Cohort study of Western Australia computed tomography utilisation patterns and their policy implications

The Great Contrast Shortage of 2022-Lessons learnt in Australia

INTRODUCTION

Computed tomography (CT) imaging is one of the most commonly used diagnostic tools. Iodine-based contrast media (IBCM) are frequently administered intravenously to improve soft tissue contrast in a wide range of CT scans. Supply chain disruptions triggered by the SARS-CoV-19 pandemic led to a global shortage of IBCM in mid-2022. The purpose of this study was to explore the impact of this shortage on the delivery of healthcare in Western Australia.

METHODS

We performed a single-centre retrospective analysis of the provision of CT studies, comparing historical patterns to the shortage period. We focussed our attention on the total number of CT scans (noncontrast CT [NCCT] and contrast-enhanced CT [CECT]) and also specifically CT pulmonary angiogram (CTPA) and CT neck angiogram with or without inclusion of circle of Willis (CTNA) examinations. We also examined whether a decrease was compensated by increasing frequency of alternate examinations such as ventilation/perfusion (V/Q) scans, carotid Doppler ultrasound studies and Magnetic Resonance Angiograms (MRAs).

RESULTS

Since 2012, there has been an approximate linear increase in the frequency of CT examinations. During the period of contrast shortage, there was an abrupt drop-off by approximately 50% in the CECT, CTPA and CTNA groups compared with the preceding 6 weeks (49%, 55% and 44%, respectively, with P < 0.001 in all cases). During the contrast shortage, the frequency of V/Q scans increased fivefold (from 13 to 65; P < 0.001). However, the provision of carotid Doppler ultrasound studies and MRAs remained approximately stable in frequency across recent time intervals.

CONCLUSION

Our findings demonstrate that the IBCM shortage crisis had a very significant impact on the delivery of healthcare. While V/Q scans could (partially) substitute for CTPA studies in suspected pulmonary emboli, there appeared to be no valid alternative for CTNA studies in stroke calls. The unexpected and critical shortage of IBCM forced healthcare professionals to conserve resources, prioritise indications, triage patients based on risk, explore alternate imaging strategies and prepare for similar events recurring in the future.

Trends in utilisation of ultrasound by older Australians (2010-2019)

BACKGROUND

Older people have increasingly complex healthcare needs, often requiring appropriate access to diagnostic imaging, an essential component of their health and disease management planning. Ultrasound is a safe imaging tool used to diagnose several conditions commonly experienced by older people such as deep vein thrombosis.

PURPOSE

To evaluate the utilisation of major ultrasound services by Australians ≥ 65 years old between 2009- and 2019.

METHODS

This population-based and yearly cross-sectional study of ultrasound utilisation per 1,000 Australians ≥ 65 years old was conducted using publicly available data sources. Overall, examination site and age- and sex-specific incidence rate (IR) of ultrasound per 1,000 people, adjusted incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were calculated using negative binomial regression models.

RESULTS

Over the study period, the crude utilisation of ultrasound increased by 83% in older Australians. Most ultrasound examinations were conducted on extremities (39%) and the chest (21%), with 25% of all ultrasounds investigating the vascular system. More men than women use ultrasounds of the chest (184/1,000 vs 268/1,000 people), particularly echocardiograms (177/1,000 vs 261/1,000 people), and abdomen (88/1,000 vs 92/1,000 people), especially in those ≥ 85 years old. Hip and pelvic ultrasound were used more by women than men (212/1,000 vs 182/1,000 people). There were increases in vascular abdominal (IRR:1.07, 95%CI:1.06-1.08) and extremeties (IRR:1.06, 95%CI:1.05-1.07) ultrasounds over the study period, particularly in ≥ 75 years old men.

CONCLUSIONS

Ultrasound is a common and increasingly used diagnostic tool for conditions commonly experienced by older Australians.

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.

Factors driving CT utilisation in tertiary hospitals: a decomposition analysis using linked administrative data in Western Australia

OBJECTIVES

While CT scanning plays a significant role in healthcare, its increasing use has raised concerns about inappropriate use. This study investigated factors driving the changing use of CT among people admitted to tertiary hospitals in Western Australia (WA).

DESIGN AND SETTING

A repeated cross-sectional study of CT use in WA in 2003-2005 and 2013-2015 using linked administrative heath data at the individual patient level.

PARTICIPANTS

A total of 2 375 787 tertiary hospital admissions of people aged 18 years or older.

MAIN OUTCOME MEASURE

Rate of CT scanning per 1000 hospital admissions.

METHODS

A multivariable decomposition model was used to quantify the contribution of changes in patient characteristics and changes in the probability of having a CT over the study period.

RESULTS

The rate of CT scanning increased by 112 CT scans per 1000 admissions over the study period. Changes in the distribution of the observed patient characteristics were accounted for 62.7% of the growth in CT use. However, among unplanned admissions, changes in the distribution of patient characteristics only explained 17% of the growth in CT use, the remainder being explained by changes in the probability of having a CT scan. While the relative probability of having a CT scan generally increased over time across most observed characteristics, it reduced in young adults (-2.8%), people living in the rural/remote areas (-0.8%) and people transferred from secondary hospitals (-0.8%).

CONCLUSIONS

Our study highlights potential improvements in practice towards reducing medical radiation exposure in certain high risk population. Since changes in the relative probability of having a CT scan (representing changes in scope) rather than changes in the distribution of the patient characteristics (representing changes in need) explained a major proportion of the growth in CT use, this warrants more in-depth investigations in clinical practices to better inform health policies promoting appropriate use of diagnostic imaging tests.

Medical Imaging Outpatients' Experiences With Receiving Information Required for Informed Consent and Preparation: A Cross-Sectional Study

BACKGROUND

Medical imaging outpatients often experience inadequate information provision and report high levels of anxiety. However, no studies have assessed patients' receipt of preparatory information in this setting.

OBJECTIVE

To examine medical imaging outpatients' perceived receipt or non-receipt of preparatory information from health professionals and imaging department staff prior to their procedure.

METHOD

Computed tomography and magnetic resonance imaging outpatients at one Australian hospital self-completed a touchscreen computer survey assessing their perceived receipt of 33 guideline-recommended preparatory information items.

RESULTS

Of 317 eligible patients, 280 (88%) consented to participate. Eight percent (95% confidence interval: 5%-12%) of participants reported receiving all information items. The median number of information items not received was 18 (interquartile range: 8-25). Items most frequently endorsed as "not received" were: how to manage anxiety after (74%) and during the scan (69%). Items most commonly endorsed as "received" were: reason for referral (85%) and how to find the imaging department (74%).

CONCLUSION

Few medical imaging outpatients recalled receiving recommended preparatory information. Preparatory communication needs to be improved to better meet patient-centered service imperatives.