Considerations for the use of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) in cross-country comparisons of cognitive aging and dementia.

TitleConsiderations for the use of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) in cross-country comparisons of cognitive aging and dementia.
Publication TypeJournal Article
Year of PublicationForthcoming
AuthorsNichols, E, Gross, AL, Zhang, YS, Meijer, E, Hayat, S, Steptoe, A, Langa, KM, Lee, J
JournalAlzheimers & dementia: the journal of the Alzheimer's Association
ISSN Number1552-5279
KeywordsIQCODE; cross‐national; dementia; global; informants; measurement
Abstract

INTRODUCTION: Informant reports are a critical component of dementia diagnoses, but the comparability of informant reports across countries is not well understood.

METHODS: We compared the performance of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) using population-representative surveys in the United States (N = 3183), England (N = 1050), and India (N = 4047).

RESULTS: Analyses of regression splines and comparisons of model fit showed strong associations between IQCODE and objective cognition at low cognitive functioning in the United States and England; in India, the association was weaker but consistent over the range of cognition. Associations between IQCODE score and informant generation (analysis of variance [ANOVA] p = 0.001), caregiver status (p < 0.001), and years known by the informant (p = 0.015) were different across countries after adjusting for objective cognition.

DISCUSSION: In India, the IQCODE was less sensitive to impairments at the lowest levels of cognitive functioning. Country-specific adjustments to IQCODE scoring based on informant characteristics may improve cross-national comparisons.

HIGHLIGHTS: Associations between IQCODE and cognitive testing were similar in the United States and England but differed in India. In India, the IQCODE may be less sensitive to impairments among those with low cognition and no education. Informant characteristics may differentially impact informant reports of decline across countries. Adjustments or culturally sensitive adaptations may improve cross-national comparability.

DOI10.1002/alz.13895
Citation Key13998
PubMed ID38805356
Grant ListU01AG058499 / / National Institutes of Health/National Institute on Aging /
R01AG051125 / / National Institutes of Health/National Institute on Aging /
RF1AG055273 / / National Institutes of Health/National Institute on Aging /
U01AG064948 / / National Institutes of Health/National Institute on Aging /
R01AG017644 / / National Institutes of Health/National Institute on Aging /
R01AG030153 / / National Institutes of Health/National Institute on Aging /
R01AG070953 / / National Institutes of Health/National Institute on Aging /