Peritonitis is a common and devastating complication in patients on peritoneal dialysis (PD). It is a known fact that persistent inflammatory state and nutritional deterioration are closely associated with increased mortality in PD patients.And resting energy expenditure(REE) is significantly increased in acute and chronic inflammation in patients with chronic kidney disease (including dialysis patients).However,it is limited to the changing trend and duration of REE in peritonitis.Investigators hypothesize that the increase in total energy consumption resulting from the increase of REE which may accompany with decreased energy intake will lead to negative energy balance and nutritional deterioration, which may affect the prognosis of patients.Therefore,a prospective cohort study will be designed to dynamically research the change of REE accompanied with the nutrition status in peritonitis and provide the basis for peritonitis management in the future.

Inclusion Criteria:

• Receiving PD for>3 months
• Age between 18 and 80 years
• Confirm diagnosis of peritonitis

Exclusion Criteria:

• Disability
• Other acute complications: including systemic infections except for peritonitis, acute cardia-cerebrovascular disease in one month
• Active hepatitis and musculoskeletal diseases in the past
• Cancer and is treated with chemoradiotherapy within 1 year
• Severe edema of the whole body or a large amount of body cavity effusion
• Thyroid dysfunction
• History of hormonal drugs use
• During pregnancy or lactation
• Mental disorder

PD patients with confirm diagnosis of peritonitis