Utilization patterns of diagnostic imaging across the late life course: A population-based study in Ontario, Canada

Rising use of diagnostic imaging in Australia: An analysis of Medicare-funded radiology services between 2000 and 2021

INTRODUCTION

The use of diagnostic imaging services is increasing worldwide. This has important impacts on healthcare resource allocation and potential risks to the population. This study aimed to quantify trends in medical imaging in Australia over the past two decades.

METHODS

Data were extracted from the Australian Medicare Benefits Schedule (MBS) between 2000 and 2021. Simple linear regression analyses were performed to assess changes in absolute utilisation and utilisation rate per 100,000 population of total imaging services as well as by each imaging modality. Logistic regression analysis was performed to assess changes in total imaging services as a proportion of total Medicare services over time. Chi-squared test was used to assess for change in modality composition of imaging services.

RESULTS

There were 436,255,500 imaging studies performed between 2000 and 2021. The absolute utilisation of total imaging services increased annually by an average of 864,404 (95% CI: 808,235-920,573, p < 0.001). For each consecutive year, the proportion of total Medicare services attributed to total imaging services increased by 0.01% (95% CI: 0.01-0.01, p < 0.01). There was also a statistically significant increase in the utilisation rates of imaging services per 100,000 population for each imaging modality. The number of imaging services per radiologist increased on average by 74 (95% CI: 26-122, p < 0.05) annually.

CONCLUSION

The utilisation of diagnostic imaging services has increased in Australia between 2000 and 2021, outpacing the population growth, total healthcare services, and the radiologist workforce.

Frailty in Late Midlife to Old Age and Its Relationship to Medical Imaging Use and Imaging-related Costs: A Longitudinal Study

Background Frailty, defined as an increased vulnerability to and impaired recovery from stressors, is common in individuals in late midlife to old age. While frailty predisposes individuals to adverse health outcomes and increased health care utilization, how it impacts imaging service use and related costs remains unclear. Purpose To determine whether frailty is associated with greater use of imaging services and higher imaging-related costs. Materials and Methods This longitudinal study included a subset of participants from the Helsinki Birth Cohort Study who were clinically assessed up to three times from late midlife to old age between August 2001 and September 2018. A frailty index (FI) based on 41 variables was calculated, and an FI of 0.25 or more indicated frailty. Associations of baseline frailty and its rate of change during the study with medical imaging service use and imaging-related costs were assessed using covariate-adjusted negative binomial and other generalized linear models. Results Of the 1995 participants (mean age, 61.5 years ± 2.9 [SD]; 1074 female participants) included in this study, 569 (28.5%) were identified as frail at baseline, and these participants underwent 10 677 (42.4%) of the 25 172 medical imaging examinations among the participants. Compared to participants who were not frail at baseline, participants who were frail at baseline showed increased use of all imaging modalities (incidence rate ratio [IRR], 2.28 [95% CI: 1.97, 2.64]; P < .001) and higher imaging costs (log annual cost, 3.26 [95% CI: 2.36, 4.50]; P < .001). Compared to participants with stable or slow change in frailty (<0.0010 FI units per year), participants with a rapid increase in frailty (>0.0064 FI units per year) from late midlife to old age showed greater use of all medical imaging services, independent of FI at baseline (IRR, 1.82 [95% CI: 1.53, 2.17]; P < .001) and had higher imaging costs (log annual cost, 1.62 [95% CI: 1.30, 2.01)]; P < .001). Conclusion The presence of frailty and its progression rate are associated with increased use of imaging services and higher imaging-related costs. © RSNA, 2023 Supplemental material is available for this article.

Utilisation and time to performance of diagnostic imaging in patients admitted to Danish emergency departments: a nationwide register-based study from 2007 to 2017

OBJECTIVES

To describe the development of diagnostic imaging utilisation in Denmark from 2007 to 2017, coinciding with a major national reform of the emergency healthcare system.

DESIGN

Nationwide descriptive register-based study.

SETTING

All public hospitals in Denmark.

PARTICIPANTS

All unplanned hospital contacts ≥18 years old at somatic hospitals in Denmark from 1 January 2007 to 31 December 2017.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure was the probability of having CT, X-ray, MRI or ultrasound performed during hospitalisation in 2017 compared with 2007. The secondary outcome measure was receiving diagnostic imaging within 4 hours of hospitalisation.

