Comparative Effectiveness and Costs of Enoxaparin Monotherapy Versus Unfractionated Heparin Monotherapy in Treating Acute Coronary Syndrome.

Background Enoxaparin and unfractionated heparin (UFH) are guideline-recommended anticoagulants for patients with acute coronary syndrome (ACS), including unstable angina (UA) and myocardial infarction with (STEMI) or without ST-segment elevation (NSTEMI). Prior efficacy and safety evidence are mainly from clinical trials. Economic data are insufficient. This study examined the differences in utilization, effectiveness, safety, and costs in treating ACS between enoxaparin and UFH monotherapy using real-world data. Methods Using data from 859 US hospitals, inpatients ≥ 18 years of age with a diagnosis of an initial episode of ACS between 2010 and 2016 were identified. Outcomes included 30-day risk of non-fatal myocardial infarction (MI), recurrent angina, in-hospital mortality, composite ischemic complication (having MI/recurrent angina/death), major bleeding, and costs. Multivariable regression was used to compare outcomes between enoxaparin and UFH monotherapy. Results Among 1,048,053 eligible patients (UA: 219,259; NSTEMI: 582,134; STEMI: 246,660), the prevalence of enoxaparin monotherapy was 12.0%, 13.9%, and 5.1%, and the prevalence of UFH monotherapy was 45.1%, 43.1% and 59.8%, for UA, NSTEMI, and STEMI patients, respectively. Enoxaparin was associated with a lower risk of ischemic complications and death among NSTEMI, but not in UA or STEMI patients, and with a lower risk of major bleeding in all patients. Cost savings per patient during index admission and 30-day follow-up for enoxaparin over UFH was $2972 for UA, $2475 for NSTEMI, and $3050 for STEMI. Conclusions Enoxaparin was associated with a lower risk of ischemic complications (including death), lower costs, and better safety than UFH among NSTEMI patients. Improving upstream selection of anticoagulants in appropriate populations may help optimize clinical outcomes and costs.