Incidence and effects of deep vein thrombosis on the outcome of patients with coronavirus disease 2019 infection

BACKGROUND: Deep vein thrombosis (DVT) has been reported to occur at different rates in patients with coronavirus disease 2019 (COVID-19). Limited data exist regarding comparisons with non–COVID-19 patients with similar characteristics. Our objective was to compare the rates of DVT in patients with and without COVID-19 and to determine the effect of DVT on the outcomes. METHODS: We performed a retrospective, observational cohort study at a single-institution, level 1 trauma center comparing patients with and without COVID-19. The 573 non–COVID-19 patients (age, 61 ± 17 years; 44.9% male) had been treated from March 20, 2019 to June 30, 2019, and the 213 COVID-19 patients (age, 61 ± 16 years; 61.0% male) had been treated during the same interval in 2020. Standard prophylactic anticoagulation therapy consisted of 5000 U of heparin three times daily for the medical patients without COVID-19 who were not in the intensive care unit (ICU). The ICU, surgical, and trauma patients without COVID-19 had received 40 mg of enoxaparin daily (not adjusted to weight). The patients with COVID-19 had also received enoxaparin 40 mg daily (also not adjusted to weight), regardless of whether treated in the ICU. The two primary outcomes were the rate of deep vein thrombosis (DVT) in the COVID-19 group vs that in the historic control and the effect of DVT on mortality. The subgroup analyses included patients with adult respiratory distress syndrome (ARDS), pulmonary embolism (PE), and intensive care unit patients (ICU). RESULTS: The rate of DVT and PE for the non–COVID-19 patients was 12.4% (71 of 573) and 3.3% (19 of 573) compared with 33.8% (72 of 213) and 7.0% (15 of 213) for the COVID-19 patients, respectively. Unprovoked PE had developed in 10 of 15 COVID-19 patients (66.7%) compared with 8 of 497 non–COVID-19 patients (1.6%). The 60 COVID-19 patients with ARDS had had an incidence of DVT of 46.7% (n = 28). In contrast, the incidence of DVT for the 153 non–COVID-19 patients with ARDS was 28.8% (n = 44; P = .01). The COVID-19 patients requiring the ICU had had an increased rate of DVT (39 of 90; 43.3%) compared with the non–COVID-19 patients (33 of 123; 33.3%; P = .01). The risk factors for mortality included age, DVT, multiple organ failure syndrome, and prolonged ventilatory support with the following odd ratios: 1.030 (95% confidence interval [CI], 1.002-1.058), 2.847 (95% CI, 1.356-5.5979), 4.438 (95% CI, 1.973-9.985), and 5.321 (95% CI, 1.973-14.082), respectively. CONCLUSIONS: The incidence of DVT for COVID-19 patients receiving standard-dose prophylactic anticoagulation that was not weight adjusted was high, especially for ICU patients. DVT is one of the factors contributing to increased mortality. These results suggest a reevaluation is necessary of the present standard-dose thromboprophylaxis for patients with COVID-19.