RESULTS

The probability of having a radiological examination during unplanned hospital admission increased from 2007 to 2017 (CT: 3.5%-10.3%; MRI: 0.2%-0.8%; ultrasound: 2.3%-4.5%; X-ray: 23.8%-26.8%). For CT scan, the adjusted OR was 3.09 (95% CI: 2.73, 3.51); for MRI, the adjusted OR was 3.39 (95% CI: 1.87, 6.12) and for ultrasound, the adjusted OR was 1.93 (95% CI: 1.56, 2.38). The likelihood of having the examination within the first 4 hours in the hospital increased from 2007 to 2017. For X-ray, the adjusted OR was 1.39 (95% CI: 1.07, 1.56); for CT scan, the adjusted OR was 1.35 (95% CI: 1.16, 1.59); for MRI, the adjusted OR was 1.34 (95% CI: 1.09, 1.66) and for ultrasound, the adjusted OR was 1.38 (95% CI: 1.16, 1.64).

CONCLUSION

This nationwide study describes the development of diagnostic imaging utilisation in Denmark from 2007 to 2017. The probability of receiving radiological examinations during unplanned hospitalisation increased over this period, and the time from hospital contact to performance decreased. This supports the notion that enhancement in radiological equipment will also lead to more frequent and faster utilisation.

Geographic Variations in Growth of Radiologists and Medicare Enrollees From 2012 to 2019

OBJECTIVE

Analyze changes in the number of Medicare-serving radiologists and Medicare enrollees nationwide and by geographic region and state from 2012 to 2019 to understand variations in allocation of imaging health care services over the past decade.

METHODS

The number of radiologists submitting claims to Medicare was extracted from the CMS Physician and Other Supplier Public Use File Database. The number of Medicare enrollees by state was obtained from the Kaiser Family Foundation. National-, regional-, and state-level changes in rates of growth of radiologists, Medicare enrollees, and radiologists per 100,000 Medicare enrollees from 2012 to 2019 were tabulated.

RESULTS

The overall number of radiologists per 100,000 Medicare enrollees was 79.7 in 2012, increasing to 79.9 in 2019. In 2012, the number of radiologists per 100,000 enrollees was lower than the national average in the South (66.9; 16% lower) and Midwest (79.1; 0.7% lower) and higher in the Northeast (98.3; 23% higher) and West (88.8; 11% higher). In 2019, the number of radiologists per 100,000 enrollees was lower than the national average in the South (69.8; 12% lower) only and was higher in the Midwest (81.4; 1.9% higher), Northeast (99.3; 24% higher), and West (80.2; 0.4% higher). By state, there was a 4.2-fold variation in the number of radiologists per 100,000 Medicare enrollees, ranging from 38.8 in Wyoming to 161.4 in Minnesota (200.5 in Washington, DC).

DISCUSSION

The growth of Medicare-serving radiologists and Medicare enrollees was stable nationally and demonstrated tremendous variations by US region and state. These variations bring to light potential implications for patient access to care and distribution of health care resources.

Incidental detection, imaging modalities and temporal trends of differentiated thyroid cancer in Ontario: a population-based retrospective cohort study

BACKGROUND

Incidence rates of thyroid cancer in Ontario have increased more rapidly than those of any other cancer, whereas mortality rates have remained relatively stable. We evaluated the extent to which incidental detection of differentiated thyroid cancer during unrelated prediagnostic imaging procedures contributed to Ontario's incidence rates.

METHODS

We conducted a retrospective cohort study involving Ontarians who received a diagnosis of differentiated thyroid cancer from 1998 to 2017 using linked health care administrative databases. We classified cases as incidentally detected if a nonthyroid diagnostic imaging test (e.g., computed tomography [CT]) preceded an index event (e.g., prediagnostic fine-needle aspiration biopsy); all other cases were nonincidentally detected cases. We used Joinpoint and negative binomial regressions to characterize sex-specific rates of differentiated thyroid cancer by incidentally detected status and to quantify potential age, diagnosis period and birth cohort effects.

