188 NATURE CLINICAL PRACTICE NEPHROLOGY APRIL 2008 VOL 4 NO 4 www.nature.com/clinicalpractice/neph Original article Wiggins KJ et al. (2007) High membrane transport status on peritoneal dialysis is not associated with reduced survival following transfer to hemodialysis. Nephrol Dial Transplant 22: 3005–3012 SYNOPSIS KEYWORDS hemodialysis, peritoneal dialysis, peritoneal membrane, survival, transport BACKGROUND If the putative survival disadvantage of high peritoneal membrane transport status is caused solely by membrane characteristics, it should diminish upon transfer to hemodialysis. OBJECTIVE To determine whether outcomes in patients who have switched from peritoneal dialysis to hemodialysis are influenced by peritoneal membrane transport status. DESIGN AND INTERVENTION Incident peritoneal dialysis patients who trans- ferred to hemodialysis for ≥1 month during the period 1 April 1999 to 31 March 2004 and who had a 4 h dialysate:plasma creatinine ratio measurement taken ≤6 months after initiating peritoneal dialysis were identified from the Australia and New Zealand Dialysis and Transplant Registry. The cohort was divided into 4 groups according to peritoneal membrane transport status, as based on the 4 h dialysate:plasma creatinine ratio: low (<0.50); low-average (0.50–0.64; reference group); high-average (0.65–0.80); and high (≥0.81). OUTCOME MEASURES The primary outcome measures were survival on hemodialysis (censored for transplanta- tion and return to peritoneal dialysis) and hemodialysis failure (defined as a return to peritoneal dialysis for ≥1 month, and censored for death and transplantation). Deaths that occurred ≤2 months after modality change were attributed to the previous modality. No apparent survival disadvantage of high peritoneal membrane transport status after transfer to hemodialysis RESULTS The 918 patients analyzed (55.9% male) had a mean age of 58 years and a mean peritoneal dialysis vintage of 16.1 months. Glomerular filtration rate (as estimated by the Modification of Diet in Renal Disease equation at initiation of peritoneal dialysis) and BMI varied significantly between the 36 (3.9%) low transporters, the 257 (28.0%) low-average transporters, the 472 (51.4%) high-average transporters and the 153 (16.7%) high transporters (P = 0.05 and P = 0.04 for glomerular filtration rate and BMI, respectively). Other clinical and demographic characteristics did not differ significantly between the groups. There were 138 deaths (15.0%) during the study period, and 243 patients (26.5%) switched back to peritoneal dialysis. Multivariate Cox regression analysis revealed that the low transporter group had a trend toward better survival than the low- average transporter group (hazard ratio [HR] for mortality 0.24 [95% CI 0.06–1.01]; P = 0.051), but survival in the high and high-average trans- porter groups did not differ significantly from that in the low-average transporter group (HRs for mortality 0.70 [95% CI 0.41–1.19]; P = 0.18, and 0.96 [95% CI 0.65–1.40]; P = 0.82, respectively). Mechanical complications were the cause of initial peritoneal dialysis failure that most strongly predicted return to peritoneal dialysis in the multivariate analysis (HR 2.37 [95% CI 1.50–3.74]; P = 0.03). Increasing 4 h dialysate: plasma creatinine ratio at commencement of peritoneal dialysis and increasing BMI were associated with a decreasing likelihood of return to peritoneal dialysis (HRs 0.32 per unit [95% CI 0.12–0.89]; P = 0.03, and 0.97 per kg/m 2 [95% CI 0.94–0.99]; P = 0.01, respectively). CONCLUSION Patients with high peritoneal membrane transport status do not seem to have a survival disadvantage following transfer to hemodialysis. PRACTICE POINT