Association between serum short-chain fatty acid levels and the risk of all-cause and cardiovascular disease mortality in Chinese patients undergoing maintenance hemodialysis: a retrospective cohort study

Background. The association between short-chain fatty acid (SCFA) levels and the risk of all-cause and cardiovascular disease (CVD) mortality in patients undergoing maintenance hemodialysis (MHD) is inconclusive. Furthermore, no studies on the significance of SCFA levels in MHD patients have been conducted in China. Therefore, this association was investigated in MHD patients. Methods. In this retrospective cohort study, 260 MHD patients were followed up at Central Hospital of Dalian University of Technology between January 2015 and December 2017. Serum SCFA levels were categorized into three tertiles, and the lowest tertile served as the reference group. Survival curves were obtained using the Kaplan-Meier method. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazard models. Results. There were 141 all-cause deaths during the follow-up period of (91.00 +/- 0.84) months, of which 85 were due to CVDs. Kaplan-Meier analysis revealed that the risk of CVD mortality in the highest tertile of serum butyric acid level was significantly lower than that in the lowest tertile (log-rank P < .05). The level of serum butyric acid was negatively associated with the risk of CVD mortality (HR 0.368, 95% CI 0.187-0.724) after adjusting for potential confounders, and a linear trend was evident in this association (P < .05). A linear dose-response relationship was also observed between butyric acid and CVD mortality (P nonlinearity >.05). However, none of the SCFAs was associated with the risk of all-cause mortality after adjusting for potential confounders. Conclusion. Serum butyric acid level was associated with lower risk of CVD mortality among MHD patients. Further prospective large-scale studies are needed to confirm this finding.