Highlights
The administration of heparin was associated with lower mortality in patients admitted with Covid-19.
Our findings support that there is a thrombotic component in the development of respiratory distress for these patients.
The positive effect of heparin seems consistent and its use, when indicated, could be considered in clinical settings.
Randomized controlled trials are necessary to complement observational studies, and assess the causal associations between heparin, in different therapeutic regimes, and clinical outcomes.
Heparin is easy to administer, its use in ambulatory patients, to prevent admissions, or reduce their duration, could also be considered by clinicians and future researchers.