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Performance of Machine Learning Algorithms for Predicting Progression to Dementia in Memory Clinic Patients
James C, Ranson JM, Everson R, Llewellyn DJ.. JAMA network open, 2021-12-01
Topic: Risk, prevention and care in population studies
Importance Machine learning algorithms could be used as the basis for clinical decision-making aids to enhance clinical practice. Objective To assess the ability of machine learning algorithms to predict dementia incidence within 2 years compared with existing models and determine the optimal analytic approach and number of variables required. Design, setting, and participants This prognostic study used data from a prospective cohort of 15 307 participants without dementia at baseline to perform a secondary analysis of factors that could be used to predict dementia incidence. Participants attended National Alzheimer Coordinating Center memory clinics across the United States between 2005 and 2015. Analyses were conducted from March to May 2021. Exposures 258 variables spanning domains of dementia-related clinical measures and risk factors. Main outcomes and measures The main outcome was incident all-cause dementia diagnosed within 2 years of baseline assessment. Results In a sample of 15 307 participants (mean [SD] age, 72.3 [9.8] years; 9129 [60%] women and 6178 [40%] men) without dementia at baseline, 1568 (10%) received a diagnosis of dementia within 2 years of their initial assessment. Compared with 2 existing models for dementia risk prediction (ie, Cardiovascular Risk Factors, Aging, and Incidence of Dementia Risk Score, and the Brief Dementia Screening Indicator), machine learning algorithms were superior in predicting incident all-cause dementia within 2 years. The gradient-boosted trees algorithm had a mean (SD) overall accuracy of 92% (1%), sensitivity of 0.45 (0.05), specificity of 0.97 (0.01), and area under the curve of 0.92 (0.01) using all 258 variables. Analysis of variable importance showed that only 6 variables were required for machine learning algorithms to achieve an accuracy of 91% and area under the curve of at least 0.89. Machine learning algorithms also identified up to 84% of participants who received an initial dementia diagnosis that was subsequently reversed to mild cognitive impairment or cognitively unimpaired, suggesting possible misdiagnosis. Conclusions and relevance These findings suggest that machine learning algorithms could accurately predict incident dementia within 2 years in patients receiving care at memory clinics using only 6 variables. These findings could be used to inform the development and validation of decision-making aids in memory clinics.
Key findings
- Objective To assess the ability of machine learning algorithms to predict dementia incidence within 2 years compared with existing models and determine the optimal analytic approach and number of variables required.
- Results In a sample of 15 307 participants (mean [SD] age, 72.3 [9.8] years; 9129 [60%] women and 6178 [40%] men) without dementia at baseline, 1568 (10%) received a diagnosis of dementia within 2 years of their initial assessment.
- Compared with 2 existing models for dementia risk prediction (ie, Cardiovascular Risk Factors, Aging, and Incidence of Dementia Risk Score, and the Brief Dementia Screening Indicator), machine learning algorithms were superior in predicting incident all-cause dementia within 2 years.
- The gradient-boosted trees algorithm had a mean (SD) overall accuracy of 92% (1%), sensitivity of 0.45 (0.05), specificity of 0.97 (0.01), and area under the curve of 0.92 (0.01) using all 258 variables.
- Analysis of variable importance showed that only 6 variables were required for machine learning algorithms to achieve an accuracy of 91% and area under the curve of at least 0.89.
Why it matters
In 15,307 participants without dementia at baseline, machine learning algorithms were assessed for predicting dementia incidence within 2 years and compared with two existing risk prediction models. The study concerns prediction and clinical decision-making aids, not treating, curing, or preventing Alzheimer's disease.
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Study details
- Study designprospective cohort
- Participants307
- Evidence strengthModerate
How this study scored 66/100
Published in a leading specialty journal, and it is a prospective cohort study, followed forward from enrollment. Scored zero for effect reported and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (JAMA network open) |
| Journal's citation record | 2 / 4 | JAMA Network Open: journal h-index 235 (OpenAlex, 2026-10-29) |
| Study design | 7 / 12 | A prospective cohort study, followed forward from enrollment |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 3 / 5 | 2021 — within 6 year(s) of the newest study here |
| Sample size | 2 / 4 | 307 participants |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 5 / 7 | Cited 119 times (OpenAlex, 2026-10-10) |
| Citations per year | 3 / 5 | 17.0 citations a year over 7 year(s) since 2021 |
| Impact for its field and year | 4 / 6 | Cited 12.1× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 3 / 6 | Cited by 10 other studies in this library |
| Still being cited | 3 / 4 | Cited 71 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 3 / 4 | Last-listed author David J. Llewellyn: h-index 68 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | University of Exeter: institution h-index 905 (OpenAlex) |
| Multi-centre collaboration | 1 / 3 | OpenAlex lists 2 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 34913981) |
| Free to read | 2 / 2 | Free to read |
| Total | 66 / 100 | — |
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Read the original
- DOI: 10.1001/jamanetworkopen.2021.36553
- PubMed: 34913981
- Original source →
- Free full text: JAMA Network Open →
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.
APA 7th
James, C., Ranson, J. M., Everson, R., & Llewellyn, D. J. (2021). Performance of Machine Learning Algorithms for Predicting Progression to Dementia in Memory Clinic Patients. JAMA network open. https://doi.org/10.1001/jamanetworkopen.2021.36553
Vancouver
James C, Ranson JM, Everson R, Llewellyn DJ. Performance of Machine Learning Algorithms for Predicting Progression to Dementia in Memory Clinic Patients. JAMA network open. 2021. doi:10.1001/jamanetworkopen.2021.36553. PMID: 34913981.
BibTeX
@article{james2021-34913981,
author = {James, C. and Ranson, J. M. and Everson, R. and Llewellyn, D. J.},
title = {{Performance of Machine Learning Algorithms for Predicting Progression to Dementia in Memory Clinic Patients}},
journal = {JAMA network open},
year = {2021},
doi = {10.1001/jamanetworkopen.2021.36553},
pmid = {34913981},
url = {https://doi.org/10.1001/jamanetworkopen.2021.36553}
}
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