論文種別	原著(症例報告除く)
言語種別	英語
査読の有無	その他(不明)
表題	The Japanese Version of 26-Item Informant Questionnaire on Cognitive Decline in the Elderly: Development and Validation Study.
掲載誌名	正式名：Geriatrics & gerontology international 略　 称：Geriatr Gerontol Int ISSNコード：14470594/14470594
掲載区分	国外
巻・号・頁	26(7),pp.e70626
著者・共著者	Megumi Mizoguchi, Shuhei Ikeda, Yusuke Yakushiji, Makoto Eriguchi, Jun Tanaka, Kohei Suzuyama, Toshihiro Ide, Masaaki Yoshikawa, Hiromu Minagawa, Yuki Hoshino, Kotaro Iida, Rintaro Hirahara, Keisuke Tsumura, Maiko Sakamoto, Etsuo Horikawa, Masataka Nakamura, Hideo Hara, Haruki Koike
発行年月	2026/07
概要	AIM:To develop and validate a Japanese version of the 26-item Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE-J) for detecting dementia.METHODS:In this cross-sectional study, consecutive outpatients attending a university memory clinic between 2019 and 2021 completed the IQCODE-J through informants. Dementia was diagnosed according to DSM-5 criteria, independent of IQCODE-J scores. Diagnostic accuracy was assessed using receiver operating characteristic analysis and bootstrap internal validation. Concurrent validity was examined by correlations with the Ascertain Dementia 8-item Informant Questionnaire (AD8-J), Clinical Dementia Rating (CDR-J), Mini-Mental State Examination (MMSE-J), and Frontal Assessment Battery (FAB), and by multivariable logistic regression.RESULTS:Of 166 participants, 93 had non-dementia and 73 had dementia. IQCODE-J scores were higher in the Dementia group (p < 0.001). The apparent optimal cut-off in the development dataset was 4.06. Bootstrap internal validation showed an optimism-corrected area under the curve of 0.74, with sensitivity and specificity of 47.5% and 81.8%, respectively. The bootstrap median cut-off was 4.00. At cut-offs of 3.4-3.6, sensitivity ranged from 87.7% to 78.1%, and specificity from 33.3% to 54.8%. Each 1-point increase in IQCODE-J was associated with higher odds of dementia (adjusted odds ratio 7.55, 95% CI 3.31-18.74). IQCODE-J correlated with the AD8-J, CDR-J, MMSE-J, and FAB (rho = 0.77, 0.45, -0.47, and -0.44, respectively; all p < 0.001).CONCLUSIONS:IQCODE-J is a valid and feasible informant-based tool for assessing cognitive decline in Japanese patients. A cut-off around 4.0 may be practical when specificity is prioritized in referral-based settings.
DOI	10.1111/ggi.70626
PMID	42390234