Clinical research in a modern Chinese peritoneal dialysis center

Trimethylamine-N-oxide (TMAO) and clinical outcomes in patients with end-stage kidney disease receiving peritoneal dialysis

BACKGROUND

Trimethylamine-N-oxide (TMAO) is a gut bacteria-derived metabolite of l-carnitine and choline. A high concentration of TMAO has been proven to relate to cardiovascular disease (CVD), all-cause mortality and chronic kidney disease progression. We aimed to investigate the relation between the value of serum TMAO and outcomes for peritoneal dialysis (PD) patients.

METHODS

This is a prospective cohort study with data retrospectively analysed. All incident PD patients were enrolled and followed up. Log-rank test, competing risk survival analysis and COX regression were performed to test the effect of serum TMAO on developing first-episode peritonitis, all-cause and CVD mortality.

RESULTS

A wide distribution of serum TMAO concentration was observed in 513 PD patients, with a median level of 72.3 (43.7, 124.7) µmol/L. Patients with lower TMAO concentration were more likely to be without diabetes and hypertension. Patients with lower TMAO concentration showed better residual kidney function and solute clearance at baseline. Participants in the higher three TMAO quartiles showed an increased risk for first-episode peritonitis (p = 0.039). By competing risk survival analysis, after adjusting for age, sex, diabetes mellitus, CVD, body mass index, albumin, high-sensitive C-reactive protein, potassium, phosphorus, residual kidney function, normalised protein equivalent of total nitrogen appearance and calendar year of catheter implantation, patients in the higher three TMAO quartiles had a statistically or marginally higher risk for first-episode peritonitis compared with patients in the lowest quartile, with hazard ratio (HR) 1.65 (1.05, 2.58), 1.46 (0.92, 2.31) and 1.66 (1.05, 2.61), respectively. In the COX model, patients in the third quartile TMAO group had significantly higher CVD mortality risk compared with the lowest quartile group, as HR 2.27 (1.02, 5.05) after adjusting for various factors. As for all-cause mortality, TMAO did not show any associated effects.

CONCLUSIONS

Serum TMAO concentration is associated with the risk of first-episode peritonitis and CVD mortality in PD patients. No obvious association between serum TMAO and all-cause mortality was observed.

The Association of Cognitive Impairment with Peritoneal Dialysis-Related Peritonitis

Background:Research on the association between cognitive impairment (CI) and peritoneal dialysis (PD)-related peritonitis is limited. Therefore, we investigated whether CI contributed to the risk of PD-related peritonitis.Methods:This prospective cohort study enrolled 458 patients from 5 PD centers between 1 March 2013, and 30 November 2013, and continued until 31 May 2016. We used the Modified Mini-Mental State Examination (3MS) to assess general cognition, the Trail-Making Test to assess executive function, and subtests of the Battery for the Assessment of Neuropsychological Status to assess immediate and delayed memory, visuospatial skills, and language ability. Patients were assigned to CI and non-CI groups based on their 3MS scores. The first episode of peritonitis was the primary endpoint event. Treatment failure of peritonitis was defined as peritonitis-associated death or transfer to hemodialysis. We used competing risk models to analyze the association between CI and the risk of peritonitis. The association of CI with treatment failure after peritonitis was analyzed using logistic regression models.Results:Ninety-four first episodes of peritonitis were recorded during a median follow-up of 31.4 months, 18.1% of which led to treatment failure. No significant group differences were observed for the occurrence, distribution of pathogenic bacteria, or outcomes of first-episode peritonitis. Immediate memory dysfunction was independently associated with a higher risk of PD-related peritonitis (hazard ratio [HR] 1.736, 95% confidence interval [CI] 1.064 - 2.834, p < 0.05), adjusting for confounders.Conclusions:Immediate memory dysfunction was a significant, independent predictor of PD-related peritonitis. Neither general nor specific domains of CI predicted treatment failure of peritonitis.