Padua Prediction Score for Risk of VTE

Why did you develop the Padua Prediction Score? Was there a clinical experience that inspired you to create this tool for clinicians?
Medical inpatients are at risk for venous thromboembolism (VTE). About 25% of all cases of VTE are related to hospitalization, and up to 75% of them occur in medical patients. High risk inpatients not receiving thromboprophylaxis develop deep-vein thrombosis in 5 to 15% of cases and pulmonary embolism in up to 1.5%.

Even though the usefulness of thromboprophylaxis is well known, the choice to prescribe it in clinical practice, especially in complex medical patients, is challenging. Age, immobility, active cancer, infections and acute inflammatory states are known major risk factors for hospitalization-related VTE; however, the contribution of each risk factor to the “magnitude” of VTE risk and the interaction between them is not easy to determine in clinical practice.

The Padua Prediction Score (PPS) has been created to guide clinicians in identifying patients at "sufficient" risk to warrant prophylaxis.

What pearls, pitfalls and/or tips do you have for users of the Padua Prediction Score? Are there cases in which it has been applied, interpreted, or used inappropriately?
The PPS has been created to stratify VTE risk in general medical inpatients, but it has not been validated for specific populations as Intensive Care Unit patients or others. This is the most common mistake made. Moreover, PPS is a guide, but its value is not "universal" and it can never overwhelm clinical judgment.

What recommendations do you have for health care providers once they have applied the Padua Prediction Score? Are there any adjustments or updates you would make to the score given recent changes in medicine?
PPS can be applied in all patients admitted in general medicine wards.  It is a guide to thromboprophylaxis, but it doesn't take into account hemorrhagic risk that could easily be evaluated, at the moment, with the use of IMPROVE bleeding score (Decousus 2011).

Do you have any thoughts on the sepsis trial by Vardi and colleagues which demonstrated no relationship between a positive Padua score and VTE?
Vardi et al tested PPS in a sub-selected medical population of medical inpatients with sepsis. The PPS has been recently tested (and compared with another risk assessment model, namely Geneva score) in a cohort of around 1500 general medical inpatients (Nendaz 2014). Both scores demonstrated a good discrimination between low- and high-risk patients (cumulative rate of VTE and VTE-related death at 90 days post-discharge 3.5 vs. 1.1% [p=0.002] in high- vs. low-risk patients according to PPS).

Many of the patients that developed VTE during your study had active cancer. How could this have affected your prediction rule?
Cancer is a very well known and strong risk factor for VTE. Thrombotic risk is particularly increased when associated with other conditions such as bed-rest or acute infections. Accordingly, the weight of this risk factor has been calculated with a score of 3 in PPS.

Are there any further prospective trials in the works to validate the Padua score?
Further studies are ongoing to adapt/validate PPS in other setting of patients, with special regard to nursing home resident and outpatients with comorbidities when experiencing acute conditions. In fact, both of these populations are at increased risk of VTE and data on management of these patients are scanty in literature.

Sofia Barbar, MD, is a physician at Civic Hospital of Cittadella (Padua) in Italy. She graduated with honors from Medical School at Padua University, where she also completed Internal Medicine training, subsequently majoring in Emergency Medicine. She is an active researcher studying prevalence and treatment of venous thromboembolism. Her scientific interests particularly focus on clinical research in the field of venous thromboembolism (VTE), with special regards to prevention of VTE in medical ill patients and diagnosis and treatment of VTE even in unusual sites.

Paolo Prandoni, PhD, is professor of the Department of Medical and Surgical Sciences, Thromboembolism Unit, at the University of Padua. He trained at the University of Padua from 1971 to 1979 before moving to Holland, where he studied for his PhD at the University of Amsterdam in 1992. Professor Prandoni’s research and professional experiences encompass the epidemiology, diagnosis, and management of thromboembolism. Of particular interest to him are studies addressing cancer-associated venous thromboembolism (VTE).