Low molecular weight heparin is useful in adult COVID-19 inpatients. Experience during the first Spanish wave: observational study

Gonzalez-Porras, J. R.; Belhassen-Garcia, M.; Lopez-Bernus, A.; Vaquero-Roncero, L. M.; Rodriguez, B.; Carbonell, C.; Azibeiro, R.; Hernandez-Sanchez, A.; Martin-Gonzalez, J. I.; Manrique, J. M.; Alonso-Claudio, G.; Alvarez-Navia, F.; Madruga-Martin, J. I.; Macias-Casanova, R. P.; Garcia-Criado, J.; Lozano, F.; Moyano, J. C.; Sanchez-Hernandez, M. V.; Sagredo-Meneses, V.; Borras, R.; Bastida, J. M.; Hernandez-Perez, G.; Chamorro, A. J.; Marcos, M.; Martin-Oterino, J. A.

BACKGROUND: The intensity of the thromboprophylaxis needed as a potential factor for preventing inpatient mortality due to coronavirus disease-19 (COVID-19) remains unclear. OBJECTIVE: To explore the association between anticoagulation intensity and COVID-19 survival. DESIGN AND SETTING: Retrospective observational study in a tertiary-level hospital in Spain. METHODS: Low-molecular-weight heparin (LMWH) status was ascertained based on prescription at admission. To control for immortal time bias, anticoagulant use was analyzed as a time-dependent variable. RESULTS: 690 patients were included (median age, 72 years). LMWH was administered to 615 patients, starting from hospital admission (89.1%). 410 (66.7%) received prophylactic-dose LMWH;120 (19.5%), therapeutic-dose LMWH;and another 85 (13.8%) who presented respiratory failure, high D-dimer levels (> 3 mg/l) and non-worsening of inflammation markers received prophylaxis of intermediate-dose LMWH. The overall inpatient-mortality rate was 38.5%. The anticoagulant nonuser group presented higher mortality risk than each of the following groups: any LMWH users (HR 2.1;95% CI: 1.40-3.15);the prophylactic-dose heparin group (HR 2.39;95% CI, 1.57-3.64);and the users of heparin dose according to biomarkers (HR 6.52;95% CI, 2.95-14.41). 3.4% of the patients experienced major hemorrhage. 2.8% of the patients developed an episode of thromboembolism. CONCLUSIONS: This observational study showed that LMWH administered at the time of admission was associated with lower mortality among unselected adult COVID-19 inpatients. The magnitude of the benefit may have been greatest for the intermediate-dose subgroup. Randomized controlled trials to assess the benefit of heparin within different therapeutic regimes for COVID-19 patients are required.