Efficacy and safety of
vorapaxar (a
protease-activated receptor 1 antagonist) was analyzed across ages as a continuous and a categorical variable in the 12,944 patients with NSTE ACS enrolled in the TRACER trial. To evaluate the effect of age, Cox regression models were developed to estimate hazard ratios (HRs) with the adjustment of other baseline characteristics and randomized treatment for the primary efficacy composite of cardiovascular death,
myocardial infarction (MI),
stroke, recurrent
ischemia with
rehospitalization, or urgent coronary revascularization, and the primary safety composite of moderate or severe Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO)
bleeding.
RESULTS: The median age of the population was 64years (25th, 75th percentiles = 58, 71). Also, 1,791 patients (13.8%) were ≤54years of age, 4,968 (38.4%) were between 55 and 64 years, 3,979 (30.7%) were between 65 and 74 years, and 2,206 (17.1%) were 75years or older. Older patients had higher rates of
hypertension, renal insufficiency, and previous
stroke and worse Killip class. The oldest age group (≥75years) had substantially higher 2-year rates of the composite ischemic end point and moderate or severe GUSTO
bleeding compared with the youngest age group (≤54years). The relationships between treatment assignment (
vorapaxar vs placebo) and efficacy outcomes did not vary by age. For the primary efficacy end point, the HRs (95% CIs) comparing
vorapaxar and placebo in the 4 age groups were as follows: 1.12 (0.88-1.43), 0.88 (0.76-1.02), 0.89 (0.76-1.04), and 0.88 (0.74-1.06), respectively (P value for interaction = .435). Similar to what was observed for efficacy outcomes, we did not observe any interaction between
vorapaxar and age on
bleeding outcomes. For the composite of moderate or severe
bleeding according to the GUSTO classification, the HRs (95% CIs) comparing
vorapaxar and placebo in the 4 age groups were 1.73 (0.89-3.34), 1.39 (1.04-1.86), 1.10 (0.85-1.42), and 1.73 (1.29-2.33), respectively (P value for interaction = .574).
CONCLUSION: Older patients had a greater risk for ischemic and
bleeding events; however, the efficacy and safety of
vorapaxar in NSTE ACS were not significantly influenced by age.