Correct Dose of Anti-Clotting Rx in Elderly Continues to Elude
(HealthDay News) – There are no differences in ischemic or bleeding outcomes with reduced-dose prasugrel vs. clopidogrel in elderly patients with acute coronary syndromes (ACS), according to a study published in the Aug. 20 issue of Circulation.
Matthew T. Roe, MD, from the Duke Clinical Research Institute in Durham, NC, and colleagues randomized 9,326 (7,243 <75 years) medically managed ACS patients participating in the TRILOGY ACS (Targeted Platelet Inhibition to Clarify the Optimal Strategy to Medically Manage Acute Coronary Syndromes ) trial to prasugrel (10mg/d; 5mg/d for those ≥75 years or <75 years and <60kg) or clopidogrel (75mg/d), plus aspirin, for ≤30 months. In a platelet-function sub-study (PFS), 515 patients ≥75 years had serial platelet reactivity unit (PRU) measurements.
The researchers found that cumulative risks of the primary end point (cardiovascular death/myocardial infarction/stroke) and TIMI (thrombolysis in myocardial infarction) major bleeding increased with age, with more than a two-fold higher risk in older participants. In patients over 75 years, reduced-dose prasugrel and clopidogrel had similar primary end point rates and similar TIMI-major bleeding (4.1% and 3.4% for prasugrel and clopidogrel, respectively; hazard ratio, 1.09; 95% confidence interval, 0.57–2.08). There was a non-significant treatment-by-weight interaction for PRU values among participants over 75 years in the PFS (P=0.06), despite a correlation between lower 30-day on-treatment PRU values and lower weight in the prasugrel group. After analyzing data from all patients over 75 years, no differences in weight were noted between those with and those without TIMI major/minor bleeding.
"Older age is associated with substantially increased long-term cardiovascular risk and bleeding among medically managed ACS patients, with no differences in ischemic or bleeding outcomes with reduced-dose prasugrel vs. clopidogrel in elderly patients," the authors write.
Several authors disclosed financial ties to pharmaceutical companies, including Eli Lilly and Daiichi Sankyo, both of which funded the study.