IMPROVE Risk Score for VTE
Predicts 3-month risk of VTE in hospitalized patients.
Creator
Dr. Alex C. Spyropoulos, MD, FACP, FCCP, FRCPCInstructions
This tool is meant to risk stratify hospitalized patients who have a potential risk for VTE, not to diagnose VTE.
IMPROVE VTE Risk Score
The IMPROVE VTE Risk Score (sometimes called the IMPROVE Associative Score) estimates the risk of venous thromboembolism in acutely ill, hospitalized medical patients. It's the companion tool to the IMPROVE Bleeding Risk Score and together they form a standard paired approach: IMPROVE VTE identifies who's at high enough clotting risk to need prophylaxis, while IMPROVE Bleeding identifies who's at too high a bleeding risk to safely receive it pharmacologically.
Development
Like the IMPROVE Bleeding Risk score, the IMPROVE VTE Risk Score was derived from the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE), a multinational observational registry of hospitalized medical patients. Using regression analysis on data from this registry, researchers identified independent predictors of in-hospital VTE and developed a weighted point score from them.
Scoring
Addition of the selected points:
Variable | Points | |
Previous VTE | Yes | 3 |
No | 0 | |
Known thrombophilia | Yes | 2 |
No | 0 | |
Current lower-limb paralysis | Yes | 2 |
No | 0 | |
Current cancer | Yes | 2 |
No | 0 | |
Immobilized ≥7 days* | Yes | 1 |
No | 0 | |
ICU/CCU stay | Yes | 1 |
No | 0 | |
Age >60 years | Yes | 1 |
No | 0 |
*Immediately prior to and during hospital admission.
Maximum possible score: 12 points. Previous VTE is weighted most heavily, consistent with the well-established principle across many VTE scores (including Padua Prediction Score for Risk of VTE) that a prior clot is one of the single strongest predictors of a future one.
Interpretation & Management Considerations
IMPROVE Score | 3-month VTE risk |
0 | 0.4% |
1 | 0.6% |
2 | 1.0% |
3 | 1.7% |
4 | 2.9% |
5-10 | 7.2% |
>10 | >7.2% |
The American Society of Hematology (ASH) 2018 guidelines use a simpler actionable threshold: a score of ≥2 points is the trigger to consider pharmacologic thromboprophylaxis. Patients scoring 0 or 1 have an estimated baseline 3-month VTE risk of less than 1% and are considered unlikely to benefit from prophylaxis, since the bleeding risk of unnecessary anticoagulation would likely outweigh a clotting risk that's already very low.
Score <2: Pharmacologic thromboprophylaxis is not warranted. Early ambulation with or without mechanical prophylaxis may be appropriate.
Score ≥2: Start appropriate pharmacologic (e.g., low molecular weight heparin) or mechanical (e.g., compression stockings, intermittent pneumatic compression) prophylaxis.
If pharmacologic prophylaxis is warranted, evaluate for and weigh the risk of bleeding. Consider combining this assessment with the IMPROVE Bleeding Risk Score.
Consider addressing modifiable risk factors for bleeding.
Risk and benefits of anti-coagulation should be considered in patients, to include shared decsion-making and informed consent, prior to initiating therapy.
Clinical judgement and best practice guidelines supersede adjunct standalone decision tools.
Clinical Guidelines
IMPROVEDD: Adding D-dimer
A further refinement, the IMPROVEDD score, adds D-dimer level as an additional recognized risk factor on top of the conventional 7-item Associative score. Incorporating a lab value that reflects current coagulation activity (rather than only static clinical risk factors) has been explored as a way to improve discrimination, particularly useful since D-dimer is often already drawn as part of routine inpatient workups.
Practical note: As with every other score in this series, IMPROVE VTE is intended to structure — not replace — clinical judgment. It's most useful as part of the paired VTE/bleeding framework rather than in isolation, since VTE risk alone doesn't capture the full risk-benefit picture of starting pharmacologic prophylaxis.
