European Primary Care Cardiovascular Society

Incidence of thrombotic complications in hospitalized COVID-19 patients remained high in second wave

Incidence of thrombotic complications and overall survival in hospitalized patients with COVID-19 in the second and first wave

Literature - Kaptein FHJ, Stals MAM, Grootenboers M et al., - Thrombosis Research 2020. S0049-3848(20)30675-7 doi: 10.1016/j.thromres.2020.12.019

Introduction and methods

Coagulopathy and high incidences of thrombotic complications have been linked with severe COVID-19 [1-3]. Treatment of hospitalized COVID-19 patients has evolved since the first wave. In response to the high rates of thrombotic complications, guidelines were adjusted to improve proper diagnosis of venous thromboembolism (VTE) and appropriate treatment with low-molecular-weight heparin (LMWH) thromboprophylaxis in COVID-19 patients [4-7]. Remdesivir was suggested to be beneficial in shortening time to recovery in hospitalized COVID-19 patients, compared to placebo [8]. It was also shown that dexamethasone reduces mortality in critically ill patients [9]. It is unknown whether these treatment developments have resulted in less thrombotic complications and mortality in COVID-19 patients in second wave, compared to the first wave. This observational study assessed the incidence of thrombotic complications and overall mortality in COVID-19 patients in the Netherlands in the second wave and compared results with data from patients hospitalized in the first wave.

A total of 947 adult COVID-19 patients admitted between September 1st and November 30th 2020 to eight hospitals in the Netherlands were included in this study. 860 Patients were admitted to general wards, 358 patients to the ICU and 271 patients were admitted to both general ward and ICU. Mean age was 66 (SD 13) years, 64% were male and 13% used therapeutic anticoagulation at admission. All patients received pharmacological thromboprophylaxis according to local protocols. Remdesivir and dexamethasone were given to ward patients with need for supplemental oxygen. Patients on ICU were not treated with remdesivir [10]. Incidence of thrombotic complications and mortality were compared with data from a previous study in 579 COVID-19 patients hospitalized in the Netherlands in the first wave (between February 24th and April 26th 2020) [11].

Main results


This observational study showed that risk of overall mortality in COVID-19 patients hospitalized in the Netherlands was lower in the second wave, compared with the first wave. Cumulative incidences of thrombotic complications remained high in the second wave. Cumulative incidences of thrombotic complications among all patients (ward and ICU combined) in the second wave were comparable with those in the first wave. However, an increased cumulative incidence was found in ward patients in the second wave compared to the first wave, while a decrease in cumulative incidence was observed in ICU patients. These data underline the need for provision of appropriate thromboprophylaxis in hospitalized COVID-19 patients and a low threshold for diagnostic imaging upon suspicion of thrombotic complications. Randomized trials are needed to examine whether treatment with anticoagulants results in lower incidences of thrombotic complications in COVID-19 patients.


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