Trends in CAPD Technique Failure: Canada, 1981–1997

Objective

Although important enhancements to continuous ambulatory peritoneal dialysis (CAPD) have occurred since its inception, few studies have explicitly evaluated trends over time in CAPD technique failure rates. To assist in quantifying the net benefit of improvements to CAPD for patient outcomes, we examined trends in technique failure rates among Canadian CAPD patients.

Patients

Patients initiating renal replacement therapy on CAPD ( n = 7110) between 1981 and 1997.

Main Outcome Measures

Technique failure ( i.e., switch to hemodialysis).

Results

Total follow-up was 12 831 patient-years (pt-yr). There were 1976 technique failures, for a crude CAPD failure rate of 154.0/1000 pt-yr. Technique failure rate ratios (RR) estimated using Poisson regression and adjusted for age, gender, race, province, primary renal diagnosis, and follow-up time, were significantly reduced for the 1990–93 [RR = 0.75, 95% confidence interval (CI) = (0.68, 0.83)], 1994–95 [RR = 0.83, CI (0.75, 0.93)], and 1996–97 [RR = 0.78, CI (0.70, 0.87)] calendar periods relative to 1981–89 (RR = 1, reference). Among cause-specific technique failure rates, the greatest improvement was observed for peritonitis-attributable technique failure, with RR = 0.46, CI (0.41, 0.50) for 1990–97 relative to 1981–89. However, rates of technique failure due to inadequate dialysis were significantly elevated for the 1990–97 period [RR = 1.68, CI (1.44, 1.96)].

Conclusions

The collection of more detailed data on practice patterns would enable future studies to elucidate the cause-and-effect relationship between CAPD descriptors and technique failure, and hence assist in clinical decision-making.

Growth Hormone and Malnutrition in Dialysis Patients

Objective

To review the normal function of the growth hormone (GH) insulin-like growth factor (IGF) axis, how it is altered in end-stage renal failure, how this may contribute to malnutrition in dialysis patients, and how therapy with recombinant human growth hormone (rHuGH) and recombinant human IGF-I (rHuIGF-1)might be used to treat malnutrition in these patients.

Data Sources

Studies in the literature dealing with the GH-IGF endocrine axis and its role in uremic malnutrition.

Study Selection

Eight studies in which uremic adults were treated with either rHuGH or rHuIGF-I.

Data Extraction

Data were abstracted from all of these studies.

Results

The review shows that there are marked abnormalities of the GH-IGF axis in uremic patients and that these lead to a state of GH resistance, which can be overcome by pharmacological doses of rHuGH. A small number of clinical studies in uremic adults suggests that both rHuGH and rHuIGF-I have dramatic beneficial effects on nutritional status in these patients.

Conclusions

rHuGH and rHuIGF-I have both been shown to have a beneficial effect on nutritional status in shortterm studies on small numbers of patients. Further studies need to be done for longer periods in larger groups of patients. Areas for additional research are suggested.

Peritoneal Dialysis in Asia: An External Perspective

There are almost 30 000 patients maintained on peritoneal dialysis (PD) in Asia, representing about 8% of all Asian dialysis patients. The largest numbers of PD patients are in Japan and China, but the highest PD penetration is in Hong Kong, Korea, and Singapore. Notable features of PD in Asia include the varying rates of use across the different countries. The reasons for this are reviewed here, with particular emphasis on the significance of whether dialysis providers are predominantly private or public. The excellent rates of both patient and technique survival in the richer Asian countries are also examined and interpreted in the context of recent data showing that Asian patients living in North America have generally superior survival on dialysis and better compliance with PD than their Caucasian counterparts. It is concluded that the healthier baseline health status in South East Asian patients, in particular, contributes to their impressive outcomes. The approach to both clearance and ultrafiltration is less aggressive in Asian countries than in the West. Studies looking at the relationship between clearance and clinical outcome in Asia are reviewed and it is concluded that the benefits of higher clearances have been harder to show than in North America because of the relatively better outcomes of the patients. The concern about sclerosing encapsulating peritonitis in Japan particularly is emphasized. The Hong Kong model of dialysis delivery with its high use of PD and the arguments for and against it are also reviewed.

