Correlation analysis of blood trimethylamine N-oxide level with heart failure and its influencing factors in patients undergoing maintenance hemodialysis / 中华肾脏病杂志

ABSTRACT

Objective:To investigate the level of trimethylamine N-oxide (TMAO), one of gut metabolites, in patients undergoing maintenance hemodialysis (MHD) accompanied by congestive heart failure (HF) and its influencing factors.Methods:Those patients of 18-75 years old who received three or more times of hemodialysis sessions per week for three months or longer during Nov 2018 and Mar 2019 were enrolled. Those attended health checkup at the same time without obvious kidney abnormality served as non-kidney disease controls. Serum TMAO concentrations were measured using high-performance liquid chromatography electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS). The levels of TMAO were compared between patients on hemodialysis and controls, between those with heart failure and without heart failure using logrithmically transformed TMAO (lnTMAO). Linear regression analysis was performed to investigate factors influencing TMAO levels.Results:A total of 195 patients undergoing MHD and 40 controls were enrolled. Among them, 30 hemodialysis cases (15.4%) manifested as heart failure symptoms and/or left ventricular ejection fraction less than 50%. Males accounted for 67.2% in patients on hemodialysis and 37.5% in controls ( χ2=12.426, P<0.001) respectively, while the median ages in both groups were 62.0(48.0, 71.0), 45.0(33.3, 55.0) years old respectively ( Z=5.685, P<0.001). TMAO concentrations were significantly higher in patients on hemodialysis than controls [5.54(3.84, 8.91) mg/L vs 0.17(0.11, 0.30) mg/L, after log transformed, t=21.687, P<0.001]. However, there was no statistically significant difference between those with heat failure and those without in male [63.3% vs 67.9%, χ2=0.238, P=0.626], age [64.5(56.8, 71.0) years old vs 61.0(47.0, 72.0) years old, Z=0.894, P=0.372] and TMAO [5.17(3.30, 9.46) mg/L vs 5.57(3.87, 8.95) mg/L, after log transformed, t=-1.537, P=0.135]. Multivariate linear regression analysis demonstrated that in all the participants, serum urea was the main risk factor for TMAO [standardized coefficient ( SB)=0.483]. lnTMAO=0.078×[serum urea(mmol/L)]+0.001×[serum creatinine (μmol/L)]-0.002×[serum uric acid (μmol/L)]-0.003×[platelet (×10 9/L)]+0.014×[age (years old)]+0.344 (if diabetic)-1.266. While in those undergoing MHD, ultrafiltration volume had the most significant effect on TMAO levels ( SB=0.279). lnTMAO=0.249×[ultrafiltration volume(L)]+0.059×[serum albumin (g/L)]+0.008×[age (years old)-0.526 (if heart failure existed)-1.865. Conclusions:MHD patients have gut dysbiosis, while those hemodialysis patients accompanied by heart failure may have peculiar gut microbiota which induces lower serum TMAO levels than those without heart failure after adjusting for multiple related factors. Serum TMAO levels may be associated with ultrafiltration volume and nutrition status etc.