19. On the other hand, intermediate dose and prophylactic dose demonstrated similar thromboembolism risk and major bleeding risk. For noncritically ill patients with COVID-19, therapeutic dose of anticoagulants was associated with lower thrombotic risk (RR, 0.50; 95% CI: 0.34-0.72) but, at the same time, increased the risk of major bleeding (RR, 2.01; 95% CI: 1.22-3.33). However, intermediate dose showed lower thromboembolism risk (RR, 0.38; 95% CI: 0.21-0.69) while maintaining a similar major bleeding risk. In critically ill patients, additional antiplatelet therapy showed similar thromboembolism, major bleeding risk, and mortality when compared to no treatment. For outpatients, additional prophylactic anticoagulation showed similar thromboembolism, major bleeding risk, and mortality when compared to no treatment. For postdischarge patients, postdischarge prophylaxis reduced thromboembolism risk (RR, 0.49; 95% CI: 0.31-0.76) but increased major bleeding risk (RR, 2.63; 95% CI: 1.13-6.14).

CONCLUSION

For noncritically ill patients, therapeutic dose prophylactic anticoagulation significantly reduced venous thromboembolism but increases major bleeding risk. Intermediate dose effectively lowered venous thromboembolism without raising major bleeding risk. The optimal dose and need for additional antiplatelet therapy in critically ill patients, as well as the necessity of prophylactic anticoagulation in outpatient and postdischarge patients, required further investigation and confirmation through rigorous evidence studies.

2023 ISTH update of the 2022 ISTH guidelines for antithrombotic treatment in COVID-19

Based on emerging evidence from the COVID-19 pandemic, the International Society on Thrombosis and Haemostasis (ISTH) guidelines for antithrombotic treatment in COVID-19 were published in 2022. Since then, at least 16 new randomized controlled trials have contributed additional evidence, which necessitated a modification of most of the previous recommendations. We used again the American College of Cardiology Foundation/American Heart Association methodology for assessment of level of evidence (LOE) and class of recommendation (COR). Five recommendations had the LOE upgraded to A and 2 new recommendations on antithrombotic treatment for patients with COVID-19 were added. Furthermore, a section was added to answer questions about COVID-19 vaccination and vaccine-induced immune thrombotic thrombocytopenia (VITT), for which studies have provided some evidence. We only included recommendations with LOE A or B. Panelists agreed on 19 recommendations, 4 for nonhospitalized, 5 for noncritically ill hospitalized, 3 for critically ill hospitalized, and 2 for postdischarge patients, as well as 5 for vaccination and VITT. A strong recommendation (COR 1) was given for (a) use of prophylactic dose of low-molecular-weight heparin or unfractionated heparin in noncritically ill patients hospitalized for COVID-19, (b) for select patients in this group, use of therapeutic-dose low-molecular-weight heparin/unfractionated heparin in preference to prophylactic dose, and (c) for use of antiplatelet factor 4 enzyme immunoassays for diagnosing VITT. A strong recommendation was given against (COR 3) the addition of an antiplatelet agent in hospitalized, noncritically ill patients. These international guidelines provide recommendations for countries with diverse healthcare resources and COVID-19 vaccine availability.

The effect of current antithrombotic therapy on mortality in nursing home residents with COVID-19: a multicentre retrospective cohort study

BACKGROUND

The first wave of COVID led to an alarmingly high mortality rate among nursing home residents (NHRs). In hospitalised patients, the use of anticoagulants may be associated with a favourable prognosis. However, it is unknown whether the use of antithrombotic medication also protected NHRs from COVID-19-related mortality.

OBJECTIVES

To investigate the effect of current antithrombotic therapy in NHRs with COVID-19 on 30-day all-cause mortality during the first COVID-19 wave.

METHODS

We performed a retrospective cohort study linking electronic health records and pharmacy data in NHRs with COVID-19. A propensity score was used to match NHRs with current use of therapeutic dose anticoagulants to NHRs not using anticoagulant medication. The primary outcome was 30-day all-cause mortality, which was evaluated using a logistic regression model. In a secondary analysis, multivariable logistic regression was performed in the complete study group to compare NHRs with current use of therapeutic dose anticoagulants and those with current use of antiplatelet therapy to those without such medication.

RESULTS

We included 3521 NHRs with COVID-19 based on a positive RT-PCR for SARS-CoV-2 or with a well-defined clinical suspicion of COVID-19. In the matched propensity score analysis, NHRs with current use of therapeutic dose anticoagulants had a significantly lower all-cause mortality (OR = 0.73; 95% CI: 0.58-0.92) compared to NHRs who did not use therapeutic anticoagulants. In the secondary analysis, current use of therapeutic dose anticoagulants (OR: 0.62; 95% CI: 0.48-0.82) and current use of antiplatelet therapy (OR 0.80; 95% CI: 0.64-0.99) were both associated with decreased mortality.

CONCLUSIONS

During the first COVID-19 wave, therapeutic anticoagulation and antiplatelet use were associated with a reduced risk of all-cause mortality in NHRs. Whether these potentially protective effects are maintained in vaccinated patients or patients with other COVID-19 variants, remains unknown.

Effect of anticoagulation on the incidence of venous thromboembolism, major bleeding, and mortality among hospitalized COVID-19 patients: an updated meta-analysis

Objective

Anticoagulation is crucial for patients hospitalized with coronavirus disease 2019 (COVID-19) due to the high risk of venous thromboembolism (VTE). However, the optimal anticoagulation regimen needs further exploration. Therefore, we evaluated the efficacy and safety of diverse anticoagulation dosage dosages for COVID-19.

Methods

An updated meta-analysis was performed to assess the effect of thromboprophylaxis (standard, intermediate, and therapeutic dose) on the incidence of VTE, mortality and major bleeding among COVID-19 patients. Literature was searched via PubMed, EMBASE, Web of Science, and China National Knowledge Infrastructure (CNKI) database. The odds ratio (OR) and 95% confidence interval (CI) were calculated for effect estimates.

Results

Nineteen studies involving 25,289 participants without VTE history were included. The mean age of patients was 59.3 years old. About 50.96% were admitted to the intensive care unit. In the pooled analysis, both therapeutic-dose and intermediate-dose anticoagulation did not have a significant advantage in reducing VTE risk over standard dosage (OR = 1.09, 95% CI: 0.58-2.02, and OR = 0.89, 95% CI: 0.70-1.12, respectively). Similarly, all-cause mortality was not further decreased in either therapeutic-dose group (OR = 1.12, 95% CI: 0.75-1.67) or intermediate-dose group (OR = 1.34, 95% CI: 0.83-2.17). While the major bleeding risk was significantly elevated in the therapeutic-dose group (OR = 2.59, 95%CI: 1.87-3.57) as compared with the standard-dose regimen. Compared with intermediate dosage, therapeutic anticoagulation did not reduce consequent VTE risk (OR = 0.85, 95% CI: 0.52-1.38) and all-cause mortality (OR = 0.84, 95% CI: 0.60-1.17), but significantly increased major bleeding rate (OR = 2.42, 95% CI: 1.58-3.70). In subgroup analysis of patients older than 65 years, therapeutic anticoagulation significantly lowered the incidence of VTE in comparation comparison with standard thromboprophylaxis, however, at the cost of elevated risk of major bleeding.

