New research shows that each measurable drop in mobility during a hospital stay increases the risk of venous thromboembolism (VTE). The results support the use of graded measurement of mobility, as opposed to current binary methods.
“Hospital-acquired VTE is a major cause of morbidity and mortality, but thromboprophylaxis can lead to adverse effects. Risk assessment models have therefore been developed to identify patients at risk for VTE who would most benefit from thromboprophylaxis,” wrote the authors, led by Erik Hoyer of Johns Hopkins University in Baltimore, Maryland.
The authors reviewed two widely used risk scores, Padua and IMPROVE, which apply more than 10 clinical factors, including mobility, which is an established risk factor for VTE that is modifiable. However, these tools measure mobility with only one yes‑or‑no question, despite the fact that mobility is on a continuum and involves significant complexity. This “overlooks a sizable proportion of patients who have varying and dynamic levels of mobility, ranging from complete bed rest to full mobility,” the authors wrote.
Therefore, they sought to assess whether a method that grades mobility can better predict VTE risk. The Johns Hopkins Highest Level of Mobility (JH‑HLM) scale includes eight mobility milestones, from lying in bed to walking more than 250 feet. It is designed to be used multiple times per day over the course of hospitalization.
The study included 25,763 adult patients admitted to two large academic hospitals from January 2021 to April 2024. Nurses and rehabilitation therapists used the JH-HLM each shift and recorded each patient’s maximum mobility level. New VTEs occurred in 169 patients (0.66%). Those who developed VTEs were older (65 versus 61 years), had more comorbidities (7.0 versus 5.1), had higher scores on the Padua tool (2.3 versus 2.0), and were hospitalized for a longer period of time (23.3 versus 10.1 days).
The incidence of new VTEs rose as JH-HLM scores decreased. Each one-level drop in mobility increased VTE risk by approximately 15%. Those with a score of 6 (walking less than 25 feet) had a 1.4-fold higher risk of VTE than those with a score of 8 (walking more than 250 feet). Those with a score of 4 (limited to transfers) had a 1.9-fold risk, and those who were bed-bound (score of 1) had a threefold risk.
“Embedding graded scores, such as JH-HLM, into electronic risk calculators could refresh VTE estimates in real-time, nudge clinicians when a patient’s movement declines, and direct preventive therapy to those who need it most,” the authors concluded
Reference
Hoyer E, Streiff M, Brotman D. Every step counts: Quantifying VTE risk across various mobility levels in the hospital setting. Abstract 1069. Presented at: the 67th American Society of Hematology Annual Meeting and Exposition, Dec. 6-9, 2025, Orlando, FL.
