Background: In surgical patients, the risk of deep vein thrombosis (DVT) associated with immobilization is well recognized, whereas the level of risk conferred by immobility in patients hospitalized in medical wards is less clear.

Aims: The aim of this study was to establish the relevance and how the length of immobilization relates to the risk of developing DVT in acutely ill medical patients.

Methods: A single centre longitudinal study was performed. Patients from medical wards of our academic hospital with suspected lower-extremity DVT were evaluated with whole leg ultrasound to confirm the presence of DVT. Immobility was defined as total bed rest or sedentary without bathroom privileges as defined in the EXCLAIM study.

Results: Among 500 inpatients (age 78.1±13.2 y, males 40.6%), frequency of immobilization was 50.4%. Thromboprophylaxis was used in 63.9% of patients with immobilization and in 47.6% of patients without immobilization (p< 0.001). Whole leg ultrasound showed 112 (22.4%) DVTs, of which 47 (42.0%) were proximal and 65 (58.0%) were isolated distal DVT. Patients with immobilization had a two-fold risk for DVT (2.4 CI 95% 1.6-3.8, p< 0.001) vs. patients without immobilization. After three day of immobilization, the frequency of DVT was similar in patients with and without immobilization, whereas after 7 and 14 days the frequency was 0.29±0.04 vs. 0.20±0.03 and 0.57±0.06 vs. 0.31±0.07, respectively. At multivariable analysis, predictors of DVT were immobilization (HR 1.6, 95%CI: 1.1-2.2, p=0.03) and thromboprophylaxis (HR 0.57, 95%CI: 0.38-0.85, p=0.005), whereas age, sex, cancer, heart failure, recent stroke were not.

Conclusions: In medical hospitalized patients, immobility is an important DVT risk factor and DVT risk is correlated with the duration of immobilization.

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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/relevance-of-immobility-as-deep-vein-thrombosis-risk-factor-for-medically-ill-patients/