RESULTS

The study included 36 531 patients with differentiated thyroid cancer, of which 78.7% were female. Incidentally detected cases increased from 7.0% to 11.0% of female patients and from 13.5% to 18.2% of male patients over the study period. Age-standardized incidence rates increased more rapidly for incidentally detected cases (4.2-fold for female and 3.7-fold for male patients) than for nonincidentally detected cases (2.6-fold for female and 3.0-fold for male patients; p < 0.001). Diagnosis period was the primary factor associated with increased incidence rates of differentiated thyroid cancer, adjusting for other factors. Within each period, incidentally detected rates increased faster than nonincidentally detected rates, adjusting for age. Our results showed that CT was the most common imaging procedure preceding incidentally detected diagnoses.

INTERPRETATION

Incidentally detected cases represent a large and increasing component of the observed increases in differentiated thyroid cancer in Ontario over the past 20 years, and CT scans are primarily associated with these cases despite the modality having similar, increasing rates of use compared with magnetic resonance imaging (1993-2004). Recent increases in rates of differentiated thyroid cancer among males and incidentally detected cases among females in Ontario appear to be unrelated to birth cohort effects.

The relationship between hospital adoption and use of high technology medical imaging and in-patient mortality and length of stay

PURPOSE

The purpose of this paper is to investigate the relationship between hospital adoption and use of computed tomography (CT) scanners, and magnetic resonance imaging (MRI) machines and in-patient mortality and length of stay.

DESIGN/METHODOLOGY/APPROACH

This study used panel data (2007-2010) from 124 hospital corporations operating in Ontario, Canada. Imaging use focused on medical patients accounting for 25 percent of hospital discharges. Main outcomes were in-hospital mortality rates and average length of stay. A model for each outcome-technology combination was built, and controlled for hospital structural characteristics, market factors and patient characteristics.

FINDINGS

In 2010, 36 and 59 percent of hospitals had adopted MRI machines and CT scanners, respectively. Approximately 23.5 percent of patients received CT scans and 3.5 percent received MRI scans during the study period. Adoption of these technologies was associated with reductions of up to 1.1 percent in mortality rates and up to 4.5 percent in length of stay. The imaging use-mortality relationship was non-linear and varied by technology penetration within hospitals. For CT, imaging use reduced mortality until use reached 19 percent in hospitals with one scanner and 28 percent in hospitals with 2+ scanners. For MRI, imaging use was largely associated with decreased mortality. The use of CT scanners also increased length of stay linearly regardless of technology penetration (4.6 percent for every 10 percent increase in use). Adoption and use of MRI was not associated with length of stay.

RESEARCH LIMITATIONS/IMPLICATIONS

These results suggest that there may be some unnecessary use of imaging, particularly in small hospitals where imaging is contracted out. In larger hospitals, the results highlight the need to further investigate the use of imaging beyond certain thresholds. Independent of the rate of imaging use, the results also indicate that the presence of CT and MRI devices within a hospital benefits quality and efficiency.

ORIGINALITY/VALUE

To the authors' knowledge, this study is the first to investigate the combined effect of adoption and use of medical imaging on outcomes specific to CT scanners and MRI machines in the context of hospital in-patient care.

Adoption of high technology medical imaging and hospital quality and efficiency: Towards a conceptual framework

Measuring the value of medical imaging is challenging, in part, due to the lack of conceptual frameworks underlying potential mechanisms where value may be assessed. To address this gap, this article proposes a framework that builds on the large body of literature on quality of hospital care and the classic structure-process-outcome paradigm. The framework was also informed by the literature on adoption of technological innovations and introduces 2 distinct though related aspects of imaging technology not previously addressed specifically in the literature on quality of hospital care: adoption (a structural hospital characteristic) and use (an attribute of the process of care). The framework hypothesizes a 2-part causality where adoption is proposed to be a central, linking factor between hospital structural characteristics, market factors, and hospital outcomes (ie, quality and efficiency). The first part indicates that hospital structural characteristics and market factors influence or facilitate the adoption of high technology medical imaging within an institution. The presence of this technology, in turn, is hypothesized to improve the ability of the hospital to deliver high quality and efficient care. The second part describes this ability throughout 3 main mechanisms pointing to the importance of imaging use on patients, to the presence of staff and qualified care providers, and to some elements of organizational capacity capturing an enhanced clinical environment. The framework has the potential to assist empirical investigations of the value of adoption and use of medical imaging, and to advance understanding of the mechanisms that produce quality and efficiency in hospitals.

