European Heart Journal Advance Access originally published online on June 2, 2008
European Heart Journal 2008 29(15):1827-1833; doi:10.1093/eurheartj/ehn236
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Outcomes in elderly patients with acute coronary syndromes randomized to enoxaparin vs. unfractionated heparin: results from the SYNERGY trial
1 Duke Clinical Research Institute, Box 3850, 2400 Pratt Street, Room 311, Terrace Level, Durham, NC 27705, USA
2 Green Lane Cardiovascular Service, Auckland, New Zealand
3 University of the Sciences in Philadelphia, Philadelphia, PA, USA
4 Clinique Universitaire St Luc, Brussels, Belgium
5 Flinders Medical Centre, Adelaide, Australia
Received 31 December 2007; revised 22 April 2008; accepted 15 May 2008; online publish-ahead-of-print 2 June 2008.
* Corresponding author. Tel: +1 919 668 8241, Fax: +1 919 668 7056, Email: renato.lopes{at}duke.edu
Aims: Elderly patients are at high risk from non-ST-segment elevation acute coronary syndromes (NSTE ACS) as well as from treatment-related complications. Age-associated changes in physiology may alter the risk and benefit expected from therapy. The SYNERGY database was used to study the influence of age on treatment outcomes with enoxaparin vs. unfractionated heparin (UFH) in patients with high-risk NSTE ACS.
Methods and results: Age was analysed as a continuous and categorical variable (<65, 65–74, and 
75 years, and <75 and 75 years) for descriptive purposes. Logistic regression was used to adjust the outcomes of 30-day death, death or myocardial infarction (MI), and major bleeding for baseline characteristics. Odds ratios compared outcomes by age and by treatment within age groups. Model interaction terms were used to test for statistically different outcomes by treatment and age. Overall, 9977 randomized patients had age information, of whom 25.5% (2540) were 75 years of age. Elderly patients (75 years) had more cardiovascular risk factors, prior cardiac disease, and higher acuity at presentation. After adjustment, advanced age (per 10 years) was associated with 30-day death or MI [risk odds ratios (ROR): 1.14, P = 0.002], 30-day death (ROR: 1.54, P < 0.0001), and 1-year death (ROR: 1.47, P < 0.0001), as well with TIMI major bleeding (ROR: 1.21, P = 0.001), GUSTO severe bleeding (ROR: 1.20, P = 0.047), and transfusion (ROR: 1.04, P = 0.324). Although there was a higher rate of GUSTO severe bleeding noted with enoxaparin in elderly patients, the overall relationships between treatment (UFH or enoxaparin) and outcomes did not vary significantly as a function of the patient's age.
Conclusion: Although higher rates of adverse events are seen in the oldest subgroup (age 75 years) treated with enoxaparin, statistical comparisons confirm similar efficacy and safety of enoxaparin and UFH across age subgroups as was demonstrated overall in SYNERGY.
Key Words: Non-ST-segment elevation acute coronary syndromes • Age • Enoxaparin • Unfractionated heparin • Outcomes