Conclusion

Our results indicated that for most hospitalized patients with COVID-19, standard-dose prophylactic anticoagulation might be the optimal choice. For elderly patients at low risk of bleeding, therapeutic-dose anticoagulation could further reduce VTE risk and should be considered especially when there were other strong risk factors of VTE during hospital stay.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO, identifier, CRD42023388429.

Comparison of Standard Versus Intermediate Prophylaxis Dose for Venous Thromboembolism Prophylaxis in Patients Hospitalized With COVID-19 Infection

Background: COVID-19 infection is associated with a high risk of venous thromboembolism (VTE) events. VTE prophylaxis reduces the risk of these events. The optimal dose of VTE prophylaxis however remains uncertain. Objectives: To compare the incidence of VTE in patients treated with either standard dose VTE versus intermediate dose VTE prophylaxis. Methods: In this retrospective cohort study, we analyzed data from 1786 adult patients admitted into the hospital with polymerase chain reaction confirmed COVID-19 infection between April 2020 to September 2021. For analysis, patients were divided into 2 cohorts: either standard dose prophylaxis treatment group (patients who received either unfractionated heparin 5000units 3 times a day or enoxaparin 30-40 mg daily subcutaneously) or intermediate dose VTE prophylaxis group (patients received either unfractionated heparin 7500 units 3 times daily or enoxaparin 30-40 mg twice a day subcutaneously). The primary outcome was incidence of VTE events described as either deep vein thrombosis (DVT) or pulmonary embolism (PE). Secondary outcome was bleeding events. Results: During the study period, 398 (22%) patients were primarily treated with standard dose VTE prophylaxis, whereas 1388 (78%) patients were treated with intermediate dose VTE prophylaxis. There was a significantly higher incidence of venous thromboembolism events noted in the standard dose prophylaxis treatment group when compared with the intermediate dose prophylaxis group (25/398 (6.3%) vs 35/1388 (2.5%) P < .001, [Odds Ratio 2.6197, 95% confidence interval = 1.5482-4.4327]). Multivariable-adjusted logistic regression, adjusting for age, obesity, and smoking, with the intermediate dose prophylaxis treatment group as the referent category revealed higher odds for incident venous thromboembolism events in the standard dose prophylaxis group. There was no statistically significant difference in bleeding events between the 2 treatment groups (9 (2.3%) for standard dose prophylaxis group vs 46 (3.3%) for intermediate dose prophylaxis group P = .26). Conclusions: Among patients hospitalized with COVID-19 infection, patients receiving intermediate dose VTE prophylaxis experienced lower incident rates of venous thromboembolism events compared to those receiving standard dose VTE prophylaxis without a statistically significant increase in the risk of bleeding events.

COVID-19 thromboprophylaxis. New evidence

Recent publications have questioned the efficacy of using therapeutic or intermediate doses of low molecular weight heparin (LMWH) in COVID-19 patients, especially in the most severe patients. In order to update these recommendations, a non-systematic review has been carried out in the main medical databases. A total of 14 randomized clinical trials, 14 meta-analyses and the recommendations of 12 scientific societies were selected, stratified according to the type of patient (outpatient, hospitalized, admitted to critical care or post-discharge). The efficacy of LMWH and other therapeutic approaches (rivaroxaban, apixaban, sulodexide, acetylsalicylic acid and P2Y12 inhibitors) has been analyzed. The findings recommend using standard doses of LMWH as thromboprophylaxis in critically hospitalized COVID-19 patients and therapeutic doses in non-critically hospitalized patients if the risk of bleeding is low. In outpatients and those discharged from the hospital, LMWH could be used at a prophylactic dose if there are thrombotic risk factors, and the bleeding risk is low. It is not recommended to associate antiplatelet agents with LMWH unless previously indicated.

Low-molecular-weight heparin for the prevention of clinical worsening in severe non-critically ill COVID-19 patients: a joint analysis of two randomized controlled trials

Coronavirus disease 2019 (COVID-19) carries a high risk of vascular thrombosis. However, whether a specific anticoagulation intensity strategy may prevent clinical worsening in severe COVID-19 patients is still debated. We conducted a joint analysis of two randomized controlled trials, COVID-19 HD (NCT044082359) and EMOS-COVID (NCT04646655), to assess the efficacy and safety of two anticoagulant regimens in hospitalized severe COVID-19 patients. Subjects with COVID-19-associated respiratory compromise and/or coagulopathy were randomly assigned to low (4000 IU qd) or high (70 IU Kg-1 every 12 h) enoxaparin dose. The primary efficacy endpoint was clinical worsening within 30 days, defined as the occurrence of at least one of the following events, whichever came first: in-hospital death, evidence of arterial or venous thromboembolism, acute myocardial infarction, need for either continuous positive airway pressure (CPAP) or non-invasive ventilation (NIV) in patients receiving standard oxygen therapy or none at randomization, and need for mechanical ventilation in any patient. The safety endpoint was major bleeding. We estimated the relative risk (RR) and its 95% confidence interval (CI) for the outcomes. Among 283 patients included in the study (144 in the low-dose and 139 in the high-dose group), 118 (41.7%) were on NIV or CPAP at randomization. 23/139 (16.5%) patients in the high-dose group reached the primary endpoint compared to 33/144 (22.9%) in the low-dose group (RR 0.72, 95% CI 0.45-1.17). No major bleeding was observed. No significant differences were found in the clinical worsening of hospitalized COVID-19 patients treated with high versus low doses of enoxaparin.

The 2023 Belgian clinical guidance on anticoagulation management in hospitalized and ambulatory COVID-19 patients

COVID-19 is associated with an increased risk for thrombotic complications. The trials investigating the optimal thromboprophylactic dose are performed in challenging times and seemingly produce conflicting evidence. The burdensome circumstances, divergent endpoints, and different analytical approaches hamper comparison and extrapolation of available evidence. Most importantly, clinicians should provide thromboprophylaxis in hospitalized COVID-19 patients while (re)assessing bleeding and thrombotic risk frequently. The COVID-19 Thromboprophylaxis Working Group of the BSTH updated its guidance document. It aims to summarize the available evidence critically and to guide clinicians in providing the best possible thromboprophylaxis.

Subgroup analyses in venous thromboembolism trials reporting pharmacological interventions: A systematic review

INTRODUCTION

Randomized controlled trials (RCTs) that conduct subgroup analyses have the potential to provide information on treatment decisions in specific groups of patients from heterogeneous populations. Although we understand several factors can modify the incidence of venous thromboembolism (VTE) and the benefit/risk ratio of anticoagulation treatments, further evidence is warranted to show the heterogeneity of treatment effects in different subgroups of patients.

AIMS

The primary purpose was to evaluate the appropriateness and interpretation of subgroup analysis performed on VTE RCTs reporting pharmacological interventions.

MATERIALS AND METHODS

A systematic review of RCTs published between January 2017 and January 2022 was conducted. Claims of subgroup effects were evaluated with predefined criteria. High-quality claims of subgroup effect were further analyzed and discussed.

RESULTS

Overall, 28 RCTs with a generally low bias risk were included. The purposes of the treatments included pharmacologic thromboprophylaxis (17), therapeutic dose anticoagulation (9), and catheter-directed pharmacologic thrombolysis (2). The evaluated subgroup analyses generally presented: a high number of subgroup analyses reported, a lack of prespecification, and a lack of usage of statistical tests for interaction. The authors reported 13 claims of subgroup effect; only two were considered potentially reliable to represent heterogeneity in the direction or magnitude of treatment effect.

