title: Serum creatinine level, a surrogate of muscle mass, predicts mortality in peritoneal dialysis patients.
abstract: BACKGROUND
  In hemodialysis patients, higher serum creatinine (Cr) concentration represents larger muscle mass and predicts greater survival. However, this association remains uncertain in peritoneal dialysis (PD) patients.
  
  
  METHODS
  In a cohort of 10 896 PD patients enrolled from 1 July 2001 to 30 June 2006, the association of baseline serum Cr level and change during the first 3 months after enrollment with all-cause mortality was examined.
  
  
  RESULTS
  The cohort mean ± SD age was 55 ± 15 years old and included 52% women, 24% African-Americans and 48% diabetics. Compared with patients with serum Cr levels of 8.0-9.9 mg/dL, patients with serum Cr levels of <4.0 mg/dL and 4.0-5.9 mg/dL had higher risks of death {HR 1.36 [95% confidence interval (95% CI) 1.19-1.55] and 1.19 (1.08-1.31), respectively} whereas patients with serum Cr levels of 10.0-11.9 mg/dL, 12.0-13.9 mg/dL and ≥14.0 mg/dL had lower risks of death (HR 0.88 [95% CI 0.79-0.97], 0.71 [0.62-0.81] and 0.64 [0.55-0.75], respectively) in the fully adjusted model. Decrease in serum Cr level over 1.0 mg/dL during the 3 months predicted an increased risk of death additionally. The serum Cr-mortality association was robust in patients with PD treatment duration of ≥12 months, but was not observed in those with PD duration of <3 months.
  
  
  CONCLUSIONS
  Muscle mass reflected in serum Cr level may be associated with survival even in PD patients. However, the serum Cr-mortality association is attenuated in the early period of PD treatment, suggesting competing effect of muscle mass versus residual renal function on mortality.
authors.affiliation: Harold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California Irvine, School of Medicine, Orange, CA, USA.
authors.forename: Jongha
authors.initials: J
authors.lastname: Park
authors.forename: Rajnish
authors.initials: R
authors.lastname: Mehrotra
authors.forename: Connie M
authors.initials: CM
authors.lastname: Rhee
authors.forename: Miklos Z
authors.initials: MZ
authors.lastname: Molnar
authors.forename: Lilia R
authors.initials: LR
authors.lastname: Lukowsky
authors.forename: Sapna S
authors.initials: SS
authors.lastname: Patel
authors.forename: Allen R
authors.initials: AR
authors.lastname: Nissenson
authors.forename: Joel D
authors.initials: JD
authors.lastname: Kopple
authors.forename: Csaba P
authors.initials: CP
authors.lastname: Kovesdy
authors.forename: Kamyar
authors.initials: K
authors.lastname: Kalantar-Zadeh
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood*; D003404:Creatinine / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology*; D010530:Peritoneal Dialysis / Q000401:mortality*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D012709:Serum Albumin / Q000032:analysis; D015996:Survival Rate
chemical_list: D015415:Biomarkers; D012709:Serum Albumin; D003404:Creatinine
keywords: creatinine; malnutrition; mortality; muscle; peritoneal dialysis