The IMPROVEDD VTE Risk Score: Incorporation of D-Dimer into the IMPROVE Score to Improve Venous Thromboembolism Risk Stratification

Abstract

Background The IMPROVE score is a validated venous thromboembolism (VTE) assessment tool to risk stratify hospitalized, medically ill patients based on clinical variables. It was hypothesized that addition of D-dimer measurement to derive a new IMPROVEDD score would improve identification of at risk of VTE. Methods The association of the IMPROVE score and D-dimer ≥ 2 × the upper limit of normal (ULN) with the risk of symptomatic deep vein thrombosis, nonfatal pulmonary embolism, or VTE-related death was evaluated in 7,441 hospitalized, medically ill patients randomized in the APEX trial. Based on the Cox regression analysis, the IMPROVEDD score was derived by adding two points to the IMPROVE score if the D-dimer was ≥ 2 × ULN. Results Baseline D-dimer was independently associated with symptomatic VTE through 77 days (adjusted HR: 2.22 [95% CI: 1.38–1.58], p = 0.001). Incorporation of D-dimer into the IMPROVE score improved VTE risk discrimination (ΔAUC: 0.06 [95% CI: 0.02–0.09], p = 0.0006) and reclassification (continuous NRI: 0.34 [95% CI: 0.17–0.51], p = 0.001; categorical NRI: 0.13 [95% CI: 0.03–0.23], p = 0.0159). Patients with an IMPROVEDD score of ≥2 had a greater VTE risk compared with those with an IMPROVEDD score of 0 to 1 (HR: 2.73 [95% CI: 1.52–4.90], p = 0.0007). Conclusion Incorporation of D-dimer into the IMPROVE VTE risk assessment model further improves risk stratification in hospitalized, medically ill patients who received thromboprophylaxis. An IMPROVEDD score of ≥2 identifies hospitalized, medically ill patients with a heightened risk for VTE through 77 days.

Inverse relationship of serum albumin to the risk of venous thromboembolism among acutely ill hospitalized patients: Analysis from the APEX trial

“…14,15,17,27,28 The present study demonstrated that the addition of albumin to validated risk assessment models (such as the IMPROVE score or Padua score) improved their performance in risk discrimination and reclassification. 14,15,17,27,28 The present study demonstrated that the addition of albumin to validated risk assessment models (such as the IMPROVE score or Padua score) improved their performance in risk discrimination and reclassification.…”

“…Several risk assessment models have been developed to identify hospitalized patients at risk of VTE. 14,15,17,27,28 The present study demonstrated that the addition of albumin to validated risk assessment models (such as the IMPROVE score or Padua score) improved their performance in risk discrimination and reclassification. These findings suggest that laboratory tests or biomarkers may be used in conjunction with risk assessment models comprised of clinical variables to refine VTE prediction.…”

“…ill hospitalized patients represent a population with a heterogeneous predisposition to VTE, 17 this finding indicates that albumin should not be considered as the stand-alone tool for identifying patient subsets that would benefit from extended-duration prophylaxis.…”

“…The lack of statistical significance in preventing VTE among hypoalbuminemic patients may be attributable to the inadequate sample size (approximately one third of the group with normal albumin levels). As acutely ill hospitalized patients represent a population with a heterogeneous predisposition to VTE, 17 this finding indicates that albumin should not be considered as the stand-alone tool for identifying patient subsets that would benefit from extended-duration prophylaxis.…”

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“…6 The IMPROVEDD VTE risk score shows how incorporation of D-Dimer into the IMPROVE score would improve venous thromboembolism risk stratification. 7 Impact of venous thromboembolism on the formation and progression of carotid atherosclerosis is also demonstrated from the Tromsø Study.…”