CONCLUSIONS

Subgroup analyses of VTE RCTs reporting pharmacologic interventions are generally methodologically poor. Most claims of subgroup effect did not meet critical criteria and lacked credibility. Clinicians in this field may proceed with scepticism when assessing claims of subgroup effects due to methodological concerns and misleading interpretations.

COVID-19-Associated Pulmonary Embolism: Review of the Pathophysiology, Epidemiology, Prevention, Diagnosis, and Treatment

COVID-19 is associated with endothelial activation in the setting of a potent inflammatory reaction and a hypercoagulable state. The end result of this thromboinflammatory state is an excess in thrombotic events, in particular venous thromboembolism. Pulmonary embolism (PE) has been of special interest in patients with COVID-19 given its association with respiratory deterioration, increased risk of intensive care unit admission, and prolonged hospital stay. The pathophysiology and clinical characteristics of COVID-19-associated PE may differ from the conventional non-COVID-19-associated PE. In addition to embolic events from deep vein thrombi, in situ pulmonary thrombosis, particularly in smaller vascular beds, may be relevant in patients with COVID-19. Appropriate prevention of thrombotic events in COVID-19 has therefore become of critical interest. Several changes in viral biology, vaccination, and treatment management during the pandemic may have resulted in changes in incidence trends. This review provides an overview of the pathophysiology, epidemiology, clinical characteristics, and risk factors of COVID-19-associated PE. Furthermore, we briefly summarize the results from randomized controlled trials of preventive antithrombotic therapies in COVID-19, focusing on their findings related to PE. We discuss the acute treatment of COVID-19-associated PE, which is substantially similar to the management of conventional non-COVID-19 PE. Ultimately, we comment on the current knowledge gaps in the evidence and the future directions in the treatment and follow-up of COVID-19-associated PE, including long-term management, and its possible association with long-COVID.

Intermediate dose enoxaparin in hospitalized patients with moderate-severe COVID-19: a pilot phase II single-arm study, INHIXACOVID19

BACKGROUND

Randomized clinical trials in non-critically ill COVID-19 patients showed that therapeutic-dose heparin increased survival with reduced organ support as compared with usual-care thromboprophylaxis, albeit with increased bleeding risk. The purpose of the study is to assess the safety of intermediate dose enoxaparin in hospitalized patients with moderate to severe COVID-19.

METHODS

A phase II single-arm interventional prospective study including patients receiving intermediate dose enoxaparin once daily according to body weight: 60 mg for 45-60 kg, 80 mg for 61-100 kg or 100 mg for > 100 kg for 14 days, with dose adjustment according to anti-factor Xa activity (target range: 0.4-0.6 UI/ml); an observational cohort (OC) included patients receiving enoxaparin 40 mg day for comparison. Follow-up was 90 days. Primary outcome was major bleeding within 30 and 90 days after treatment onset. Secondary outcome was the composite of all-cause 30 and 90-day mortality rates, disease severity at the end of treatment, intensive care unit (ICU) admission and length of ICU stay, length of hospitalization. All outcomes were adjudicated by an independent committee and analyzed before and after propensity score matching (PSm).

RESULTS

Major bleeding was similar in IC (1/98 1.02%) and in the OC (none), with only one event observed in a patient receiving concomitantly anti-platelet therapy. The composite outcome was observed in 53/98 patients (54%) in the IC and 132/203 (65%) patients in the OC (p = 0.07) before PSm, while it was observed in 50/90 patients (55.6%) in the IC and in 56/90 patients (62.2%) in the OC after PSm (p = 0.45). Length of hospitalization was lower in the IC than in OC [median 13 (IQR 8-16) vs 14 (11-21) days, p = 0.001], however it lost statistical significance after PSm (p = 0.08). At 30 days, two patients had venous thrombosis and two pulmonary embolism in the OC. Time to first negative RT-PCR were similar in the two groups.

CONCLUSIONS

Weight adjusted intermediate dose heparin with anti-FXa monitoring is safe with potential positive impact on clinical course in COVID-19 non-critically ill patients.

TRIAL REGISTRATION

The study INHIXACOVID19 was registred on ClinicalTrials.gov with the trial registration number (TRN) NCT04427098 on 11/06/2020.

A retrospective multicenter cohort study of the association between anti-Factor Xa values and death, thromboembolism, and bleeding in patients with critical COVID-19

BACKGROUND

Patients with critical COVID-19 have a high risk of thromboembolism, but intensified thromboprophylaxis has not been proven beneficial. The activity of low-molecular-weight heparins can be monitored by measuring anti-Factor Xa. We aimed to study the association between anti-Factor Xa values and death, thromboembolism, and bleeding in patients with critical COVID-19.

METHOD

This retrospective cohort study included adult patients with critical COVID-19 admitted to an intensive care unit at three Swedish hospitals between March 2020 and May 2021 with at least one valid peak and/or trough anti-Factor Xa value. Within the peak and trough categories, patients' minimum, median, and maximum values were determined. Logistic regressions with splines were used to assess associations.

RESULTS

In total, 408 patients had at least one valid peak and/or trough anti-Factor Xa measurement, resulting in 153 patients with peak values and 300 patients with trough values. Lower peak values were associated with thromboembolism for patients' minimum (p = 0.01), median (p = 0.005) and maximum (p = 0.001) values. No association was seen between peak values and death or bleeding. Higher trough values were associated with death for median (p = 0.03) and maximum (p = 0.002) values and with both bleeding (p = 0.01) and major bleeding (p = 0.02) for maximum values, but there were no associations with thromboembolism.

CONCLUSIONS

Measuring anti-Factor Xa activity may be relevant for administrating low-molecular-weight heparin to patients with critical COVID-19. Lower peak values were associated with an increased risk of thromboembolism, and higher trough values were associated with an increased risk of death and bleeding. Prospective studies are needed to confirm the results.

TRIAL REGISTRATION

The study was retrospectively registered at Clinicaltrials.gov, NCT05256524, February 24, 2022.

Endothelium dysfunction and thrombosis in COVID-19 with type 2 diabetes

SARS-CoV-2 can directly or indirectly damage endothelial cells. Endothelial injury, especially phosphatidylserine (PS) exposure on the outer membrane of cells, can more easily promote thrombosis. Type 2 diabetes(T2D) patients were more susceptible to COVID-19, they had more severe symptoms, higher risk of thrombotic complications, and longer duration of post-COVID-19 sequelae. This review provided a detailed overview of the mechanisms underlying endothelial dysfunction in T2D patients with COVID-19 (including long COVID), which may be influenced by hyperglycemia, hypoxia, and pro-inflammatory environments. The mechanisms of thrombosis in T2D patients with COVID-19 are also explored, particularly the effects of increased numbers of PS-exposing particles, blood cells, and endothelial cells on hypercoagulability. Given the high risk of thrombosis in T2D patients with COVID-19, early antithrombotic therapy can both minimize the impact of the disease on patients and maximize the chances of improvement, thereby alleviating patient suffering. We provided detailed guidance on antithrombotic drugs and dosages for mild, moderate, and severe patients, emphasizing that the optimal timing of thromboprophylaxis is a critical factor in influencing prognosis. Considering the potential interactions between antidiabetic, anticoagulant, and antiviral drugs, we proposed practical and comprehensive management recommendations to supplement the incomplete efficacy of vaccines in the diabetic population, reduce the incidence of post-COVID-19 sequelae, and improve patient quality of life.

