Measuring stroke outcomes using linked administrative data: Population-based estimates and validation of “home-time” as a surrogate measure of functional status

Background Administrative data offer cost-effective, whole-of-population stroke surveillance yet the lack of validated outcomes is a short-coming. The number of days spent living at home after stroke (“home-time”) is a patient-centred outcome that can be objectively ascertained from administrative data. Population-based validation against both severity and outcome measures and for all subtypes is lacking. Methods Stroke hospitalisations from a state-wide census in New South Wales, Australia, from July 1, 2005 to March 31, 2014 were linked to pre-hospital data, post-stroke admissions and deaths. We calculated correlations between 90-day home-time and Glasgow Coma Scale (GCS) scores, measured upon a patient’s initial contact with paramedics, and Functional Independence Measure (FIM) scores, measured upon entry to rehabilitation after the acute hospital stroke admission. Negative binomial regression models were used to identify predictors of home-time. Results Patients with stroke (N=74,501) spent a median of 53 days living at home after the event. Median home-time was 60 days after ischaemic stroke, 49 days after subarachnoid haemorrhage and 0 days after intracerebral haemorrhage. GCS and FIM scores significantly correlated with home-time (p-values<0.001). Female sex predicted less home-time in ischaemic stroke, while being married increased home time after ischaemic stroke and subarachnoid haemorrhage. Conclusions Home-time measured using administrative data is a robust, replicable and valid patient-centred outcome enabling inexpensive population-based surveillance.