Cited by 285Dementia and Cognitive Impairment ResearchAlzheimer's disease research and treatmentsDiabetes Treatment and Management

The DOI matches its Crossref record; 106 of the 113 references it cites were found in a registry or an index; none of the 53 sources its claims cite is checked for support yet.

Metformin in Amnestic Mild Cognitive Impairment: Results of a Pilot Randomized Placebo Controlled Clinical Trial

Open access

Abstract

Diabetes and hyperinsulinemia may be risk factors for Alzheimer's disease (AD). We conducted a pilot study of metformin, a medication efficacious in treating and preventing diabetes while reducing hyperinsulinemia, among persons with amnestic mild cognitive impairment (aMCI) with the goal of collecting preliminary data on feasibility, safety, and efficacy. Participants were 80 men and women aged 55 to 90 years with aMCI, overweight or obese, without treated diabetes. We randomized participants to metformin 1000 mg twice a day or matching placebo for 12 months. The co-primary clinical outcomes were changes from baseline to 12 months in total recall of the Selective Reminding Test (SRT) and the score of the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog). The secondary outcome was change in relative glucose uptake in the posterior cingulate-precuneus in brain fluorodeoxyglucose positron emission tomography. Change in plasma Aβ42 was an exploratory outcome. The mean age of participants was 65 years. Fifty percent of participants were women. The only baseline variable that was different between the arms was the ADAS-Cog. Metformin could not be tolerated by 7.5% of participants; 15% tolerated 500 mg/day, 35% tolerated 1000 mg/day, 32.5% tolerated 1500 mg/day, and only 10% tolerated the maximum dose. There were no serious adverse events related to metformin. The 7.5% of persons who did not tolerate metformin reported gastrointestinal symptoms. After adjusting for baseline ADAS-cog, changes in total recall of the SRT favored the metformin group (9.7±8.5 versus 5.3±8.5; p = 0.02). Differences for other outcomes were not significant. A larger trial seems warranted to evaluate the efficacy and cognitive safety of metformin in prodromal AD.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

In a 12-month pilot randomized placebo-controlled trial of metformin in 80 overweight/obese adults with amnestic mild cognitive impairment, metformin was feasible and safe but poorly tolerated at the maximum dose. After adjustment for baseline ADAS-cog, metformin improved Selective Reminding Test total recall versus placebo, while ADAS-cog, imaging, and plasma Aβ42 outcomes did not differ significantly.

Key findings

  • Metformin was not tolerated by 7.5% of participants; 15% tolerated 500 mg/day, 35% tolerated 1000 mg/day, 32.5% tolerated 1500 mg/day, and only 10% tolerated the maximum 2000 mg/day. No serious adverse events related to metformin were reported; the 7.5% who did not tolerate it reported gastrointestinal symptoms.
  • After adjusting for baseline ADAS-cog, SRT total recall favored metformin (9.7 ± 8.5 vs. 5.3 ± 8.5; p = 0.02), with a metformin-vs-placebo difference in change of 4.4 ± 8.5 words. The highest metformin dose was associated with 5.3 ± 10.0 more words in SRT total recall (p = 0.03) in post hoc analysis.
  • ADAS-cog differences were not significant after adjustment; the posterior cingulate-precuneus rCMRgl difference favored metformin but was not significant (2.0 ± 6.3% vs. 0.0 ± 6.0%; p = 0.36). Plasma Aβ42 changes were not significant (metformin 0.69 ± 18.5 pg/ml vs. placebo −4.40 ± 23.51 pg/ml; p = 0.3).
  • Fasting insulin increased more in placebo than metformin (13.8 vs. 4.7 IU/ml; p = 0.09), and hsCRP decreased with metformin but increased with placebo (−0.3 vs. 1.0 mg/dl; p = 0.07).

Methods

  • Double-blind, placebo-controlled randomized pilot trial at a single site (Columbia University Medical Center); 80 men and women aged 55–90 years with amnestic MCI by Petersen criteria, BMI ≥25 kg/m², and without treated diabetes were randomized 1:1 to metformin 1000 mg twice daily or matching placebo for 12 months, stratified by APOE-ε4.
  • Co-primary clinical outcomes were 12-month changes in Selective Reminding Test total recall and ADAS-cog; secondary imaging outcome was change in posterior cingulate-precuneus relative glucose uptake on FDG PET/MRI; plasma Aβ42 was exploratory.
  • Analysis used ANCOVA with intent-to-treat and last-observation-carried-forward imputation, adjusting for baseline variables that differed between arms; post hoc analyses examined metformin dose and strata by age, APOE-ε4, BMI, HbA1c, and fasting insulin.

