Incidence of Thrombosis and Associated Risk Factors in Hospitalized COVID-19 Patients in a New York City Hospital System

Objective New York City (NYC) became the first epicenter of the 2019 novel coronavirus disease (COVID-19) in the United States. Factors upon admission associated with the development of thrombosis in hospitalized COVID-19 patients are less well defined. Our aim is to characterize the incidence of thrombosis and the associated clinical and demographic risk factors of patients hospitalized across a NYC hospital system.

Material and Methods We conducted a retrospective observational study of all patients, age ≥ 18, hospitalized with a reverse transcriptase-polymerase chain reaction confirming severe acute respiratory syndrome coronavirus 2 infection between March 13 and April 4, 2020 in two hospitals in NYC. Clinical demographics, admission labs and medications prior to admission were collected. Thrombotic events were identified manually by chart review and were defined as experiencing arterial and/or venous thrombotic events.

Results 1,352 patients were hospitalized during the study period. Overall median age was 62 years (IQR:49-72), with 455 females (33.7%). There were 160 (11.8%) thrombotic events, including 102 with venous thromboembolism, 45 with pulmonary embolism, 69 with deep vein thrombosis, 32 with cerebrovascular accident and 55 with other thrombotic events (e.g. myocardial infarction, acute limb ischemia, splenic infarct). Females were 46% less likely than males to experience a thrombotic event (OR:0.54[CI:0.36-0.79]). Patients who racially self-identify as Asian or Pacific Islander were observed to have a 2.06 odds compared to other races of having a thrombotic event with COVID-19 (95%[CI:1.27-3.34]). Traditional risk factors including age, admission BMI, ethnicity, smoking status, and comorbidities were not associated with the incidence of thrombosis during hospitalization. Thrombotic events were associated with higher mortality in hospitalized COVID-19 patients (35% vs 25.3%, p=0.009).

Tab 1. Demographic and clinical characteristics of hospitalized patients by incidence of thrombotic events.

Conclusion Traditional risk factors were not associated with an increased risk for thrombotic events in COVID-19 patients, while inflammatory marker values on admission were significantly different, highlighting the impact of the cytokine storm in mediating thrombotic events. Since the incidence of COVID-19-associated thrombosis may vary according to clinical demographics, further investigation to identify high risk patients may enable us to consider the role of adjunctive treatment, such as therapeutic coagulation.

Publication History

Article published online:
18 June 2021