Microbiome-Derived TMAO as a Multifaceted Biomarker in Cardiovascular Disease: Challenges and Opportunities
Current evidence does not support plasma TMAO as a clinically validated cardiovascular biomarker, as associations with outcomes are frequently attenuated or eliminated after adjustment for renal function.
| Population | Adults with cardiovascular diseases (ischemic stroke, CAD, HF, PAD, CKD) or at elevated cardiovascular risk |
|---|---|
| Intervention | Plasma TMAO measurement as diagnostic, prognostic, or pharmacodynamic biomarker |
| Komparator | Established biomarkers (NT-proBNP, eGFR, traditional risk factors) alone or in combined models |
| Endpunkt | Diagnostic accuracy for ischemic stroke; Diagnostic accuracy for heart failure; Diagnostic accuracy for coronary artery disease; All-cause mortality in peripheral artery disease; Mortality in chronic kidney disease; Incremental value of TMAO added to NT-proBNP in HFpEF; Attenuation of TMAO-outcome association after eGFR adjustment |
Ergebniszusammenfassung
| Endpunkt | Effekt | 95%-KI | Sicherheit | Klinische Relevanz | Anmerkungen |
|---|---|---|---|---|---|
| Diagnostic accuracy for ischemic stroke | AUC 0.729-0.78 (range across studies; in the pooled IC available) | — | Niedrig | — | 3 studies |
| Diagnostic accuracy for heart failure | AUC 0.63-0.881 (range across HF subtypes; in the pooled IC available) | — | Niedrig | — | 3 studies |
| Diagnostic accuracy for coronary artery disease | AUC 0.56-0.60 (range across studies; in the pooled IC available) | — | Niedrig | — | 2 studies |
| All-cause mortality in peripheral artery disease | HR 2.06 (follow-up 5y; IC not reported in source) | — | Niedrig | — | 1 studies |
| Mortality in chronic kidney disease | HR range 1.13-4.32 across studies (IC not reported; high heterogeneity) | — | Niedrig | — | 5 studies |
| Incremental value of TMAO added to NT-proBNP in HFpEF | no improvement in AUC vs NT-proBNP alone (quantitative IC not reported) | — | Niedrig | — | 1 studies |
| Attenuation of TMAO-outcome association after eGFR adjustment | partial or complete attenuation reported in majority of eGFR-adjusted studies (IC not pooled; qualitative finding across >7 studies) | — | Niedrig | — | 7 studies |
Kontext
TMAO is a gut microbiota-derived metabolite produced from choline, carnitine, and their derivatives, then oxidized hepatically by FMO3. Its association with atherosclerosis and cardiovascular risk has driven intense research into its biomarker potential. Clinical validation requires that a biomarker add independent value beyond already established predictors.
Was die Studie zeigte
Diagnostic accuracy of TMAO is moderate for ischemic stroke (AUC 0.729–0.78) and HF (AUC 0.817–0.881), but low for CAD (AUC 0.56–0.60) and HFpEF (AUC 0.63). Prognostically, associations with mortality and MACE are reported (e.g., HR 2.06 for mortality in PAD; HR 4.32 in CKD), but multiple studies show partial or complete attenuation after eGFR adjustment. Adding TMAO to NT-proBNP did not improve diagnostic accuracy in HFpEF.
Wie es durchgeführt wurde
Narrative (non-systematic) review integrating observational studies, cohorts, and clinical trials on TMAO as a cardiovascular biomarker, without formal meta-analysis. No registered protocol; no systematic literature screening or formal risk-of-bias assessment of included studies. Review covers multiple cardiovascular and renal conditions.
Effektgröße
Prognostic effects vary widely: HR 1.13 to 4.32 for mortality depending on population; diagnostic AUC between 0.56 and 0.881. Heterogeneity precludes a reliable pooled effect estimate.
Bias-Risiko
Narrative review without registered protocol and without formal risk-of-bias assessment (AMSTAR-2 not applicable; tool not used by authors). Most primary studies did not adjust for eGFR, introducing critical residual confounding. High inter- and intra-individual TMAO variability (diet, renal function, FMO3 activity, sex, ethnicity) limits reproducibility. Absence of standardized cutoff values and uniform measurement methods.
Was diese Studie NICHT beweist
This study does not prove that TMAO causes cardiovascular disease or that its reduction improves clinical outcomes. It does not establish validated cutoff values nor demonstrate that TMAO adds diagnostic or prognostic value beyond established biomarkers in unselected populations.
In der klinischen Praxis
There is no basis for incorporating routine plasma TMAO measurement into clinical cardiovascular assessment. Clinicians should verify whether eGFR adjustment was performed before attributing independent prognostic value to TMAO findings. eGFR assessment remains superior and mandatory.
Einschränkungen
Narrative review without registered protocol and without formal risk-of-bias assessment (AMSTAR-2 not applicable; tool not used by authors). Most primary studies did not adjust for eGFR, introducing critical residual confounding. High inter- and intra-individual TMAO variability (diet, renal function, FMO3 activity, sex, ethnicity) limits reproducibility. Absence of standardized cutoff values and uniform measurement methods.
Was noch fehlt
Large prospective studies with systematic adjustment for eGFR, diet, and FMO3 polymorphisms are needed. Clinical trials evaluating whether TMAO reduction via intervention (probiotics, diet, CutC inhibitors) improves cardiovascular outcomes are the next priority.
Technischer Anhang
Versionsverlauf
- 1.0 · 2026-06-21 — Auto-generated under Evidence Standard v1.0