Thrombotic Events in Covid-19: Incidence and their Association with Lab Parameters, Vaccination Status and Mortality

Background & Objectives: Major arterial or venous thrombotic complications occur frequently with COVID-19. This risk seems to be present despite no known underlying thrombophilia and even adequate anticoagulation does not diminish its risk. Whilst pulmonary embolism may seem to be the most common thrombotic complication, others may also occur. A vaccination link to thrombotic events in COVID-19 has not been studied to the best of our knowledge. Methods: In this retrospective cross-sectional study we determined the incidence of total thrombotic events, individual Venous Thromboembolisms (VTE) and Arterial Thromboembolisms (ATE) that occurred in patients requiring ICU admission for COVID-19 in one of Bahrain’s main COVID ICU facilities for a period of 6 months. We also aim to determine mortality rate in this group of patients, links with specific baseline characteristics, laboratory parameters and patient vaccination status. Results: We studied 1597 patients over 6 months, 6% of patients were found to have VTE or ATE with a cumulative incidence of 6.5% thrombotic events. Elevated D dimer >1 was associated with an increased risk of thrombosis and an increased risk of mortality. There was a higher risk of thrombotic events in unvaccinated individuals. All-cause mortality in COVID-19 patients complicated with thrombosis and mortality solely secondary to thrombotic event were both significantly higher in unvaccinated individuals. Conclusions: Based on the findings of this study, unvaccinated individuals are at significantly higher risk of developing thrombotic events. This will assist in enabling physicians to lower their threshold of diagnosing such events. The urgency of lab parameters the swift management of other risk factors and the importance of vaccination against COVID-19 can be further studied.