Therapeutic-dose anticoagulation or thromboprophylaxis with low-molecular-weight heparin for moderate Covid-19: meta-analysis of randomized controlled trials

BACKGROUND

We carried out a meta-analysis since there is not enough evidence to recommend for or against therapeutic-dose anticoagulation compared with thromboprophylaxis in noncritically ill patients hospitalized with Covid-19.

METHODS

We performed a systematic literature search using PubMed, Embase, Cochrane Library, and MedRxiv for randomized trials that included therapeutic-dose with low-molecular-weight heparin (LMW) or thromboprophylaxis with LMW heparin in noncritically ill patients admitted to the hospital with Covid-19. We identified five open-label studies for analysis with a total of 3220 patients. Two independent researchers selected, assessed, and extracted the data in duplicate. The outcomes evaluated were all-cause mortality, progression to invasive mechanical ventilation, incidence of venous thromboembolism, and major bleeding. The studies did not show risk for selection, detection, attrition, or reporting bias.

RESULTS

Therapeutic-dose anticoagulation with LMW heparin compared with thromboprophylaxis with LMW heparin had no significant effect of all-cause death (risk ratio [RR] 0.85; 95% confidence interval [CI] 0.67-1.07; P = 0.16; I2 = 48%), or progression to invasive mechanical ventilation (RR 0.89; CI 0.73-1.08; P = 0.24; I2: 0%). Therapeutic-dose anticoagulation significantly reduced the risk of venous thromboembolic disease (RR 0.42; 95% CI 0.28-0.62; P = 0.0001; I2 = 0%) [Number needed to treat = 37]. Major bleeding occurred in 1.79% of the patients receiving therapeutic-dose anticoagulation and in 0.97% of those receiving thromboprophylaxis [Number needed to harm 125].

CONCLUSION

Therapeutic-dose anticoagulation in noncritically ill patients with Covid-19 could be indicated for patients at high risk of venous thromboembolic disease and low risk of bleeding.

Increased Thrombotic Risk in COVID-19: Evidence and Controversy

The pandemic of respiratory disease caused by the novel coronavirus named SARS-CoV-2, which emerged at the end of 2019, is still ongoing [...].

Role of Therapeutic Anticoagulation in COVID-19: The Current Situation

Thrombotic complications from COVID-19 are now well known and contribute to significant morbidity and mortality. Different variants confer varying risks of thrombotic complications. Heparin has anti-inflammatory and antiviral effects. Due to its non-anticoagulant effects, escalated-dose anticoagulation, especially therapeutic-dose heparin, has been studied for thromboprophylaxis in hospitalized patients with COVID-19. Few randomized, controlled trials have examined the role of therapeutic anticoagulation in moderately to severely ill patients with COVID-19. Most of these patients had elevated D-dimers and low bleeding risks. Some trials used an innovative adaptive multiplatform with Bayesian analysis to answer this critical question promptly. All the trials were open-label and had several limitations. Most trials showed improvements in the meaningful clinical outcomes of organ-support-free days and reductions in thrombotic events, mainly in non-critically-ill COVID-19 patients. However, the mortality benefit needed to be more consistent. A recent meta-analysis confirmed the results. Multiple centers initially adopted intermediate-dose thromboprophylaxis, but the studies failed to show meaningful benefits. Given the new evidence, significant societies have suggested therapeutic anticoagulation in carefully selected patients who are moderately ill and do not require an intensive-care-unit level of care. There are multiple ongoing trials globally to further our understanding of therapeutic-dose thromboprophylaxis in hospitalized patients with COVID-19. In this review, we aim to summarize the current evidence regarding the use of anticoagulation in patients with COVID-19 infection.

Effect of weight-adjusted intermediate-dose versus fixed-dose prophylactic anticoagulation with low-molecular-weight heparin on venous thromboembolism among noncritically and critically ill patients with COVID-19: the COVI-DOSE trial, a multicenter, randomised, open-label, phase 4 trial

Background

Venous thromboembolism is a major complication of coronavirus disease 2019 (COVID-19). We hypothesized that a weight-adjusted intermediate dose of anticoagulation may decrease the risk of venous thromboembolism COVID-19 patients.

Methods

In this multicenter, randomised, open-label, phase 4, superiority trial with blinded adjudication of outcomes, we randomly assigned adult patients hospitalised in 20 French centers and presenting with acute respiratory SARS-CoV-2. Eligible patients were randomly assigned (1:1 ratio) to receive an intermediate weight-adjusted prophylactic dose or a fixed-dose of subcutaneous low-molecular-weight heparin during the hospital stay. The primary outcome corresponded to symptomatic deep-vein thrombosis (fatal) pulmonary embolism during hospitalization (COVI-DOSE ClinicalTrials.gov number: NCT04373707).

Findings

Between May 2020, and April 2021, 1000 patients underwent randomisation in medical wards (noncritically ill) (80.1%) and intensive care units (critically ill) (19.9%); 502 patients were assigned to receive a weight-adjusted intermediate dose, and 498 received fixed-dose thromboprophylaxis. Symptomatic venous thromboembolism occurred in 6 of 502 patients (1.2%) in the weight-adjusted dose group and in 10 of 498 patients (2.1%) in the fixed-dose group (subdistribution hazard ratio, 0.59; 95% CI, 0.22-1.63; P = 0.31). There was a twofold increased risk of major or clinically relevant nonmajor bleeding: 5.9% in the weight-adjusted dose group and 3.1% in the fixed-dose group (P = 0.034).

Interpretation

In the COVI-DOSE trial, the observed rate of thromboembolic events was lower than expected in patients hospitalized for COVID-19 infection, and the study was unable to show a significant difference in the risk of venous thromboembolism between the two low-molecular-weight-heparin regimens.

Funding

French Ministry of Health, CAPNET, Grand-Est Region, Grand-Nancy Métropole.

Optimal dosing of heparin for prophylactic anticoagulation in critically ill COVID-19 patients a systematic review and meta-analysis of randomized controlled trials

PURPOSE

The optimal amount of anticoagulation for critically ill COVID-19 patients is controversial. Therefore, we aimed to evaluate the efficacy and safety of escalated doses of anticoagulation in critically ill patients with severe COVID-19.

MATERIALS AND METHODS

We conducted a systematic search of three major databases, including PubMed, Cochrane Library, and Embase, from inception to May 2022. Randomized controlled trials (RCTs) were included comparing therapeutic or intermediate doses to standard prophylactic doses of anticoagulants in critically ill COVID-19 patients, with heparins as the only anticoagulation therapy considered.

RESULTS

Out of the six RCTs, 2130 patients were administered escalated dose anticoagulation (50.2%) and standard thromboprophylaxis therapy (49.8%). The escalated dose showed no significant impact on mortality (RR, 1.01; 95% CI, 0.90-1.13). Although there was no significant difference in DVT (RR, 0.81; 95% CI, 0.61-1.08), the risk of PE was significantly reduced in patients receiving escalated dose anticoagulation (RR, 0.35; 95% CI, 0.21-0.60), with an increased risk of bleeding events (RR, 1.65; 95% CI, 1.08-2.53).

CONCLUSION

This systematic review and meta-analysis fail to support escalated anticoagulation doses to reduce mortality in critically ill COVID-19 patients. However, higher doses of anticoagulants appear to reduce thrombotic events while increasing the risk of bleeding effectively.