Lifelong Health and Health Services Use: A New Focus for Gerontological Nursing Research and Practice

It is commonly believed that older adults are often ill and therefore high users of health services. A pilot study involving adults 60 and older living in the Canadian province of Alberta was conducted to (a) raise interest in the concepts of lifelong health and health services use; (b) develop a lifelong health data collection tool; (c) obtain information about lifelong and recent health services use, and self-perceived lifelong and current health; and (d) reveal links (if any) between perceived health and lifelong health services use. A questionnaire was developed, pilot tested, and posted for completion by 100 volunteers. Most older adults reported good or very good current and lifelong health. Comorbidities and low finances were associated with higher health services use. These findings suggest community-dwelling older adults may be healthy currently and throughout their lives. Gerontological nursing research, practice, and advocacy are needed because myths about aging must be addressed to refocus attention on the importance of lifelong health promotion for older adults. [Journal of Gerontological Nursing, 43(2), 28-32.].

Patterns and trends of computed tomography usage in outpatients of the Brazilian public healthcare system, 2001-2011

While the patterns and trends of computed tomography (CT) are well documented in developed countries, relatively little is known about CT usage in developing countries, including Brazil. We evaluated CT usage among outpatients from the public healthcare system in Brazil (SUS), which is the unique healthcare provider to about 75% of the Brazilian population. We collected the annual number of CT procedures and type of CT examinations performed in SUS for the period 2001-2011. Age at examination was evaluated for 2008-2011. CT usage in Brazil has more than tripled during the study period, but the most striking annual increase (17.5%) was observed over the years 2008-2011. Head was the most frequently examined region for all age groups, but a decreasing trend of proportional contribution of head CT, with a simultaneous increase of abdomen/pelvis and chest CT over time was observed. CT examination for pediatric and young adult patients was about 13% of all CTs (9% if we considered age-standardized CT rates). CT usage has grown rapidly in Brazil and may still be increasing. Increased CT usage may certainly be associated with improved patient care. However, given the high frequency of pediatric and young adult CT procedures and the suggested associated cancer risk, efforts need to be undertaken to reduce unwarranted CT scans in Brazil.

The influence of population aging and size on the number of CT examinations in The Netherlands

Exposures to ionizing radiation from medical examinations are on the rise. An important cause for this has been the advent and ever-increasing use of computed tomography (CT) scans for diagnostic purposes. It is often implied that population aging contributes significantly to this rise. Here, the trends in population statistics are compared to the trend in the number of CT scans in the Netherlands for the period 2002-2010. It is concluded that population growth and population aging cannot explain the observed rise in CT examinations. In fact, these factors contribute only 17% to this rise, indicating that there must be other factors that are far more important.

Population based analysis of the increasing incidence of kidney cancer in the United States: evaluation of age specific trends from 1975 to 2006

PURPOSE

An increase in kidney cancer was reported in the United States but overall rates may obscure trends in age specific groups. We explored whether the increase in kidney cancer incidence differs across age groups.

MATERIALS AND METHODS

We ascertained the 63,843 incident renal cancer cases in SEER (Surveillance, Epidemiology and End Results) cancer registries for 1975 to 2006. Yearly incidence rates of renal cancer were calculated and stratified by age group. Age specific trends in cancer diagnosis were evaluated by Poisson regression.

RESULTS

From 1975 to 2006 the overall age adjusted renal cancer incidence increased 238% from 7.4/100,000 to 17.6/100,000 adults. From 1991 to 2006 the mean age at diagnosis decreased from 64.7 to 62.7 years and the proportion of patients diagnosed before age 65 years increased from 45.9% to 55.3%. Age specific incidence rates of renal cancer increased in all age groups from 1975 to 2006 (p <0.0001). However, the rates changed at different rates. Overall renal cancer diagnosis in the youngest age group (20 to 39 years) increased more quickly than all other age groups (p <0.0001). The renal cancer incidence in patients 60 to 69 and 70 to 79 years old increased more rapidly than in those 40 to 49 and 50 to 59 years old (p <0.01).

