antibiotics Article Beneficial Effects of Anticoagulants on the Clinical Outcomes of COVID-19 Patients Zubia Jamil 1 , Azmat Ali Khan 2 , Samreen Khalid 1 , Muhammad Asghar 3,4 , Khalid Muhammad 5 and Yasir Waheed 6, *   Citation: Jamil, Z.; Khan, A.A.; Khalid, S.; Asghar, M.; Muhammad, K.; Waheed, Y. Beneficial Effects of Anticoagulants on the Clinical Outcomes of COVID-19 Patients. Antibiotics 2021, 10, 1394. https:// doi.org/10.3390/antibiotics10111394 Academic Editor: Albert Figueras Received: 21 October 2021 Accepted: 10 November 2021 Published: 13 November 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Department of Medicine, Foundation University Medical College, Foundation University Islamabad, Islamabad 44000, Pakistan; zubiajamil321@gmail.com (Z.J.); samreendoctor@gmail.com (S.K.) 2 Pharmaceutical Biotechnology Laboratory, Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia; azkhan@ksu.edu.sa 3 Division of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, 17177 Stockholm, Sweden; asghar.muhammad@ki.se 4 Department of Infectious Diseases, Karolinska University Hospital, 17164 Stockholm, Sweden 5 Department of Biology, College of Sciences, United Arab Emirates University, Al Ain 15551, United Arab Emirates; k.muhammad@uaeu.ac.ae 6 Multidisciplinary Lab, Foundation University Medical College, Foundation University Islamabad, Islamabad 44000, Pakistan * Correspondence: yasir_waheed_199@hotmail.com Abstract: (1) Background: Severe coronavirus disease can be complicated by a hypercoagulable state in conjunction with sepsis, increasing the risk of venous thromboembolism. This study aimed to observe the effect of anticoagulants on 30-day high-dependency unit (HDU) outcomes of moderate to severe coronavirus disease 2019 (COVID-19) patients of a tertiary care hospital at Rawalpindi, Pakistan. (2) Methods: A retrospective propensity-based case–control study was carried out to examine COVID-19 patients admitted to the HDU. Patient groups who did and did not receive anticoagulants were labeled as “anticoagulant” and “non-anticoagulant”, respectively. Case–control matching (1:1) was performed via propensity scores (calculated by a regression model). Kaplan–Meier and logrank analyses were used to study survival probability. Single predictors of outcomes were determined by Cox regression analysis. (3) Results: The anticoagulant group had elevated D-dimers, advanced age, more comorbidities and a higher frequency of severe disease compared to the non- anticoagulant group (p < 0.05). Therefore, 47 cases and 47 matched controls were selected based on their propensity scores. The primary endpoint was outcome (survived vs. died). The 30-day in-HDU mortality was 25.5% for cases and 61.7% for controls (p = 0.0004). The median time from admission to death was 16 days for the case group and 7 days for the control group (p < 0.0001). The 30-day mortality was 19.1% for the enoxaparin group and 16.4% for the heparin group (p > 0.05). Enoxaparin (therapeutic and prophylactic doses) and heparin (prophylactic dose) were found to be independent factors affecting the outcomes of these patients (p < 0.001). (4) Conclusions: Anticoagulants play a beneficial role in reducing mortality among COVID-19 patients. Both anticoagulant formulations, enoxaparin (therapeutic and prophylactic doses) and heparin (prophylactic dose), were associated with improving survival among these patients. Keywords: COVID-19; SARS-CoV-2; heparin; enoxaparin; acute respiratory distress syndrome; pulmonary embolism 1. Introduction Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a major public health burden worldwide. It has resulted in a frightening increase in mortality around the world. As of 1 November 2021, over 247 million confirmed cases of COVID-19 have been reported worldwide, includ- Antibiotics 2021, 10, 1394. https://doi.org/10.3390/antibiotics10111394 https://www.mdpi.com/journal/antibiotics