The Impact of Increasing the Daytime Dialysis Exchange Frequency on Peritoneal Dialysis Adequacy and Nutritional Status of Chinese Anuric Patients

Abstract

♦ Objective To study the effect of increasing the daytime dialysis exchange frequency on dialysis adequacy and nutritional status of Chinese anuric patients. ♦ Setting University teaching hospital. ♦ Patient 100 anuric patients on continuous ambulatory peritoneal dialysis (CAPD). ♦ Design 50 patients had one additional daytime 2-L exchange (intervention group); the dialysis regimen remained unchanged in the other 50 patients (control group). ♦ Outcome Dialysis adequacy [Kt/V, weekly creatinine clearance (wCCr), and net ultrafiltration (UF)] and nutritional status [serum albumin, dietary protein intake, represented by normalized protein nitrogen appearance (nPNA), and percent lean body mass (%LBM)] were measured at 0 and 6 months. ♦ Results Baseline dialysis adequacy and nutritional indices were comparable between the two groups. In the control group, all parameters remained stable at month 6. In the intervention group, there were significant increases in UF, Kt/V, wCCr, nPNA, and %LBM from months 0 to 6. The improvement in nPNA was affected by daily exchange volume. In 30 patients, the number of exchanges was increased from 3 to 4 per day; their Kt/V and nPNA rose significantly from month 0 to month 6. In the other 20 patients, the number of exchanges was increased from 4 to 5 per day; there was a significant increase in Kt/V but nPNA remained static. The change in nPNA correlated inversely with Kt/V at month 0 (Pearson's r = –0.352, p = 0.012). Multivariate analysis with a general linear model showed that age, Kt/V at month 0, and 3 dialysis exchanges per day at month 0 (versus 4 exchanges) were independent predictors of the change in nPNA. ♦ Conclusions Increasing the number of peritoneal dialysis exchanges effectively increased Kt/V in Chinese anuric CAPD patients. However, the improvement in nPNA correlated inversely with baseline Kt/V. Although increasing the number of exchanges from 3 to 4 per day improved nPNA, increasing the number of daily exchanges beyond 4 may not improve nPNA further.

Effect of Kt/V on survival and clinical outcome in CAPD patients in a randomized prospective study

“…The nPNA was lower in group A but was similar between groups B and C. This finding may suggest that the negative impact of low Kt/V on protein intake was more prominent with Kt/V level below 1.7 in our patients. This is in line with a recent report from Hong Kong showing that improvement in nPNA with increased dialysis prescription in Chinese anuric peritoneal dialysis patients was not seen in patients with Kt/V above 1.9 [24].…”

Number of Daily Peritoneal Dialysis Exchanges and Mortality Risk in a Chinese Population

“…In 2 clinical trials, however, "more" CAPD was arguably better than "less." In the first, increasing the CAPD dose from 3 to 4 exchanges per day improved dietary protein intake and possibly reduced hospitalization (34,35). In the second, a Kt/V of ≥ 1.7 resulted in significantly better outcomes for patients than a Kt/V of < 1.7 (30).…”

“…In several single-center cohort studies, outcomes on 3 times 2-L exchanges per day appear to be satisfactory (22,23,29–33), albeit often in the presence of considerable residual renal function (22) or in the first 48 months after dialysis inception (32). In 2 clinical trials, however, “more” CAPD was arguably better than “less.” In the first, increasing the CAPD dose from 3 to 4 exchanges per day improved dietary protein intake and possibly reduced hospitalization (34,35). In the second, a Kt/V of ≥ 1.7 resulted in significantly better outcomes for patients than a Kt/V of < 1.7 (30).…”

Influence of Different Payment Schemes on the Clinical Outcome in Peritoneal Dialysis Patients

“…Unfortunately, it is still uncertain what the adequate Kt/V is for our PD patients (4). Based on ADEMEX (ADEquacy of PD in MEXico) and a series of other studies (5-11), several guidelines set a minimum target for small solute clearance of Kt/V urea at 1.70 (12,13), but the guidelines also mention that when these targets cannot be met, targets should be balanced against potential side effects, the patient's lifestyle, and cost considerations. The present study added more evidence to this notion.…”