title: Survival on home dialysis in New Zealand.
abstract: BACKGROUND
  New Zealand (NZ) has a high prevalence of both peritoneal dialysis (PD) and home haemodialysis (HD) relative to other countries, and probably less selection bias. We aimed to determine if home dialysis associates with better survival than facility HD by simultaneous comparisons of the three modalities.
  
  
  METHODS
  We analysed survival by time-varying dialysis modality in New Zealanders over a 15-year period to 31-Dec-2011, adjusting for patient co-morbidity by Cox proportional hazards multivariate regression.
  
  
  RESULTS
  We modelled 6,419 patients with 3,254 deaths over 20,042 patient-years of follow-up. Patients treated with PD and facility HD are similar; those on home HD are younger and healthier. Compared to facility HD, home dialysis (as a unified category) associates with an overall 13% lower mortality risk. Home HD associates with a 52% lower mortality risk. PD associates with a 20% lower mortality risk in the early period (<3 years) that is offset by a 33% greater mortality risk in the late period (>3 years), with no overall net effect. There was effect modification and less observable benefit associated with PD in those with diabetes mellitus, co-morbidity, and in NZ Maori and Pacific People. There was no effect modification by age or by era.
  
  
  CONCLUSIONS
  Our study supports the culture of home dialysis in NZ, and suggests that the extent and duration of survival benefit associated with early PD may be greater than appreciated. We are planning further analyses to exclude residual confounding from unmeasured co-morbidity and other sociodemographic factors using database linkage to NZ government datasets. Finally, our results suggest further research into the practice of PD in NZ Maori and Pacific People, as well as definitive study to determine the best timing for switching from PD in the late phase.
authors.affiliation: Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand; Department of Renal Medicine, Counties Manukau District Health Board, Auckland, New Zealand; Australia and New Zealand Dialysis and Transplant Registry (ANZDATA), The Royal Adelaide Hospital, Adelaide, South Australia, Australia.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Marshall
authors.affiliation: Renal Department, Hawke's Bay District Health Board, Hastings, New Zealand; Sydney School of Public Health, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Rachael C
authors.initials: RC
authors.lastname: Walker
authors.affiliation: Australia and New Zealand Dialysis and Transplant Registry (ANZDATA), The Royal Adelaide Hospital, Adelaide, South Australia, Australia; Department of Nephrology, Monash Medical Centre, Clayton, Victoria, Australia; Departments of Medicine and Epidemiology and Preventive Medicine, Monash University, Clayton, Victoria, Australia.
authors.forename: Kevan R
authors.initials: KR
authors.lastname: Polkinghorne
authors.affiliation: Kidney Health New Zealand, Christchurch, New Zealand.
authors.forename: Kelvin L
authors.initials: KL
authors.lastname: Lynn
mesh_terms: D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000473:pathology / Q000628:therapy; D005260:Female; D006437:Hemodialysis, Home; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009520:New Zealand; D010530:Peritoneal Dialysis; D012307:Risk Factors