CONTINUOUS PERITONEAL-DIALYSIS IN HEAVYWEIGHT INDIVIDUALS - UREA AND CREATININE CLEARANCES

Objective: To study whether or not continuous peritoneal dialysis (CPD ) can provide acceptable levels of normalized urea and creatinine clea rance in heavyweight individuals. Design: Retrospective analysis of ur ea and creatinine clearance studies. Setting: CPD patients followed in four dialysis units in Albuquerque, two dialysis units in Thessalonik i, and two dialysis units in Athens. Participants: Orae hundred and ni nety-nine patients on CPD with 266 clearance determinations between 19 91 and 1995. Interventions: The heavyweight group consisted of 22 pati ents (24 clearance studies) weighing 100 kg or more (109.0+/-8.7 kg) a t the time of the clearance study. All subjects were obese. The refere nce group consisted of 177 CPD subjects (242 clearance studies) of nor mal weight (68.7+/-12.2 kg). Urea Fractional clearance Is(TN) and norm alized creatinine clearance (Ccr) were compared between the heavyweigh t and the reference groups. Main Outcome Measures: The lowest acceptab le weekly levels were set at 1.70 for KT/V and 54.4 L/1.73 m(2) for Cc r. Results: Weekly KT/V was 1.75+/-0.41 in the heavyweight group and 1 .94+/-0.52 in the reference group (p = 0.047). Corresponding weekly Cc r levels were 64.0+/-24.3 and 77.6+/-40.3 L/1.73 m(2), respectively (p = 0.021). In the heavyweight group, 13 studies (54.2%) had acceptable KT/V values compared to 160 studies (66.1%) in the reference group (N S). Corresponding values for acceptable Ccr were 17 (70.8%) and 165 (6 8.2%), respectively (NS). Drain volume was 12.96+/-4.40 L/24 hours in the heavyweight group and 9.63+/-2.58 L/24 hours in the reference grou p (p = 0.001). High daily exchange volume was delivered by a combinati on of daily continuous ambulatory peritoneal dialysis (CAPD) and noctu rnal automated peritoneal dialysis (APD) in 13/16 heavyweight studies. This combination was tolerated better than any other method of delive ring a Targe daily exchange volume. Conclusion: Although normalized ur ea and creatinine clearances are lower in obese, heavyweight individua ls than in lean CPD subjects with lower weight, approximately equal pe rcentages of these two groups achieve acceptable clearance levels. How ever, heavyweight individuals require larger-than-usual daily exchange volumes. The preferred way to deliver these large dialysate volumes i s a combination of daily CAPD and nocturnal APD.