Acute Thromboembolism in Non-ICU Hospitalized Patients with COVID-19 infection: Examining the Impact of Prior COVID Vaccination

ABSTRACT

Background. Patients hospitalized with severe COVID-19 infections are at risk for acute thromboembolism. There are few data on the impact of vaccines on COVID-associated acute thromboembolism (CA-ATE) in patients hospitalized with COVID-19 infection. Methods. Retrospective cohort of CA-ATE between March 2020 and March 2022 (Torrance Memorial Medical Center, pre-pandemic ATE incidence < 1%). Inclusion criteria were confirmed COVID infection, > 18 years, not admitted to ICU, and standard-dose thromboprophylaxis. Exclusion criteria were pregnancy, partial vaccination, and therapeutic dose anticoagulation. Primary outcome was CA-ATE incidence identified by routine clinical testing. We performed a multiple logistic regression for CA-ATE risk factors. Results. Of 3,218 hospitalized COVID-19 patients, 1,428 patients were included;185 were vaccinated (13%) and 1,243 unvaccinated (87%). Vaccinated status was associated with older age, diabetes, heart failure, and chronic kidney disease (p< 0.01). CA-ATE was noted in 7.0% (2.2% deep vein thrombosis (DVT), 0.5% pulmonary embolism (PE), 2.7% myocardial infarction (MI), 1.6% Ischemic stroke (IS)) in the vaccinated and 3.9% (2.7% DVT, 1.5% PE, 1.0% MI, 0.8% IS) in the unvaccinated. In our multivariate model, we found no significant difference in incident CA-ATE between vaccinated and unvaccinated (7.0% vs 3.9%, adj OR=1.35, [95% CI 0.67-2.58], p=0.38). CA-ATE was associated with older age (68 vs 61 years, OR=1.03, [95% CI 1.01-1.05], p=0.01) and heart failure (24% vs 7%, OR=2.84, [95% CI 1.35-6.00], p=0.006). No significant difference was seen in mortality (3.8% vs 4.8%, OR=0.79, [95% CI 0.35-1.69], p=0.56), CRP AUC24hr (5.7 vs 4.7, p=0.18), or D-dimer AUC24hr (596 vs 653, p=0.77) between vaccinated and unvaccinated patients. Conclusion. Adult, non-ICU, hospitalized, COVID-19 patients are at high risk for ATE. We found no association between vaccination status and ATE, but older age and congestive heart failure were predictive in this population. Decisions to anticoagulate non-ICU patients hospitalized with acute COVID-19 infections may not need to consider COVID vaccination status in as part of medical decision making, but may instead need to focus on underlying, high-risk, co-morbidities.