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Closing the Gap Between Observational Research and Randomized Controlled Trials for Prevention of Alzheimer Disease and Dementia
Power MC, Engelman BC, Wei J, Glymour MM.. Epidemiologic reviews, 2022-12-01
Topic: Risk, prevention and care in population studies
Although observational studies have identified modifiable risk factors for Alzheimer disease and related dementias (ADRD), randomized controlled trials (RCTs) of risk factor modification for ADRD prevention have been inconsistent or inconclusive. This finding suggests a need to improve translation between observational studies and RCTs. However, many common features of observational studies reduce their relevance to designing related RCTs. Observational studies routinely differ from RCTs with respect to eligibility criteria, study population, length of follow-up, treatment conditions, outcomes, and effect estimates. Using the motivating example of blood pressure reduction for ADRD prevention, we illustrate the need for a tighter connection between observational studies and RCTs, discuss barriers to using typically reported observational evidence in developing RCTs, and highlight methods that may be used to make observational research more relevant to clinical trial design. We conclude that the questions asked and answered by observational research can be made more relevant to clinical trial design and that better use of observational data may increase the likelihood of successful, or at least definitive, trials. Although we focus on improving translation of observational studies on risk factors for ADRD to RCTs in ADRD prevention, the overarching themes are broadly applicable to many areas of biomedical research.
Key findings
- We conclude that the questions asked and answered by observational research can be made more relevant to clinical trial design and that better use of observational data may increase the likelihood of successful, or at least definitive, trials.
Why it matters
This paper discusses why randomized controlled trials of risk factor modification for Alzheimer's disease prevention have been inconsistent or inconclusive despite observational findings. It argues that better use of observational data in designing trials may increase the likelihood of successful or at least definitive prevention trials.
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Study details
- Evidence strengthHigh
How this study scored 42/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, effect reported and studied in people because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Epidemiologic reviews) |
| Journal's citation record | 2 / 4 | Epidemiologic Reviews: journal h-index 178 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 5 / 5 | Rated “high” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 3 / 5 | 2022 — within 6 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 1 / 2 | Randomised (as stated in the record) |
| Times cited | 3 / 7 | Cited 17 times (OpenAlex, 2026-10-10) |
| Citations per year | 1 / 5 | 2.8 citations a year over 6 year(s) since 2022 |
| Impact for its field and year | 2 / 6 | Cited 1.7× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | 2 / 4 | Cited 16 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 3 / 4 | Last-listed author M. Maria Glymour: h-index 83 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | George Washington University: institution h-index 881 (OpenAlex) |
| Multi-centre collaboration | 0 / 3 | OpenAlex lists 1 institution(s) in 1 country — scores zero (affiliation lists can be incomplete) |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 35442427) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 42 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
Full text: free to read — PubMed Central lists this copy as free to read: the link above (checked 10 Oct 2026).
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
Power, M. C., Engelman, B. C., Wei, J., & Glymour, M. M. (2022). Closing the Gap Between Observational Research and Randomized Controlled Trials for Prevention of Alzheimer Disease and Dementia. Epidemiologic reviews. https://doi.org/10.1093/epirev/mxac002
Vancouver
Power MC, Engelman BC, Wei J, Glymour MM. Closing the Gap Between Observational Research and Randomized Controlled Trials for Prevention of Alzheimer Disease and Dementia. Epidemiologic reviews. 2022. doi:10.1093/epirev/mxac002. PMID: 35442427.
BibTeX
@article{power2022-35442427,
author = {Power, M. C. and Engelman, B. C. and Wei, J. and Glymour, M. M.},
title = {{Closing the Gap Between Observational Research and Randomized Controlled Trials for Prevention of Alzheimer Disease and Dementia}},
journal = {Epidemiologic reviews},
year = {2022},
doi = {10.1093/epirev/mxac002},
pmid = {35442427},
url = {https://doi.org/10.1093/epirev/mxac002}
}
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