Antithrombotic therapy in the management of hospitalised patients with COVID-19

Hospitalised patients with coronavirus disease 2019 (COVID-19) are at a significantly higher risk of having thromboembolic events while in hospital and in the immediate post-hospital discharge period. Based on early data from observational studies, multiple high quality randomised controlled trials have been conducted worldwide to evaluate optimal thromboprophylaxis regimens to reduce thromboembolism and other COVID-19-related adverse outcomes in hospitalised patients. The International Society on Thrombosis and Haemostasis has published evidence-based guideline recommendations using established methodology for the management of antithrombotic therapy of COVID-19 patients, both in-hospital and in the immediate post-hospital discharge period. A good clinical practice statement supplemented these guidelines based on topics for which there was no or limited high-quality evidence. This review summarises the main recommendations of these documents to serve as a quick access tool for hospital doctors to use in their everyday practice when treating COVID-19 patients.

Anticoagulation strategy and safety in critically ill COVID-19 patients: a French retrospective multicentre study

BACKGROUND

Patients with critical illness due to COVID-19 exhibit increased coagulability associated with a high risk of venous thrombo-embolism (VTE). Data on prophylactic anticoagulation for these patients are limited and conflicting. The purpose of this study was to evaluate whether intermediate-dose prophylactic anticoagulation in patients with COVID-19 requiring ICU admission was associated with better outcomes compared to standard-dose prophylactic anticoagulation.

METHODS

We retrospectively included adults admitted with severe COVID-19 to any of 15 ICUs, in 2020 or 2021. We compared the groups given intermediate-dose vs. standard-dose prophylactic anticoagulation. The primary outcome was all-cause day-90 mortality. Secondary outcomes were VTE (pulmonary embolism or deep vein thrombosis), ICU stay length, and adverse effects of anticoagulation.

RESULTS

Of 1174 included patients (mean age, 63 years), 399 received standard-dose and 775 intermediate-dose prophylactic anticoagulation. Of the 211 patients who died within 90 days, 86 (21%) received intermediate and 125 (16%) standard doses. After adjustment on early corticosteroid therapy and critical illness severity, there were no significant between-group differences in day-90 mortality (hazard ratio [HR], 0.73; 95%CI, 0.52-1.04; p = 0.09) or ICU stay length (HR, 0.93; 95%CI, 0.79-1.10; p = 0.38). Intermediate-dose anticoagulation was significantly associated with fewer VTE events (HR, 0.55; 95%CI, 0.38-0.80; p < 0.001). Bleeding events occurred in similar proportions of patients in the two groups (odds ratio, 0.86; 95%CI, 0.50-1.47; p = 0.57).

CONCLUSIONS

Mortality on day 90 did not differ between the groups given standard-dose and intermediate-dose prophylactic anticoagulation, despite a higher incidence of VTE in the standard-dose group.

Effects of Standard-Dose Prophylactic, High-Dose Prophylactic, and Therapeutic Anticoagulation in Patients With Hypoxemic COVID-19 Pneumonia: The ANTICOVID Randomized Clinical Trial

Importance

Given the high risk of thrombosis and anticoagulation-related bleeding in patients with hypoxemic COVID-19 pneumonia, identifying the lowest effective dose of anticoagulation therapy for these patients is imperative.

Objectives

To determine whether therapeutic anticoagulation (TA) or high-dose prophylactic anticoagulation (HD-PA) decreases mortality and/or disease duration compared with standard-dose prophylactic anticoagulation (SD-PA), and whether TA outperforms HD-PA; and to compare the net clinical outcomes among the 3 strategies.

Design, Settings, and Participants

The ANTICOVID randomized clinical open-label trial included patients with hypoxemic COVID-19 pneumonia requiring supplemental oxygen and having no initial thrombosis on chest computer tomography with pulmonary angiogram at 23 health centers in France from April 14 to December 13, 2021. Of 339 patients randomized, 334 were included in the primary analysis-114 patients in the SD-PA group, 110 in the HD-PA, and 110 in the TA. At randomization, 90% of the patients were in the intensive care unit. Data analyses were performed from April 13, 2022, to January 3, 2023.

Interventions

Patients were randomly assigned (1:1:1) to receive either SD-PA, HD-PA, or TA with low-molecular-weight or unfractionated heparin for 14 days.

Main Outcomes and Measures

A hierarchical criterion of all-cause mortality followed by time to clinical improvement at day 28. Main secondary outcome was net clinical outcome at day 28 (composite of thrombosis, major bleeding, and all-cause death).

Results

Among the study population of 334 individuals (mean [SD] age, 58.3 [13.0] years; 226 [67.7%] men and 108 [32.3%] women), use of HD-PA and SD-PA had similar probabilities of favorable outcome (47.3% [95% CI, 39.9% to 54.8%] vs 52.7% [95% CI, 45.2% to 60.1%]; P = .48), as did TA compared with SD-PA (50.9% [95% CI, 43.4% to 58.3%] vs 49.1% [95% CI, 41.7% to 56.6%]; P = .82) and TA compared with HD-PA (53.5% [95% CI 45.8% to 60.9%] vs 46.5% [95% CI, 39.1% to 54.2%]; P = .37). Net clinical outcome was met in 29.8% of patients receiving SD-PA (20.2% thrombosis, 2.6% bleeding, 14.0% death), 16.4% receiving HD-PA (5.5% thrombosis, 3.6% bleeding, 11.8% death), and 20.0% receiving TA (5.5% thrombosis, 3.6% bleeding, 12.7% death). Moreover, HD-PA and TA use significantly reduced thrombosis compared with SD-PA (absolute difference, -14.7 [95% CI -6.2 to -23.2] and -14.7 [95% CI -6.2 to -23.2], respectively). Use of HD-PA significantly reduced net clinical outcome compared with SD-PA (absolute difference, -13.5; 95% CI -2.6 to -24.3).

Conclusions and Relevance

This randomized clinical trial found that compared with SD-PA, neither HD-PA nor TA use improved the primary hierarchical outcome of all-cause mortality or time to clinical improvement in patients with hypoxemic COVID-19 pneumonia; however, HD-PA resulted in significantly better net clinical outcome by decreasing the risk of de novo thrombosis.

Trial Registration

ClinicalTrials.gov Identifier: NCT04808882.

Safety and Efficacy of Different Anticoagulant Doses for Patients with COVID-19 in the ICU: A Systematic Review and Meta-Analysis

Critically ill COVID-19 patients have a high incidence of thromboembolic events, which significantly influence the risk of mortality. Anticoagulant therapy is generally recommended to these patients but the optimal dosing regimens require further investigations. The objective of this systematic review and meta-analysis was to assess the efficacy and safety of prophylactic, intermediate and therapeutic dose anticoagulation in COVID-19 patients admitted to the ICU. A systematic search for original prospective observational studies and clinical trials was performed in online databases from 2020 to 2022. A total of 13 studies (3239 patients) were included. The type of anticoagulant dosing showed no significant influence on short-term mortality (p = 0.84), deep vein thrombosis (p = 0.66), arterial thrombosis (p = 0.44), major bleeding (p = 0.35) and minor bleeding incidence (p = 0.46). An anticoagulation regimen significantly influenced pulmonary embolism occurrence (16% for prophylactic dose vs. 4% for therapeutic dose, p = 0.02), but the number of studies in the analysis was relatively low. In conclusion, the results of this meta-analysis suggest that critically ill COVID-19 patients admitted in the ICU have no benefit from therapeutic doses of anticoagulants and that all three thromboprophylaxis regimes have a comparable effect on short term mortality and venous thromboembolism incidence but for pulmonary embolism, for which the results were inconclusive.

