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Diagnostic Pathways to Alzheimer Disease: Costs Incurred in a Medicare Population
Daniel M Gilden1, Joanna M Kubisiak, Khaled Sarsour
1*JEN Associates, Cambridge, MA †Genentech, South San Francisco, CA ‡Eli Lilly and Company, Indianapolis, IN.
Insights
Understanding Alzheimer disease (AD) diagnostic journeys is crucial. Patients with cognitive impairment (CI) transitioning to AD incur significantly higher Medicare costs than those with an initial AD diagnosis.
Area of Science:
- Gerontology
- Neurology
- Health Economics
Background:
- Little is known about the diagnostic pathways for patients with cognitive impairment (CI) before an Alzheimer disease (AD) diagnosis.
- Understanding these pathways is critical for both personal and policy implications.
Purpose of the Study:
- To identify and analyze the diagnostic pathways leading to an Alzheimer disease (AD) diagnosis in patients with prior cognitive impairment (CI).
- To assess the associated healthcare costs of these diagnostic pathways.
Main Methods:
- Analysis of Medicare claims data from 2001 to 2006.
- Identification of four major diagnostic pathways transitioning to AD.
- Linear regression modeling to determine cost determinants, adjusting for demographics, comorbidities, and frailty.
Main Results:
- Four distinct diagnostic pathways were identified, including transitions from cognitive disturbance or dementia to AD.
- All pathways showed a cost peak at initial diagnosis, with subsequent higher-than-baseline costs.
- Transitional CI diagnoses significantly increased Medicare expenditures by $4600 to $14,200 compared to initial AD diagnoses.
Conclusions:
- Diagnostic pathways involving cognitive impairment (CI) before an Alzheimer disease (AD) diagnosis are associated with substantially higher Medicare costs.
- Inpatient and skilled nursing facility services were major cost drivers in these transitional pathways.
- Comorbidities, rather than CI, were often the primary diagnoses recorded for the AD event.
Abstract:
Despite its implications on the personal and policy level, little is currently known about the specific diagnostic pathways that patients with cognitive impairment (CI) pass through before being diagnosed with Alzheimer disease (AD). Four major diagnostic pathways were identified in the Medicare claims records for 2001 to 2006: AD as initial diagnosis, cognitive disturbance followed by AD; dementia with suspected etiologies followed by AD; dementia without known cause followed by AD; and 1 triple pathway, cognitive disturbance followed by dementia without known cause followed by AD. For all of these pathways, previously low medical costs peaked during patients' month of initial diagnosis and then declined to a level substantially higher than before. The 3 CI pathways that transition to AD included another peak in costs when a secondary AD diagnosis occurred. Each time, inpatient and skilled nursing facility services were major cost contributors. The primary diagnoses on Medicare claims for the AD event were usually comorbidities rather than CI. A linear regression model adjusting for demographic factors, selected comorbidities, and overall frailty found that the transitional CI diagnoses were significant independent cost determinants. They increased Medicare expenditures by an estimated $4600 to $14,200 relative to patients whose initial CI diagnosis was AD.
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