Results
Of the 1316 patients who were hospitalized with proven COVID-19 between
1th of March and 31st of May 2020, 239 patients were
excluded because of reasons depicted in Figure 1. Of the 1154 patients
included in this study, 92 (8%) used VKA and 98 (8%) used DOAC, and
964 (84%) patients did not use therapeutic anticoagulation prior to
COVID-19 diagnosis. All patients in the exposed group were continued on
therapeutic anticoagulation during hospitalization. Among patients who
did not use therapeutic anticoagulation prior to admission, 856 (89%)
received prophylactic LMWH during hospitalization. COVID-19 was
confirmed by a positive PCR test in 1124 (97%) patients or considered
confirmed by clinical features in combination with a CT scan with a very
high level of suspicion (CO-RADS 5) in 30 (3%) patients.
Baseline patient characteristics are shown in table 1. Patients who used
therapeutic anticoagulation prior to hospitalization were older, more
likely of male sex, and more likely to have cardiovascular comorbidities
or a no-ICU policy compared to patients who did not use prior
therapeutic anticoagulation. Subsequent propensity score matching
retained 164 (86%) patients who used prior therapeutic anticoagulation
and 410 unexposed patients. The main covariates were balanced between
the groups after the propensity score matching (table 1).
The results from the total cohort and the propensity score-matched
analysis on the associations between therapeutic anticoagulation use and
the dichotomous outcomes are presented in table 2A. In the crude total
cohort analysis, therapeutic anticoagulation use was associated with an
increased risk of mortality and decreased risks of ICU admission,
mechanical ventilation, and PE. In the propensity score-matched
analyses, however, no associations between therapeutic anticoagulation
use and the outcomes were observed, except for a decreased risk of PE
among patient with therapeutic anticoagulation (RR 0∙19 (95% CI
0∙05-0∙80)) (Table 2, supplementary Figure S2). In addition, therapeutic
anticoagulation use was not associated with length of hospital stay
(table 2B).
Similar to the primary analysis, no associations were found between VKA
or DOAC use prior to admission and COVID-19 related clinical outcome
parameters after propensity score matching (see tables S1-S6, in the
online supplement).