The aim of the study is to asses the hydration status of incident peritoneal dialysis (PD) patients and its evolution over a period of four years, independent of the PD treatment modality (APD or CAPD) and the PD solution type.

Achieving optimal fluid balance remains a major clinical challenge in peritoneal dialysis (PD) patients. With the recent development of a new bioimpedance spectroscopy (BIS) device, the BCM-Body Composition Monitor (BCM), it is now possible to quantify deviations of hydration status and to define target weight directly.

It has been observed that more than 50% of the PD patients are overhydrated, as compared to the healthy population. This overhydration seems to be associated with modifiable practice-related factors, such as correct PD prescription according to membrane transport status, and dietary fluid intake.

The aim of this study is to assess the hydration status of incident PD patients, and diagnose the underlying reasons for incorrect fluid status. In addition, changes in fluid status, residual renal function and nutritional status, over a follow-up period of up to four years will be registered.

The investigators assume that the use of the BCM-Body Composition Monitor (BCM) provides quantitative measurement of hydration status and thereby supports physicians in identifying patients who are not euvolaemic. Hence, the BCM allows an improved management of underlying causes of non-euvolaemic hydration state and appropriate monitoring of fluid status.

Inclusion Criteria:

• Incident patients directly before start of peritoneal dialysis
• Patients in whom routine measurement of body composition monitoring is performed

Exclusion Criteria:

• Patients treated with HD before start of PD
• Patients in whom body composition monitoring cannot be performed

Adult patients with chronic kidney disease (CKD) starting renal replacement therapy on APD or CAPD