In Reply
Article Outline
In Reply:
We agree with Dr Nayak that it is impossible to eliminate bias in an open-label study. Unfortunately it is impossible to conduct a double-blind study comparing different continuous ambulatory peritoneal dialysis (CAPD) connection systems. To eliminate bias when comparing ANDY-Disc and UltraBag in this study,1 we took numerous statistical and clinical steps including independent and blinded verification of the peritonitis episodes and centralized training of CAPD nurses. Touch contamination occurring during the change in transfer set and training for ANDY-Disc should manifest as peritonitis during the 1-month wash-in period. The number of peritonitis episodes occurring in each month of the 1-year follow-up period was similar for each system, clearly demonstrating that changing of transfer set and training for ANDY-Disc were not the reasons for the difference in the peritonitis rate (Table 1). As patients were followed up for 1 year, the higher number of peritonitis episodes occurring in the middle portion of the 2-year study period was a reflection of the larger number of study subjects during that period where most patients have not completed the study. Li and co workers2 did not demonstrate any difference between StaySafe and UltraBag, but their study was not designed to test for equivalence and their study population was much smaller. To amplify any differences in the 2 systems, we recruited CAPD patients who were at high risk of developing CAPD peritonitis. This probably explains the higher peritonitis rates in this study1 when compared to those reported by other authors.3, 4
Table 1. Number of Peritonitis and Staphylococcus epidermidis Peritonitis Episodes After Enrollment
| Month | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | |
| All peritonitis | ||||||||||||
 ANDY-Disc | 7 | 5 | 5 | 6 | 6 | 7 | 8 | 3 | 3 | 1 | 8 | 5 |
| UltraBag | 10 | 4 | 2 | 5 | 7 | 3 | 1 | 4 | 2 | 2 | 2 | 1 |
| S epidermidis peritonitis | ||||||||||||
| ANDY-Disc | 3 | 0 | 3 | 2 | 1 | 1 | 0 | 0 | 2 | 0 | 0 | 1 |
| UltraBag | 2 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
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References
- A randomized, multicenter, open-label trial to determine peritonitis rate, product defect, and technique survival between ANDY-Disc® and UltraBag® in patients on CAPD. Am J Kidney Dis. 2006;48:464–472
- Comparison of clinical outcome and ease of handling in two double-bag systems in continuous ambulatory peritoneal dialysis: A prospective, randomized, controlled, multicenter study. Am J Kidney Dis. 2002;40:373–380
- . Twin- versus single-bag disconnect systems: Infection rates and cost of continuous ambulatory peritoneal dialysis. J Am Soc Nephrol. 1996;7:2392–2398
- Peritonitis during the first year after commencement of peritoneal dialysis has an impact on technique survival and patient morbidity. Adv Perit Dial. 2006;22:50–54
Support: Supported in part by grants from Fresenius Medical Care and Baxter. Potential conflicts of interest: None.
PII: S0272-6386(06)01694-5
doi:10.1053/j.ajkd.2006.11.025
© 2006 National Kidney Foundation, Inc. Published by Elsevier Inc All rights reserved.
Refers to article:
- “Biased” Comparison Between ANDY-Disc® and UltraBag® in Patients on CAPD
- A Randomized, Multicenter, Open-Label Trial to Determine Peritonitis Rate, Product Defect, and Technique Survival Between ANDY-Disc® and UltraBag® in Patients on CAPD , 27 July 2006
