Post TIA care in Ontario: a population-based cohort study on secondary prevention

Background — Transient ischemic attacks (TIAs) often precede ischemic strokes. Little is known about adherence to secondary prevention guidelines among individuals post TIA.

Methods — We conducted a population-level, retrospective cohort study of individuals in Ontario, Canada, with a TIA between April 2010 to March 2019, that survived at least one year. We assessed low density lipoprotein (LDL) and glycated hemoglobin (HbA1C) testing, receipt of important secondary prevention medications for individuals aged 65 years and older, and receipt of influenza vaccines. Health care utilization was described in the 90 days following the TIA. We compared these rates to a cohort of individuals after first ischemic stroke.

Results — After exclusions, 36,487 individuals were included (mean age 68.6 years; 50.0 % female). LDL testing was performed in 66.3 % of individuals, and 58.4 % had an HbA1C test in the year following their TIA. Lipid lowering medications were prescribed to 75.2 %, while 82.7 % received an antihypertensive. Among individuals with diabetes, 68.6 % were prescribed an anti-hyperglycemic, and among those with atrial fibrillation, 81.1 % were prescribed an anticoagulant. Influenza vaccines were administered to 43.6 % of individuals. Within 90 days, 30.2 % visited an emergency department, and 94.2 % saw a primary care provider. Results were similar when individuals were followed for three years post TIA. Compared to ischemic stroke survivors, individuals post-TIA were less likely to have an HbA1C test (p-value <0.001) or receive important secondary prevention medications, but were more likely to receive an influenza vaccine (p-value <0.001).

Conclusions — Observance of secondary prevention guidelines following a TIA could be improved for several clinical recommendations, especially when compared to ischemic stroke survivors.