Abstract 179: Bending the Curve: Are We Labelling More Low-risk People as TIA or Has Modern Medical Management of TIA Reduced Stroke Recurrence Over Time?

Abstract

Background: Management of transient ischemic attacks (TIA) in specialized stroke centres and prevention clinics have been shown to decrease stroke recurrence and mortality. The impact of these services on a population level are unknown. We aimed to analyze whether modern medical management of TIA has decreased the rate of stroke recurrence and mortality over time in Ontario. Methods: Administrative data from the Canadian Institute for Health Information’s Discharge Abstract Database (DAD) and National Ambulatory Care Reporting System (NACRS) database 2003-2015 were analyzed and rates of stroke recurrence and mortality were calculated. Results: From 2003 to 2015 in Ontario, there were an increasing number of discharges from emergency departments (ED) and a decreasing number of discharges from hospitals. Linear regressions of stroke recurrence at 24 hours, 48 hours, day 7, 30, 90, 180, and 1 year after a TIA showed significantly faster decline between 2003-2015 (p <0.01). Overall stroke recurrence at 1 year decreased from 5.8% to 2.7% between 2003 and 2015, a rate greater than could be explained just from increasing numbers of people labelled as TIA. From 2003-2015, mortality after ED discharge following a TIA decreased from 1.3% to 0.3% (p<0.001), also a greater decline than expected. Interpretations: There is increasing outpatient management of TIAs in Ontario. The observed decline in stroke recurrence was greater than can be explained by referral bias alone, and the increasingly negative slopes of these lines from 24 hours to 1 year suggest a cumulative benefit of improved TIA management over time rather than just increased labelling of low-risk patients. On a population-level, stroke recurrence and mortality after TIA have declined from 2003 to 2015 with a province-wide system of organized stroke care. In contrast to other studies that have shown reduced stroke recurrence and mortality at specialized centres, this study demonstrates the impact of these programs at a population level.