title: Is obesity a favorable prognostic factor in peritoneal dialysis patients?
abstract: OBJECTIVE
  To determine the influence of an elevated body mass index (BMI) on cardiovascular outcomes and survival in peritoneal dialysis (PD) patients.
  
  
  METHODS
  Prospective, observational study of a prevalent PD cohort at a single center.
  
  
  METHODS
  Tertiary care institutional dialysis center.
  
  
  METHODS
  The study included all patients with a BMI of at least 20 who had been receiving PD for at least 1 month as of 31 January 1996 (n = 43). Patients were classified as overweight [BMI > 27.5; mean +/- standard error of mean (SEM): 32.1 +/- 1.1; n = 14] or normal weight (BMI 20-27.5; mean +/- SEM: 23.8 +/- 0.4; n = 29).
  
  
  METHODS
  Patient survival and adverse cardiovascular events (myocardial infarction, congestive cardiac failure, cerebrovascular accident, and symptomatic peripheral vascular disease) were recorded over a 3-year period.
  
  
  RESULTS
  At baseline, no significant differences were seen between the groups in clinical, biochemical, nutritional, or echocardiographic parameters, except for a lower dietary protein intake (0.97 +/- 0.10 g/kg/day vs 1.44 +/- 0.10 g/kg/day, p = 0.004) and a higher proportion of well-nourished patients by subjective global assessment (100% vs 72%, p < 0.05) in the overweight group. After 3 years of follow-up, 29% of overweight patients and 69% of normal-weight patients had died (p < 0.05). Using a Cox proportional hazards model, a BMI greater than 27.5 was shown to be an independent positive predictor of patient survival, with an adjusted hazard ratio (HR) of 0.09 [95% confidence interval (CI): 0.01-0.85; p < 0.05]. However, being overweight did not significantly influence myocardial infarction-free survival (adjusted HR: 0.33; 95% CI: 0.07-1.48; p = 0.15) or combined adverse cardiovascular event-free survival (adjusted HR: 0.67; 95% CI: 0.23-1.93; p = 0.46).
  
  
  CONCLUSIONS
  Obesity conferred a significant survival advantage in our PD population. Obese patients should therefore not be discouraged from receiving PD purely on the basis of BMI. Moreover, maintaining a higher-than-average BMI to preserve "nutritional reserve" may help to reduce the mortality and morbidity rates associated with PD.
authors.affiliation: Department of Renal Medicine, Princess Alexandra Hospital, Brisbane, Queensland, Australia. johnsond@health.qld.gov.au
authors.forename: D W
authors.initials: DW
authors.lastname: Johnson
authors.forename: K A
authors.initials: KA
authors.lastname: Herzig
authors.forename: D M
authors.initials: DM
authors.lastname: Purdie
authors.forename: W
authors.initials: W
authors.lastname: Chang
authors.forename: A M
authors.initials: AM
authors.lastname: Brown
authors.forename: R J
authors.initials: RJ
authors.lastname: Rigby
authors.forename: S B
authors.initials: SB
authors.lastname: Campbell
authors.forename: D L
authors.initials: DL
authors.lastname: Nicol
authors.forename: C M
authors.initials: CM
authors.lastname: Hawley
mesh_terms: D000368:Aged; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000209:etiology; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications / Q000401:mortality* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D010530:Peritoneal Dialysis; D011379:Prognosis; D015996:Survival Rate