D-dimer Adjusted Versus Therapeutic Dose Low-molecular-weight Heparin in Patients With COVID-19 Pneumonia

Inclusion Criteria: * All adult (\>18 years) patients from both sexes with COVID-19 pneumonia with positive nucleic acid test for severe acute respiratory syndrome Coronavirus (SARS-CoV-2) hospitalized either in the ward or intensive care unit Exclusion Criteria: * Patients with absolute contraindication of pharmacological thromboprophylaxis and/ anticoagulation * Congenital hemorrhagic disorders * Hypersensitivity to heparin * Personal history of heparin-induced thrombocytopenia * Active major bleeding or conditions predisposing to major bleeding. Major bleeding is defined as fulfilling any one of these three criteria: a) occurs in a critical area or organ (e.g.intracranial, intraspinal, intraocular, retroperitoneal, intra-articular or pericardial, intra-uterine or intramuscular with compartment syndrome), b) causes a fall in haemoglobin level (Hb) of ≥2g/dL in a 24h period, or c) leads to transfusion of 2 or more units of whole blood or red blood cells (13). * Suspected or confirmed bacterial endocarditis * Ongoing or planned therapeutic anticoagulation for any other indication * Platelet count \<50,000/μL within the past 24 hours or Hb level \<8g/dL * Prothrombin time (PT) ≥2 seconds above the upper limit of age-appropriate local reference range within the past 24 hours * Activated partial thromboplastin time (aPTT) ≥4 seconds above the upper limit of age-appropriate local reference range within the past 24 hours * Fibrinogen \<2.0 g/L * Severe renal impairment (CrCl\<30 mL/min) or acute kidney injury * Use of dual antiplatelet therapy * Pregnancy * Unwillingness to consent