The use of heparin has been shown to decrease the mortality in hospitalized patients with severe COVID-19. The aim of our study was to evaluate the clinical impact of venous thromboembolism prophylaxis with fondaparinux versus enoxaparin among 100 hospitalized COVID-19 patients. The incidence of pulmonary embolism, deep venous thrombosis, major bleeding (MB), clinically relevant non-MB, acute respiratory distress syndrome, and in-hospital mortality was compared between patients on fondaparinux versus enoxaparin therapy. The 2 groups were homogeneous for demographic, laboratory, and clinical characteristics. In a median follow-up of 28 (IQR: 12–45) days, no statistically significant difference in venous thromboembolism (14.5% vs. 5.3%; P = 0.20), MB and clinically relevant non-MB (3.2% vs. 5.3%, P = 0.76), ARDS (17.7% vs. 15.8%; P = 0.83), and in-hospital mortality (9.7% vs. 10.5%; P = 0.97) has been shown between the enoxaparin group versus the fondaparinux group. Our preliminary results support the hypothesis of a safe and effective use of fondaparinux among patients with COVID-19 hospitalized in internal medicine units.

Background: Since the outbreak of novel coronavirus SARS-CoV2 around the world, great attention has been paid to the effects of such antithrombotic drugs as heparinoids, because they have antiviral action in vitro and antithrombotic actions in vivo. We conducted a retrospective analysis in inpatients with confirmed COVID-19 on the anti-inflammatory and antithrombotic effects of enoxaparin and fondaparinux at prophylactic doses. Methods: This retrospective cohort study used patients with confirmed COVID-19 during the first months of the Italian outbreak from February 18 to April 30, 2020. Our aim was to compare clinical characteristics, prophylactic treatment, markers of inflammation, and thrombotic outcomes in inpatients positive for SARS-CoV2 during hospitalization associated with thromboprophylaxis with enoxaparin (40 mg or 60 mg once daily) or fondaparinux (2.5 mg once daily). Statistical analysis was conducted with using MatLab R2016B and ad hoc functions. Results: There were no significatant differences in clinical characteristics between patients that used enoxaparin or fondaparinux as thromboprophylaxis for SARS-CoV2. No differences were found in D-dimer and fibrinogen levels either, which were used as markers of inflammation during the infection at testing on admission and after 3 weeks.Significant differences in CRP, IL6, and LDH were found in patients after 21 days' treatment. Discussion: Increased levels of fibrinogen and D-dimer in patients with confirmed COVID-19 have been reported in several studies. Our results showed that anti-inflammatory effects of fondaparinux and enoxaparin after 3 weeks of prophylactic treatment were similar when levels of fibrinogen and D-dimer were considered. Furthermore, levels of CRP showed a decrease in patients treated with enoxaparin and fondaparinux, although the decrease in the fondaparinux group seems to be more relevant.

Importance: The use of anticoagulant therapy with heparins decreased mortality in hospitalized patients with severe coronavirus disease 2019 (COVID-19). Even if enoxaparin and fondaparinux have the same clinical indication for venous thromboembolism (VTE) prevention; to date, there are no data about the use of fondaparinux in terms of safety, effectiveness, and impact on clinical prognosis among COVID-19 patients.Objective: To evaluate the safety, effectiveness, and clinical impact of VTE prophylaxis with fondaparinux and enoxaparin among COVID-19 patients hospitalized in internal medicine units.Design, Setting, and Participants: This was a retrospective multicenter observation study, including consecutive symptomatic patients with laboratory-proven COVID-19 admitted to internal medicine units of five Italian hospitals from 15th February to 15th March 2020.Main Outcomes and Measures: The primary safety outcome was the composite of major bleeding and clinically relevant non-major bleeding; the primary effectiveness outcome was the composite of all events classified as pulmonary embolism and deep venous thrombosis. The secondary effectiveness outcome included acute respiratory distress syndrome and all-cause death.Results: Among 120 COVID-19 patients enrolled in the study, 74 were taking enoxaparin (4,000 or 6,000 units/day) and 46 fondaparinux (2.5 units/day). No statistically significant difference in demographic and laboratory and clinical characteristics between the two groups has been shown. During a median follow-up of 32 (interquartile range: 14–51) days, the cumulative incidence rates of VTE and bleeding events on pharmacological thromboprophylaxis with heparins were 19% and 8%, respectively. The incidence of both VTE (6.5 vs. 13.5%; P = 0.36) and bleeding events (6.5 vs. 4.1%; P = 0.68) did not show a significant difference between COVID-19 patients on fondaparinux compared with those on enoxaparin therapy. The regression model for the risk of outcome events according to different VTE prophylaxis drugs did not show significant differences.Conclusions and Relevance: Although these results need confirmation by prospective studies including a larger population, our study provides preliminary evidence of a safe and efficacy use of fondaparinux for VTE prophylaxis in hospitalized COVID-19 patients.

Background. According to recent guidelines, all hospitalized patients with COVID-19 should receive pharmacological prophylaxis for venous thromboembolism (VTE), unless there are specific contraindications. However, the optimal preventive strategy in terms of intensity of anticoagulation for these patients is not well established. Objectives. To investigate the impact of individualized regimens of enoxaparin on the development of VTE and on the risk of major bleeding complications during hospitalization in patients with COVID-19 infection. Methods. All consecutive patients admitted to the medical wards of six Italian hospitals between 15 September and 15 October 2020 with COVID-19 infection of moderate severity were administered enoxaparin in subcutaneous daily doses adjusted to the Padua Prediction Score stratification model: No heparin in patients scoring less than 4, 4000 IU daily in those scoring 4, 6000 IU in those scoring 5, and 8000 in those scoring six or more. Objective tests were performed in patients developing clinical symptoms of deep vein thrombosis and/or pulmonary embolism. Bleeding complications were defined according to the ISTH classification. Results. From the 154 eligible patients, enoxaparin was administered in all: 4000 IU in 73 patients, 6000 IU in 53, and 8000 IU in the remaining 28. During the course of hospitalization, 27 patients (17.5%) died. VTE developed in 14 of the 154 patients (9.1%; 95% CI, 4.6% to 13.6%), and was fatal in 1. Major bleeding complications developed in 35 patients (22.7%; 95% CI, 16.1% to 29.3%), and were fatal in 8. Conclusions. Despite the use of risk-adjusted doses of enoxaparin, the rate of VTE events was consistent with that reported in contemporary studies where fixed-dose low-molecular-weight heparin was used. The unexpectedly high risk of bleeding complications should induce caution in administering enoxaparin in doses higher than the conventional low ones.

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