Efficacy of different anticoagulant doses for patients with COVID-19: a systematic review and network meta-analysis

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.

Comparing Therapeutic versus Prophylactic Enoxaparin Therapy in Severe COVID-19 Patients: A Randomized Clinical Trial

Background

Coronavirus disease 2019 (COVID-19) has been associated with a hypercoagulopathy state; however, the efficacy of different anticoagulant regimens in preventing thrombotic events is not clear. We aimed to compare therapeutic versus prophylactic enoxaparin therapy in severe COVID-19 patients.

Methods

In this single-center, open-label, randomized controlled trial, adult patients with severe COVID-19 presentations and an increased D-dimer level of more than 4 times the normal upper limit were randomly assigned to receive either prophylactic or therapeutic dose of enoxaparin. All patients were observed for at least 4 months regarding the overall survival as the primary outcome. Hospitalization duration, the need for intensive care unit (ICU) admission, the need for mechanical ventilation, and major adverse events (MAEs) were also analyzed as the secondary outcomes. Survival analysis was done via Kaplan-Meier curves and the Log-rank test. Cox regression was used, adjusting for baseline variables.

Results

Overall, 237 patients (152 men and 85 women) were randomized to either arm (121 to prophylactic and 116 to therapeutic groups). The mortality rate was 27 (22.3%) and 52 (44.8%) in prophylactic and therapeutic arms, respectively. Prophylactic enoxaparin was associated with better survival in the log-rank test (P < 0.001; HR, 0.42). Additionally, a significantly lower rate of ICU admission, a lower rate of MAEs, and shorter hospitalization were observed in the prophylactic arm (P < 0.001, P = 0.009, and P = 0.028, respectively).

Conclusion

The results of the current study were in favor of anticoagulant treatment with prophylactic doses of enoxaparin. Still, due to the limitations of this paper, we suggest that these findings be treated cautiously.

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.

Failed clinical trials on COVID-19 acute respiratory distress syndrome in hospitalized patients: common oversights and streamlining the development of clinically effective therapeutics

INTRODUCTION

The coronavirus disease 2019 (COVID-19) pandemic has put a strain on global healthcare systems. Despite admirable efforts to develop rapidly new pharmacotherapies, supportive treatments remain the standard of care. Multiple clinical trials have failed due to design issues, biased patient enrollment, small sample sizes, inadequate control groups, and lack of long-term outcomes monitoring.

AREAS COVERED

This narrative review depicts the current situation around failed and success COVID-19 clinical trials and recommendations in hospitalized patients with COVID-19, oversights and streamlining of clinically effective therapeutics. PubMed, EBSCO, Cochrane Library, and WHO and NIH guidelines were searched for relevant literature up to 5 August 2022.

EXPERT OPINION

The WHO, NIH, and IDSA have issued recommendations to better clarify which drugs should be used during the different phases of the disease. Given the biases and high heterogeneity of published studies, interpretation of the current literature is difficult. Future clinical trials should be designed to standardize clinical approaches, with appropriate organization, patient selection, addition of control groups, and careful identification of disease phase to reduce heterogeneity and bias and should rely on the integration of scientific societies to promote a consensus on interpretation of the data and recommendations for optimal COVID-19 therapies.