Abstract TP181: Prior Antiplatelet Use and Baseline Stroke Severity: A Population-Based Study

Introduction: There is conflicting evidence on the association of antiplatelet (AP) use prior to admission with baseline ischemic stroke (IS) severity. We evaluated this association within a large, bi-racial population. Methods: We identified all hospital-ascertained cases of IS that occurred in 2010 (including ED arriving, direct admits, and in-hospital strokes) within a population of 1.3 million. Specific AP used prior to presentation for IS were aspirin, clopidogrel, dipyridamole, prasugrel, and cilostazol. We excluded those on an anticoagulant (AC) medication for this analysis. Baseline IS severity was defined as NIH stroke scale score (NIHSS) on admission. A multivariable linear regression model including demographic and clinical variables with log-transformed NIHSS as the dependent variable was used to evaluate the effect of prior AP use on stroke severity (results shown as percentage change in NIHSS). Results: In 2010, there were 2259 IS cases, of which 1982 (22% black, 55% female, median age 70 years [58, 81]) were included in the analysis, and 998 (50%) had history of prior AP use. Unadjusted, minor stroke (NIHSS ≤5) was slightly less common in those with prior AP use compared with those without (68% vs. 72%; p=0.04). In the multivariable model among patients with history of atrial fibrillation (AF) yet not on AC, a significant 23% reduction in NIHSS (average NIHSS 6.00 to 4.88, p=0.02) was seen in those with prior AP use. No such association was found in patients with no history of AF. The table displays the multivariable model of stroke severity. Conclusion: We found that prior AP use did not have significant association with baseline stroke severity in the multivariable analysis. However, a subgroup of patients with history of AF had significantly less severe strokes with prior antiplatelet use.