Hospitalized patients with coronavirus disease 2019 (COVID-19) treated with enoxaparin were found to have lower rates of thrombosis, kidney injury, and mortality than patients treated with unfractionated heparin, according to a recent study published in medRxiv.

Although the anticoagulants enoxaparin and unfractionated heparin are currently both being used as treatments to mitigate coagulopathy for patients with COVID-19, data regarding clinical outcomes had not yet been investigated to analyze their efficacy, according to the study. For this reason, the study authors retrospectively analyzed the complete electronic health records of 671 hospitalized patients with COVID-19 who were administered either enoxaparin or unfractionated heparin, but not both.

The results of the study demonstrated that patients who received unfractionated heparin but not enoxaparin had higher rates of mortality, thrombotic events, acute kidney injury, and bacterial pneumonia compared with those administered enoxaparin alone.

Additionally, the authors note that the differences in the rates between the enoxaparin and unfractionated heparin patient cohorts remain statistically significant even after controlling for potential confounding factors, such as demographics, comorbidities, admission diagnosis, initial ICU status, and initial level of oxygen support.

Of the 158 patients in the cohort receiving enoxaparin, 5.6% eventually deceased, compared with 15% in the heparin cohort.

However, treatment with enoxaparin did not significantly decrease the length of time patients were in the hospital, as the mean hospital length of stay for the heparin cohort was 6.9 days, whereas the mean was 5.8 days for the enoxaparin cohort. Additionally, the mean length of stay in the ICU for patients receiving heparin was 1.9 days, compared with 1.1 days for patients receiving enoxaparin.

The authors also assessed the differences in rates among certain types of complications. Specifically, incidence of acute kidney injury occurred at a higher rate in the heparin cohort than the enoxaparin cohort (7.7% vs 1.4%, respectively ) as did bacterial pneumonia (5.6% vs 0%, respectively). However, the authors explained that because of the small cohort sizes, these differences were not statistically significant in consideration of the potential for multiple hypotheses.

According to the authors, these results show there is a need for further studies and trials that could support the development of standards of practice with greater efficacy in the administration of anticoagulants in COVID-19 patients.

Pawlowski C, Venkatakrishnan AJ, Kirkup C, et al. Enoxaparin is associated with lower rates of thrombosis, kidney injury, and mortality than Unfractionated Heparin in hospitalized COVID patients. medRxiv. 2020.