Abstract
STUDY OBJECTIVE: Guidelines recommend low-molecular-weight heparin (LMWH) and direct oral anticoagulants (DOACs) rather than unfractionated heparin (UFH) for treatment of acute pulmonary embolism (PE) given their efficacy and reduced risk of bleeding. Using data from a large consortium of US hospitals, we examined trends in initial anticoagulation among hospitalized patients diagnosed with acute PE. METHODS: We conducted a retrospective study of inpatient and observation cases between January 1, 2011, and December 31, 2020, among individuals aged more than or equal to 18 years treated at acute care hospitals contributing data to the Premier Healthcare Database. Included cases received a diagnosis of acute PE, underwent imaging for PE, and received anticoagulation at the time of admission. The primary outcome was the initial anticoagulant selected for treatment. RESULTS: Among 299,016 cases at 1,045 hospitals, similar proportions received initial treatment with UFH (47.4%) and LMWH (47.9%). Between 2011 and 2020, the proportion of patients initially treated with UFH increased from 41.9% to 56.3%. Over this period, use of LMWH as the initial anticoagulant was reduced from 58.1% in 2011 to 37.3% in 2020. The proportion of cases admitted to the ICU, treated with mechanical ventilation or vasopressors, and inpatient mortality were stable. Factors most strongly associated with receipt of UFH were admission to the ICU (odds ratio [OR] 6.90; 95% confidence interval [CI] 6.31 to 7.54) or step-down unit (OR 2.30; 95% CI 2.16 to 2.45), receipt of thrombolysis (OR 4.25; 95% CI 3.09 to 5.84) or vasopressors (OR 1.83; 95% CI 1.32 to 2.54), and chronic renal disease (OR 1.67; 95% CI 1.54 to 1.81). CONCLUSIONS: Despite recommendations that LMWH and DOACs be considered first-line for most patients with acute PE, use of UFH is common and increasing. Further research is needed to elucidate factors associated with persistent use of UFH and opportunities for deimplementation of low-value care.