Renal function is associated with plasma trimethylamine-N-oxide, choline, L-carnitine and betaine: a pilot study

Int Urol Nephrol. 2021 Mar;53(3):539-551. doi: 10.1007/s11255-020-02632-6. Epub 2020 Sep 18.


Introduction: Chronic kidney disease (CKD) is characterized by decreased glomerular filtration rate (GFR) due to a variety of causes. Most patients remain undiagnosed at early stage of CKD and proceed to end stage CKD due to unawareness and lacking of efficient biomarkers. Trimethylamine-N-oxide (TMAO) and its predecessor products: choline, L-carnitine and betaine are associated with reduced renal function. However, whether the combined variation of the four metabolites could contribute in prediction and stratification of impaired glomerular function in Chinese CKD patients is unknown. Our aim is to investigate the associations of plasma TMAO, choline, L-carnitine and betaine with glomerular filtration in CKD patients.

Materials and methods: A total of 65 CKD patients and 64 healthy controls were enrolled in this study. Fasting plasma metabolites were detected using liquid chromatography-based method.

Results: Plasma TMAO, choline, betaine and L-carnitine levels were differentially correlated with eGFR. The four metabolites were independently associated with CKD after adjustment for multiple traditional risk factors. The combination of the four metabolites had good performance at discriminating CKD from healthy controls (AUC = 0.96) as well as discriminating low eGFR from high eGFR in CKD (AUC = 0.96).

Conclusion: Combinations of TMAO and its precursors were associated with glomerular function and might be utilized in evaluation of CKD.

Keywords: Betaine; Biomarkers; Choline; Chronic kidney disease; L-carnitine; TMAO.

MeSH terms

  • Betaine / blood*
  • Biomarkers / blood
  • Carnitine / blood*
  • Choline / blood*
  • Female
  • Glomerular Filtration Rate*
  • Humans
  • Kidney / physiopathology*
  • Male
  • Methylamines / blood*
  • Middle Aged
  • Pilot Projects
  • Renal Insufficiency, Chronic / blood*
  • Renal Insufficiency, Chronic / physiopathology*
  • Retrospective Studies


  • Biomarkers
  • Methylamines
  • Betaine
  • trimethyloxamine
  • Choline
  • Carnitine