Association between the use of fondaparinux vs low-molecular-weight heparin and clinical outcomes in patients with non-ST-segment elevation myocardial infarction

Importance Fondaparinux was associated with reduced major bleeding events and improved survival compared with low-molecular-weight heparin (LMWH) in a large randomized clinical trial involving patients with non–ST-segment elevation myocardial infarction (NSTEMI). Large-scale experience of the use of fondaparinux vs LMWH in a nontrial setting is lacking. Objective To study the association between the use of fondaparinux vs LMWH and outcomes in patients with NSTEMI in Sweden. Design, Setting, and Patients Prospective multicenter cohort study from the Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies registry involving 40 616 consecutive patients with NSTEMI who received fondaparinux or LMWH between September 1, 2006, through June 30, 2010, with the last follow-up on December 31, 2010. Exposures In-hospital treatment with fondaparinux or LMWH during the hospital stay. Main Outcomes and Measures In-hospital severe bleeding events and death and 30- and 180-day death, MI, stroke, and major bleeding events. Logistic regression models adjusted for calendar time, admitting hospital, baseline characteristics, and in-hospital revascularization. Results In total, 14 791 patients (36.4%) were treated with fondaparinux and 25 825 (63.6%) with LMWH. One hundred sixty-five patients (1.1%) in the fondaparinux group vs 461 patients (1.8%) in the LMWH group experienced in-hospital bleeding events (adjusted odds ratio [OR], 0.54; 95% CI, 0.42-0.70). A total of 394 patients (2.7%) in the fondaparinux group died while in the hospital vs 1022 (4.0%) in the LMWH group (adjusted OR, 0.75; 95% CI, 0.63-0.89). The differences in major bleeding events and mortality between the 2 treatments were similar at 30 and 180 days. There were no significant differences in the number of recurrent MI and stroke events at 30 or 180 days among the 2 treatment groups. Conclusions and Relevance In routine clinical care of patients with NSTEMI, fondaparinux was associated with lower odds than LMWH of major bleeding events and death both in-hospital and up to 180 days afterward.