Comparison between DOQI and Canadian Guidelines for Peritoneal Dialysis

The recently published Canadian Society of Nephrology (CSN) Guidelines for Peritoneal Dialysis Adequacy differ in a number of ways from the United States National Kidney Foundation Dialysis Outcomes Quality Initiative (DOQI) guidelines on the same topic. The three main differences are ( 1 ) the CSN targets are the same for continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD), whereas the DOQI targets are higher for APD; ( 2 ) the CSN guidelines have a lower creatinine clearance (CCr) target of 50 L/wk for low and low-average transporters compared to 60 L/wk for high and high-average transporters, but no such distinction is made by DOQI; and ( 3 ) the CSN has set lower limit targets as well as preferred targets for Kt/V and CCr.

Other differences are that the CSN recommendations do not give Kt/V the same primacy over CCr that DOQI does. Also, the CSN recommendations give greater emphasis to the risks associated with high transport status.

This review looks at the reasons for these differences and demonstrates that some are due to information that has become available since the publication of the DOQI guidelines. However, it is emphasized that, when recommendations are predominantly opinion- rather than evidence-based, geographic and economic factors may also account for differences.

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.

Attitudes of Canadian Nephrologists toward Dialysis Modality Selection

Objective

To determine the opinions and attitudes of Canadian nephrologists about dialysis modality decisions and optimal dialysis system design.

Participants

Members of the Canadian Society of Nephrology.

Intervention

A mailed survey questionnaire.

Results

A 66% response rate was obtained. Decisions about modality are reported to be based most strongly on patient preference (4.4 on a scale from 1 to 5), followed by quality of life (4.06), morbidity (3.97), mortality (3.85), and rehabilitation (3.69), while neither facility (1.78) nor physician (1.62) reimbursement are important. When asked about the current relative utilization of each modality, nephrologists felt that hospital-based hemodialysis (HD) is slightly overutilized (2.53), continuous ambulatory peritoneal dialysis (CAPD) is about right (3.00), while cycler peritoneal dialysis (PD) (3.53), community-based full (3.83) and self-care HD (3.91), and home HD (4.02) are underutilized. A hypothetical question about optimal distribution to maximize survival revealed that a type of HD should constitute 62.8% of the mix, with more emphasis on cycler PD (14.9%), community-based full care HD (13.8%), self-care HD (14.5%), and home HD (9.0%) than is current practice. However, when the goal was to maximize cost effectiveness, HD fell slightly to 57.8%.

Conclusions

These survey results suggest that the current national average 66%/34% HD/PD ratio is reasonable. However, there appears to be a consensus that Canada could evolve to a more cost-effective, community-based dialysis system without compromising patient outcomes.

Comparison of Measured and Predicted Creatinine Excretion is An Unreliable Index of Compliance in Pd Patients

Objective

To evaluate the use of the ratio of measured to predicted creatinine excretion as an index of compliance in peritoneal dialysis (PD) patients.

Design

A prospective analysis.

Setting

Academic teaching hospital dialysis unit.

Patients

Forty-three patients on PD.

Measurements

Creatinine excretion in daily dialysate and urine collections was measured on one occasion in 10 patients and on two occasions in 33 patients, and, after adding an estimate for extrarenal creatinine degradation, was divided by predicted creatinine excretion to give a creatinine excretion ratio, which has been proposed as an index of compliance with exchanges in PD patients. Values above 1.24 have been suggested to indicate non-compliance. Lean body mass was also estimated from creatinine excretion.

Results

The mean creatinine excretion ratio was 1.12, and 30% of patients had a value above 1.3. Only one patient admitted noncompliance. Studies on four consecutive days of guaranteed compliance in 7 patients with high ratios showed that creatinine excretion remained constant, suggesting that the patients were high creatinine producers rather than noncompliant. Creatinine excretion was stable when measured at intervals of days, but over months it tended to change markedly in many patients. Lean body mass estimations using creatinine excretion were low in most patients.

