A prospective cohort study of long-term cognitive changes in older Medicare beneficiaries.

TitleA prospective cohort study of long-term cognitive changes in older Medicare beneficiaries.
Publication TypeJournal Article
Year of Publication2011
AuthorsWolinsky, FD, Bentler, SE, Hockenberry, J, Jones, MP, Weigel, PA, Kaskie, B, Wallace, RB
JournalBMC Public Health
Date Published2011 Sep 20
ISSN Number1471-2458
KeywordsAged, Aged, 80 and over, Aging, Cognition, Cognition Disorders, Cohort Studies, Female, Humans, Interviews as Topic, Male, Medicare, Mental Health, Outcome Assessment, Health Care, Prospective Studies, Regression Analysis, Risk Factors, United States

BACKGROUND: Promoting cognitive health and preventing its decline are longstanding public health goals, but long-term changes in cognitive function are not well-documented. Therefore, we first examined long-term changes in cognitive function among older Medicare beneficiaries in the Survey on Assets and Health Dynamics among the Oldest Old (AHEAD), and then we identified the risk factors associated with those changes in cognitive function.

METHODS: We conducted a secondary analysis of a prospective, population-based cohort using baseline (1993-1994) interview data linked to 1993-2007 Medicare claims to examine cognitive function at the final follow-up interview which occurred between 1995-1996 and 2006-2007. Besides traditional risk factors (i.e., aging, age, race, and education) and adjustment for baseline cognitive function, we considered the reason for censoring (entrance into managed care or death), and post-baseline continuity of care and major health shocks (hospital episodes). Residual change score multiple linear regression analysis was used to predict cognitive function at the final follow-up using data from telephone interviews among 3,021 to 4,251 (sample size varied by cognitive outcome) baseline community-dwelling self-respondents that were ≥ 70 years old, not in managed Medicare, and had at least one follow-up interview as self-respondents. Cognitive function was assessed using the 7-item Telephone Interview for Cognitive Status (TICS-7; general mental status), and the 10-item immediate and delayed (episodic memory) word recall tests.

RESULTS: Mean changes in the number of correct responses on the TICS-7, and 10-item immediate and delayed word recall tests were -0.33, -0.75, and -0.78, with 43.6%, 54.9%, and 52.3% declining and 25.4%, 20.8%, and 22.9% unchanged. The main and most consistent risks for declining cognitive function were the baseline values of cognitive function (reflecting substantial regression to the mean), aging (a strong linear pattern of increased decline associated with greater aging, but with diminishing marginal returns), older age at baseline, dying before the end of the study period, lower education, and minority status.

CONCLUSIONS: In addition to aging, age, minority status, and low education, substantial and differential risks for cognitive change were associated with sooner vs. later subsequent death that help to clarify the terminal drop hypothesis. No readily modifiable protective factors were identified.

User Guide Notes


Endnote Keywords

Cognition/Cognitive decline/public policy/Medicare/cognitive Function/TICS Scale

Endnote ID


Alternate JournalBMC Public Health
Citation Key7580
PubMed ID21933430
PubMed Central IDPMC3190354
Grant ListU01 AG009740 / AG / NIA NIH HHS / United States
R01 AG-022913 / AG / NIA NIH HHS / United States
R21 AG-030333 / AG / NIA NIH HHS / United States