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The Association between a Previous Diagnosis of Mild Cognitive Impairment as a Proxy for an Early Diagnosis of Dementia and Mortality: A Study of Secondary Care Electronic Health Records

Research output: Contribution to journalArticlepeer-review

Original languageEnglish
Pages (from-to)267-274
Number of pages8
JournalJournal of Alzheimer's Disease
Issue number1

Bibliographical note

Funding Information: CRIS is supported by the NIHR Biomedical Research Centre for Mental Health BRC Nucleus at the South London and Maudsley NHS Foundation Trust and Institute of Psychiatry, Psychology and Neuroscience, King’s College London jointly funded by the Guy’s and St Thomas’ Trustees and the South London and Maudsley Trustees. Funding Information: EC is supported by a studentship from ESRC LISS-DTP. Publisher Copyright: © 2021-IOS Press. All rights reserved. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

King's Authors


Background: Dementia policy states that the early diagnosis of dementia can keep people living well for longer; however, there is little robust evidence to support this. Mild cognitive impairment (MCI) is considered a prodrome to dementia and can aid with the earlier diagnosis of dementia. Objective: The objective of this study was to use a previous diagnosis of MCI, before dementia, as a proxy for early diagnosis to investigate the relationship between an early diagnosis and mortality. Methods: A retrospective cohort study of electronic health care records from South London and Maudsley NHS. Patients aged 50+, diagnosed with dementia between January 2008 and November 2018, were divided into two groups: those with a previous diagnosis of MCI (early diagnosis) and those without. Cox regression models used to compare the risk of mortality between groups. Results: Of 18,557 participants, 5.6%(n = 1,030) had an early diagnosis; they had fewer cognitive, psychiatric, and functional problems at dementia diagnosis. The early diagnosis group had a reduced hazard of mortality (HR = 0.86, CI = 0.77-0.97). However, the magnitude of this effect depended on the scale used to adjust for cognitive difficulties. Conclusion: A previous diagnosis of MCI is a helpful proxy for early diagnosis. There is some evidence that an early diagnosis is associated with a reduced risk of mortality; however, it is not clear how Mini-Mental State Exam scores affect this relationship. While these findings are promising, we cannot be conclusive on the relationship between an early diagnosis and mortality.

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