title: Clinical Significance of the Edema Index in Incident Peritoneal Dialysis Patients.
abstract: BACKGROUND
  Proper monitoring for volume overload is important to improve prognosis in peritoneal dialysis (PD) patients. The association between volume status and residual renal function (RRF) remains an unresolved issue. The aim of the present study was to evaluate the association between the edema index and survival or RRF in incident PD patients.
  
  
  METHODS
  We identified all adults who underwent PD. The edema index was defined as the ratio of extracellular fluid to total body fluid. Participants with available data regarding survivorship or non-survivorship during the first year after PD initiation were included in the area under the receiver operating characteristic curve analysis. The cutoff value of the edema index for 1-year mortality was >0.371 in men and >0.372 in women. Participants were divided into two groups according to the cutoff value of their baseline edema indices: High (>cutoff value) and Low (≤ cutoff value). Survivors during the first year after PD initiation were divided into two groups according to the initial and 1-year edema index: Non-improvement (maintenance of criteria in the initial Low group during the year) and Other (all participants except those in the Non-improvement group).
  
  
  RESULTS
  In total, 631 patients were enrolled in the present study. The cutoff value of the edema index for 1-year mortality was >0.371 in men and >0.372 in women. The respective mean initial RRF values (mL · min(-1) · 1.73 m(-2)) in the Low and High groups, respectively, were 4.88 ± 4.09 and 4.21 ± 3.28 in men (P = 0.108), and 3.19 ± 2.57 and 2.98 ± 2.70 in women (P = 0.531). There were no significant differences between groups in either sex. The respective mean RRF values at 1 year after PD initiation in the Low and High groups, respectively, were 3.56 ± 4.35 and 2.73 ± 2.53 in men, and 2.80 ± 2.36 and 1.85 ± 1.51 in women. RRF at 1 year after PD initiation was higher in the Low group than in the High group (men: P = 0.027; women: P = 0.001). In men, the cumulative 5-year survival rates were 78.7% and 46.2% in the Low and High groups, respectively, whereas in women, rates were 77.2% and 58.8% in the Low and High groups, respectively. For survivors during the first year after PD initiation, the Non-improvement group was associated with a poor survival rate compared with the Other group for both sexes.
  
  
  CONCLUSIONS
  A high edema index was associated with mortality in incident PD patients at baseline and follow-up. The edema index may be used as a new marker for predicting mortality in PD patients.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Yeungnam University Hospital, Daegu, Republic of Korea.
authors.forename: Seok Hui
authors.initials: SH
authors.lastname: Kang
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Yeungnam University Hospital, Daegu, Republic of Korea.
authors.forename: Eun Woo
authors.initials: EW
authors.lastname: Choi
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Yeungnam University Hospital, Daegu, Republic of Korea.
authors.forename: Jong Won
authors.initials: JW
authors.lastname: Park
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Yeungnam University Hospital, Daegu, Republic of Korea.
authors.forename: Kyu Hyang
authors.initials: KH
authors.lastname: Cho
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Yeungnam University Hospital, Daegu, Republic of Korea.
authors.forename: Jun Young
authors.initials: JY
authors.lastname: Do
mesh_terms: D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D004487:Edema / Q000209:etiology / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000009:adverse effects*; D012737:Sex Factors; D015996:Survival Rate