Transient ischaemic attack and ischaemic stroke: constructing episodes of care using hospital claims data.

Background: Stroke patients may have multiple hospital separations relating to the same stroke. Understanding the pattern of hospitalisations for these patients enables first and recurrent events to be distinguished to better understand care. The aim of this study was to investigate reasons for hospital separations after transient ischaemic attack (TIA) or ischaemic stroke and construct episode of care criteria.

Methods: A retrospective observational study was conducted using the Australian Government Department of Veterans' Affairs administrative claims database. All patients hospitalised for TIA or ischaemic stroke in 2008-2009 were included. Reasons for hospital separations in the 60 days after TIA or ischaemic stroke were classified by a clinical panel as 'probably', 'possibly' or 'unlikely' to be related to the index separation. Based on panel assessment and time between separations, episode of care criteria for TIA and ischaemic stroke were constructed.

Results: Of the 4520 veterans alive after the index separation, 32% of TIA patients (n=782) and 63% of ischaemic stroke patients (n=1323) had another separation within 60 days. The clinical panel reviewed 460 unique reasons for readmission. Of the 3263 separations, 55% and 85% were classified as related to the index TIA and ischaemic stroke separation, respectively.

Conclusions: Patients hospitalised for ischaemic stroke are likely to have multiple hospital separations for treatment of the same event. Multiple separations for treatment of TIA were less frequent. Consideration of these related separations is recommended when assessing health service utilisation from claims databases.