All questions & possible results
Risk factorsTitle not visible
Previous VTE
Select one option:
- No
- Yes
Known thrombophilia
Select one option:
- No
- Yes
Current lower-limb paralysis
Select one option:
- No
- Yes
Current cancer
Select one option:
- No
- Yes
Immobilized ≥7 days
Immobilization immediately prior to and during admission.
Select one option:
- No
- Yes
ICU/CCU stay
Select one option:
- No
- Yes
Age >60 years
Select one option:
- No
- Yes
Possible results
IMPROVE Score: 3-month risk of VTE 0.6%
Pharmacologic thromboprophylaxis is not warranted. Early ambulation with or without mechanical prophylaxis may be appropriate.
If pharmacologic prophylaxis is warranted, evaluate for and weigh the risk of bleeding. Consider combining this assessment with the IMPROVE Bleeding Risk Score.
Consider addressing modifiable risk factors for bleeding.
Risk and benefits of anti-coagulation should be considered in patients, to include shared decsion-making and informed consent, prior to initiating therapy.
Clinical judgement and best practice guidelines supersede adjunct standalone decision tools.
Clinical Guidelines
IMPROVE Score: 3-month risk of VTE 1.0%
Start appropriate pharmacologic (e.g., low molecular weight heparin) or mechanical (e.g., compression stockings, intermittent pneumatic compression) prophylaxis.
If pharmacologic prophylaxis is warranted, evaluate for and weigh the risk of bleeding. Consider combining this assessment with the IMPROVE Bleeding Risk Score.
Consider addressing modifiable risk factors for bleeding.
Risk and benefits of anti-coagulation should be considered in patients, to include shared decsion-making and informed consent, prior to initiating therapy.
Clinical judgement and best practice guidelines supersede adjunct standalone decision tools.
Clinical Guidelines
IMPROVE Score: 3-month risk of VTE 1.7%
Start appropriate pharmacologic (e.g., low molecular weight heparin) or mechanical (e.g., compression stockings, intermittent pneumatic compression) prophylaxis.
If pharmacologic prophylaxis is warranted, evaluate for and weigh the risk of bleeding. Consider combining this assessment with the IMPROVE Bleeding Risk Score.
Consider addressing modifiable risk factors for bleeding.
Risk and benefits of anti-coagulation should be considered in patients, to include shared decsion-making and informed consent, prior to initiating therapy.
Clinical judgement and best practice guidelines supersede adjunct standalone decision tools.
Clinical Guidelines
IMPROVE Score: 3-month risk of VTE 2.9%
Start appropriate pharmacologic (e.g., low molecular weight heparin) or mechanical (e.g., compression stockings, intermittent pneumatic compression) prophylaxis.
If pharmacologic prophylaxis is warranted, evaluate for and weigh the risk of bleeding. Consider combining this assessment with the IMPROVE Bleeding Risk Score.
Consider addressing modifiable risk factors for bleeding.
Risk and benefits of anti-coagulation should be considered in patients, to include shared decsion-making and informed consent, prior to initiating therapy.
Clinical judgement and best practice guidelines supersede adjunct standalone decision tools.
Clinical Guidelines
IMPROVE Score: 3-month risk of VTE 7.2%
Start appropriate pharmacologic (e.g., low molecular weight heparin) or mechanical (e.g., compression stockings, intermittent pneumatic compression) prophylaxis.
If pharmacologic prophylaxis is warranted, evaluate for and weigh the risk of bleeding. Consider combining this assessment with the IMPROVE Bleeding Risk Score.
Consider addressing modifiable risk factors for bleeding.
Risk and benefits of anti-coagulation should be considered in patients, to include shared decsion-making and informed consent, prior to initiating therapy.
Clinical judgement and best practice guidelines supersede adjunct standalone decision tools.
Clinical Guidelines
IMPROVE Score: 3-month risk of VTE >7.2%
Start appropriate pharmacologic (e.g., low molecular weight heparin) or mechanical (e.g., compression stockings, intermittent pneumatic compression) prophylaxis.
