RT Journal Article SR Electronic T1 Prevalence and clinical implication of thrombocytopenia and heparin-induced thrombocytopenia in patients who are critically ill with COVID-19 JF Clinical Medicine JO Clin Med FD Royal College of Physicians SP 403 OP 408 DO 10.7861/clinmed.2022-0054 VO 22 IS 5 A1 Reut Kassif Lerner A1 Dor Lotan A1 Daniel Oren A1 Edward Itelman A1 Yuval Neeman A1 Shahar Dekel A1 Eyal Heller A1 Arsalan Abu-Much A1 Noya Shilo A1 Rami Gilead A1 Evyatar Hubara A1 Meir Mouallem A1 Yael Haviv A1 Alexander Kogan A1 Haim Mayan A1 Itai M Pessach YR 2022 UL http://www.rcpjournals.org/content/22/5/403.abstract AB As the COVID-19 pandemic continues to evolve, different clinical manifestations are better understood and studied. These include various haematologic disorders that have been shown to be associated with increased morbidity and mortality. We studied the prevalence of one unusual manifestation, heparin-induced thrombocytopenia (HIT) and its clinical implications in patients who are severely ill with COVID-19 in a single tertiary centre in Israel. The presence of thrombocytopenia, disseminated intravascular coagulation (DIC) and HIT, and their association with clinical course and outcomes were studied. One-hundred and seven patients with COVID-19 were included. Fifty-seven (53.2%) patients developed thrombocytopenia, which was associated with the worst outcomes (ventilation, DIC and increased mortality). Sixteen (28.0%) patients with thrombocytopenia were positive for HIT, all of which were supported by extracorporeal devices. HIT was independently associated with ventilation days, blood product transfusions, longer hospitalisation and mortality.Platelet abnormalities and HIT are common in patients who are critically ill with COVID-19 and are associated with the worst clinical outcomes. The mechanisms underlying HIT in COVID-19 are yet to be studied; HIT may contribute to the dysregulated immunologic response associated with COVID-19 critical illness and may play a significant part in the coagulopathy seen in these patients. As many patients with COVID-19 require aggressive thromboprophylaxis, further understanding of HIT and the implementation of appropriate protocols are important.