Background: The first reports of COVID-19 came from Wuhan, China, associated with high rates of mortality and end organ damage1. As the virus rapidly spread across the globe, many large tertiary centers found a strong association between COVID-19 and venous thrombus events. One of the first studies in Italy analyzed blood samples from COVID-19 patients with thromboelastography which revealed that patients with COVID-19 carry higher rates of inflammation, and specifically hypercoagulability.2 Early reports in China revealed that 36% of COVID-19 patients had elevated D-dimers and in May 2020, the American Society of Hematology released evidence that in patients with COVID-19, elevated D-dimers was related to increased mortality.3,4 There is no current national guideline regarding venous thromboembolism (VTE) prophylaxis in COVID-19 patients. As such, we developed this quality improvement project to identify if COVID-19 patients within our hospital system (Legacy Health) are at an increased risk of VTE compared to non-COVID-19 patients. By comparing rates of VTE our goal was to identify a gap in patient care, better understand the role of d-dimer testing and offer a new VTE prophylaxis standard to ultimately provide a higher level of care for our COVID-19 population.
Methods: Using our hospital system (all 6 Legacy Inpatient centers) as our population of interest, we compiled all hospitalized patients who tested positive for COVID between March 25-June 1, 2020. We performed a retrospective analysis to identify how many of these patients had a diagnosed VTE during the same hospitalization with the definition of VTE being pulmonary embolism and deep venous thrombosis. The incidence of VTE was calculated and compared to the average incidence of hospital-acquired VTE in the United States of 0.239%.3 We then evaluated how many COVID-19 positive patients had d-dimers obtained. Patients with positive d-dimer values obtained were then separated into positive VTE, negative VTE and no confirmatory testing categories.
Results: 169 COVID-19 positive patients were identified. Of those, 13 had a confirmed VTE resulting in an observed VTE incidence of 7.69%. We compared the incidence of VTE in Legacy’s COVID-19 patients to the average incidence of VTE in all hospitalized patients as most recently published by the CDC. This revealed a statistically significant increased rate of VTE in COVID-19 positive patients (p-value <0.0001). Of the 169 patients, 69 had d-dimers obtained at some point during their hospitalization. 59 of the 69 d-dimers were elevated with 7 confirmed VTE, 21 negative for VTE and 31 of which confirmatory testing was not completed.
Conclusions: COVID-19 patients do have an increased incidence of VTE compared to the average hospitalized patient. Based the increase in hypercoagulability as well as our data results, the current VTE guidelines within our hospital system should be revised to include COVID-19 infection as a risk factor for VTE. Our hospital system inconsistently orders d-dimer levels and confirmatory testing, making it difficult to use d-dimer levels as an accurate measure of VTE. More national data needs to be obtained before d-dimers can be utilized to guide treatment in COVID-19 patients..