If pharmacologic prophylaxis is warranted, evaluate for and weigh the risk of bleeding. Consider combining this assessment with the IMPROVE Bleeding Risk Score.
Consider addressing modifiable risk factors for bleeding.
Risk and benefits of anti-coagulation should be considered in patients, to include shared decsion-making and informed consent, prior to initiating therapy.
Clinical judgement and best practice guidelines supersede adjunct standalone decision tools.
Clinical Guidelines
IMPROVE Score: 3-month risk of VTE 0.4%
Pharmacologic thromboprophylaxis is not warranted. Early ambulation with or without mechanical prophylaxis may be appropriate.
If pharmacologic prophylaxis is warranted, evaluate for and weigh the risk of bleeding. Consider combining this assessment with the IMPROVE Bleeding Risk Score.
Consider addressing modifiable risk factors for bleeding.
Risk and benefits of anti-coagulation should be considered in patients, to include shared decsion-making and informed consent, prior to initiating therapy.
Clinical judgement and best practice guidelines supersede adjunct standalone decision tools.
Clinical Guidelines
Citation
Spyropoulos AC, Anderson FA Jr, FitzGerald G, Decousus H, Pini M, Chong BH, Zotz RB, Bergmann JF, Tapson V, Froehlich JB, Monreal M, Merli GJ, Pavanello R, Turpie AGG, Nakamura M, Piovella F, Kakkar AK, Spencer FA; IMPROVE Investigators. Predictive and associative models to identify hospitalized medical patients at risk for VTE. Chest. 2011 Sep;140(3):706-714.
Literature
Spyropoulos AC, Anderson FA Jr, FitzGerald G, Decousus H, Pini M, Chong BH, Zotz RB, Bergmann JF, Tapson V, Froehlich JB, Monreal M, Merli GJ, Pavanello R, Turpie AGG, Nakamura M, Piovella F, Kakkar AK, Spencer FA; IMPROVE Investigators. Predictive and associative models to identify hospitalized medical patients at risk for VTE. Chest. 2011 Sep;140(3):706-714.
https://pubmed.ncbi.nlm.nih.gov/21436241/Mahan CE, Liu Y, Turpie AG, Vu JT, Heddle N, Cook RJ, Dairkee U, Spyropoulos AC. External validation of a risk assessment model for venous thromboembolism in the hospitalised acutely-ill medical patient (VTE-VALOURR). Thromb Haemost. 2014 Oct;112(4):692-9.
https://pubmed.ncbi.nlm.nih.gov/24990708/Rosenberg D, Eichorn A, Alarcon M, McCullagh L, McGinn T, Spyropoulos AC. External validation of the risk assessment model of the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) for medical patients in a tertiary health system. J Am Heart Assoc. 2014 Nov 17;3(6):e001152.
https://pubmed.ncbi.nlm.nih.gov/25404191/Greene MT, Spyropoulos AC, Chopra V, Grant PJ, Kaatz S, Bernstein SJ, Flanders SA. Validation of Risk Assessment Models of Venous Thromboembolism in Hospitalized Medical Patients. Am J Med. 2016 Sep;129(9):1001.e9-1001.e18.
https://pubmed.ncbi.nlm.nih.gov/27107925/Moumneh T, Riou J, Douillet D, Henni S, Mottier D, Tritschler T, Le Gal G, Roy PM. Validation of risk assessment models predicting venous thromboembolism in acutely ill medical inpatients: A cohort study. J Thromb Haemost. 2020 Jun;18(6):1398-1407.
https://pubmed.ncbi.nlm.nih.gov/32168402/Wilkinson KS, Sparks AD, Gergi M, Repp AB, Al-Samkari H, Thomas R, Roetker NS, Zakai NA. Validation of the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) risk scores for venous thromboembolism and bleeding in an independent population. Res Pract Thromb Haemost. 2024 May 15;8(4):102441.
