SynthesisFrontiers in endocrinology2021

The Protective Effect of Metformin on Abdominal Aortic Aneurysm: A Systematic Review and Meta-Analysis.

Zhen Yuan, Zhijian Heng, Yi Lu, Jia Wei, Zhejun Cai

Open access · goldFull text readMeta-AnalysisSystematic Review
In one paragraph

Synthesis in Frontiers in endocrinology, 2021. The graph read 1 number from its abstract, feeding 1 cell of the map, but none could be read as for or against, so it casts no vote. It also reports an association that does not count as treatment evidence, such as OR 0.61 (0.41 to 0.92) for pharmacokinetics & dosing. Cited by 14 papers, 1 of them a synthesis that pooled it.

1number the graph read from it
0cells of the map it votes in
14citing papers in PubMed, 1 pooled it
2.3field-weighted citation impact, top 10% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

Read, but not usablea number the graph found but could not read as for or against

Pharmacokinetics & dosingan association or prognostic statement, not a treatment comparison · t2dfeeds one cell of the map
OR 0.610.41 to 0.92
Besides, metformin exposure was associated with a lower frequency of AAA events (odds ratio (OR) 0.61 [95% CI 0.41-0.92]).

clause the extractor read what became the number

2 · Its place on the map

Where it lands on the map

Rows are treatments, columns are outcomes. The coloured squares are the cells this paper feeds, coloured by the vote it casts there. Click one to jump to what this paper adds to it.

supports the treatmentfavours the comparatorno clear differenceread, but no usable result
3 · What it changes

What it adds to each cell

For every cell the paper feeds: the belief in the claim with and without this paper, and this paper's estimate drawn against every other readable study in the cell. The ringed dot is this paper.

Metformin×pharmacokinetics & dosing

No readable resultOpen on the map →What to test next →

2 readable studies in this cell: 0 favour the treatment, 2 find no difference, 0 favour the comparator.

Belief with this paper
0.25no deciding trial · 0 families support, 0 contradict · against placebo
Without itNot a counted family in this claim, so removing it changes nothing.
← favours the treatmentfavours the comparator →
0 · no effect
NCT00631488146 enrolled · 2008
Δ 22.6-0.60 to 45.8
NCT0200488674 enrolled · 2006
Δ -6.60-34.0 to 20.8

This paper's own estimate is on a different scale from the rest of the cell, so it is not drawn here.

4 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

5 · Its place in the literature

Who cites it

14 citing papers in PubMed, 1 synthesis or guideline pooled it, 24 citations in OpenAlex.

  1. Pooled it
  2. Review
  3. Metformin Use and Long-term Outcomes Including Aneurysm Sac Dynamics Following EVAR for Infrarenal Abdominal Aortic Aneurysm: "A Retrospective Study".Journal of endovascular therapy : an official journal of the International Society of Endovascular Specialists · 2026
    Article
  4. Article
  5. Article
  6. Review
  7. Article
  8. Review
  9. Article
  10. Article
  11. Review
  12. Status of diagnosis and therapy of abdominal aortic aneurysms.Frontiers in cardiovascular medicine · 2023
    Review
  13. Review
  14. Review
6 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

7 · Who and what money

Authors and funding

5 authors at 2 institutions in 1 country.

Zhen YuanDepartment of Cardiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Zhijian HengDepartment of Oncology, Hospital of Chinese Medicine of Changxing County, Huzhou, China.
Yi LuDepartment of Cardiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Jia WeiDepartment of Urology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Zhejun CaiDepartment of Cardiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Second Affiliated Hospital of Zhejiang University · CNChildren's Hospital of Zhejiang University · CN

Funding

No grant is acknowledged in the PubMed record.

8 · The paper itself

Abstract

The marked sentences are the ones the graph read a number from.

Background: Type 2 diabetes mellitus (T2DM) patients have a lower risk of abdominal aortic aneurysm (AAA) and its comorbidities, which might be associated with the usage of metformin. The objective of the study was to evaluate the role of metformin in the process of AAA development. Method: PubMed, Embase and Cochrane Library were searched up to May 15 Result: Ten articles were enrolled after screening 151 articles searched from databases. The pooled results showed that, compared with T2DM patients without metformin, metformin prescription was associated with a slower annual growth rate of the aneurysm (mean difference (MD) -0.67 cm [95% confidence interval (CI) -1.20 ~ -0.15 cm]). Besides, metformin exposure was associated with a lower frequency of AAA events (odds ratio (OR) 0.61 [95% CI 0.41-0.92]). Conclusion: Metformin alleviated both annual expansion rate and aneurysm rupture frequency in AAA patients with T2DM. Systematic Review Registration: PROSPERO, identifier https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=217859 (CRD42020217859).

Indexed as

Aortic Aneurysm, AbdominalComorbidityDiabetes Mellitus, Type 2Diabetic AngiopathiesHumansHypoglycemic AgentsMetforminRisk FactorsHypoglycemic AgentsMetforminabdominal aortic aneurysmaneurysm ruptureexpansion rateinflammationmetformin

Identifiers

PMID34394010
PMCPMC8355809
OpenAlexW3186769821

What OpenQuestion holds

Textfull text, public
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.