Health Services Research and PolicyOriginal ArticleUpdated Trends, Disparities, and Clinical Impact of Neuroimaging Utilization in Ischemic Stroke in the Medicare Population: 2012 to 2019
Introduction
In the past decade, the United States population experienced demographic changes impacting stroke care, such as growth in the elderly population and continued increase in the prevalence of obesity and diabetes mellitus, which are stroke risk factors. At the same time, advances in stroke care made lifesaving medical and endovascular treatments available to more patients than in the previous decade. Every year, approximately 795,000 patients suffer a stroke in the United States, with ischemic stroke accounting for 87% of these [1]. Stroke risk increases with age, doubling every 10 years after 55 [1]. Approximately three-quarters of all strokes occur in persons aged ≥65 years, which corresponds to the Medicare population [2].
Intravenous thrombolysis (IVT) with recombinant tissue-type plasminogen activator and endovascular thrombectomy (EVT) are the only early treatments for ischemic stroke endorsed by the American Heart Association [3]. Several studies have shown favorable clinical outcomes with IVT [4, 5, 6] and EVT [7,8], using the results of advanced imaging. CT and MRI, including angiography and perfusion studies, provide valuable information to select patients beyond the previously limited therapeutic time windows for ischemic stroke treatment. In the United States, overall use of IVT and EVT in stroke cases increased from 7.0% in 2008 to 19.1% in 2018 [9]. Concomitantly, the utilization of CT and MRI increased markedly in patients with ischemic stroke [10,11]. From 2006 to 2010, CT angiography (CTA) increased by 142% and CT perfusion (CTP) grew by 6,429% [10]. Additionally, MRI use increased by 235% from 1999 to 2008 [11]. Published trends in nationwide neuroimaging and treatment utilization, particularly relating to other components of stroke care, do not exist beyond 2012 [10,12]. Furthermore, the literature does not address socioeconomic disparities in stroke imaging [10,12].
Understanding recent trends and socioeconomic disparities in neuroimaging utilization among patients with ischemic stroke, and how imaging relates to clinical treatment decisions and outcomes, is critically important for clinicians and health care policymakers as we strive to ensure optimal and equitable access to high-quality stroke care across an increasingly diverse and aging population. We hypothesized that advanced neuroimaging (CTA, CTP, MRI, MR angiography [MRA]) utilization in patients with ischemic stroke has continued to increase in the United States from 2012 to 2019. Furthermore, we hypothesized that (1) these trends were associated with increased acute treatment utilization and improved clinical outcomes and (2) sociodemographic disparities associated with ischemic stroke imaging utilization exist. We focused our analyses on the Medicare population given the much higher incidence of stroke compared with commercially insured patients [13].
Section snippets
Study Population and Data Collection
We performed a retrospective study to assess trends in the utilization of advanced neuroimaging in ischemic stroke care using the Medicare 5% Research Identifiable Files (RIF; 2012-2019). The RIF data contain individual level fee-for-service administrative claims data for a 5% nationally representative sample of Medicare beneficiaries across all places of service (ie, emergency departments, inpatient and outpatient facilities, skilled nursing and hospice facilities, and home health agencies).
Results
During the 2012 to 2019 study period, there were 85,547 stroke episodes in patients aged 65 years and older. Sociodemographic and clinical characteristics of patients with stroke episodes during this period are shown in Table 1. CTA was performed in 29.7%, CTP in 4.2%, MRI in 68.6%, and MRA in 26.8% of stroke episodes. From 2012 to 2019, we observed significant increasing trends in utilization of CTA (from 15.7% to 54.9%, P < .0001), CTP (from 2.2% to 11.4%, P < .0001), and MRI (from 62.1% to
Discussion
Using Medicare claims data from 2012 to 2019, we identified a marked increase in advanced neuroimaging utilization of CTA (250%) and CTP (428%) in patients with ischemic stroke similar to, and a continuation of, the upward trends reported from 2006 to 2010 [10]. It is likely that these utilization trends are a consequence of several landmark clinical trials, starting in 2015, which showed the significant benefit of EVT [19, 20, 21, 22, 23, 24] and led to the American Heart Association [3] and
Take-Home Points
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From 2012 to 2019, we found significantly increased use of CTA, CTP, and MRI for patients with ischemic stroke based on Medicare claims data. Over the same period, MRA use was on the decline.
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Overall, neuroimaging was performed less often among rural, older (≥80 years), Black, and female patients.
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CTA and CTP uptrends were significantly associated with increased IVT and EVT utilization, which decreased the risk of mortality.
Acknowledgments
This work was supported by the National Institute of Neurological Disorders and Stroke (NINDS) of the National Institutes of Health, under award R56NS114275, and a research partnership between Siemens Healthineers and The Feinstein Institutes for Medical Research, Northwell Health. Funding support was received from the Harvey L. Neiman Health Policy Institute through a research partnership.
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Dr Wang and Dr Katz have received grants from Siemens Healthineers and NINDS during the conduct of the study. Dr Boltyenkov has received grants from Siemens Healthineers and NINDS during the conduct of the study and grants, personal fees, and nonfinancial support from Siemens Healthineers outside the submitted work. Dr Sanelli has received research grants from Siemens Healthineers and NINDS during the conduct of the study and research grants from the Harvey L. Neiman Health Policy Institute outside the submitted work. The other authors state that they have no conflict of interest related to the material discussed in this article. The authors are non-partner/non-partnership track/employees.