CONCLUSIONS

In the last 15 years mean age at diagnosis of renal cancer has decreased. During our study period the most rapidly increasing kidney cancer incidence was seen in those younger than 40 and 60 to 79 years old. The renal cancer increase in younger patients should direct attention toward further evaluation of renal cancer risk factors.

Application of magnetic resonance imaging and magnetic resonance angiography as diagnostic measures for the first attack of suspected cerebrovascular diseases in Korea

PURPOSE

No precise data are available showing how magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) can be applied to diagnosis for the first attack of a suspected cerebrovascular disease in Korea. The purpose of this study was to evaluate the application level of MRI and MRA as diagnostic tools and the related factors to the use of these techniques.

MATERIALS AND METHODS

This study used the health benefit claim data of 89,890 patients who were hospitalized for the first time due to suspected cerebrovascular disease in 2007 without having visited medical institutions as an outpatient or inpatient from 2003 to 2006.

RESULTS

Of the 89,890 cases, 28.4% took both MRI and MRA, 10.7% took only MRI and 6.9% took only MRA. The related factors identified in the multivariate logistic regression analysis were gender, type of insurance, type of medical institution, type of department, duration of hospitalization, and type of disease.

CONCLUSION

This study showed that the application level of MRI and MRA as diagnostic measures for the first attack of a suspected cerebrovascular diseases varied depending on several factors. It is necessary to study more accurate levels of computerized tomography (CT), computerized tomography angiography (CTA), MRI or MRA as measures to diagnose a first attack of suspected cerebrovascular disease.

A population-based cohort study of ambulatory care service utilization among older adults

RATIONALE, AIMS AND OBJECTIVES

Age-related effects on ambulatory care service utilization are not well understood. We aim to measure the utilization patterns of ambulatory health care services (i.e. family physician visits, specialist physician visits and emergency room visits) in the late life course (65 years and older).

METHODS

A population-based retrospective cohort study was conducted for the period 1 April 2005 to 31 March 2006. All Ontario, Canada, residents aged 65+ and eligible for government health insurance were included in the analysis.

RESULTS

This population-based cohort study demonstrates considerable increase in utilization rates and variability of ambulatory services as age increases. Variations in utilization were observed by gender as overall women were more likely to consult a family physician, and men more likely to visit specialists and the emergency room. A small group of high users, constituting 5.5% of the total population, accounted for 18.7% of total ambulatory visits. Finally, we report socio-economic status (SES) based disparity for specialist services in which high users were more likely to have higher SES.

CONCLUSIONS

There is increasing utilization and variability in ambulatory service utilization with increase in age. Further research is required to explain the gender and SES differences reported in this study.

Trends in health services utilization, medication use, and health conditions among older adults: a 2-year retrospective chart review in a primary care practice

BACKGROUND

Population aging poses significant challenges to primary care providers and healthcare policy makers. Primary care reform can alleviate the pressures, but these initiatives require clinical benchmarks and evidence regarding utilization patterns. The objectives of this study is to measure older patients' use of health services, number of health conditions, and use of medications at the level of a primary care practice, and to investigate age- and gender-related utilization trends.

METHODS

A cross-sectional chart audit over a 2-year study period was conducted in the academic family practice clinic of Sunnybrook Health Sciences Centre in Toronto, Ontario, Canada. All patients 65 years and older (n = 2450) were included. Main outcome measures included the number of family physician visits, specialist visits, emergency room visits, surgical admissions, diagnostic test days, inpatient hospital admissions, health conditions, and medications.

RESULTS

Older patients (80-84 and 85+ age-group) had significantly more family physician visits (average of 4.4 visits per person per year), emergency room visits (average of 0.22 ER visits per year per patient), diagnostic days (average of 5.1 test days per person per year), health conditions (average of 7.7 per patient), and medications average of 8.2 medications per person). Gender differences were also observed: females had significantly more family physician visits and number of medications, while men had more specialist visits, emergency room visits, and surgical admissions. There were no gender differences for inpatient hospital admissions and number of health conditions. With the exception of the 85+ age group, we found greater intra-group variability with advancing age.

CONCLUSION

The data present a map of greater interaction with and dependency on the health care system with advancing age. The magnitudes are substantial and indicate high demands on patients and families, on professional health care providers, and on the health care system itself. There is the need to create and evaluate innovative models of care of multiple chronic conditions in the late life course.