Outcomes after diagnosis of mild cognitive impairment in a large autopsy series

Erin L. Abner, Richard J. Kryscio, Frederick A. Schmitt, David W. Fardo, Daniela C. Moga, Eseosa T. Ighodaro, Gregory A. Jicha, Lei Yu, Hiroko Dodge, Chengjie Xiong, Randall (Randy) Woltjer, Julie A. Schneider, Nigel J. Cairns, David A. Bennett, Peter T. Nelson

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Abstract

Objective: To determine clinical and neuropathological outcomes following a clinical diagnosis of mild cognitive impairment (MCI). Methods: Data were drawn from a large autopsy series (N = 1,337) of individuals followed longitudinally from normal or MCI status to death, derived from 4 Alzheimer Disease (AD) Centers in the United States. Results: Mean follow-up was 7.9 years. Of the 874 individuals ever diagnosed with MCI, final clinical diagnoses were varied: 39.2% died with an MCI diagnosis, 46.8% with a dementia diagnosis, and 13.9% with a diagnosis of intact cognition. The latter group had pathological features resembling those with a final clinical diagnosis of MCI. In terms of non-AD pathologies, both primary age-related tauopathy (p < 0.05) and brain arteriolosclerosis pathology (p < 0.001) were more severe in MCI than cognitively intact controls. Among the group that remained MCI until death, mixed AD neuropathologic changes (ADNC; ≥1 comorbid pathology) were more frequent than "pure" ADNC pathology (55% vs 22%); suspected non-Alzheimer pathology comprised the remaining 22% of cases. A majority (74%) of subjects who died with MCI were without "high"-level ADNC, Lewy body disease, or hippocampal sclerosis pathologies; this group was enriched in cerebrovascular pathologies. Subjects who died with dementia and were without severe neurodegenerative pathologies tended to have cerebrovascular pathology and carry the MCI diagnosis for a longer interval. Interpretation: MCI diagnosis usually was associated with comorbid neuropathologies; less than one-quarter of MCI cases showed "pure" AD at autopsy.

Original languageEnglish (US)
JournalAnnals of Neurology
DOIs
StateAccepted/In press - 2017

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ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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Abner, E. L., Kryscio, R. J., Schmitt, F. A., Fardo, D. W., Moga, D. C., Ighodaro, E. T., Jicha, G. A., Yu, L., Dodge, H., Xiong, C., Woltjer, R. R., Schneider, J. A., Cairns, N. J., Bennett, D. A., & Nelson, P. T. (Accepted/In press). Outcomes after diagnosis of mild cognitive impairment in a large autopsy series. Annals of Neurology. https://doi.org/10.1002/ana.24903