Time Trends in the Prevalence of Neurocognitive Disorders and Cognitive Impairment in the United States: The Effects of Disease Severity and Improved Ascertainment

TitleTime Trends in the Prevalence of Neurocognitive Disorders and Cognitive Impairment in the United States: The Effects of Disease Severity and Improved Ascertainment
Publication TypeJournal Article
Year of Publication2018
AuthorsAkushevich, I, Yashkin, AP, Kravchenko, J, Ukraintseva, S, Stallard, E, Yashin, AI
JournalJournal of Alzheimer's Disease
Volume64
Issue1
Pagination137-148
ISSN Number13872877
KeywordsCIND, Cognitive Ability, Dementia, Medicare linkage, Medicare/Medicaid/Health Insurance
Abstract

Background:

Trends in the prevalence of cognitive impairment (CI) based on cognitive assessment instruments are often inconsistent with those of neurocognitive disorders (ND) based on Medicare claims records.

Objective:
We hypothesized that improved ascertainment and resulting decrease in disease severity at the time of diagnosis are responsible for this phenomenon.

Methods:
Using Medicare data linked to the Health and Retirement Study (1992–2012), we performed a joint analysis of trends in CI and ND to test our hypothesis.

Results:
We identified two major contributors to the divergent directions in CI and ND trends: reductions in disease severity explained more than 60% of the differences between CI and ND prevalence over the study period; the remaining 40% was explained by a decrease in the fraction of undiagnosed individuals.

Discussion:
Improvements in the diagnoses of ND diseases were a major contributor to reported trends in ND and CI. Recent forecasts of CI and ND trends in the U.S. may be overly pessimistic.

URLhttp://www.medra.org/servlet/aliasResolver?alias=iospress&doi=10.3233/JAD-180060
DOI10.3233/JAD-180060
Short TitleJAD
Citation Key9730