Five Things to Know About Incremental Peritoneal Dialysis

Incremental peritoneal dialysis (PD) offers patients newly starting dialysis less than the standard "full dose" of PD, reducing treatment burden and intrusiveness while minimizing symptoms of renal failure. Incremental PD is a cost-effective approach that has been associated with slower rates of decline in residual kidney function. This approach also produces less waste and in turn reduces environmental footprint compared to standard PD prescriptions. It also aligns with the International Society of Peritoneal Dialysis (ISPD) Practice Recommendations for high-quality, goal-oriented therapy. Awareness of incremental PD along with its advantages and limitations provides practitioners with the tools to provide more patient-centered dialysis prescriptions in appropriate populations.

Incremental Versus Standard (Full-Dose) Peritoneal Dialysis

Incremental peritoneal dialysis (PD), defined as less than “standard dose” PD prescription, has a number of possible benefits, including better preservation of residual kidney function (RKF), reduced risk of peritonitis, lower peritoneal glucose exposure, lesser environmental impact, and reduced costs. Patients commencing PD are often new to kidney replacement therapy and possess substantial RKF, which may allow safe delivery of an incremental prescription, often in the form of lower frequency or duration of PD. This has the potential to help improve quality of life (QOL) and life participation through reducing time requirements and burden of treatment. Alternatively, incremental PD could potentially contribute to reduced small solute clearance, fluid overload, or patient reluctance to increase dialysis prescription when later needed. This review discusses the definition, rationale, uptake, potential advantages and disadvantages, and clinical trial evidence pertaining to the use of incremental PD.

Individualized Prescription of Peritoneal Dialysis Therapy

Prescribing PD has become more challenging, but also more rewarding and stimulating in recent years. The number of technical aids and strategies has increased, and a potential exists to optimize clearances and ultrafiltration in a way that has not been seen before and that will, it is to be hoped, translate into better patient outcomes. It is crucial, however, that the technologies and strategies be applied with an awareness of the individual patient's particular lifestyle, aspirations, and social circumstances. A failure to consider these factors may lead to noncompliance and, ultimately, to “burnout” and technique failure. Patients must be educated about the importance of clearance targets so that they will accept the alterations in, or the onerous aspects of, the prescriptions they require. Successful prescribing of PD requires an awareness of both clearance and lifestyle factors so that the two can be integrated to give an effective and acceptable regimen. Finally, cost factors should also be considered.

Changes in Peritoneal Dialysis Practices in Canada 1996 – 1999

← Objective

Over the past decade, clinical studies and clinical practice guidelines have suggested the use of higher small solute clearance targets for patients on peritoneal dialysis (PD). This study asks whether these recommendations have translated into changes in clinical prescription of PD.

← Study Design

Data were collected annually from 1996 to 1999 on all prevalent dialysis patients in 24 Canadian centers, accounting for approximately 40% of the Canadian chronic dialysis population. Approximately a third of these patients were on PD. Full details of each patient's prescription were recorded, with particular attention to dwell volumes and frequency of exchanges for continuous ambulatory PD (CAPD) and to total treatment volumes and day dwells for automated PD (APD). The most recent Kt/V and creatinine clearance values available were recorded for each patient and the overall results for each year were compared to present treatment recommendations.

← Setting

24 university- and community-based hospitals.

← Results

From 1996 to 1999, the use of APD, relative to CAPD, grew from 14% to 28% of all PD patients. Among CAPD patients, the proportion using dwell volumes greater than 2 L rose from 14% to 32%, and the proportion doing more than 4 dwells per day rose from 16% to 28%. The mean daily volume of prescribed fluid for CAPD patients increased from 8.3 to 9.1 L. As a result, the proportion of patients achieving a weekly Kt/V above 2.0 rose from 54% to 72%, and those receiving a Kt/V less than 1.7 fell from 22% to 10%. For creatinine clearance, those exceeding 60 L per week rose from 63% to 73%. For APD, the mean treatment volume rose from 11.8 L in 1996 to plateau at about 13.4 L in 1998 and 1999. However, the proportion of patients receiving more than 1 day dwell grew from 31% in 1998 to 40% in 1999, and the proportion that were “day dry” fell from 25% to 17%. For APD, the proportion of patients with a Kt/V above 2.0 rose from 67% to 77%, and with a creatinine clearance above 60 L, from 62% to 70%. The proportion with no recent clearance value recorded fell during the course of the study, from 45% to 27%.

← Conclusion

There was a marked change in PD prescription practices in Canada during the second half of the 1990s. This occurred in response to clinical studies and publication of guidelines. There is room for further improvement, especially with respect to the proportion of patients that did not have regular clearance measurements made.

What is the Optimal Frequency of Cycling in Automated Peritoneal Dialysis?

