Background: There is limited evidence in the literature regarding the administration of clopidogrel to acute coronary syndrome (ACS) in patients over 75 years of age. Most studies excluded this age group, making the subject controversial due to the increased risk of bleeding in this population. Objective: This is a retrospective, unicentric, and observational study aimed at assessing whether the administration of clopidogrel loading dose increases bleeding rates in patients over 75 years of age. Methods: Patients were divided into two groups: group I: 75 mg of clopidogrel; group II: 300-to 600-mg loading dose of clopidogrel. A total of 174 patients (129 in group I and 45 in group II) were included between May 2010 and May 2015. Statistical analysis: The primary outcome was bleeding (major and/or minor). The secondary outcome was combined events (cardiogenic shock, reinfarction, death, stroke and bleeding). The comparison between groups was performed through Q-square and T-test. The multivariate analysis was performed by logistic regression, being considered significant p < 0.05. Results: Comparisons between groups I and II showed differences in the prevalence of diabetes (46.5% vs. 24.4%, p = 0.01), arterial hypertension (90.7% vs. 75, p = 0.01), dyslipidemia (62% vs. 42.2%, p = 0.021), ST segment elevation (11.6% vs. 26.6%, p = 0.016) and coronary intervention percutaneous (16.5% vs. 62.2%, p < 0.0001), respectively. In the multivariate analysis, significant differences were observed between groups I and II in relation to the occurrence of bleeding (8.5% vs. 20%, OR = 0.173, 95% CI: 0.049 - 0.614, p = 0.007). Conclusion: A loading dose of 300 mg or more of clopidogrel.