https://pubmed.ncbi.nlm.nih.gov/38953050/Schünemann HJ, Cushman M, Burnett AE, Kahn SR, Beyer-Westendorf J, Spencer FA, Rezende SM, Zakai NA, Bauer KA, Dentali F, Lansing J, Balduzzi S, Darzi A, Morgano GP, Neumann I, Nieuwlaat R, Yepes-Nuñez JJ, Zhang Y, Wiercioch W. American Society of Hematology 2018 guidelines for management of venous thromboembolism: prophylaxis for hospitalized and nonhospitalized medical patients. Blood Adv. 2018 Nov 27;2(22):3198-3225.
https://pubmed.ncbi.nlm.nih.gov/30482763/
- Creator
- Provided by
EVAL Foundation
- Contributor · Reviewer
Jennifer Glen, DNP, FNP-BCEVAL Health, Chief Medical Officer EVAL Foundation
Related evaluations
IMPROVE Bleeding Risk Score
Evaluates bleeding risk at hospital admission.
Dr. Hervé Décousus, MDPadua Prediction Score for Risk of VTE
Determines anticoagulation need in hospitalized patients by risk of VTE.
Dr. Sofia Barbar, MDIMPEDE-VTE
Predicts risk of venous thromboembolism in multiple myeloma
Dr. Kristen M. Sanfilippo, MD, MPHSISTH-SSC Bleeding Assessment Tool (ISTH-SCC BAT)
Evaluates bleeding symptoms in patients with inherited bleeding disorders.
Dr. Francesco Rodeghiero, M.D.ATRIA Bleeding Risk Score
Determines bleeding risk for patients being considered for warfarin anticoagulation
Dr. Daniel Singer, MDAspirin Deprescribing Guidelines
Patient-specific recommendations to change or discontinue aspirin that may lead to fewer adverse events
Venous Thromboembolism Evaluation & Management in the Emergency Department
App for the evaluation, diagnosis, & management of ED patients with VTE to stratify for In- vs. Out-patient treatment.
OSU Center for Health SciencesRIETE Predictive Score for Bleeding
Determine the risk of major bleeding during anticoagulant therapy.
Dr. Nuria Ruíz-Giménez Arrieta, MDPulmonary Embolism Severity Index (PESI)
Predicts 30-day outcome of patients with pulmonary embolism using 11 clinical criteria.
Dr. Drahomir Aujesky, MD, MSSimplified PESI (Pulmonary Embolism Severity Index: sPESI)
Estimates the 30-day mortality risk following acute pulmonary embolism.
OSU Center for Health SciencesIMPROVEDD Risk Score for VTE
Predicts risk of VTE in hospitalized patients, adding D-dimer to IMPROVE Risk Score.
Dr. C. Michael Gibson, MS, MDAlso from EVAL Foundation
Alcohol Use Disorders Identification Test - C (AUDIT-C)
A 3-item tool to screen for unhealthy alcohol use in patients who may not be alcohol-dependent.
Dr. Katharine Bradley, MD, MPHAlcohol Use Disorders Identification Test (AUDIT)
A 10-item tool to screen for hazardous alcohol use, harmful use, and alcohol dependence.
World Health Organization Collaborative ProjectAmerican Shoulder and Elbow Surgeons (ASES) Shoulder Score
15-item assessment of shoulder pain and functional limitations in activities of daily living.
Dr. Robin R. Richards, MD, FRCSC, FAAOS, FAOABehavioral Activity Rating Scale (BARS)
A 1-item rating scale to quantify a patient's level of agitation in acute care or psychiatric settings.
Drug Abuse Screening Test (DAST-10)
A patient self-report questionnaire to screen for problematic drug use (excluding alcohol/tobacco).
Dr. Harvey A. Skinner, Ph.D.Foot and Ankle Ability Measure (FAAM)
Assesses functional limitations and disability related to foot and ankle conditions in daily activities and sports.
Dr. Jesse Van Swearingen, PhD, PT, FAPTAFoot and Ankle Disability Index (FADI)
Assess functional limitations of those with a variety of foot and ankle conditions
Dr. RobRoy Martin, PhD, PT, CSCSGeneral Anxiety Disorder (GAD-7)
Measure severity of anxiety
Dr. Robert L. Spitzer, MD