Association of Socio-Economic Position with Technique Failure and Mortality in Australian Non-Indigenous Peritoneal Dialysis Patients.
BACKGROUND
Few studies have examined the relationship between socio-economic position (SEP) and peritoneal dialysis (PD) outcomes, particularly at a country level. The aim of this study was to investigate the relationships between SEP, technique failure, and mortality in PD patients undertaking treatment in Australia.


METHODS
The study included all Australian non-indigenous incident PD patients between January 1, 1997, and December 31, 2014, using Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry data. The SEP was assessed by quartiles of postcode-based Australian Socio-Economic Indexes for Areas (SEIFA), including Index of Relative Socio-economic Advantage and Disadvantage (IRSAD - primary index), Index of Relative Socio-economic Disadvantage (IRSD), Index of Economic Resources (IER), and Index of Education and Occupation (IEO). Technique and patient survival were evaluated by multivariable Cox proportional hazards survival analyses.


RESULTS
The study included 9,766 patients (mean age 60.6 ± 15 years, 57% male, 38% diabetic). Using multivariable Cox regression, no significant association was observed between quartiles of IRSAD and technique failure (30-day definitionp= 0.65, 180-day definitionp= 0.68). Similar results were obtained using competing risks regression. However, higher SEP, defined by quartiles of IRSAD, was associated with better patient survival (Quartile 1 reference; Quartile 2 adjusted hazards ratio [HR] 0.96, 95% confidence interval [CI] 0.86 - 1.06; Quartile 3 HR 0.87, 95% CI 0.77 - 0.99; Quartile 4 HR 0.86, 95% CI 0.76 - 0.97). Similar results were found when IRSD was analyzed, but results were no longer statistically significant for IER and IEO.


CONCLUSIONS
In Australia, where there is universal free healthcare, SEP was not associated with PD technique failure in non-indigenous PD patients. Higher SEP was generally associated with improved patient survival.
Australian and New Zealand Dialysis and Transplant Registry, Adelaide, South Australia, Australia.|Department of Nephrology, Princess Alexandra Hospital, Brisbane, Queensland, Australia.|School of Medicine, The University of Queensland, Brisbane, Queensland, Australia.
Samuel
S
Chan
Australian and New Zealand Dialysis and Transplant Registry, Adelaide, South Australia, Australia.|Department of Nephrology, Princess Alexandra Hospital, Brisbane, Queensland, Australia.|School of Medicine, The University of Queensland, Brisbane, Queensland, Australia.
Yeoungjee
Y
Cho
Department of Nephrology, Princess Alexandra Hospital, Brisbane, Queensland, Australia.|School of Medicine, The University of Queensland, Brisbane, Queensland, Australia.
Yung H
YH
Koh
Australian and New Zealand Dialysis and Transplant Registry, Adelaide, South Australia, Australia.|Sir Charles Gairdner Hospital Unit, The University of Western Australia, Perth, Australia.
Neil C
NC
Boudville
Australian and New Zealand Dialysis and Transplant Registry, Adelaide, South Australia, Australia.|Central Northern Adelaide Renal and Transplantation Service, Royal Adelaide Hospital, Adelaide, South Australia, Australia.|School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.
Philip A
PA
Clayton
Australian and New Zealand Dialysis and Transplant Registry, Adelaide, South Australia, Australia.|Central Northern Adelaide Renal and Transplantation Service, Royal Adelaide Hospital, Adelaide, South Australia, Australia.|School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.
Stephen P
SP
McDonald
Department of Nephrology, Princess Alexandra Hospital, Brisbane, Queensland, Australia.
Elaine M
EM
Pascoe
Department of Nephrology, Princess Alexandra Hospital, Brisbane, Queensland, Australia.|School of Medicine, The University of Queensland, Brisbane, Queensland, Australia.
Ross S
RS
Francis
Department of Nephrology, Princess Alexandra Hospital, Brisbane, Queensland, Australia.|School of Medicine, The University of Queensland, Brisbane, Queensland, Australia.
David W
DW
Mudge
Australian and New Zealand Dialysis and Transplant Registry, Adelaide, South Australia, Australia.|School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.
Monique
M
Borlace
Australian and New Zealand Dialysis and Transplant Registry, Adelaide, South Australia, Australia.|School of Medicine, The University of Queensland, Brisbane, Queensland, Australia.|Department of Nephrology, St. George Hospital, Sydney, Australia.
Sunil V
SV
Badve
Australian and New Zealand Dialysis and Transplant Registry, Adelaide, South Australia, Australia.|Departments of Renal Medicine, Nepean and Westmead Hospitals, Sydney, Australia.|School of Medicine, Faculty of Health Sciences, University of Adelaide.
Kamal
K
Sud
Australian and New Zealand Dialysis and Transplant Registry, Adelaide, South Australia, Australia.|Department of Nephrology, Princess Alexandra Hospital, Brisbane, Queensland, Australia.|School of Medicine, The University of Queensland, Brisbane, Queensland, Australia.
Carmel M
CM
Hawley
Australian and New Zealand Dialysis and Transplant Registry, Adelaide, South Australia, Australia david.johnson2@health.qld.gov.au.|Department of Nephrology, Princess Alexandra Hospital, Brisbane, Queensland, Australia.|School of Medicine, The University of Queensland, Brisbane, Queensland, Australia.
David W
DW
Johnson
D000368:Aged; D001315:Australia / Q000453:epidemiology; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000401:mortality* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D010530:Peritoneal Dialysis; D044469:Racial Groups / Q000706:statistics & numerical data*; D012042:Registries; D012959:Socioeconomic Factors; D016019:Survival Analysis; D017211:Treatment Failure
Education; income; mortality; outcomes; peritoneal dialysis; socio-economic status; survival; technique survival