ECHO: the Western Australian Emergency Care Hospitalisation and Outcome linked data project

To describe and assess the quality of the data resources linked for the Western Australian Emergency Care Hospitalisation and Outcome (ECHO) project.

The ECHO project links electronic records from the WA Emergency Department Information System to the St John Ambulance Service Pre-Hospital Care Database, the WA Hospital Morbidity Data System and the WA Mortality Database. Linkages are created using standard probabilistic matching techniques with extensive clerical review. Commencing with all metropolitan Perth public emergency departments from July 2000, these linkages will be updated annually for at least five successive years. The proportion of actual linkages between emergency department records and ambulance, admission and death records was assessed in comparison to expected linkage rates.

Of 578,200 total emergency department records, there were 144,897 emergency presentations recorded as arriving by ambulance, of which 135,332 (93.4%) were linked to an ambulance record pertaining to the same episode. Of the 165,650 presentations recorded as admitted, 162,216 (97.9%) were linked to a hospital morbidity record relating to the same episode. Furthermore, 96.2% of the 2,084 cases recorded as 'dead on arrival' and 98.9% of the 624 cases recorded as 'died in emergency' were linked to a corresponding death record.

Linkage quality consistent with international standards has been achieved, resulting in an information infrastructure capable of supporting an extensive research agenda focusing on the interaction and outcomes of both pre-hospital and within-hospital emergency medical care services.