Substantial underestimation of the need for outpatient services for TIA and minor stroke.

Objectives: To measure the number of all transient ischaemic attack (TIAs) and minor strokes managed as outpatients, and hence, the need for 'TIA clinics' in comparison to current estimates of 20,000 TIAs annually in England, based on previous rates of incident-definite events.

Subjects: All individuals with confirmed or suspected TIA or stroke between 2002 and 2005 in a population-based study of 91,105 individuals in Oxfordshire, UK.

Outcome Measures: Numbers, rates, and risks of recurrent stroke for incident-definite TIA, any probable or definite TIA, stroke, and all referrals of suspected TIA and stroke, stratified according to inpatient versus outpatient management.

Results: Of 1,174 confirmed or suspected events ascertained, 729 (62.1%) were managed as outpatients and 445 (37.9%) as inpatients. Among 757 probable or definite events, 432 (57%) were managed as outpatients. Incident-definite TIAs accounted for only 18% of all referrals to outpatient services. Annual rates per 1,000 population were 2.98 (2.77-3.2) for all referrals to outpatient services and 1.88 (1.71-2.06) for inpatient admissions. Of 73 recurrent strokes within 90 days of initial TIA or stroke, 48 (65.8%) occurred in the outpatient population. Applying these rates to the population of England yields approximately 150,000 new referrals annually to TIA clinics with about 10,000 early recurrent strokes.

Conclusion: More patients with TIA or stroke are managed as outpatients than inpatients in the UK, and this group has the majority of possibly preventable early recurrent strokes. Current projections of need for TIA clinics in England substantially underestimate the overall requirement for outpatient services.