Prophylactic or therapeutic doses of heparins for COVID-19 infection? A retrospective study

Coronavirus disease 19 (COVID-19) is a global outbreak. COVID-19 patients seem to have relevant coagulative abnormalities, even if they are not typical of disseminated intravascular coagulopathy (DIC) of the kind seen in septicaemia. Therefore, anticoagulant therapy with heparins is increasing in interest for a clinical approach to these patients, particularly if older. Studies comparing if prophylactic doses are more effective than therapeutic ones are still missing.

Data were collected in the Geriatric Section of the Dolo Hospital, ULSS 3 "Serenissima", Venice from 31st March to 01st May 2020. Heparins (calciparin, fondaparinux, enoxaparine) were divided into prophylactic or therapeutic doses. People previously treated with oral anticoagulants were removed. Vital status was assessed using administrative data. Cox's regression analysis, adjusted for potential confounders, was used for assessing the strength of the association between heparins and mortality. The data were reported as hazard ratio (HR) with 95% confidence intervals (CIs).

81 older people (mean age 84.1 years; females = 61.9%) were included. No significant differences in terms of demographic and clinical characteristics emerged between people treated with prophylactic or therapeutic doses, including age, gender, X-rays findings or severity of disease. Therapeutic doses were not associated to a better survival rate (HR 1.06; 95% CI 0.47-2.60; p = 0.89), even after adjusting for 15 confounders related to mortality (HR 0.89; 95% CI 0.30-2.71; p = 0.84).

Our paper indicates that in older people affected by COVID-19 there is no justification for using therapeutic doses instead of prophylactic ones, having a similar impact on mortality risk.