Objective

The recent increase in the use of automated peritoneal dialysis (APD) has led to concerns about the adequacy of clearances delivered by this modality. Few clinical studies looking at the effects of varying the individual components of the APD prescription on delivered clearance have been done, and most published data are derived from computer modeling. Most controversial is the optimal frequency of exchanges per APD session. Many centers prescribe 4 to 6 cycles per night but it is unclear if this is optimal. The purpose of this study was to address at what point the beneficial effect of more frequent cycles is outweighed by the concomitant increase in the proportion of the total cycling time spent draining and filling.

Methods

A comparison was made between the urea and creatinine clearances (CCrs) achieved by 4 different APD prescriptions, used for 7 days each, in 18 patients. The prescriptions were for 9 hours each and were all based on 2-L dwell volumes, but differed in the frequency of exchanges. They were 5 x 2 L, 7 x 2 L, and 9 x 2 L, as well as a 50% tidal peritoneal dialysis (TPD) prescription using 14 L. Ultrafiltration, dwell time, glucose absorption, sodium and potassium removal, protein excretion, and relative cost were also compared. Clearances due to day dwells and residual renal function were not included in the calculation.

Results

Mean urea clearances were 7.5, 8.6, 9.1, and 8.3 L/night for the four prescriptions respectively. Urea clearance with 9 x 2 L was significantly greater than with the other three prescriptions ( p < 0 0.05). Urea clearance with 7 x 2 L and TPD were superior to 5 x 2 L ( p < 0.05). Mean CCr was 5.1, 6.1, 6.4, and 5.6 L/night, respectively. Compared to 5 x 2-L, the 7 x 2-L, 9 x 2-L, and TPD prescriptions achieved greater CCr ( p < 0.05). Taking both urea and CCr into account, 9 x 2 L was the optimal prescription in 12 of the 18 patients. Ultrafiltration and sodium and potassium removals were all significantly greater with the higher frequency prescriptions.

Conclusion

The 5 x 2-L prescription significantly underutilizes the potential of APD to deliver high clearances, and 7 x 2 L is a consistently superior prescription if 2-L dwells are being used. Although more costly, 9 x 2 L should be considered if higher clearances are required.

Peritoneal dialysis adequacy and risk of death

The debate on the relationship between small solute clearance and patient outcome on peritoneal dialysis has intensified in the past year with the publication or presentation of a number of important new studies. Previous studies had found a correlation between clearances and subsequent patient survival. However, this effect was all accounted for by residual renal clearance. The failure to detect an independent effect of peritoneal clearance on outcomes had been attributed to a lack of well-done studies with sufficient variation in peritoneal clearance to detect such an effect. New prospective and randomized studies suggest, however, that the relationship between peritoneal clearance and outcome is weak or absent within the usual dose ranges delivered in clinical practice. Existing clearance targets may need to be reviewed.

Cycler adequacy and prescription data in a national cohort sample: the 1997 core indicators report. Health Care Financing Administration Peritoneal Dialysis Core Indicators Study Group

BACKGROUND

The Health Care Financing Administration Peritoneal Dialysis Core Indicator Project obtains data yearly in four areas of patient care: dialysis adequacy, anemia, blood pressure, and nutrition.

METHODS

Adequacy and dialysis prescription data were obtained using a standardized data abstraction form from a random sample of adult U.S. peritoneal dialysis patients who were alive on December 31, 1996.

RESULTS

For the cohort receiving cycler dialysis, 22% were unable to meet the National Kidney Foundation Dialysis Outcome Quality Initiatives (NKF-DOQI) dialysis adequacy guidelines because they did not have at least one adequacy measure during the six-month period of observation. Thirty-six percent of patients met NKF-DOQI guidelines for weekly Kt/V urea, 33% met guidelines for weekly creatinine clearance (CCr), and 24% met guidelines for both urea and creatinine clearances. The mean weekly adequacy values were 2.24 +/- 0.56 for Kt/V urea and 67.5 +/- 24.4 liter/1.73 m2 for CCr, and the median values were 2.20 and 62.25 liter/1.73 m2, respectively. The mean prescribed 24-hour volume was 12,040 +/- 3255 ml, and the median prescribed volume was 11,783 ml. Only 60% of patients were prescribed at least one daytime dwell. By logistic regression analysis, risk factors for an inadequate dose of dialysis included being in the highest quartile of body surface area (odds ratio = 3.3 for CCr and 3.4 for Kt/V urea) and a duration of dialysis greater than two years (odds ratio = 4.2 for CCr and 2.1 for Kt/V urea).

CONCLUSION

There is much room for improvement in providing an adequate dose of dialysis to cycler patients. Practitioners should be more aggressive in increasing dwell volumes, adding daytime dwells, and adjusting nighttime dwell times in order to compensate for the loss of residual renal function over time. These changes can only be accomplished if practitioners measure periodically the dose of dialysis as outlined in the NKF-DOQI guidelines.