title: ESRD patients without co-morbid risk factors at the start of haemodialysis are ideal as survival comparison population.
abstract: BACKGROUND
  Our aim was to identify co-morbid risk factors in ESRD patients at the start of the treatment, to select patients in the low-risk group (LRG) and to compare overall survival, adjusted overall survival and LRG survival in three centres (A, B and C).
  
  
  METHODS
  Population includes 531 patients entering haemodialysis from 1 January 1981 to 31 December 1996 (mean age 59.6 +/- 16.7 years). Demographics and co-morbidity data collected at the start of HD were independent variables for the analysis. Univariate and multivariate analysis of survival were used to identify significant prognostic factors (Kaplan-Meier and Cox hazard regression model respectively). According to this analysis the LRG was defined by the absence of the identified significant mortality risk factors except age.
  
  
  RESULTS
  The overall median survival was 7.92 years, with 92.0% survival at 1 year, 65.2% at 5 years and 40.4% at 10 years. The median survival in centre C (10.83 years) was significantly higher than median survival in centre A (7.0 years) and in centre B (7.83 years). Centres A and B were afterwards analysed together (A-B). In the multivariate analysis, five variables (starting age, diabetes, cancer, smoking habit, and arteriosclerotic heart disease) were associated with survival. The variable centre (A-B or C) was not significant. The adjusted survival curve for centres A-B and C were not different. The LRG included patients of any age, without diabetes, cancer, smoking habit, and arteriosclerotic heart disease. The frequency of the patients in the LRG was 66.3% in centre C and 45.7% in centre A-B (P = 0.0004). Taking into account only the LRG, the survival comparison between centres A-B and C, did not show significant differences (P = 0.196).
  
  
  CONCLUSIONS
  We conclude that for purposes of comparison of mortality in ESRD, low-risk population is better than overall ESRD population.
authors.affiliation: Instituto de Nefrología y Urología, Servicio de Asistencia Renal Integral, Montevideo, Uruguay.
authors.forename: N
authors.initials: N
authors.lastname: Mazzuchi
authors.forename: E
authors.initials: E
authors.lastname: Carbonell
authors.forename: J
authors.initials: J
authors.lastname: Fernández-Cean
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000401:mortality* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D006435:Renal Dialysis; D012307:Risk Factors; D015996:Survival Rate; D014583:Uruguay / Q000453:epidemiology