LAUSR

Is There a Role for Thromboprophylaxis in Selected Outpatients With COVID-19? To the Editor Mr Xie and colleagues1 provide important information on an understudied topic: incident venous thromboembolism (VTE) in outpatients with COVID-19. The findings of their study are commendable and provide useful conclusions. First, COVID-19 was associated with increased VTE risk, even in the outpatient setting given that a higher VTE incidence was shown among 18 818 outpatients with COVID-19 compared with 93 179 propensity score matched, noninfected participants. Second, patients with specific characteristics (older age, male sex, obesity, no/partial vaccination, and inherited thrombophilia) had higher VTE risk. Third, the VTE risk was high for up to 30 days after diagnosis. These findings are highly important and may advance case management and treatment for outpatients with COVID-19. At present, the available data are generally against the routine use of pharmacologic thromboprophylaxis in outpatients with COVID-19.2,3 Moreover, current guidelines do not provide specific recommendations.4 However, it is common sense that selected outpatients with VTE risk factors are therefore at higher risk for disease worsening and would benefit from thromboprophylaxis on an individualized basis and after careful assessment of bleeding risk. Indeed, data show that major adverse events tend to occur early in patients hospitalized with COVID-19 who have a high-risk profile; prompt thromboprophylaxis would benefit these patients.5 The study by Mr Xie and colleagues1 was performed during a period when only 41% of patients with COVID-19 had been fully vaccinated; a percentage that has increased worldwide. Thus, it would be interesting to study VTE risk factors separately among the fully vaccinated group—despite VTE events having been infrequent. Moreover, apart from the patient risk factors, the disease characteristics may play a role. Symptoms that indicate disease activity or severity, ie, the duration of the fever, could be contributing to an increased VTE risk in selected patients. In addition, SARS-CoV-2 variants may exhibit a different risk regarding VTE. If these data are available, they would make for another interesting study. Although thromboprophylaxis among outpatients with COVID-19 is not generally recommended, the data and findings derived from studies, such as this one by Mr Xie and colleagues,1 show that selected outpatients carry an increased VTE risk. On the other hand, widespread immunization, as well as the availability of the antiviral therapies, may be substantially reducing VTE risk. Whether thromboprophylaxis would benefit high-risk outpatients with COVID-19 is unclear, but it seems reasonable to conclude that an individualized strategy would improve their prognosis.