The Australian Congenital Heart Disease Registry - Linkage to National Administrative Health Data

BackgroundCongenital Heart Disease (CHD) research must focus on outcomes that affect the whole-of-life course. To achieve this, datasets with long term follow up and patient-relevant outcomes are required. This paper reports on the linkage of The Australian and New Zealand Congenital Heart Disease Registry (ANZCHD Registry) (>80 000 unique individuals) with Australian National Administrative Health records and describes the final dataset. MethodsLinkage on two cohorts was conducted by accredited linkage agencies, after all appropriate Ethics and Governance approvals. Cohort 1 included people who were identified from the ANZCHD Registry and Cohort 2 included people with an inpatient admission with a CHD diagnosis who had not been identified in Cohort 1. Healthcare events linked from 2010 to 2024 included outpatient encounters and medications, hospital admissions and emergency department presentations. Linked data was cleaned and curated to minimize the impacts of errors from the probabilistic linkage process. ResultsThe final dataset included 94,383 subjects with structural CHD (58,523 from Cohort 1 and 35,860 from Cohort 2). There were over 35 million linked healthcare events recorded for this population, from 2010 to 2025. Cohort 1 was younger by an average of 14 years (95% CI: 13.2 - 13.9, p<0.001) and had a higher proportion of severe CHD lesions (20%) compared to Cohort 2 (6%) ({chi}2 = 7433.1, p<0.001). ConclusionsThe linkage described here represent a significant enrichment of the large and comprehensive Australian National CHD Registry. This will provide important research infrastructure that will enable better quality research in CHD. Key MessagesO_LIWe sought to link the Australia and New Zealand Congenital Heart Disease Registry with comprehensive, national Australian administrative healthcare records. C_LIO_LIThe final dataset included a total of 95,383 individuals with over 35 million healthcare events from 2010 to 2025. C_LIO_LICongenital Heart Disease is a whole-of-life condition with a growing and ageing population and comprehensive datasets such as these need to be made available to improve healthcare for people with Congenital Heart Disease. C_LI