At the end of 2019, an outbreak of severe respiratory infection known as COVID-19 has rapidly spread across the globeSeveral therapies to treat COVID-19 are currently under investigation to improve patient outcomes across the disease spectrum. Many of these therapies have been anecdotally in clinical practice but evidence on the efficacy is limited. One of these promising treatments was therapeutic parenteral anticoagulation with heparin. To undertake a formal assessment of the efficacy and safety of therapeutic parenteral anticoagulation with heparin, an international, Bayesian, multi-platform trial was undertaken including the Antithrombotic Therapy to Ameliorate Complications of Covid-19 (ATTACC) trial and the Accelerating Covid-19 Therapeutic Interventions and Vaccines (ACTIV-4) Trial. These trials evaluated the efficacy of therapeutic-dose parenteral heparin versus usual care in hospitalized COVID-19 using a Bayesian response adaptive design. The primary analysis for ATTACC/ACTIV-4 trials has been completed, alongside data from a third platform, indicating the therapeutic parenteral anticoagulation with heparin was effective at increasing the probability of survival and the number of organ-support free days. The purpose of this project is to undertake a range of secondary analyses using the data from ATTACC/ACTIV4 trials to further explore the impact of therapeutic parenteral anticoagulation with heparin on hospitalized patients with COVID-19.