術後せん妄が長期認知機能低下を予測(Delirium after surgery is a strong predictor of cognitive decline in older adults)

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2026-06-08 ブラウン大学

米国ブラウン大学などの研究チームは、高齢患者にみられる術後せん妄(postoperative delirium)が、その後の長期的な認知機能低下と関連することを明らかにした。研究では、手術を受けた高齢者を対象に認知機能の変化を追跡し、術後せん妄を発症した患者と発症しなかった患者を比較した。その結果、術後せん妄を経験した患者では認知機能の低下速度がより速く、術前から認知機能が低下していた患者ではその傾向がさらに顕著であった。術後せん妄は一時的な意識混乱として捉えられがちだが、今回の研究は、脳の脆弱性や神経変性プロセスと関連し、長期的な認知機能の悪化を示す重要な警告サインである可能性を示唆している。研究チームは、手術前後における認知機能評価や、せん妄予防・早期介入の重要性を強調しており、高齢化社会における周術期医療と認知症予防戦略に新たな知見を提供した。

<関連情報>

高齢者における再入院と術後せん妄と認知機能低下との関連性 Rehospitalization and the Association of Postoperative Delirium With Cognitive Decline in Older Adults

Tammy T. Hshieh, MD, MPH; Zachary J. Kunicki, PhD, MS, MPH; Tamara G. Fong, MD, PhD;et al
JAMA Internal Medicine  Published:June 8, 2026
DOI:10.1001/jamainternmed.2026.1910

Key Points

Question Do illness and frailty, as measured by rehospitalization, mediate the association of postoperative delirium with cognitive decline in older adults?

Findings In this cohort study of 560 older adults, rehospitalization was more common among participants who developed incident postoperative delirium than among those who did not. In those with and without delirium, rehospitalization was associated with cognitive decline, but rehospitalization did not mediate the observed association of delirium with long-term cognitive decline.

Meaning These findings suggest that postoperative delirium remains the strongest risk factor associated with long-term cognitive decline in older adults.

Abstract

Importance Postoperative delirium is associated with long-term cognitive decline in older adults. This might be caused by the delirium itself or because delirium is more common in persons who are ill and frail, and these conditions are also associated with cognitive decline.

Objective To determine whether cognitive decline associated with postoperative delirium is mediated by illness and frailty, as measured by recurrent hospitalizations.

Design, Setting, and Participants This prospective cohort study included community-dwelling older adults (age ≥70 years), enrolled from June 2010 to August 2013 with 5 years of follow-up data in the ongoing Successful Aging after Elective Surgery longitudinal study. Data were analyzed from November 2022 to May 2026.

Exposures Incident delirium following major elective surgery, with and without rehospitalizations, combined and by type (rehospitalization alone, rehospitalization with intensive care unit stay, rehospitalization with postacute care stay).

Main Outcomes and Measures The main outcome was long-term cognitive decline, measured as change in General Cognitive Performance (GCP) score, a composite measure of 11 neuropsychological tests, between preoperative baseline and 10 repeated assessments over 5 years.

Results In the cohort of 560 older adults (mean [SD] age, 76.7 [5.2] years; 326 female [58%]), the mean (SD) GCP score at baseline was 57.6 (7.3). Each rehospitalization was associated with a decline of −0.19 (95% CI, −0.31 to −0.09) GCP units per year. Delirium was associated with more marked cognitive decline of −0.33 (95% CI, −0.67 to −0.06) GCP units per year. Rehospitalizations were more common among patients who developed delirium (adjusted incidence rate ratio, 1.42 [95% CI, 1.17 to 1.72]). However, adjustment for combined rehospitalizations and for each type of rehospitalization resulted in only a minimal percentage change that was not statistically significant (−6% to −9%) in the association of delirium with cognitive decline.

Conclusions and Relevance In this cohort study, contrary to expectations, rehospitalization did not mediate the association between delirium and long-term cognitive decline. Future work will be needed to elucidate the pathways by which delirium is associated with long-term cognitive decline.

 

医療・健康
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