Early Diagnostic Markers for Encapsulating Peritoneal Sclerosis: A Case-Control Study

Abstract

Encapsulating peritoneal sclerosis (EPS) is a severe complication of long-term peritoneal dialysis (PD). The aim of this study was to investigate whether dialysate levels of cancer antigen-125 (CA125), K(+), interleukin (IL)-6, and vascular endothelial growth factor (VEGF) are early diagnostic markers of EPS. Therefore, we analyzed the time courses of the above described dialysate markers in EPS patients and controls. Dialysate and serum samples of 11 EPS patients and 31 control patients, all treated with PD for at least 57 months, were longitudinally collected during standard peritoneal permeability analyses. CA125 and IL-6 were measured in dialysate only, K(+) and VEGF were measured in both dialysate and serum. CA125 and IL-6 are expressed as appearance rates (AR). The linear mixed model was used to analyze the time courses. Sensitivity and specificity were calculated based on the results of the last 2 time points. No differences in the time courses of the different markers were present between the groups. For K(+) and VEGF attributed to local production, no differences between the groups were found. However, AR-CA125 was lower during the last 3 years prior to EPS (p < 0.05) and AR-IL-6 tended to be higher 2 years prior to EPS (p = 0.09). The combination of AR-CA125 < 33 U/min and AR-IL-6 > 350 pg/min had a sensitivity of 70% and a specificity of 89% for the development of EPS. Compared to controls, AR-CA125 showed lower values and AR-IL-6 tended to be higher during the last years prior to the diagnosis of EPS. The sensitivity and specificity of the combination of CA125 and IL-6 indicate their potential use for an early diagnosis of EPS.