Real-World Study Supports Fondaparinux Over Heparin for NSTEMI

Fondaparinux is associated with lower risks of severe bleeding and death compared with low-molecular-weight heparin (LMWH) in patients with NSTEMI treated in routine clinical practice, supporting prior trial findings, according to a study published in the February 17, 2015, issue of the Journal of the American Medical Association. Rates of recurrent MI and stroke, however, are similar between the 2 treatments.

Karolina Szummer, MD, PhD, of Karolinska University Hospital (Stockholm, Sweden), and colleagues looked at data from the SWEDEHEART registry on 40,616 consecutive patients with NSTEMI (median age 73; 37.2% female) treated at 72 Swedish hospitals providing acute cardiac care from September 2006 through June 2010. In all, 41.6% of patients underwent PCI during the initial hospital stay.

Use of fondaparinux increased from 0.7% of patients in the first calendar year to 84.8% in the last year. Overall, 36.4% of patients received in-hospital fondaparinux and 63.6% received LMWH.

After adjustment for year, admitting hospital, baseline characteristics, and in-hospital revascularization, rates of severe bleeding and death were lower in fondaparinux-treated patients while hospitalized and at 30 and 180 days postprocedure (table 1). Recurrent MI and stroke rates were comparable between the 2 groups.

Irrespective of renal function, fondaparinux was associated with lower rates of severe bleeding. Mortality risk was generally lower with fondaparinux than with LMWH, as well, although there was no difference between the treatments among patients with the most severe renal dysfunction, which “may indicate that the elevated risk of death in those with the lowest renal function category is explained by other mechanisms unrelated to bleeding,” the authors write.

In addition, the findings from the main analysis were consistent in the subgroup of patients who underwent PCI during the initial hospital stay; odds ratios suggested a benefit from fondaparinux, although none of the differences reached statistical significance.

Registry Results Match Trial Data

In the OASIS-5 trial, fondaparinux reduced severe in-hospital bleeding and mortality compared with the LMWH enoxaparin and was noninferior for ischemic outcomes in patients with NSTEMI.

The current study provides information on real-world outcomes after the European Society of Cardiology and the Swedish National Board of Health and Welfare recommended fondaparinux as a first-line anticoagulant for NSTEMI patients. Compared with the trial participants, registry patients had a median age about 5 years older, a similar rate of diabetes, a lower rate of hypertension, and higher frequencies of prior MI or stroke and of at least moderately severe renal dysfunction.

“The results from our study provide more certainty to the use of fondaparinux in routine clinical care, showing that in the broader population, the lower bleeding and death rates associated with fondaparinux treatment were consistent with the trial data,” Dr. Szummer and colleagues conclude.

They acknowledge that the study is limited by the likely presence of residual confounding, the fact that bleeding is often underreported in registries, and the lack of information on the dose and duration of fondaparinux and LMWH used.

Source:
Szummer K, Oldgren J, Lindhagen L, et al. Association between the use of fondaparinux vs low-molecular-weight heparin and clinical outcomes in patients with non–ST-segment elevation myocardial infarction. JAMA. 2015;313:707-716.

Related Stories:

• Fondaparinux Superior to Heparin for Most ACS Patients
• Fondaparinux Cuts Bleeding in ACS Patients Regardless of Other Antiplatelet Agents