96 Appropriate Stroke Prophylaxis Action After US Emergency Department Diagnosis and Discharge of Atrial Fibrillation and Flutter Patients

Abstract

Oral anticoagulation (OAC) reduces stroke and mortality risk in patients with nonvalvular atrial fibrillation and flutter (AFF). The incidence of US emergency department (ED) OAC initiation is poorly understood, as are the appropriate actions following discharge. We examined stroke prophylaxis actions on, and shortly following, ED discharge of stroke-prone AFF patients in a large integrated health care delivery system. We included all adults with a primary diagnosis of nonvalvular AFF, high stroke risk (CHA2DS2-VASc ≥2), and no recent (<90d) OAC at discharge from 21 EDs in Kaiser Permanente Northern California between 2010-2017. Rates of appropriate stroke prevention action were calculated for all eligible discharges per calendar year. Actions were defined as either (1) an OAC prescription by an ED or follow-up provider, (2) a referral to a pharmacy-led anticoagulation management service (AMS), or (3) receipt of both an OAC prescription and AMS referral, within 10 days of ED discharge. We estimated appropriate OAC action (yes/no) with a mixed logistic model with sex, age, race, Hispanic ethnicity, stroke (CHA2DS2-VASc) and bleeding (HAS-BLED) risk and year as a fixed effect, and accounting for clustering by patient. Among 10,281 eligible ED discharges, mean age was 73.7 (STD 11.4) years, 61% were female, and mean CHA2DS2-VASc score was 3.7 (STD 1.62). From 2010 to 2017, there was steady increase in patients receiving both an OAC prescription and referral to AMS, 16.0 to 27.9% (Figure). The rate of no intervention decreased from 82.4 to 65.0% of eligible patients. Factors inversely associated with stroke prevention action within 10 days of ED discharge include female sex (aOR 0.79, 95% CI 0.71-0.88), age >74 years (0.59, 0.45-0.76) vs <64yo, high bleeding risk by HAS-BLED score (0.70, 0.58-0.85) vs low risk respectively, and highest stroke risk (CHA2DS2-VASc score 6-9) (0.70, 0.60-0.84) vs lower risk (CHA2DS2-VASc scores 2-4). The odds of receiving any action was 2.6 times higher in 2017 compared to 2010 (aOR 2.60, 2.08-3.24). Within a community-based ED population of AFF patients at high-stroke risk, the rate of appropriate stroke prevention action increased over the 7-year study period. However, there remains an opportunity to improve AFF thromboprophylaxis as more than half of the eligible patients in 2017 were not receiving appropriate stroke prevention action within 10 days of their index visit. Additionally, female sex and those greater than 74yo were less likely to receive appropriate action compared to men and those younger than 65yo. The undertreatment of those greater than 74yo suggests a misunderstanding of the net clinical benefit associated with OAC in the elderly. Furthermore, opportunities to address sex disparities exist as we seek to improve stroke prophylaxis in nonvalvular AF patients discharged from the ED.