Real-world use of diagnostic tests for mild cognitive impairment, Alzheimer's disease, and other dementias in Medicare fee-for-service beneficiaries

Abstract

INTRODUCTION: This study assessed real-world use of diagnostic tests, such as neuroimaging (e.g., magnetic resonance imaging [MRI], or positron emission tomography [PET]), and computed tomography (CT), cerebrospinal fluid (CSF) biomarker, and blood tests for mild cognitive impairment (MCI), Alzheimer's disease (AD), and other dementias in a large US elderly population. METHODS: Medicare fee-for-service data (2015–2020) were used to identify patients aged ≥ 67 newly diagnosed with MCI, AD, or other dementias. Descriptive analyses were conducted to understand the test use within 1 year before disease diagnosis and trends. RESULTS: Among 653,420 patients (9.1% MCI, 30.3% AD, 60.6% other dementias), 71.9% had blood tests, 53.9% neuroimaging (46.4% CT, 17.7% MRI, and 0.7% PET), and 2.2% CSF test. Test use slightly increased from 2015 to 2020. DISCUSSION: Findings from this study suggest low use of diagnostic tests, especially PET and CSF. Highlights: Blood tests, magnetic resonance imaging, and computed tomography were predominant for diagnosing mild cognitive impairment, Alzheimer's disease, or other dementias prior to the arrival of disease-modifying therapies. Cerebrospinal fluid biomarker and positron emission tomography tests were infrequently used despite their diagnostic value. The study indicates a modest increase in diagnostic test usage over 6 years between 2015 and 2020. Patients often received combined or repeated diagnostic tests.