3. Study hypothesis: Patients on peritoneal dialysis are frequently hypervolemic, which is associated with increasing hazard of death and cardiovascular events. Bioimpedance analysis is a safe, and easy way, which appears to be more useful and sensitive than other techniques for assessing volume status in dialysis patients. Therefore we hypothesize that more concise and strict fluid management guided by BIA may help to improve patients' survival, decrease cardiovascular events and hospitalization rate.