# Evaluation of the IMPROVE-DD score in COVID-19 patients submitted to venous thromboembolism investigation at a hospital in Brazil

## TL;DR

This study found that 18.6% of hospitalized COVID-19 patients in Brazil developed blood clots, and a tool called IMPROVE-DD helped identify those at higher risk.

## Contribution

The study validates the IMPROVE-DD score for identifying high-risk hospitalized COVID-19 patients likely to develop VTE in a Brazilian cohort.

## Key findings

- The in-hospital VTE incidence among hospitalized COVID-19 patients was 18.6%.
- The IMPROVE-DD score was significantly higher in patients with VTE compared to those without.
- D-dimer levels twice the upper limit of normal identified 94% of VTE cases.

## Abstract

To evaluate the incidence of venous thromboembolism (VTE) in hospitalized patients with COVID-19 who underwent diagnostic tests for suspected VTE, and to correlate the IMPROVE-DD score with the incidence of VTE in this cohort.

This retrospective study included consecutive patients with COVID-19 and suspected VTE, admitted between March 2020 and September 2021 at a private hospital in Salvador (BA), Brazil, who underwent lower or upper limb venous Doppler ultrasound or chest angiotomography. Descriptive analyses and comparisons using the chi-square test were performed to identify factors potentially associated with the risk of VTE.

A total of 517 patients were included, with an in-hospital VTE incidence of 18.6% (96 events). Risk factors significantly associated with VTE included obesity, ICU admission, central venous catheter use, longer hospital stays, greater lung tomographic involvement/severity, the need for mechanical ventilation, D-dimer levels at least twice the upper limit of normal (2xULN), and the IMPROVE-DD score. The mean IMPROVE-DD score among patients with VTE was 4.7 (±3) versus 3.3 (±2.4) in those without VTE (p < 0.0001). D-dimer 2xULN was sensitive in identifying 94% of the 96 patients with VTE (p < 0.0001). The in-hospital mortality rate was 14.1%, with higher rates observed in patients with VTE (24%) compared to those without VTE (11.9%) (p = 0.003).

The incidence of VTE in hospitalized COVID-19 patients was high and correlated with increased mortality. The IMPROVE-DD score effectively identified patients at risk for in-hospital VTE, suggesting it could help to identify a high-risk subgroup that may benefit from extended thromboprophylaxis.