The fourth Auckland Regional Community Stroke study (ARCOS IV) identified all hospitalised and nonhospitalised cases of transient ischaemic attack (TIA) that occurred over a 12-month period from 1 March 2011 in people aged ≥16 years usually resident in Auckland. During the study period, 785 people presented with TIA (402 [51.2%] women, mean age 71.5 years); 614 (78%) of European origin, 84 (11%) Māori/Pacific, and 75 (10%) Asian/Other. The annual incidence of TIA was 40, and attack rate was 63, in age-standardised rates per 100,000 population, standardised to the World Health Organization (WHO) world standard population. Approximately twothirds of people were known to be hypertensive or were being treated with blood pressure-lowering agents, half were taking antiplatelet agents and just under half were taking lipid-lowering therapy before the index TIA. Of 210 people were known to have atrial fibrillation at the time of the TIA, only 61 (29%) were taking anticoagulant therapy, suggesting a failure to identify or treat atrial fibrillation.
