The energy and nutrition states are closely associated with dialysis patients' complications and outcomes. To reach the energy balance target, we need the accurate resting energy expenditure level of patients. Traditional equations do not focus on and applicable to peritoneal dialysis patients, so we aim to develop and validate an equation for estimating resting energy expenditure in peritoneal patients.

Inclusion Criteria:

• Peritoneal dialysis patients and hemodialysis patients
• Dialysis length >3 months
• >18 years old
• Consented to participate in all aspects of the study

Exclusion Criteria:

• Acute complications to hospitalization 1 month prior to the study;
• Acute or chronic infections, cancer, and other wasting diseases in the past year;
• Thyroid dysfunction;
• Acute onset of podagra; Musculoskeletal diseases;
• Respiratory diseases (asthma, pleural effusion, pneumothorax, COPD);
• History of hormonal drug use;
• During pregnancy or lactation;
• Can not maintain posture and complete the REE test.

All peritoneal dialysis patients meet the inclusion and exclusion criteria in a single center