Original Article The effectiveness of early anticoagulant treatment in Covid-19 patients Yakup Arslan 1 , Gulden Yilmaz 2 , Deniz Dogan 1 , Mine Hasirci 2 , Hatice Cetindogan 1 , Nesrin Ocal 1 , Umit Savasci 2 , Gonca Fidan 2 and Canturk Tasci 1 Abstract Objectives: Coronavirus disease 2019 (Covid-19) is an emerging, fast-spreading and worldwide infectious disease that would be deteriorated with the precipitation of systemic or local thrombosis. The aim of current study was evaluating the effects of early anticoagulant treatment in hospitalized Covid-19 patients. Method: The present retrospective and comparative cohort study investigated 413 hospitalized Covid-19 patients treated with or without Low Molecular Weight Heparin (LMWH) (n ¼ 187 and 226, respectively) in the Covid Clinics of Gulhane Education and Research Hospital in Ankara, Turkey, between March 18 and May 03, 2020. The treatment groups were consisted of the patients evaluated before and after The Covid-19 Treatment Guide update on April 12, 2020 that included the anticoagulant treatment thereafter. Results: The mean age of all 413 patients (204 male and 209 female) at disease onset was 50.6 Æ 16.7 years. The LMWH-treated patients had significantly higher coagulation markers such as d-dimer and platelet count than LMWH- untreated patients (p values < 0.05). The inflammatory markers, ferritin, interleukin-6 and procalcitonin were signifi- cantly increased in LMWH-untreated patients (p values < 0.05). The presence of any comorbidity was significantly more common in LMWH-treated patients compared to LMWH-untreated group (39.6% vs 19.9%, respectively; p < 0.001). Hypertension and diabetes mellitus were the most frequent comorbidities in both groups. The number of intensive care unit (ICU) transfer and longer length of hospital stay were more commonly observed in LMWH-untreated patients (p values <0.05). Conclusions: Early anticoagulant treatment with relatively higher doses of LMWH may improve the clinical outcome of Covid-19 patients and shorten the length of hospital stay. Keywords Covid-19 disease, infectious disease, anticoagulation, heparin, thrombosis Introduction The novel severe acute respiratory syndrome coronavi- rus 2 (SARS-CoV2) causes coronavirus disease 2019 (Covid-19) that was first reported in Wuhan, Hubei Province in January 2020. It has quickly become an emerging, serious, fast-spreading, and worldwide health disaster. Covid-19 has a high mortality rate that was reported as high as 8%. Until June 2020, 529.601 of people died among 11.219.696 infected cases in 213 different countries around the world. 1 Mostly the pulmonary system was defined as the main target of SARS-CoV2, but the mortality concept of this disease presented with a more severe and systemic disease including shock, multi organ failure, pyrexia resistant to treatment, and acute lung injury with acute respiratory distress syndrome (ARDS). 2 The coagulation abnormalities that reported in most of the severe Covid-19 patients showed significant differences from the systemic coagulopathies associated with severe infections, such as disseminated intravascular coagula- tion (DIC) or thrombotic microangiopathy. 3 Substantial rate of mortality has been attributed to the abnormal coagulopathy in Covid-19 patients. 4 1 Department of Pulmonology, Gulhane Education and Research Hospital, University of Health Sciences, Ankara, Turkey 2 Department of Infectious Disease, Gulhane Education and Research Hospital, University of Health Sciences, Ankara, Turkey Corresponding author: Yakup Arslan, Department of Pulmonology, Gulhane Education and Research Hospital, University of Health Sciences, Ankara, Turkey. Email: yakuparslan75@yahoo.com Phlebology 0(0) 1–8 ! The Author(s) 2020 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/0268355520975595 journals.sagepub.com/home/phl