AGIHO guideline on evidence-based management of COVID-19 in cancer patients: 2022 update on vaccination, pharmacological prophylaxis and therapy in light of the omicron variants

The novel coronavirus SARS-CoV-2 and the associated infectious disease COVID-19 pose a significant challenge to healthcare systems worldwide. Patients with cancer have been identified as a high-risk population for severe infections, rendering prophylaxis and treatment strategies for these patients particularly important. Rapidly evolving clinical research, resulting in the recent advent of various vaccines and therapeutic agents against COVID-19, offers new options to improve care and protection of cancer patients. However, ongoing epidemiological changes and rise of new virus variants require repeated revisions and adaptations of prophylaxis and treatment strategies to meet these new challenges. Therefore, this guideline provides an update on evidence-based recommendations with regard to vaccination, pharmacological prophylaxis and treatment of COVID-19 in cancer patients in light of the currently dominant omicron variants. It was developed by an expert panel of the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Medical Oncology (DGHO) based on a critical review of the most recent available data.

Pharmacology of Heparin and Related Drugs: An Update

Heparin has been used extensively as an antithrombotic and anticoagulant for close to 100 years. This anticoagulant activity is attributed mainly to the pentasaccharide sequence, which potentiates the inhibitory action of antithrombin, a major inhibitor of the coagulation cascade. More recently it has been elucidated that heparin exhibits anti-inflammatory effect via interference of the formation of neutrophil extracellular traps and this may also contribute to heparin's antithrombotic activity. This illustrates that heparin interacts with a broad range of biomolecules, exerting both anticoagulant and nonanticoagulant actions. Since our previous review, there has been an increased interest in these nonanticoagulant effects of heparin, with the beneficial role in patients infected with SARS2-coronavirus a highly topical example. This article provides an update on our previous review with more recent developments and observations made for these novel uses of heparin and an overview of the development status of heparin-based drugs. SIGNIFICANCE STATEMENT: This state-of-the-art review covers recent developments in the use of heparin and heparin-like materials as anticoagulant, now including immunothrombosis observations, and as nonanticoagulant including a role in the treatment of SARS-coronavirus and inflammatory conditions.

Pulmonary Embolism in Patients with COVID-19: Comparison between Different Care Settings

The clinical characteristics and outcomes of patients with coronavirus disease 2019 (COVID-19) who develop pulmonary embolism (PE) in the full spectrum of patient care settings need to be elucidated. The aim of this study was to compare the clinical characteristics, treatment, and 90-day outcomes in patients diagnosed with PE while recovering from COVID-19 in the outpatient setting versus those who were diagnosed with PE while being hospitalized with COVID-19. Data from the international Registro Informatizado de Enfermedad TromboEmbólica (RIETE) registry were used. The major study outcomes were all-cause death, major bleeding, and venous thromboembolism (VTE) recurrences during the first 90 days after PE. From March 2020 to March 2021, 737 patients with COVID-19 experienced acute PE. Of these, 340 (46%) were recovering from COVID-19 as outpatients (267 patients who had been treated at home for COVID-19 and 73 discharged after being hospitalized with COVID-19). Compared with inpatients with COVID-19, those recovering in the outpatient setting upon PE were less likely to be men (odds ratio [OR]: 0.54; 95% confidence interval [CI]: 0.40-0.72) and less likely to have hypertension (OR: 0.55; 95% CI: 0.41-0.74) or diabetes (OR: 0.51; 95% CI: 0.33-0.76). At 90-day follow-up, eight patients (none recovering from COVID-19 as outpatient vs. 2.4% of inpatients with COVID-19) developed recurrent VTE, 34 (1.9 vs. 7.9%) had major bleeding, and 128 (10 vs. 24%) died. On multivariable analysis, inpatients with COVID-19 were at a higher risk of major bleeding (adjusted hazard ratio [HR]: 6.80; 95% CI: 1.52-30.4) or death (adjusted HR: 2.24; 95% CI: 1.40-3.58). In conclusion, using a large multinational registry of patients with COVID-19 who experienced PE, thromboembolic episodes occurring in those recovering from COVID-19 as outpatients were associated with less ominous outcomes than inpatients with COVID-19.

To Anticoagulate or Not to Anticoagulate in COVID-19: Lessons after 2 Years

A hypercoagulable state associated with coronavirus disease 2019 (COVID-19) has been well documented and is believed to be strongly supported by a proinflammatory state. The hypercoagulable state in turn results in increased incidence of arterial and venous thromboembolism (VTE) seen in hospitalized COVID-19 when compared with hospitalized non-COVID-19 patient cohorts. Moreover, patients with arterial or VTE and COVID-19 have higher mortality compared with COVID-19 patients without arterial or VTE. Prevention of arterial or VTE thus remains an essential question in the management of COVID-19 patients, especially because of high rates of reported microvascular and macrovascular thrombosis. This has prompted multiple randomized control trials (RCTs) evaluating different anticoagulation strategies in COVID-19 patients at various stages of the disease. Herein, we review findings from RCTs in the past 2 years of antithrombotic therapy in critically ill hospitalized patients, noncritically ill hospitalized patients, patients postdischarge from the hospital, and outpatients. RCTs in critically ill patients demonstrated therapeutic dose anticoagulation does not improve outcomes and has more bleeding than prophylaxis dose anticoagulant in these patients. Trials in noncritically ill hospitalized patients showed a therapeutic dose anticoagulation with a heparin formulation might improve clinical outcomes. Anticoagulation with a direct oral anticoagulant posthospital discharge may improve outcomes, although there is a large RCT in progress. Nonhospitalized COVID-19 patients have an insufficient burden of events to be candidates for antithrombotic therapy. Anticoagulation in pregnant and lactating patients with COVID-19, as well as antiplatelet therapy for COVID-19, is also reviewed.

COVID-19 Thrombotic Complications and Therapeutic Strategies

Shortly after the emergence of coronavirus disease 2019 (COVID-19) in late 2019, clinicians rapidly recognized an apparent association between the disease and both arterial and venous thrombotic complications, which was confirmed in epidemiologic studies. Based on these data, hospitals empirically developed and implemented protocols with different strategies for anticoagulation of hospitalized COVID-19 patients. Subsequent randomized controlled trials (RCTs) clarified the role of anticoagulation in patients hospitalized with COVID-19 and recently discharged from the hospital. In this review, we discuss the epidemiology and pathophysiology of thrombosis in patients with COVID-19, observational comparative effectiveness analyses that provided hints of a benefit from anticoagulation, and finally the RCTs that established which patients with COVID-19 benefit from treatment-dose anticoagulation. These RCTs have demonstrated that hospitalized, noncritically ill patients with COVID-19 benefit from treatment-dose anticoagulation, but patients who are hospitalized and critically ill, discharged from the hospital, or not hospitalized do not benefit.

