Covid-19 and Risk of Venous Thromboembolism in Ethnically Diverse Populations

Go, Alan S.; Reynolds, Kristi; Tabada, Grace H.; Prasad, Priya A.; Sung, Sue Hee; Garcia, Elisha; Portugal, Cecilia; Fan, Dongjie; Pai, Ashok P.; Fang, Margaret C.

Background Limited existing data suggest the novel coronavirus disease 2019 (Covid-19) may increase risk for venous thromboembolism (VTE) but information from large, ethnically diverse populations with appropriate controls are lacking. Research Question Does the rate of VTE among adults hospitalized with Covid-19 differ from matched hospitalized controls without Covid-19? Study Design and Methods We conducted a retrospective study among hospitalized adults with laboratory-confirmed Covid-19 and hospitalized adults without evidence of Covid-19 matched on age, gender, race/ethnicity, acute illness severity, and month of hospitalization between February-August 2020 from two integrated healthcare delivery systems with 36 hospitals. Outcomes included VTE (deep venous thrombosis or pulmonary embolism ascertained using diagnosis codes combined with validated natural language processing algorithms applied to electronic health records) and death from any cause at 30 days. Fine and Gray hazards regression was performed to evaluate the association of Covid-19 with VTE after accounting for competing risk of death and residual differences between groups, as well as identifying predictors of VTE in patients with Covid-19. Results We identified 6,319 adults with Covid-19 and 6,319 matched adults without Covid-19, with mean (SD) age of 60.0 (17.2) years, 46% women, 53.1% Hispanic, 14.6% Asian/Pacific Islander and 10.3% Black. During 30-day follow-up, 313 validated VTE (160 Covid-19, 153 controls) and 1172 deaths (817 Covid-19, 355 controls) occurred. Adults with Covid-19 had a more than threefold adjusted risk of VTE (adjusted hazard ratio 3.48, 95% Confidence Interval 2.03-5.98) compared with matched controls. Predictors of VTE in Covid-19 patients included age ≥55 years, Black race, prior VTE, diagnosed sepsis, prior moderate or severe liver disease, body mass index ≥40 kg/m2, and platelet count >217 k/mcL. Interpretation Among ethnically diverse hospitalized adults, Covid-19 infection increased the risk of VTE, and selected patient characteristics were associated with higher thromboembolic risk in the setting of Covid-19.