Limitations

  • Stated: the study was a pilot with a relatively small sample size, results may be due to chance, findings were inconsistent between SRT and ADAS-cog, post hoc analyses are subject to chance, and the study was not powered to detect imaging differences.
  • Stated: recruitment was challenging, requiring 32 months and screening 1426 by telephone and 331 in person; most participants could not achieve the maximum metformin dose, and some could not tolerate metformin at all.
  • Evident from the text: it was a single-site study; 65 of 80 participants completed 12 months, and imaging follow-up was completed in 33 of 40 invited participants, which further limits precision and generalizability.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.3233/jad-150493

Cites

106 of 106 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

39 Own result · 36 Not checked yet · 22 Own method · 4 Own interpretation · 4 No basis given

Verify all 53 references — free account

Show all 41 claims

  • It may state two separate claims as one. 42
  • Probably not a substantial claim. 31
64 of 64
  • The paper relies on this without support.

    The posterior cingulate-precuneus and precuneus share the same pathological features in Alzheimer's disease.

    “This ROI included the Precuneus & Posterior Cingulate gyrus together, because they share the same pathological features in AD.”
  • The paper relies on this without support.

    Persons with an HbA1c of 6.5% or less are unlikely to receive pharmacologic treatment for type 2 diabetes, including metformin, during the 12 months of the study.

    “We chose the cutoff of 6.5% in HbA1c because persons with this level of HbA1c seemed unlikely to receive pharmacologic treatment for T2D, including metformin, during the 12 months of the study.”
  • The paper relies on this without support.

    A Telephone Interview for Cognitive Status score greater than 34 out of 41 indicates normal cognition and persons with this score are unlikely to have memory impairment.

    “A TICS Score > 34 out of 41 was considered normal cognition. Persons with this score were not invited to participate.”
  • The paper relies on this without support.

    A 2-week washout period is sufficient to ensure that changes in rCMRgl are not due to acute changes in glucose due to metformin.

    “However, we conducted a washout period of 2 weeks [54] at the end of the trial before performing FDG PET to ensure that changes in rCMRgl were not due to acute changes in glucose due to metformin.”
  • The authors state this as an assumption.

    Metformin acts on the AD process through reduction of peripheral insulin levels that affect brain clearance of Aβ.

    “we postulate that it acts on the AD process through reduction of peripheral insulin levels that affect brain clearance of Aβ [79-81].”
5 of 5

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Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

1 of 1

Citations

Cites

Show all 113 references

Research works printed but not linked: 3

  1. Perez, 2011, II clinical trial of metformin in amnestic MCI: Rationale, methods, and barriers and enablers of successful recruitment, J Nutr Health Aging, 15, S14
  2. Weschler, 1987, Wechsler Memory Scale-revised manual
  3. Weschler, 1981, Manual for the adult Weschler intelligence scale-Revised

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Metadata

Authors
Luchsinger, J. A., Perez, T., Chang, H., Mehta, P., Steffener, J., Pradabhan, G., Ichise, M., Manly, J., Devanand, D. P., & Bagiella, E.
Affiliations
  • Department of Medicine, Columbia University Medical Center, New York, NY, USA
  • Columbia University Irving Medical Center (US)
  • Mount Sinai Hospital (US)
  • New York Institute for Basic Research, Staten Island, NY, USA
  • Columbia University (US)
  • New York State Psychiatric Institute (US)
Venue
Journal of Alzheimer's Disease
Published
2016-03-15
Volume
51
Issue
2
Pages
501-514
ISSN
  • 1387-2877 (ISSN-L)
  • 1875-8908
OpenAlex
W2315843281
Cited by
285
References
113
Citations by year
2026: 22 · 2025: 33 · 2024: 29 · 2023: 40 · 2022: 42 · 2021: 32 · 2020: 29 · 2019: 20 · 2018: 24 · 2017: 11 · 2016: 3
FWCI
17.17
Type
journal article
Language
en
Open access
Locations
  • Journal of Alzheimer s Disease (publishedVersion)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (acceptedVersion)
  • PubMed Central (acceptedVersion)
Funders
  • Alzheimer's Drug Discovery Foundation
  • National Institutes of Health (UL1TR000040)
  • National Institute on Aging (R01AG026413)
  • National Center for Research Resources (UL1RR024156)
  • National Center for Advancing Translational Sciences
Topics
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
  • Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Alzheimer's disease research and treatments
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetes Treatment and Management
Keywords
metformin, amnestic mild cognitive impairment
MeSH terms
Aged, Aged, 80 and over, Brain, Double-Blind Method, Female, Follow-Up Studies, Glucose, Humans, Male, Metformin, Middle Aged, Peptide Fragments, Pilot Projects, Psychological Tests, Severity of Illness Index, Amyloid beta-Peptides, Treatment Outcome, Nootropic Agents, Positron-Emission Tomography, Overweight, Cognitive Dysfunction

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