PB0502 - Factors associated with outpatient treatment among patients with low-risk pulmonary embolism

Background: One-third to one-half of acute pulmonary emboli (PE) are considered low-risk (LRPE), and there is mounting evidence for treating patients with LRPE without hospital admission. However, there are limited data on the criteria that clinicians use when selecting patients for outpatient treatment.

Aims: To identify patient characteristics associated with clinicians’ decisions to treat LRPE as outpatients.

Methods: We performed a retrospective multicenter analysis of 379 LRPE patients diagnosed in the EDs of two urban, academic medical centers. We defined LRPE as non-saddle, non-main pulmonary artery PE with troponin T < 0.1 ng/mL, NT-proBNP < 500 mg/mL, and no right ventricular dysfunction on echocardiogram (if performed). Clinicians were provided a protocol by which LRPE patients could be treated without hospitalization, with anticoagulation and follow up. After protocol implementation, 37% of LRPE patients were treated as outpatients. We performed forward stepwise logistic regression of 67 factors to identify those associated with outpatient treatment of LRPE.

Results: Demographics of LRPE patients are in Table 1. Table 2 shows that increasing age, renal insufficiency, and tachycardia were associated with a lower likelihood of outpatient treatment, while inactive/past malignancy, liver disease, and Hispanic ethnicity were associated with a higher likelihood.

Conclusion(s): Even with a protocol to support outpatient treatment of PE, most LRPE are admitted to the hospital. We identified six factors as associated with clinicians’ decision to treat LRPE as outpatients, three increasing and three decreasing the likelihood of outpatient treatment. Of these factors, only three are included in the Hestia criteria for outpatient VTE treatment. Other criteria, including pregnancy, active bleeding, and limited social support, were not associated. Future investigations should explore ways to improve the selection of LRPE patients for outpatient treatment.