Inaccuracy of Initial Clinical Mobility Assessment in Venous Thromboembolism Risk Stratification

Background: The risk of Venous Thromboembolism (VTE) often escalates in hospital settings in part due to reduced patient mobility. However, mobility assessment for VTE risk determination is often clouded by lack of clear definitions and standards. This vagueness can result in erroneous evaluations, especially near the time of admission, particularly since a patient's mobility is not static but fluctuates throughout the hospital stay.

Methods: We conducted a retrospective cohort analysis of patients who were discharged from medicine services in a large academic hospital. For each of these patients, daily nurse-collected Johns Hopkins-Highest Level of Mobility (JH-HLM) scores were used to calculate an objective measure of mobility. Reduced mobility was defined as an JH-HLM score of ≤3 on three consecutive days during hospitalization. We compared this definition of reduced mobility with clinician reported immobility as reflected by Padua scores entered on admission as part of mandatory VTE risk stratification. We also assessed the association between immobility and VTE using an adjusted odds ratio controlling for other VTE risk factors.

Results: Out of 1715 included patients, clinicians identified only 111 (6.5%) as having reduced mobility compared with 328 patients (19.1%) using the JH-HLM calculated approach. If the JH-HLM calculated measure of reduced mobility had been utilized, it would have led to the reclassification of 37 patients from a low-risk category to a high-risk category for VTE. In the cohort, 33 of 1715 (1.9%) patients developed VTE. Among these patients, JH-HLM calculated reduced mobility was identified in 12/33 (36%) of patients, whereas clinicians identified reduced mobility in 3/33 (9%) of patients. Presence of JH-HLM calculated reduced mobility was significantly associated with VTE events (aOR: 2.53, 95% CI: 1.23 - 5.22, P = 0.012). Clinician assessed reduced mobility at the time of admission was not associated with VTE events.

Conclusion: The initial clinician's assessment of mobility during VTE risk assessment did not accurately capture the extent of reduced mobility during the patient’s hospitalization. These findings highlight the importance of employing objective measures of patient mobility for assessing and reassessing VTE risk throughout the hospital stay. Healthcare organizations should consider implementing objective measures of mobility like the JH-HLM to improve VTE risk assessment and potentially reduce the occurrence of VTE.