Peritoneal and hemodialysis: II. Mortality risk associated with initial patient characteristics.
BACKGROUND
Patients initiating with peritoneal dialysis (PD) have favorable clinical conditions compared with hemodialysis (HD) patients, which may contribute to the varying results found in studies of mortality across the two therapies.


METHODS
National incidence data of end-stage renal disease patients from 1995 to 1997 were used, excluding the first 90 days of treatment and including all patients who were on either PD or HD on day 91. Patients were then followed for a one-year period. A Cox proportional hazards regression analysis was used, separating diabetics and non-diabetics, and two statistical models were applied. Model 1 included race, gender, age, initial modality, and incidence year as explanatory variables. Model 2 added body mass index (BMI), initial levels of serum albumin, creatinine, and blood urea nitrogen.


RESULTS
Age was most highly associated with mortality, followed by biochemical variables, BMI, gender, and dialysis modality. In diabetics, the hazard ratio (HR) from Model 1 indicated no difference [1.046, 95% confidence limits (CL) 0.989-1.105; P> 0.1, HD was the reference] in mortality between PD and HD, while Model 2 demonstrated that PD patients had a 13.4% (1.134, CL 1.072-1.100, P < 0.0001) higher chance of death. In non-diabetics, hazard ratios (HRs) from Models 1 and 2 indicated that PD patients had a 23.5% (0.765, 0.722-0.812, P < 0.0001) and 11.9% (0.881, 0.30-0.935, P < 0.0001), respectively, lower likelihood of death than HD patients.


CONCLUSIONS
Our study indicates that the results changed depending on the analytical methods used. We recommend that, due to the unequally distributed clinical conditions of patients at initiation, comparisons of mortality outcomes between dialysis modalities should be made with caution.
Xue
Jay L
JL
USRDS Coordinating Center and Minneapolis Medical Research Foundation, Minnesota 55404, USA. jxue@usrds.org
Everson
Susan E
SE
Constantini
Edward G
EG
Ebben
James P
JP
Chen
Shu-Cheng
SC
Agodoa
Lawrence Y
LY
Collins
Allan J
AJ
D017677:Age Distribution; D000368:Aged; D044383:Black People; D014487:Centers for Medicare and Medicaid Services, U.S. / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D015994:Incidence; D007676:Kidney Failure, Chronic / Q000401:mortality* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D010530:Peritoneal Dialysis / Q000401:mortality*; D016016:Proportional Hazards Models; D006435:Renal Dialysis / Q000401:mortality*; D012307:Risk Factors; D017678:Sex Distribution; D014481:United States; D014511:Uremia / Q000401:mortality; D044465:White People; D001741:Black or African American