The significant clinical benefit and overall safety of ticagrelor (Brilinta, AstraZeneca) compared with clopidogrel in acute coronary syndrome (ACS) patients in the PLATO cohort were not found to depend on age. These findings were published in the September issue of Circulation: Cardiovascular Quality and Outcomes.
Elderly patients with ACS are at high risk of recurrent ischemic events and death, and for both antithrombotic therapy and revascularization. The study authors also noted the increased risk of bleeding in elderly compared with younger patients using some antiplatelet and anticoagulant therapies reduced the net clinical benefit of these therapies.
“The clinical picture of ACS in the elderly is often further complicated by comorbid conditions, including atrial fibrillation, diabetes mellitus, renal impairment, heart failure and cerebrovascular disease,” wrote lead author Steen Husted, MD, DSc, of the department of cardiology at Arhus University Hospital in Arhus, Denmark, and colleagues. “With lengthening life expectancy and the expansion of the older population, these individuals will account for an increasing proportion of patients with ACS in the future.”
This prespecified analysis investigated the effect and treatment-related complications of ticagrelor vs. clopidogrel in elderly patients (75 years of age or older) with ACS compared with those less than 75 years of age.
The researchers evaluated the association between age and the primary composite outcome, as well as major bleeding in the PLATO (PLATelet inhibition and patient Outcomes) trial using Cox proportional hazards. Similar models were used to evaluate the interaction of age with treatment effects.
The clinical benefit of ticagrelor over clopidogrel was not significantly different between patients 75 years of age or older (2,878 patients) and those less than 75 years of age (15,744 patients) with respect to the composite of cardiovascular death, MI or stroke, MI, cardiovascular death, definite stent thrombosis or all-cause mortality.
The investigators also observed no increase in PLATO-defined overall major bleeding with ticagrelor versus clopidogrel in patients 75 years or older, or patients aged less than 75 years. Dyspnea and ventricular pauses were more common during ticagrelor than clopidogrel treatment, with no evidence of an age-by-treatment interaction.
The findings of the present analysis are consistent with those for the main PLATO cohort as well, which indicated that “the antithrombotic benefits of ticagrelor apply throughout the age range evaluated,” wrote Husted et al.
One limitation of the analysis is that, although the analyses based on age groups were prespecified, the subgroup of patients aged at least 75 years was “relatively small” (2,878 patients). According to the authors, that would have affected the power to reach statistical significance in comparisons between the treatment groups.