title: Relationship between glutathione S-transferase M1 polymorphism and clinical outcomes in Chinese peritoneal dialysis patients.
abstract: BACKGROUND
  Oxidative stress contributes to cardiovascular diseases in peritoneal dialysis (PD) patients. Glutathione S-transferase M1 is an antioxidative enzyme encoded by the GST M1 gene. The GST M1 (-) genotype causes deficiency of the enzyme when compared with the GST M1 (+) genotype. We investigated the effects of the GST M1 (-)/(+) polymorphism on the clinical outcomes of Chinese PD patients.
  
  
  METHODS
  We studied 441 new PD patients (232 men, age 56.6 ± 13.5 years). GST M1 (-)/(+) polymorphism was determined by multiplex polymerase chain reaction. The patients were followed for 41.4 ± 18.2 months.
  
  
  RESULTS
  The GST M1 polymorphism was not associated with 5-year patient and technique survival in the whole cohort. However, there were significant interactions between age group and the GST M1 polymorphism on 5-year patient survival (p=0.046) and technique survival (p=0.049). Post hoc analysis showed that for patients =70 years old, those with the GST M1 (+) genotype had significantly better 5-year patient survival (62.5% vs. 26.2%; log rank test, p=0.012) and technique survival (55.1% vs. 21.9%; log rank test, p=0.024) than the GST M1 (-) group. For patients younger than 70 years, the GST M1 polymorphism did not affect 5-year patient or technique survival.
  
  
  CONCLUSIONS
  The GST M1 (+) genotype is associated with better survival in elderly PD patients, who may have heavy oxidative stress as a result of the aging and PD processes.
authors.affiliation: Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Peter Yam-Kau
authors.initials: PY
authors.lastname: Poon
authors.forename: Cheuk-Chun
authors.initials: CC
authors.lastname: Szeto
authors.forename: Bonnie Ching-Ha
authors.initials: BC
authors.lastname: Kwan
authors.forename: Kai-Ming
authors.initials: KM
authors.lastname: Chow
authors.forename: Philip Kam-Tao
authors.initials: PK
authors.lastname: Li
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D044466:Asian People / Q000235:genetics*; D018572:Disease-Free Survival; D005260:Female; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics*; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D053208:Kaplan-Meier Estimate; D007674:Kidney Diseases / Q000201:enzymology / Q000208:ethnology / Q000235:genetics / Q000401:mortality / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000235:genetics; D010530:Peritoneal Dialysis / Q000009:adverse effects / Q000401:mortality; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D005982:Glutathione Transferase