Evidence map›Paper›PMID 33751019›Full record

SynthesisAdvances in nutrition (Bethesda, Md.)2021

Gut Microbiota-Derived Trimethylamine N-Oxide and Kidney Function: A Systematic Review and Meta-Analysis.

Yan Zeng, Man Guo, Xia Fang, Fangyuan Teng, Xiaozhen Tan, Xinyue Li, Mei Wang, Yang Long, Yong Xu

Open access · bronzeAbstract readMeta-AnalysisSystematic Review
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in Advances in nutrition (Bethesda, Md.), 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 58 papers, 6 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
58citing papers in PubMed, 6 pooled it
8.3field-weighted citation impact, top 1% 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.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · 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.

3 · Its place in the literature

Who cites it

58 citing papers in PubMed, 6 syntheses or guidelines pooled it, 80 citations in OpenAlex.

  1. Pooled it
  2. Pooled it
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  4. Pooled it
  5. Pooled it
  6. Pooled it
  7. Trial
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  9. Gut microbes · 2026
    Review
  10. Review
  11. Review
  12. Review
  13. Article
  14. Review
  15. Article
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  17. Article
  18. Review
  19. Gut Microbiota Metabolites and the Development of CKD.Clinical journal of the American Society of Nephrology : CJASN · 2025
    Article
  20. Article
4 · The record

Corrections and comments

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

5 · Who and what money

Authors and funding

9 authors at 1 institution in 1 country.

Yan ZengDepartment of Endocrinology and Metabolism, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.
Man GuoDepartment of Endocrinology and Metabolism, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.
Xia FangDepartment of Endocrinology and Metabolism, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.
Fangyuan TengDepartment of Endocrinology and Metabolism, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.
Xiaozhen TanDepartment of Endocrinology and Metabolism, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.
Xinyue LiDepartment of Endocrinology and Metabolism, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.
Mei WangDepartment of Endocrinology and Metabolism, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.
Yang LongDepartment of Endocrinology and Metabolism, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.
Yong XuDepartment of Endocrinology and Metabolism, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.ORCID 0000-0002-9534-6252
Affiliated Hospital of Southwest Medical University · CN

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Elevated circulating trimethylamine N-oxide (TMAO) concentrations have been observed in patients with chronic kidney disease (CKD). We aimed to systematically estimate and quantify the association between TMAO concentrations and kidney function. The PubMed, EMBASE, Cochrane Library, Scopus, and Web of Science databases were systematically searched from 1995 to 1 June, 2020, for clinical studies on circulating TMAO concentrations and kidney function indicators. We used R software to conduct meta-analyses of the extracted data. A cumulative meta-analysis was applied to test whether health status affected the pooled effect value. Meta-regression and subgroup analyses were performed to identify possible sources of heterogeneity. Ultimately, we included a total of 32 eligible clinical studies involving 42,062 participants. In meta-analyses of continuous-outcome variables, advanced CKD was associated with a 67.9 μmol/L (95% CI: 52.7, 83.2; P < 0.01) increase in TMAO concentration, and subjects with high concentrations of TMAO had a 12.9 mL/(min·1.73 m2) (95% CI: -16.6, -9.14; P < 0.01) decrease in glomerular filtration rate (GFR). In meta-analyses of the correlations, TMAO was strongly inversely correlated with GFR [Fisher's z-transformed correlation coefficient (ZCOR): -0.45; 95% CI: -0.58, -0.32; P < 0.01] and positively associated with the urine albumin-to-creatinine ratio (UACR; ZCOR: 0.26; 95% CI: 0.08, 0.43; P < 0.01), serum creatinine (sCr; ZCOR: 0.43; 95% CI: 0.28, 0.58; P < 0.01), urine albumin excretion rate (UAER; ZCOR: 0.06; 95% CI: 0.04, 0.09; P < 0.01), blood urea (ZCOR: 0.50; 95% CI: 0.29, 0.72; P < 0.01), blood uric acid (ZCOR: 0.32; 95% CI: 0.25, 0.38; P < 0.01), and serum cystatin C (CysC; ZCOR: 0.47, 95% CI: 0.44, 0.51; P < 0.01). This is the first systematic review and meta-analysis to reveal a negative association between circulating TMAO concentrations and kidney function.

Indexed as

Gastrointestinal MicrobiomeHumansKidneyMethylaminesRisk FactorsMethylaminestrimethyloxaminechronic kidney diseaseglomerular filtration rategut microbiomekidney functionkidney impairmentmeta-analysisTMAOtrimethylamine N-oxide

Identifiers

PMID33751019
PMCPMC8321840
OpenAlexW3133499425

What OpenQuestion holds

Textmetadata
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.