Abstract
OBJECTIVES: This study aimed to (1) assess Lumos data quality, a New South Wales (NSW) statewide linked health data asset; and (2) determine sociodemographic variation in health service utilisation of general practice, emergency department and admitted services. DESIGN: A retrospective cohort study using Lumos, a linked health data asset. SETTING: A representative statewide sample population of NSW, Australia. PARTICIPANTS: People residing within NSW with an electronic health record at a Lumos participating general practice between January 2010 and June 2023. PRIMARY AND SECONDARY OUTCOME MEASURES: Data quality indicators of Lumos including completeness, representativeness against NSW population data, consistency and timeliness. Furthermore, variation in general practice visits, emergency department presentations and hospital admission rates stratified by age, sex, rurality and Index of Relative Socio-economic Disadvantage (IRSD)-a measure of socioeconomic status used in Australia, where lower values represent greater relative disadvantage across a range of metrics such as education and income. RESULTS: At the time of analysis, Lumos included records from 5.2 million unique patients, representing half (49.7%) of the NSW resident population. Limiting data to 2022, the Lumos population distribution broadly aligned with the 2021 Census except for IRSD quintile four and five which were under-represented (15.0% vs 20.4% (standardised difference -0.14)), and over-represented (29.7% vs 19.9% (standardised difference 0.23)), respectively. Age and greater relative disadvantage were associated with higher rates of general practice visits and hospital admissions. Greater relative disadvantage was also associated with higher rates of emergency department presentations. CONCLUSIONS: Lumos's ability to overcome historical limitations of separately managed health data in Australia and its demonstrated data quality present an opportunity to enhance health system policy and planning in NSW. The variation in service utilisation across primary and tertiary care by population and geography apparent in Lumos reinforces the need for tailored service planning.