Risk of thrombosis recurrence among patients with COVID-19 and surgery-associated venous thromboembolism

INTRODUCTION: Recent surgery is a well-known major transient risk factor for venous thromboembolism (VTE) due to the low risk of VTE recurrence after anticoagulation is discontinued. On the other hand, the risk of VTE recurrence among patients with COVID-19-associated VTE is unknown. This study aimed to compare the risk of VTE recurrence between patients with COVID-19- and surgery-associated VTE. METHODS: A prospective observational single-center study was performed including consecutive patients diagnosed with VTE in a tertiary hospital from January 2020 to May 2022 and followed up for at least 90 days. Baseline characteristics, clinical presentation, and outcomes were assessed. The incidence of VTE recurrence, bleeding, and death was compared between both groups. RESULTS: A total of 344 patients were included in the study: 111 patients with surgery-associated VTE and 233 patients with COVID-19-associated VTE. Patients with COVID-19-associated VTE were more frequently men (65.7% vs 48.6%, p = 0.003). VTE recurrence was 3% among COVID-19 patients and 5.4% among surgical patients, with no significant differences (p = 0.364). The incidence rate of recurrent VTE was 1.25 per 1000 person-months in COVID-19 patients and 2.29 person-months in surgical patients, without significant differences (p = 0.29). In the multivariate analysis, COVID-19 was associated with higher mortality (HR 2.34; 95% CI 1.19–4.58), but not with a higher risk of recurrence (HR 0.52; 95% CI 0.17–1.61). No differences were found in recurrence in the multivariate competing risk analysis (SHR 0.82; 95% CI 0.40–2.05). CONCLUSIONS: In patients with COVID-19 and surgery-associated VTE, the risk of recurrence was low, with no differences between both groups.