Trend in CT utilisation and its impact on length of stay, readmission and hospital mortality in Western Australia tertiary hospitals: an analysis of linked administrative data 2003-2015.

OBJECTIVE: High use of CT scanning has raised concern due to the potential ionising radiation exposure. This study examined trends of CT during admission to tertiary hospitals and its associations with length of stay (LOS), readmission and mortality. DESIGN: Retrospective observational study from 2003 to 2015. SETTING: West Australian linked administrative records at individual level. PARTICIPANTS: 2 375 787 episodes of tertiary hospital admission in adults aged 18+ years. MAIN OUTCOME MEASURES: LOS, 30-day readmissions and mortality stratified by CT use status (any, multiple (CTs to multiple areas during episode), and repeat (repeated CT to the same area)). METHODS: Multivariable regression models were used to calculate adjusted rate of CT use status. The significance of changes since 2003 in the outcomes (LOS, 30-day readmission and mortality) was compared among patients with specific CT imaging status relative to those without. RESULTS: Between 2003 and 2015, while the rate of CT increased 3.4% annually, the rate of repeat CTs significantly decreased -1.8% annually and multiple CT showed no change. Compared with 2003 while LOS had a greater decrease in those with any CT, 30-day readmissions had a greater increase among those with any CT, while the probability of mortality remained unchanged between the any CT/no CT groups. A similar result was observed in patients with multiple and repeat CT scanning, except for a significant increase in mortality in the recent years in the repeat CT group. CONCLUSION: The observed pattern of increase in CT utilisation is likely to be activity-based funding policy-driven based on the discordance between LOS and readmissions. Meanwhile, the repeat CT reduction aligns with a more selective strategy of use based on clinical severity. Future research should incorporate in-hospital and out-of-hospital CT to better understand overall CT trends and potential shifts between settings over time.

Association of regulatory body actions and subsequent media coverage with use of services in a fee-for-service system: a longitudinal cohort study of CT scanning in Australia.

OBJECTIVE: The professional service review (PSR) is an Australian Government agency aiming to reduce inappropriate practices funded via Medicare, Australia's public insurer. Our objective was to examine changes in CT following the 2008-2009 PSR annual report, which noted excessive CT use. DESIGN: Interrupted time series analysis examined trends in CT use following the 2008-2009 PSR report, estimating both change in the immediate rate of CT and the slope of the trend in usage postintervention. SETTING: Medicare-funded imaging (most out-of-hospital imaging) in Australia. PARTICIPANTS: Patients receiving Medicare-funded CT and other imaging. INTERVENTION: The 2008-2009 PSR report highlighted concerns regarding excessive CT use. Two providers were financially penalised for CT overuse with these cases detailed in the PSR report and highlighted in an associated Report to the Professions, distributed to 50 000 providers. Media articles on radiation risks followed. OUTCOMES: Quarterly rates of out-of-hospital CT, MRI (as a comparator), and all other Medicare-funded diagnostic imaging examinations 2001-2019. RESULTS: CT scanning increased from 4663.5 per 100 000 person-years in 2001 to 14 506 in 2019 (211% increase), with substantial variation by type and anatomical region. The 2008-2009 PSR report was followed by an immediate reduction in CT scanning of 237.7 CTs per 100 000 people per quarter (95% CI -333.4 to -141.9) though growth in use soon continued at the preintervention rate. The degree of change in utilisation following the report differed between states/territories and by scan type, both in terms of the immediate change and the slope. For other diagnostic imaging modalities, there was an increase in the slope, while for MRI there was no change in either parameter. CONCLUSION: Actions consisting of financial disincentives for service overtesting and provider/public education components may limit excessive use of diagnostic imaging in fee-for-service systems, however, effects observed here were only short lived.