Enoxaparin Posology According to Prothrombotic Status and Bleeding Risk in Hospitalized Patients with SARS-CoV-2 Pneumonia

Some patients with COVID-19 have complex hypercoagulable abnormalities that are related to mortality. The optimal dosage of low molecular weight heparin in hospitalized patients with SARS-CoV-2 pneumonia is still not clear. Our objective is to evaluate the effects of adapting the dosage of low molecular weight heparin to thrombotic and bleeding risk scales in this setting. We performed a cohort, retrospective, observational, and analytical study at the Hospital Universitario of Jerez de la Frontera, with patients admitted with SARS-CoV-2 pneumonia from 1 October 2020 to 31 January 2021. They were classified according to whether they received prophylactic, intermediate, or therapeutic doses of enoxaparin. The primary endpoint was intrahospital mortality. Secondary endpoints were the need for invasive ventilation, thromboembolic events, bleeding, and the usefulness of thrombotic and bleeding scales. After binary logistic regression analysis, considering confounding variables, it was found that the use of enoxaparin at therapeutic doses was associated with lower mortality during admission compared to prophylactic and intermediate doses (RR 0.173; 95% CI, 0.038-0.8; p = 0.025). IMPROVE bleeding risk score correlated with a higher risk of minor bleeding (RR 1.263; 95% CI, 1.105-1.573; p = 0.037). In adult hospitalized patients with SARS-CoV-2 pneumonia presenting elevated D-dimer and severe proinflammatory state, therapeutic doses of enoxaparin can be considered, especially if bleeding risk is low according to the IMPROVE bleeding risk score.

Efficacy and safety of two heparin regimens for prevention of venous thromboembolism in hospitalized patients with COVID-19: a meta-analysis

Venous thromboembolism (VTE) is common in patients with coronavirus disease-2019 (COVID-19). The optimal heparin regimen remains unknown and should balance thromboembolic and bleeding risks. The aim of this study was to evaluate the efficacy and safety of standard or higher heparin regimens for the prevention of VTE in patients hospitalized due to COVID-19. We performed a systematic literature search; studies reporting on hospitalized patients with COVID-19 who received standard heparin prophylaxis vs. high (intermediate or therapeutic) heparin regimens were included if outcome events were reported by treatment group and more than 10 patients were included. Primary study outcome was in-hospital VTE. Secondary study outcomes were major bleeding (MB), all-cause death, fatal bleeding and fatal pulmonary embolism. Overall, 33 studies (11,387 patients) were included. Venous thromboembolic events occurred in 5.2% and in 8.2% of patients who received heparin prophylaxis with at high-dose or standard-dose, respectively (RR 0.71, 95% CI 0.55-0.90, I2 48.8%). MB was significantly higher in patients who received high- compared to the standard-dose (4.2% vs 2.2%, RR 1.94, 95% CI 1.47-2.56, I2 18.1%). Sub-analyses showed a slight benefit associated with high-dose heparin in patients admitted to non-intensive care unit (ICU) but not in those to ICU. No significant differences were observed for mortality outcomes. Heparin prophylaxis at high-dose reduces the risk of VTE, but increased the risk of MB compared to the standard-dose. No clinical benefit for heparin high-dose was observed for ICU setting, but its role in the non-ICU deserves further evaluation. PROSPERO registration number: CRD42021252550.

Thrombosis questions from the inpatient wards

The multifaceted pathophysiologic processes that comprise thrombosis and thromboembolic diseases take on a particular urgency in the hospitalized setting. In this review, we explore 3 cases of thrombosis from the inpatient wards: purpura fulminans, cancer-associated thrombosis with thrombocytopenia, and coronavirus disease 2019 (COVID-19) and the use of dose-escalated anticoagulation therapy and antiplatelet agents. We discuss the evaluation and management of purpura fulminans and the roles of plasma transfusion, protein C and antithrombin replacement, and anticoagulation in treating this disease. We present a framework for evaluating the etiologies of thrombocytopenia in cancer and review 2 strategies for anticoagulation management in patients with cancer-associated thrombosis and thrombocytopenia, including recent prospective data supporting the use of dose-modified anticoagulation based on platelet count. Last, we dissect the major clinical trials of therapeutic- and intermediate-dose anticoagulation and antiplatelet therapy in hospitalized patients with COVID-19, reviewing key recommendations from consensus guidelines while highlighting ways in which institutional and patient-tailored practices regarding antithrombotic therapies in COVID-19 may differ. Together, the cases highlight the diverse and dramatic presentations of macro- and microvascular thrombosis as encountered on the inpatient wards.

Colchicine and the combination of rivaroxaban and aspirin in patients hospitalised with COVID-19 (ACT): an open-label, factorial, randomised, controlled trial

BACKGROUND

COVID-19 disease is accompanied by a dysregulated immune response and hypercoagulability. The Anti-Coronavirus Therapies (ACT) inpatient trial aimed to evaluate anti-inflammatory therapy with colchicine and antithrombotic therapy with the combination of rivaroxaban and aspirin for prevention of disease progression in patients hospitalised with COVID-19.

METHODS

The ACT inpatient, open-label, 2 × 2 factorial, randomised, controlled trial was done at 62 clinical centres in 11 countries. Patients aged at least 18 years with symptomatic, laboratory confirmed COVID-19 who were within 72 h of hospitalisation or worsening clinically if already hospitalised were randomly assigned (1:1) to receive colchicine 1·2 mg followed by 0·6 mg 2 h later and then 0·6 mg twice daily for 28 days versus usual care; and in a second (1:1) randomisation, to the combination of rivaroxaban 2·5 mg twice daily plus aspirin 100 mg once daily for 28 days versus usual care. Investigators and patients were not masked to treatment allocation. The primary outcome, assessed at 45 days in the intention-to-treat population, for the colchicine randomisation was the composite of the need for high-flow oxygen, mechanical ventilation, or death; and for the rivaroxaban plus aspirin randomisation was the composite of major thrombosis (myocardial infarction, stroke, acute limb ischaemia, or pulmonary embolism), the need for high-flow oxygen, mechanical ventilation, or death. The trial is registered at www.

CLINICALTRIALS

gov, NCT04324463 and is ongoing.

FINDINGS

Between Oct 2, 2020, and Feb 10, 2022, at 62 sites in 11 countries, 2749 patients were randomly assigned to colchicine or control and the combination of rivaroxaban and aspirin or to the control. 2611 patients were included in the analysis of colchicine (n=1304) versus control (n=1307); 2119 patients were included in the analysis of rivaroxaban and aspirin (n=1063) versus control (n=1056). Follow-up was more than 98% complete. Overall, 368 (28·2%) of 1304 patients allocated to colchicine and 356 (27·2%) of 1307 allocated to control had a primary outcome (hazard ratio [HR] 1·04, 95% CI 0·90-1·21, p=0·58); and 281 (26·4%) of 1063 patients allocated to the combination of rivaroxaban and aspirin and 300 (28·4%) of 1056 allocated to control had a primary outcome (HR 0·92, 95% CI 0·78-1·09, p=0·32). Results were consistent in subgroups defined by vaccination status, disease severity at baseline, and timing of randomisation in relation to onset of symptoms. There was no increase in the number of patients who had at least one serious adverse event for colchicine versus control groups (87 [6·7%] of 1304 vs 90 [6·9%] of 1307) or with rivaroxaban and aspirin versus control groups (85 [8·0%] vs 91 [8·6%]). Among patients assigned to colchicine, 8 (0·61%) had adverse events that led to discontinuation of study drug, mostly gastrointestinal in nature. 17 (1·6%) patients assigned to the combination of rivaroxaban and aspirin had bleeding compared with seven (0·66%) of those allocated to control (p=0·042); the number of serious bleeding events was two (0·19%) versus six (0·57%), respectively (p=0·18). No patients assigned to rivaroxaban and aspirin had serious adverse events that led to discontinuation of study drug.

