Analysis of Prescriptions for Dual Antiplatelet Therapy After Acute Ischemic Stroke

Abstract

After the publication of the CHANCE (Clopidogrel in High Risk Patients With Acute Nondisabling Cerebrovascular Events) and POINT (Platelet-Oriented Inhibition in New Transient Ischemic Attack and Minor Ischemic Stroke) clinical trials, the American Heart Association/American Stroke Association (AHA/ASA) issued a new class 1, level of evidence A, recommendation for dual antiplatelet therapy (DAPT; aspirin plus clopidogrel) for secondary prevention in patients with minor ischemic stroke (National Institutes of Health Stroke Scale [NIHSS] score ≤3). The extent to which variations in DAPT prescribing patterns remain and the extent to which practice patterns in the US are consistent with evidence-based guidelines are unknown. To evaluate the discharge DAPT prescribing patterns after publication of the new AHA/ASA guidelines and assess the extent of hospital-level variation in the use of DAPT for secondary prevention in patients with minor stroke (NIHSS score ≤3), as indicated by guidelines, and in patients with nonminor stroke (NIHSS score >3), for whom the risks and benefits of DAPT have not been fully established. This multicenter retrospective cohort study involved 132 817 patients from 1890 hospitals participating in the AHA/ASA Get With The Guidelines-Stroke program. Patients who were hospitalized for acute ischemic stroke and prescribed antiplatelet therapy at discharge between October 1, 2019, and June 30, 2020, were included. Minor ischemic stroke (NIHSS score ≤3) vs nonminor ischemic stroke (NIHSS score >3). The primary outcome was DAPT prescription at discharge. The extent to which variations in DAPT use were explained at the hospital level was assessed by calculating the median odds ratio (OR), which was derived using multivariable logistic regression analysis and compared the likelihood that 2 patients with identical clinical features admitted to 2 randomly selected hospitals (1 with higher propensity and 1 with lower propensity for DAPT use) would receive DAPT at discharge. Associations between hospital-level DAPT use among patients with minor vs nonminor stroke were evaluated using Pearson ρ correlation coefficients. Among 132 817 patients (median [IQR] age, 68 [59-78] years; 68 768 men [51.8%]), 4282 (3.2%) were Asian, 11 254 (8.5%) were Hispanic, 27 221 (20.5%) were non-Hispanic Black, 84 468 (63.6%) were non-Hispanic White, and 5592 (4.2%) were of other races and/or ethnicities (including American Indian or Alaska Native, Native Hawaiian or Pacific Islander, and unable to determine). Overall, 86 551 patients (65.2%) presented with minor ischemic stroke, and 46 266 patients (34.8%) presented with nonminor ischemic stroke. After the 2019 AHA/ASA guideline updates, 40 661 patients (47.0%) with minor stroke (NIHSS median [IQR] score, 1 [0-2]) and 19 703 patients (42.6%) with nonminor stroke (NIHSS median [IQR] score, 6 [5-9]) received DAPT at discharge. Despite guideline recommendations, 45 890 patients (53.0%) with minor stroke did not receive DAPT. After accounting for patient characteristics, substantial hospital-level variations were found in the use of DAPT in those with minor stroke (median [IQR] hospital-level DAPT prescription rate, 44.8% [33.7%-57.7%]; range, 0%-91.7%; median OR, 2.03 [95% CI, 1.97-2.09]) when comparing 2 patients with identical risk factors discharged from 2 randomly selected hospitals, 1 with higher propensity and 1 with lower propensity for DAPT use. The use of DAPT in patients with nonminor stroke also varied significantly (median [IQR] hospital-level DAPT prescription rate, 41.4% [30.0%-53.8%]; range, 0%-100%; median OR, 1.90 [95% CI, 1.83-1.97]). Overall, hospitals that were more likely to prescribe DAPT for minor strokes were also more likely to prescribe DAPT for nonminor strokes (Pearson ρ = 0.72; P < .001). This cohort study found that despite updated AHA/ASA guidelines, more than 50% of patients with minor acute ischemic stroke did not receive DAPT at discharge. In contrast, more than 40% of patients with nonminor stroke received DAPT despite lack of evidence in this setting. These findings suggest that enhancing adherence to evidence-based DAPT practice guidelines may be a target for quality improvement in the treatment of patients with ischemic stroke.