106 Stroke Prophylaxis and 30-Day Clinical Outcomes After US Emergency Department Diagnosis and Discharge for Atrial Fibrillation

Abstract

Atrial fibrillation (AF) is a potentially serious condition that can lead to thromboembolic complications. Current guidelines recommend oral anticoagulation (OAC) to reduce the risk of stroke in high-risk AF candidates but US emergency department (ED) OAC prescribing rates and 30-day clinical outcomes after an AF diagnosis are unknown. We determined OAC prescribing practices and 30-day clinical outcomes after ED diagnosis of new AF. This was a population-based, retrospective cohort of Medicare fee-for-service beneficiaries from 2011 to 2012. The cohort included beneficiaries age ≥65, without prior OAC filled in 90 days, who were discharged from the ED with a new diagnosis of AF. We calculated proportions of patients filling an OAC prescription within 10 days of an ED AF diagnosis. Adverse events within 30 days of the ED visit were identified via ICD-9 codes from inpatient and outpatient ED claims data. We performed descriptive statistics and bivariate analyses to assess associations between filling an OAC and patient/hospital characteristics and clinical outcomes. We stratified analyses by risk for stroke (CHA2DS2-VASc) and bleeding (HAS-BLED). Of those discharged from the ED with a diagnosis of AF (n=9,147), 91.4% (n=8,363) were intermediate to high-risk (CHA2DS2-VASc≥1 in males and CHA2DS2-VASc ≥ 2 in females) for stroke. Of those eligible for stroke prophylaxis [high-stroke risk with low-moderate bleeding risk (n=3,968)], 74.5% (n=2,958) did not fill an OAC prescription within 10 days. Of those prescribed, 71.4% were prescribed by an ED provider. Warfarin was the most common OAC ED prescription (64.6%), followed by dabigatran (21.0%), enoxaparin (8.0%), and rivaroxaban (6.4%). In high stroke risk patients, ischemic strokes occurred in 3.1% (40/1302) of those with OACs filled vs. 2.1% (132/6219) of those unfilled (p<0.01). Bleeding events occurred in less than 10 patients in this cohort of OAC filled, and in 1.4% (44/3247) of those without an OAC filled. In ED patients with a new diagnosis of AF and at high stroke risk, only a minority are prescribed an OAC within 10 days. Among these patients, OAC prescribing could potentially avoid ischemic events in up to 2.1% of patients with AF. These data indicate a practice gap in appropriate OAC prescribing.Tabled 1Table 1. 30-day clinical outcomes of patients discharged from the ED* stratified by CHA2DS2-VASc1, HAS-BLED2, OAC prescription fill within 10 days of AF ED visitStroke Risk (CHA2DS2-VASC1)Bleeding Risk (HAS-BLED2)OACs3 filled, prescribed by EM provider, within 10 daysOverall N (n=9147)Any Adverse Event4Any Bleed-Related Adverse Event5Ischemic Stroke6n%n%n%n%Any riskAny risk9147100.0%OACs filled157317.2%28618.2%161.0%452.9%No OACs filled757482.8%123916.4%1001.3%1411.9%High riskAny risk7521100.0%OACs filled130217.3%25219.4%161.2%403.1%No OACs filled621982.7%111718.0%931.5%1322.1%Low/ Moderate3968100.0%OACs filled72118.2%12817.8%N/A7N/A7202.8%No OACs filled324781.8%48615.0%441.4%541.7%High3553100.0%OACs filled58116.4%12421.3%N/A7N/A7203.4%No OACs filled297283.6%63121.2%491.6%782.6%1CHA2DS2-VASc (congestive heart failure, hypertension, age≥75, diabetes mellitus, prior stroke or transient ischemic attack, sex, age 65-74 years, and vascular disease). 0 in males, 1 in females = low risk for stroke, 1 in males = moderate risk, and ≥ 2 high risk.2HAS-BLED [hypertension, abnormal renal function or liver function, stroke, bleeding, labile INR [excluded as all patients not on warfarin prior to inclusion), elderly >85yo, and drugs and alcohol]: 0 to 2 = low to moderate risk (anticoagulant could be considered), >2 = high risk (alternative to anticoagulation should be considered).3Includes: Warfarin, dabigatran, enoxaparin, rivaroxaban, and dalteparin. Excludes salicyclic acid (aspirin).4Any adverse event in 30 days of interest: Death, inpatient admission, any stroke, non-stroke brain bleed, GI bleed, CVA, occlusion of cerebral arteries, transient cerebral ischemia, AMI, mesenteric ischemia, thrombolytic event, intrathoracic hemorrhage.5 Any bleed-related AE includes: hemorrhagic stroke, CVA, non-stroke brain bleed, GI bleed.6Ischemic stroke also includes occlusion of cerebral arteries and transient cerebral ischemia.7Medicare allows the reporting of cell sizes> 10. Thus, certain fields were not reported.*ED: Emergency Department. Open table in a new tab