INTERPRETATION

Among patients hospitalised with COVID-19, neither colchicine nor the combination of rivaroxaban and aspirin prevent disease progression or death.

FUNDING

Canadian Institutes for Health Research, Bayer, Population Health Research Institute, Hamilton Health Sciences Research Institute, Thistledown Foundation.

TRANSLATIONS

For the Portuguese, Russian and Spanish translations of the abstract see Supplementary Materials section.

Clinical and laboratory factors associated with mortality among hospitalized patients with COVID-19 infection in Lebanon: A multicenter study

BACKGROUND

With the dire economic situation in Lebanon, many of the basic resources of the hospitals needed to help fight COVID-19 infections are not available. In this paper, we studied the possible factors associated with increased mortality in a sample of Lebanese adults enrolled in three hospitals.

METHOD

In this retrospective cohort study, we analyzed data from 416 adults hospitalized in three institutions for a COVID-19 infection, from the opening of the COVID unit until their closure (period extending from March 2020 to June 2021). We used multivariate analyses to assess potential factors associated with COVID-19 mortality: gender, age, the presence of underlying medical conditions, and some medication taken during hospitalization.

RESULTS

Using variables related to baseline characteristics entered as independent variables, acute kidney injury (aOR = 4.057) and older age (aOR = 1.053) were associated with a higher probability of death. After adjusting baseline characteristics and factors related to admission entered as independent variables, enoxaparin intake (aOR = 0.435) was significantly associated with a lower probability of death, whereas old age (aOR = 1.049) and ventilation (aOR = 1.2) were significantly associated with higher odds of death. When all variables that showed significance in bivariate analysis were entered, old age (aOR = 1.243) and highest PaCO2 during hospitalization (aOR = 1.192) were significantly associated with higher mortality. With a weak effect, atrial fibrillation, COPD, and higher leucocyte counts on admission were significantly associated with higher odds of death.

CONCLUSION

These findings could help us prevent severe diseases in patients with several comorbidities and adjust therapeutic care to improve future outcomes. More studies should compare the outcome of different COVID-19 strains as well as the impact of vaccination on those with multiple comorbidities, especially on the mortality rate culminating from disease complications.

Anticoagulation in COVID-19 patients - An updated systematic review and meta-analysis

BACKGROUND

Thromboembolic events are common complications of COVID-19. Clinical study results on safety and efficacy of anticoagulation in COVID-19 are controversial.

MATERIAL AND METHODS

This report updates our systematic review and random-effects meta-analysis on randomized controlled trials (RCTs) comparing standard prophylactic anticoagulation and intermediate or therapeutic anticoagulation in COVID-19 patients. We searched eligible studies for the update up to 4 February 2022 by weekly monitoring of RCTs in the Cochrane COVID-19 Study Register. Certainty of evidence was assessed using GRADE (Grading of Recommendations Assessment, Development and Evaluation).

RESULTS

For this update we included five new trials; a total of 13 RCTs with 7364 patients. Certainty of evidence was very low to low. We are uncertain whether low-dose prophylactic anticoagulation is favoured over placebo or no anticoagulation in the outpatient- or post-discharge-setting. In hospitalized patients with moderate and severe COVID-19, intermediate-dose anticoagulation may have little or no effect on thrombotic events or death (RR 1.03, 95 % CI 0.86-1.24), but may increase severe bleeding non-significantly (RR 1.48, 95 % CI 0.53-4.15). Therapeutic-dose anticoagulation may decrease thrombotic events or deaths in hospitalized patients with moderate COVID-19 (RR 0.64, 95 % CI 0.38-1.07; fixed-effect model RR 0.72, 95 % CI 0.57-0.91), but may have little or no effect in patients with severe disease (RR 0.98, 95 % CI 0.86-1.12). With therapeutic-dose anticoagulation, the risk of major bleeding may increase regardless of COVID-19 severity (RR 1.78, 95 % CI 1.15-2.74).

CONCLUSIONS

Hospitalized, moderately ill COVID-19 patients may benefit from therapeutic-dose anticoagulation, while critically ill patients may not. Risk of major bleeding must be considered.

Anticoagulation and Antiplatelet Therapy for Prevention of Venous and Arterial Thrombotic Events in Critically Ill Patients With COVID-19: COVID-PACT

BACKGROUND

The efficacy and safety of prophylactic full-dose anticoagulation and antiplatelet therapy in critically ill COVID-19 patients remain uncertain.

METHODS

COVID-PACT (Prevention of Arteriovenous Thrombotic Events in Critically-ill COVID-19 Patients Trial) was a multicenter, 2×2 factorial, open-label, randomized-controlled trial with blinded end point adjudication in intensive care unit-level patients with COVID-19. Patients were randomly assigned to a strategy of full-dose anticoagulation or standard-dose prophylactic anticoagulation. Absent an indication for antiplatelet therapy, patients were additionally randomly assigned to either clopidogrel or no antiplatelet therapy. The primary efficacy outcome was the hierarchical composite of death attributable to venous or arterial thrombosis, pulmonary embolism, clinically evident deep venous thrombosis, type 1 myocardial infarction, ischemic stroke, systemic embolic event or acute limb ischemia, or clinically silent deep venous thrombosis, through hospital discharge or 28 days. The primary efficacy analyses included an unmatched win ratio and time-to-first event analysis while patients were on treatment. The primary safety outcome was fatal or life-threatening bleeding. The secondary safety outcome was moderate to severe bleeding. Recruitment was stopped early in March 2022 (≈50% planned recruitment) because of waning intensive care unit-level COVID-19 rates.

RESULTS

At 34 centers in the United States, 390 patients were randomly assigned between anticoagulation strategies and 292 between antiplatelet strategies (382 and 290 in the on-treatment analyses). At randomization, 99% of patients required advanced respiratory therapy, including 15% requiring invasive mechanical ventilation; 40% required invasive ventilation during hospitalization. Comparing anticoagulation strategies, a greater proportion of wins occurred with full-dose anticoagulation (12.3%) versus standard-dose prophylactic anticoagulation (6.4%; win ratio, 1.95 [95% CI, 1.08-3.55]; P=0.028). Results were consistent in time-to-event analysis for the primary efficacy end point (full-dose versus standard-dose incidence 19/191 [9.9%] versus 29/191 [15.2%]; hazard ratio, 0.56 [95% CI, 0.32-0.99]; P=0.046). The primary safety end point occurred in 4 (2.1%) on full dose and in 1 (0.5%) on standard dose (P=0.19); the secondary safety end point occurred in 15 (7.9%) versus 1 (0.5%; P=0.002). There was no difference in all-cause mortality (hazard ratio, 0.91 [95% CI, 0.56-1.48]; P=0.70). There were no differences in the primary efficacy or safety end points with clopidogrel versus no antiplatelet therapy.

CONCLUSIONS

In critically ill patients with COVID-19, full-dose anticoagulation, but not clopidogrel, reduced thrombotic complications with an increase in bleeding, driven primarily by transfusions in hemodynamically stable patients, and no apparent excess in mortality.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04409834.