Association between Heparin Dose and 6-Week Mortality in Patients with COVID-19

BACKGROUND: Severe forms of SARS-CoV-2 infections are associated with high rates of thromboembolic complications. Professional societies and expert consensus reports have recommended anticoagulants for COVID-19 hospitalized patients. Our study aimed to compare the effect of therapeutic, intermediate and prophylactic doses of heparin on 6-week survival in patients hospitalized for COVID-19. METHODS: The study sample is a French cohort of COVID-19 patients hospitalized between Feb 25th and Apr 30th 2020. Patients were assigned to one of 3 anticoagulation dose groups based on the maximum dose they received for at least three days (prophylactic, intermediate or therapeutic). The main outcome was survival up to 42 days after hospital admission. Multivariate Cox regression models were performed to adjust analyses for confounding factors. RESULTS: A total of 323 patients were included. The mean age of the study sample was 71.6 ± 15 years, and 56.3% were men. Treatment with the intermediate versus prophylactic dose of anticoagulation (HR = 0.50, 95%CI = [0.26; 0.99], p = 0.047) and with therapeutic versus prophylactic dose (HR = 0.58 95%CI = [0.34; 0.98], p = 0.044) was associated with a significant reduction in 6-week mortality, after adjustment for potential confounding factors. Comparison of therapeutic versus intermediate doses showed no significant difference in survival. CONCLUSIONS: Our results reported a significant positive effect of intermediate and therapeutic doses of heparin on 6-week survival for hospitalized COVID-19 patients compared with a prophylactic dose.