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The influence of cognitive decline on the severity and quantity of drug-drug interactions
Timler W, Hoang MT, Kempa-Timler J, Religa D, Kardas P.. Research Square, 2026-10-11
Topic: Health services, long-term care and technology
Background Drug-drug interactions (DDIs) are highly prevalent among older adults and are linked bidirectionally with cognitive impairment. Most prior research has examined cognitive impairment as a consequence of medication exposure rather than as an independent predictor of DDI risk, leaving unclear whether cognition independently predict DDI number and severity. Aims To evaluate the number and severity of DDIs among medications used by older adults in relation to cognitive functioning, adjusting for depressive symptoms, self-efficacy, and health literacy. Methods 212 primary care patients aged ≥ 60 years were enrolled across three branches of a family medicine clinic in Poland. Participants were stratified by Mini-Mental State Examination score into normal cognition (27–30, n = 101), cognitive impairment without dementia (24–26, n = 57), and mild dementia (19–23, n = 54). DDIs were identified via the Medscape Drug Interaction Checker and categorized by severity. Binary logistic regression models assessed associations between cognitive group and DDI outcomes, adjusting for age, sex, daily medication count, cohabitation, education, self-efficacy, health literacy, and depressive symptoms. Results Overall, 75.5% of participants had at least one DDI and 71.7% had a clinically significant interaction. Cognitive status was not independently associated with DDI presence. Daily medication count was the strongest predictor of DDIs across all severity categories, and female sex was independently associated with significant interactions. Discussion These findings indicate that cognitive impairment may mark a population vulnerable to medication complexity rather than independently driving DDI risk, with polypharmacy emerging as the principal modifiable determinant. Conclusions Medication burden, rather than cognitive status, was the key determinant of DDI risk, supporting daily medication count as a practical trigger for structured medication review regardless of cognitive status.
Key findings
- Results Overall, 75.5% of participants had at least one DDI and 71.7% had a clinically significant interaction.
- Cognitive status was not independently associated with DDI presence.
- Daily medication count was the strongest predictor of DDIs across all severity categories, and female sex was independently associated with significant interactions.
- Discussion These findings indicate that cognitive impairment may mark a population vulnerable to medication complexity rather than independently driving DDI risk, with polypharmacy emerging as the principal modifiable determinant.
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Study details
- Participants101
- Effect size75.5%; 71.7%
- Evidence strengthLow
How this study scored 16/100
Preprint — not yet peer-reviewed. It scored 32 on the same rubric, but non-peer-reviewed sources are capped at 16, so it shows as 16. Scored zero for study design and randomised / blinded because the record does not state it. We have no data on times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record and multi-centre collaboration, so those were left out: it earned 20 of the 62 points we could judge it on, which is 32 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 2 / 10 | Tier 4 — not a peer-reviewed journal (Research Square) |
| Journal's citation record | 0 / 4 | Not a journal article, so the journal's record does not count |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 4 / 10 | Preprint — not yet peer-reviewed. Hosted on a preprint server. |
| How recent | 5 / 5 | 2026 — within 1 year(s) of the newest study here |
| Sample size | 2 / 4 | 101 participants |
| Effect reported | 2 / 3 | Effect reported as a number, without an interval or test |
| 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 | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 1 / 2 | Not in PubMed, but has a DOI |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 20 / 62 | Scored on 12 of 20 parts. We have no data for the rest, so they are left out: 20 of the 62 points we could judge it on is 32 out of 100. |
| Total | 32 / 100 | Capped to 16 because this is not a peer-reviewed article. |
What each of these 20 components measures, and what this score is not →
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Cite this study APA, Vancouver, BibTeX · download .bib or .ris
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APA 7th
Timler, W., Hoang, M. T., Kempa-Timler, J., Religa, D., & Kardas, P. (2026). The influence of cognitive decline on the severity and quantity of drug-drug interactions. Research Square. https://doi.org/10.21203/rs.3.rs-10957736/v1
Vancouver
Timler W, Hoang MT, Kempa-Timler J, Religa D, Kardas P. The influence of cognitive decline on the severity and quantity of drug-drug interactions. Research Square. 2026. doi:10.21203/rs.3.rs-10957736/v1.
BibTeX
@article{timler2026-eec99df9,
author = {Timler, W. and Hoang, M. T. and Kempa-Timler, J. and Religa, D. and Kardas, P.},
title = {{The influence of cognitive decline on the severity and quantity of drug-drug interactions}},
journal = {Research Square},
year = {2026},
doi = {10.21203/rs.3.rs-10957736/v1},
url = {https://doi.org/10.21203/rs.3.rs-10957736/v1}
}
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