Different Anticoagulant Regimens, Mortality, and Bleeding in Hospitalized Patients with COVID-19: A Systematic Review and an Updated Meta-Analysis

We conducted a systematic review and a meta-analysis to assess the association of anticoagulants and their dosage with in-hospital all-cause mortality in COVID-19 patients. Articles were retrieved until January 8, 2021, by searching in seven electronic databases. The main outcome was all-cause mortality occurred during hospitalization. Data were combined using the general variance-based method on the effect estimate for each study. Separate meta-analyses according to type of COVID-19 patients (hospitalized or intensive care unit [ICU] patients), anticoagulants (mainly heparin), and regimens (therapeutic or prophylactic) were conducted. A total of 29 articles were selected, but 23 retrospective studies were eligible for quantitative meta-analyses. No clinical trial was retrieved. The majority of studies were of good quality; however, 34% did not distinguish heparin from other anticoagulants. Meta-analysis on 25,719 hospitalized COVID-19 patients showed that anticoagulant use was associated with 50% reduced in-hospital mortality risk (pooled risk ratio [RR]: 0.50, 95% confidence interval [CI]: 0.40-0.62; I-2 : 87%). Both anticoagulant regimens (therapeutic and prophylactic) reduced in-hospital all-cause mortality, compared with no anticoagulation. Particularly in ICU patients, the anticoagulant therapeutic regimen was associated with a reduced in-hospital mortality risk (RR: 0.30, 95% CI: 0.15-0.60; I-2 : 58%) compared with the prophylactic one. However, the former was also associated with a higher risk of bleeding (RR: 2.53, 95% CI: 1.60-4.00; I-2 : 65%). Anticoagulant use, mainly heparin, reduced all-cause mortality in COVID-19 patients during hospitalization. Due to the higher risk of bleeding at therapeutic doses, the use of prophylactic dosages of anticoagulant is probably to be preferred in noncritically ill COVID-19 patients.

Automated summary

A systematic review and meta-analysis on the association of anticoagulant use and in-hospital mortality in COVID-19 patients revealed a 50% reduction in mortality risk with anticoagulant use, especially in ICU patients. However, therapeutic anticoagulant regimens were associated with higher bleeding risks. Therefore, prophylactic dosages of anticoagulants may be preferred in noncritically ill patients.