Clinical impact of prophylactic anticoagulant treatment with enoxaparin in coronavirus disease 2019 (covid-19) patients

Background and Objectives: COVID-19 patients are at increased risk of venous thromboembolism. The WHO recommends daily prophylactic anticoagulation therapy with low-molecular weight heparins in COVID-19 patients. Our study evaluated the efficacy of a prophylactic therapy with enoxaparin on clinical outcomes in COVID-19 patients. Methods: This is a retrospective analysis of 394 SARS-CoV-2 patients hospitalized from February 21st to March 7th, 2020. In this initial phase of COVID-19 pandemic, only patients at high risk of VTE according to Padua Prediction Score were treated with enoxaparin at prophylactic dosage. Based on these criteria, 229 patients (58%) received enoxaparin (Enoxaparin group, E) and 165 (42%) did not (No-Enoxaparin group, NE). Results: After applying a propensity score matching for age and gender, there were no significant differences between the two groups. During the hospitalization, a significantly higher percentage of patients in E group developed ARDS (162 [70%] vs 87 [53%], p=0.0001) and need for non-invasive ventilation (141 [62%] vs 80 [48%], p=0.01). No significative difference between the two groups was reported about incidence of intubation (20 [9%] in E vs. 19 [11%] in NE group;p=0.362) and pulmonary embolism (17 [7%] vs 5 [3%], p=0.389). In-hospital death occurred in 47 (20%) patients treated with enoxaparin and in 26 (16%) untreated patients (p=0.251). No difference on 30-days mortality was found between enoxaparin users and nonusers (7 [3%] vs 9 [5%], p=0.284). Conclusions: Among patients with SARS-CoV-2 infection, a prophylactic therapy with enoxaparin is not associated with prognostic benefit and did not affect in-hospital and 30-days mortality. A risk-adapted approach to escalating the dose of anticoagulation should be considered in selected COVID-19 patients with evidence of coagulopathy.