The following is a summary of “Gut Microbial Metabolite Trimethylamine N-oxide, Incident CKD, and Kidney Function Decline,” published in the May 2024 issue of Nephrology by Wang et al.

Trimethylamine N-oxide (TMAO), a compound from gut bacteria, is linked to kidney damage. Its impact on future kidney health, especially chronic kidney disease (CKD), remains unclear.

Researchers conducted a prospective study predicting higher TMAO levels correlated with a higher risk of CKD development and rapid decline in kidney function. 

They studied 10,564 participants from two community-based cohorts with eGFR rates ≥ 60mL/min/1.73m². TMAO levels were measured at baseline and one follow-up visit, with creatinine and cystatin C getting measured up to 4 times during follow-up. Incident CKD was defined as a drop ≥30% from baseline resulting in eGFR<60mL/min/1.73m² in kidney function. They used the Time-varying Cox model to analyze the association between TMAO and CKD risk, and the Linear mixed models assessed eGFR change in 10,009 participants. 

The result showed during a follow-up of 9.4 (9.1-11.6) years, 979 CKD cases emerged. Higher TMAO levels linked with increased CKD risk (2nd-5th vs. 1st quintile HR [95%CI] = 1.65 [1.22-2.23], 1.68[1.26-2.25], 2.28[1.72-3.02], 2.24[1.68-2.98]). TMAO also correlated with greater eGFR decline (2nd-5th vs. 1st quintile annualized eGFR change=-0.21[-0.32, -0.09], -0.17 [-0.29, -0.05], -0.35 [-0.47, -0.22], -0.43 [-0.56, -0.30]). The results were consistent across different racial and ethnic groups. eGFR decline association was similar to or larger than CKD risk factors, including diabetes, per 10 mmHg of higher systolic blood pressure per 10 years of older age. 

Investigators concluded that increasing plasma TMAO is linked with higher CKD risk and faster kidney function decline over time.

Source: journals.lww.com/jasn/abstract/9900/the_gut_microbial_metabolite_trimethylamine.282.aspx