“Biased” Comparison Between ANDY-Disc® and UltraBag® in Patients on CAPD

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To the Editor:

In their article, Wong et al¹ failed to establish therapeutic equivalence of ANDY-Disc (Fresenius Medical Care, Bad Homburg, Germany) to UltraBag (Baxter, Deerfield, IL) regarding peritonitis. The study is inherently biased against the ANDY-Disc group, in having patients shifted from UltraSet (Baxter, Deerfield, IL) and needing transfer set change. The wash-in period of a month seems inadequate as most peritonitis episodes occurred during first half of study. Nonblinded studies cannot avoid bias.² ANDY-Disc training methods are not specified. ANDY-Disc patients initiated totally new “connectology,” whereas a shift from UltraSet to UltraBag would have less difficulty and without transfer set change. The authors confess unreliable baseline data. There is lopsidedly high incidence of Staphylococcus coagulase–negative/Staphylococcus epidermidis peritonitis in the ANDY-Disc® group (14 versus 5 episodes). Authors attribute the higher incidence of peritonitis in the ANDY-Disc® group to product defects (which settled dramatically in last quarter). S epidermidis peritonitis is mild, easily treatable, and caused by touch contamination not product defects.³ Biofilms cause relapsing peritonitis necessitating catheter change.³ Did the authors follow this guideline? Disregard S epidermidis peritonitis, then the difference in peritonitis is not statistically significant. More realistic would be to follow-up for 2 years with a longer wash-in period or to compare patients starting 2 systems de novo as done earlier.⁴ This study showed similar peritonitis rates between the StaySafe double-bag disconnect system (Fresenius Medical Care, Bad Homburg, Germany) and UltraBag. StaySafe and ANDY-Disc are essentially similar except for the solution bag material. Our peritoneal dialysis center uses ANDY-Disc with peritonitis rates of 1 episode in 63.2 patient-months and low Gram-positive coccal peritonitis, suggesting good connectology.⁵, ⁶

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References 

1. Wong H-S, Ong L-M, Lim T-O, et al. 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
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2. Daly CD, Campbell MK. Is it possible for studies comparing Y-set, double bag, and standard systems of CAPD to be blinded?. Nephrol Dial Transplant. 2001;16:2440–2441
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3. Piraino B, Bailie GR, Bernardini J, et al. Peritoneal dialysis-related infections recommendations: 2005 update. Perit Dial Int. 2005;25:107–131
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4. Li PK, Law MC, Chow KM, et al. 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
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5. Subhramanyam SV, Sinoj KA, Mary B, Nayak KS. Our experience with new connectology for CAPD. Perit Dial Int. 2005;25(suppl 2):S22;abstr
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6. Nayak KS. Overcoming CAPD cost barrier in Asian developing countries. 2002;Presented at the First Asian Chapter Meeting, International Society for Peritoneal Dialysis, December 13-15, Hong Kong
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