Clinical Predictors of Prophylaxis Use Prior to the Onset of Acute Venous Thromboembolism in Hospitalized Patients: Swiss Venous ThromboEmbolism Registry (SWIVTER)

Background: Venous thromboembolism (VTE) prophylaxis among hospitalized patients remains underutilized. We investigated the use of appropriate prophylaxis and predictors for using prophylaxis prior to the onset of acute VTE.

Methods: In 14 academic and non-academic Swiss hospitals, 567 consecutive patients (306 medical and 261 surgical patients) with objectively confirmed acute VTE and hospitalization within 30 days prior to the VTE event were enrolled. Data on acute and chronic comorbidities, VTE risk factors, and prophylaxis use prior to VTE were prospectively recorded.

Results: Among the 567 patients (62±16 years), deep vein thrombosis (DVT) alone was diagnosed in 222 (39%), acute pulmonary embolism (PE) in 218 (38%), and PE plus DVT in 127 (22%). Overall, prophylaxis was used in 329 (58%) patients prior to the VTE event. Among the medical patients, 146 (48%) received prophylaxis, and among the surgical patients, 183 (70%) received prophylaxis (p <0.001). The indication for prophylaxis was present in 262 (86%) medical patients and in 217 (83%) surgical patients. Among the patients with an indication for prophylaxis, 135 (52%) of the medical patients and 165 (76%) of the surgical patients received prophylaxis (p <0.001). Admission to the intensive care unit (OR 3.28, 95% CI 1.94–5.57), recent surgery (OR 2.28, 95% CI 1.51–3.44), bed rest >3 days (OR 2.12, 95% CI 1.45–3.09), obesity (OR 2.01, 95% CI 1.03–3.90), prior DVT (OR 1.71, 95% CI 1.31–2.24), and prior PE (OR 1.54, 95% CI 1.05–2.26) were independent predictors of prophylaxis. In contrast, cancer (OR 1.06, 95% CI 0.89–1.25), age (OR 0.99, 95% CI 0.98–1.01), acute heart failure (OR 1.13, 95% CI 0.79–1.63), and acute respiratory failure (OR 1.19, 95% CI 0.89–1.59) were not predictive of prophylaxis.

Conclusions: Although an indication for prophylaxis was present in most patients who suffered acute VTE as a complication during or shortly after hospitalization, almost half did not receive any form of prophylaxis. Future effort should focus on the improvement of prophylaxis in hospitalized patients, particularly in patients with cancer, acute heart or respiratory failure, and in the elderly.