Geographic Clustering of Emergency Department Presentations for Atrial Fibrillation and Flutter in Alberta, Canada

Abstract

Objectives: Atrial fibrillation and flutter (AFF) are the most common arrhythmias seen in the outpatient setting, and they affect more than 300,000 adult Canadians. The aims of this study were to examine temporal and geographic trends in emergency department (ED) presentations made by adults (age ≥ 35 years) for AFF in Alberta, Canada, from 1999 to 2011. Statistical disease cluster detection techniques were used to identify geographic areas with higher numbers of individuals presenting with AFF and higher numbers of ED presentations for AFF than expected by chance alone. Geographic clusters of individuals with stroke or heart failure follow-up within 365 days of ED presentations for AFF were also identified.Methods: All ED presentations for AFF made by individuals aged ≥35 years were extracted from Alberta's Ambulatory Care Classification System. The Alberta Health Care Insurance Plan provided population counts and demographics for the patients presenting (age, sex, year, geographic unit). The Physician Claims File provided non-ED physician claims data after a patient's ED presentation. Statistical analyses included numerical and graphical summaries, directly standardized rates, and statistical disease cluster detection tests.Results: During 12 years, there were 63,395 ED presentations for AFF made by 32,101 individuals. Standardized rates remained relatively stable over time, at about two per 1,000 for individuals presenting to the ED for AFF and about three per 1,000 for ED presentations for AFF. The northern and southeastern parts of the province were identified as clusters of individuals presenting for AFF, and ED presentations for AFF, and several of the areas demonstrated clusters in multiple years. Further, several of the geographic clusters were also identified as potential clusters for stroke or heart failure within 365 days after the ED presentations for AFF.Conclusions: This population-based study spanned 12 fiscal years and showed variations in the number of people presenting to EDs for AFF and the number of ED presentations for AFF over geography. The potential clusters identified may represent geographic areas with higher disease severity or a lower availability of non-ED health services. The clusters are not all likely to have occurred by chance, and further investigation and intervention could occur to reduce ED presentations for AFF.

Geographic clustering of emergency department presentations for acute coronary syndromes and heart failure in Alberta: a population-based study

“…In 2010/11, we identified clusters of patients presenting to the emergency department for atrial fibrillation and flutter in several areas as well as clusters of these patients with a subsequent physician claim for stroke or heart failure. 2 In the previous study, we used a different statistical method for detecting clusters and found that most of the northern, some of the western and some of the southern areas were clusters, alone or in combination with neighbouring areas. van Rheenen and colleagues 13 also used the spatial scan test and dissemination areas to identify regional variation in ischemic stroke, transient ischemic attack, intracerebral hemorrhage, subarachnoid hemorrhage and in-hospital mortality for Alberta patients with a diagnosis of stroke who accessed the health care system (e.g., hospital admissions, ambulatory care including emergency department visits) during 2002-2008.…”

Despite Having Worse Risk Profiles, Northern Albertans Wait Longer for Specialist Follow-up After Emergency Department Visits for Atrial Fibrillation

“…In Alberta, we previously identified clusters of higher numbers of patients presenting to EDs in 2010-2011 for AFF, as well as clusters of higher numbers of patients who presented to the ED with AFF and had a subsequent physician claim for stroke or heart failure in the 365 days following the ED visit. 28 We also examined geographic clustering of higher numbers of patients presenting to Alberta EDs in 2010-2011 for acute coronary syndromes and heart failure. 29 Similar clusters were identified for the 2 conditions (northwest and southeast areas for acute coronary syndromes and north and southeast areas for heart failure).…”