Heparin in COVID-19 patients is associated with reduced in-hospital mortality: the multicentre Italian CORIST Study

https://doi.org/10.1055/a-1347-6070

In a retrospective observational study, 2,574 unselected patients hospitalised in 30 clinical centres in Italy from February 19, 2020 to May 23, 2020 with laboratory-confirmed SARS-CoV-2 infection, were analysed. The primary end-point in a time-to event analysis was in-hospital death, comparing patients who received heparin (low-molecular weight heparin (LMWH) or unfractionated heparin (UFH)) with patients who did not. We used multivariable Cox proportional-hazards regression models with inverse probability for treatment weighting by propensity scores.  Out of 2,574 COVID-19 patients, 70.1% received heparin. LMWH was largely the most used formulation (99.5%). Death rates for patients receiving heparin or not were 7.4 and 14.0 per 1,000 person-days, respectively. After adjustment for propensity scores, we found a 40% lower risk of death in patients receiving heparin (HR=0.60; 95%CI: 0.49 to 0.74; E-value=2.04). This association was particularly evident in patients with a higher severity of disease or strong coagulation activation.  In-hospital heparin treatment was associated with lower mortality, particularly in severely ill COVID-19 patients and in those with strong coagulation activation.