Activation of chronic inflammation and comorbidity in end-stage renal disease patients treated with continuous ambulatory peritoneal dialysis

The aim of the work was to determine the blood serum pro-inflammatory cytokine profile and to study their relationship with comorbidity and mortality in end-stage renal disease (ESRD) patients treated with continuous ambulatory peritoneal dialysis (CAPD). Ninety three ESRD patients treated with CAPD during 2012-2019 were included in the cohort prospective open study. The study was conducted in two stages. At the first stage, the determination of TNF-α and IL-6 levels was conducted and study of comorbidity, its quantitative assessment, baseline clinical and laboratory parameters was made. A modified polymorbidity index (MPI) which determined the quantitative assessment of comorbidity was calculated as the number of diseases per one patient excluding ESRD and its reasons. At the second stage, considering the baseline values of the studied cytokines, a prospective study of the dynamics of the prevalence of comorbid pathology, the value of MPI and mortality rate was carried out. The average duration of prospective follow-up was 26.4±6.8 months. Serum cytokines levels were determined by ELISA. Statistical analysis was performed by using "MedCalc", version 19.1.7. (Ostend, Belgium). Serum levels of TNF-α and IL-6 were significantly higher in PD-patients with 5 or more comorbid diseases. Levels of TNF-α>13.0 pg/ml have a negative effect on the dynamics of prevalence of heart failure (HF) and coronary heart disease (CHD), number of comorbid conditions in CAPD-patients. The proportion of the dead with a level of TNF-α>13.0 pg/ml was by three times higher, and deaths from cardiovascular events are almost by 10 times higher than patients who had a level of TNF-α≤13.0 pg/ml. Serum levels of IL-6>23.4 pg/ml are associated with a significant increase in number of comorbid conditions, prevalence of bacterial infections and overall and infectious mortality. Independent predictors of comorbidity and overall mortality in patients with ESRD who are treated with CAPD are serum levels of TNF-α, IL-6 and albumin. Serum levels of TNF-α and albumin are predictors of fatal cardiovascular events, and serum levels of IL-6 are predictors of fatal infectious events.