Validation of the IMPROVE‐DD risk assessment model for venous thromboembolism among hospitalized patients with COVID‐19

Abstract

Background Antithrombotic guidance statements for hospitalized patients with coronavirus disease 2019 (COVID‐19) suggest a universal thromboprophylactic strategy with potential to escalate doses in high‐risk patients. To date, no clear approach exists to discriminate patients at high risk for venous thromboembolism (VTE). Objectives The objective of this study is to externally validate the IMPROVE‐DD risk assessment model (RAM) for VTE in a large cohort of hospitalized patients with COVID‐19 within a multihospital health system. Methods This retrospective cohort study evaluated the IMPROVE‐DD RAM on adult inpatients with COVID‐19 hospitalized between March 1, 2020, and April 27, 2020. Diagnosis of VTE was defined by new acute deep venous thrombosis or pulmonary embolism by Radiology Department imaging or point‐of‐care ultrasound. The receiver operating characteristic (ROC) curve was plotted and area under the curve (AUC) calculated. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated using standard methods. Results A total of 9407 patients were included, with a VTE prevalence of 2.9%. The VTE rate was 0.4% for IMPROVE‐DD score 0‐1 (low risk), 1.3% for score 2‐3 (moderate risk), and 5.3% for score ≥ 4 (high risk). Approximately 45% of the total population scored high VTE risk, while 21% scored low VTE risk. IMPROVE‐DD discrimination of low versus medium/high risk showed sensitivity of 0.971, specificity of 0.218, PPV of 0.036, and NPV of 0.996. ROC AUC was 0.702. Conclusions The IMPROVE‐DD VTE RAM demonstrated very good discrimination to identify hospitalized patients with COVID‐19 as low, moderate, and high VTE risk in this large external validation study with potential to individualize thromboprophylactic strategies.

External validation of the IMPROVE-DD risk assessment model for venous thromboembolism among inpatients with COVID-19

“…In comparison with the original 7-factor IMPROVE RAM, addition of elevated D-dimers with the IMPROVE-DD RAM improved model discrimination of VTE in COVID-19 inpatients by 6.8%, a difference that was statistically significant. The IMPROVE-DD was also recently validated in the hospitalized COVID-19 population, which achieved an AUC of 0.702, though the study was limited by the absence of thrombophilia data [ 12 ]. In comparison, our cohort included 123 (1.31%) patients with thrombophilia and achieved similar AUC.…”

American Society of Hematology living guidelines on the use of anticoagulation for thromboprophylaxis in patients with COVID-19: July 2021 update on postdischarge thromboprophylaxis

“…Several clinical risk factors have been found to be independently associated with post-discharge VTE after COVID-19, including advanced age, cardiovascular disease, chronic kidney disease, and intensive care unit (ICU) admission.. 5 However, there are no RAMs that have been specifically derived and prospectively validated in COVID-19 patients thus far, although non-COVID RAMs have been externally validated in hospitalized COVID-19 patients, and the COVID-TE score was derived specifically in COVID-19 patients with concomitant malignancy. [34][35][36] Moreover, while the recent CORE-19 registry demonstrated a reduction in the composite outcome of VTE, ATE, and all-cause mortality with post-discharge anticoagulation, there remains a paucity of high-quality prospective and randomized data. As such, the relative risks and benefits of post-discharge thromboprophylaxis remain uncertain in this population.…”

The COVID-19 Pandemic and the Need for an Integrated and Equitable Approach: An International Expert Consensus Paper

“…VTE risk assessment models such as the IMPROVE-DD VTE model have undergone extensive external validation in hospitalized COVID-19 patients and have shown good discrimination to identify high-risk patients. 78 Cancer patients, particularly those with metastatic solid cancer with COVID-19, show about twofold higher mortality. 79 80 81 82 83 84 On the other hand, well-controlled blood pressure and glucose levels in citizens with arterial hypertension or type 2 diabetes mellitus respectively are associated with markedly lower mortality as compared with individuals with poorer control of these parameters during hospitalization for COVID-19.…”