In a new study of patients with sickle cell disease (SCD), the risk of venous thromboembolism (VTE) appeared not to be increased in the presence of severe COVID-19. Results of the study were reported in the journal Blood Advances.

Patients with SCD may be more likely to experience VTE. Additionally, VTE can arise as a complication of severe COVID-19. Because of this, the researchers who conducted the study had an aim of determining whether severe COVID-19 would further enhance the risk of VTE in the setting of SCD. “We hypothesized that patients with SCD hospitalized for COVID-19 would have higher VTE rates compared to those hospitalized for other indications,” the researchers explained in their report.

In this retrospective analysis, the researchers used electronic health records obtained through the TriNetX network to find patients with SCD who had hospitalizations in 2020 throughout more than 40 health care organizations in the US. They divided these patients into 2 groups, those who had a COVID-19 diagnosis and those who were not diagnosed with COVID-19. Hospitalization was considered associated with COVID-19 if it occurred within 14 days of either a diagnosis of COVID-19 or a positive result on a COVID-19 test. The researchers evaluated VTE rates for comparisons between these 2 groups.

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The researchers included 281 patients with SCD who were hospitalized with COVID-19 and 4873 patients who were hospitalized without a diagnosis of COVID-19. Patients who had a hospitalization associated with COVID-19 had a mean age of 31.3 years, compared with 28.0 years for the group without COVID-19 (P =.0021). The population with COVID-19 had significantly higher rates of hypertension, acute/chronic kidney disease, obesity, and deep vein thrombosis and/or pulmonary embolism in their prior histories.

An incident VTE was reported within the 6 months following the index hospitalization in 12.46% of the patients with COVID-19, compared with 8.58% of patients without COVID-19. In unadjusted analyses, patients with COVID-19 showed a higher 3-month VTE incidence (unadjusted risk ratio [RR], 1.46 [95% CI, 1.01-2.11]) and a higher 6-month VTE incidence (unadjusted RR, 1.45 [95% CI, 1.05-2.00]), compared with patients who were not hospitalized with COVID-19.

In analyses adjusted for baseline factors, however, the researchers found there were not significantly different VTE rates between the patients hospitalized with or without COVID-19 across time points. The 3-month adjusted RR for VTE incidence was 1.05 (95% CI, 0.76-1.45), and at 6 months the adjusted RR was 1.06 (95% CI, 0.79-1.41).

The researchers concluded that patients with SCD in this study did not have an enhanced risk of VTE in association with a COVID-19 hospitalization. “These data provide support for the application of current general clinical anticoagulation guidelines for COVID-19 in the general population to patients with SCD,” the researchers wrote in their report.


Singh A, Brandow AM, Wun T, Shet AS. COVID-19 and venous thromboembolism risk in patients with sickle cell disease. Blood Adv. Published online June 27, 2022. doi:10.1182/bloodadvances.2022007219