Respiratory viral infections do not increase risk of venous thromboembolism

BackgroundA major concern in emergency departments is whether acute respiratory illness (ARI) is associated with increased risk of venous thromboembolism (VTE). MethodsThis prospective cohort study includes ARI patients from the 91-hospital, U.S. CDC- sponsored Respiratory Virus Laboratory Emergency Department Network Surveillance (RESP-LENS) program from January 2022 to June 2023. We calculated incidence rates and used multivariable regression models to test the null hypothesis that there is no association between the results or absence of laboratory viral testing and the risk of new onset VTE within 30-days. FindingsOut of 620,303 ARI encounters, 65% underwent laboratory viral testing; 13% tested positive for COVID and 3%-4% tested positive for influenza-A and/or RSV. The 30-day VTE incidence rate was 0.70% among unique first patient encounters and 0.82% overall. The highest VTE incidence rate occurred among viral test negative patient encounters (1.13% [95%CI 1.08%-1.19%]) and the lowest VTE rate occurred among patients who tested positive for COVID, influenza-A or RSV, or who did not undergo viral testing (95%CI 0.09%-0.86%). In adjusted models, only among patients receiving any ICU care was fluA associated with heightened VTE risk. New VTE was associated with increased 30-day mortality risk (RR 2.7, 95%CI 2.3-3.2), but there was no difference in 30-day mortality risk among VTE patients grouped by the results of viral testing (interaction p > 0.05). ConclusionIn the U.S. from January 2022 to June 2023, laboratory confirmed viral infection was not associated with increased risk of short-term VTE diagnosis or death among patients seeking emergency care.