BACKGROUND:Several healthcare organisations strongly recommend aspirin usage for high-risk patients to preventcardiovascular disease. This study retrospectively audited the usage of aspirin as an antiplatelet agent in twocohorts of Australian residential aged care facility (RACF) residents in the Perth, Western Australia (WA) andSydney, New South Wales (NSW) metropolitan and surrounding areas. The primary objective was to comparethe appropriateness of current practice regarding aspirin usage with the National Heart Foundation of Australia(NHF) guidelines. The secondary objective was to identify predictors of aspirin usage and non-usage to permittargeting of ‘at risk’ groups.METHODS:Data on aspirin usage, resident demographics, concurrent drug use and disease states, especially thoserepresenting potential predictors of aspirin usage or non-usage, were recorded. Data analysis was performedusing independent samples t-testing, χ2 testing and univariate and multivariate logistic regression analysis.RESULTS:Rates of aspirin use were 35.2% and 32.5% in the WA and NSW cohorts, respectively, with no differencebetween the two groups (p=0.476). Common aspirin dosages were 100mg and 150mg daily. Aspirin prescribingrates for indicated cardiovascular conditions varied from 23.1% to 47.1% in the WA residents. Multivariatelogistic regression analyses on the combined data demonstrated male gender (OR=1.46, 95% CI: 1.06-2.01) andconcurrent usage of angiotensin receptor blockers (OR=1.61, 95% CI: 1.06-2.45), angiotensin convertingenzyme inhibitors (OR=1.78, 95% CI: 1.28-2.46), beta-blockers (OR=1.99, 95% CI: 1.38-2.85),antihyperlipidemics (OR=1.62, 95% CI: 1.14-2.31) and antiarrhythmics (OR=1.57, 95% CI: 1.02-2.41) to bepredictors of aspirin usage. Predictors of aspirin non-usage were clopidogrel (OR=0.28, 95% CI: 0.15-0.51) andwarfarin usage (OR=0.09, 95% CI: 0.03-0.24).CONCLUSIONS:Suboptimal aspirin usage was demonstrated among both cohorts of RACF residents in spite of strongrecommendations from national guidelines. Various predictors of aspirin usage and non-usage were identified.Significant efforts should be made to encourage aspirin usage in the elderly ‘at risk’ population.