Analysis of CKD risk, the gut microbial metabolite TMAO and decline in renal function

Below 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 produced by gut bacteria, has been linked to kidney damage. Its effects on future kidney health, particularly chronic kidney disease (CKD), are still unclear.

Researchers conducted a prospective study that predicted that higher TMAO levels correlate with a higher risk of developing CKD and rapid decline in kidney function.

They studied 10,564 participants from two community-based cohorts with eGFR rates ≥ 60 ml/min/1.73 m²TMAO levels were measured at baseline and at a follow-up visit, with creatinine and cystatin C measured up to four times during follow-up. Incident CKD was defined as a decline of ≥30% from baseline resulting in an eGFR <60 mL/min/1.73 m.² in renal function. They used the time-varying Cox model to analyze the association between TMAO and CKD risk, and the linear mixed models assessed the eGFR change in 10,009 participants.

The result showed that 979 CKD cases occurred during a follow-up of 9.4 (9.1–11.6) years. Higher TMAO levels are associated with an increased risk of CKD (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 a greater decline in eGFR (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)). Results were consistent across racial and ethnic groups. The association with decline in eGFR was similar to or greater than that for CKD risk factors, including diabetes, per 10 mmHg higher systolic blood pressure per 10 years of increased age.

The researchers concluded that increased plasma TMAO levels are associated with a higher risk of CKD and a more rapid decline in kidney function over time.

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