Conclusion

Comparison of measured and predicted creatinine excretion is not a reliable indicator of noncompliance because many compliant patients consistently excrete more creatinine than predicted. The standard formulas were not validated in dialysis patients and underestimate creatinine excretion significantly in many PD patients. Existing estimates in the literature of non-compliance, using this methodology, may not be accurate. Better methods of detecting this problem are required.

Growth Hormone and Malnutrition in Dialysis Patients

Objective

To review the normal function of the growth hormone (GH) insulin-like growth factor (IGF) axis, how it is altered in end-stage renal failure, how this may contribute to malnutrition in dialysis patients, and how therapy with recombinant human growth hormone (rHuGH) and recombinant human IGF-I (rHuIGF-1)might be used to treat malnutrition in these patients.

Data Sources

Studies in the literature dealing with the GH-IGF endocrine axis and its role in uremic malnutrition.

Study Selection

Eight studies in which uremic adults were treated with either rHuGH or rHuIGF-I.

Data Extraction

Data were abstracted from all of these studies.

Results

The review shows that there are marked abnormalities of the GH-IGF axis in uremic patients and that these lead to a state of GH resistance, which can be overcome by pharmacological doses of rHuGH. A small number of clinical studies in uremic adults suggests that both rHuGH and rHuIGF-I have dramatic beneficial effects on nutritional status in these patients.

Conclusions

rHuGH and rHuIGF-I have both been shown to have a beneficial effect on nutritional status in shortterm studies on small numbers of patients. Further studies need to be done for longer periods in larger groups of patients. Areas for additional research are suggested.

Blood Pressure, Volume, and Sodium Control in an Automated Peritoneal Dialysis Population

Objectives

To examine the control of blood pressure and volume, and the role of sodium removal in a single, large, contemporary, automated peritoneal dialysis (APD) population where icodextrin is used liberally and there is a policy to avoid long duration glucose-based daytime dwells.

Design

Observational cross-sectional study.

Setting

A university hospital.

Patients

56 APD patients, with a mean duration on peritoneal dialysis of 1.9 years; 50% were prescribed icodextrin.

Main Outcome Measures

Blood pressure, extracellular water volume (ECW)-to-intracellular water volume (ICW) ratio, and total (peritoneal and urinary) sodium removal.

Results

Sodium Removal: Mean total sodium removal, while low at 102.9 ± 64.6 mmol/day, showed a wide range, with 41% having a sodium removal of >120 mmol/day. Total sodium removal correlated with total body water, ECW, and ICW ( p < 0.001, p < 0.001, p < 0.025, respectively), as well as with height and weight ( p < 0.06, p < 0.01 respectively). On multivariate analysis, only ultra-filtration volume and urine volume were significantly associated with total sodium removal ( r2 = 0.67, p < 0.0001 for both). There was also a correlation between sodium removal and urea nitrogen appearance ( r2 = 0.31, p < 0.001), with urea nitrogen appearance in turn being closely correlated with ICW ( p < 0.001). Volume Status: The ECW/ICW ratio was 0.88 ± 0.17, which was not significantly different to that found in hemodialysis patients without clinical evidence of fluid overload, either predialysis (0.96 ± 0.16) or postdialysis (0.92 ± 0.16); p = 0.07 and 0.36 respectively. Blood Pressure: Mean ± standard deviation systolic blood pressure (BP) was 111.9 ± 18.2 mmHg and diastolic BP was 63.3 ± 11.9 mmHg, with only 4 (7%) patients having a systolic BP > 140 mmHg and 1 (2%) having a diastolic BP > 80 mmHg. Median number of antihypertensives was 1 per day. Blood pressure control and ECW/ICW ratio were similar in those with sodium removal >120 mmol/day compared to those with sodium removal ≤120 mmol/day ( p = 0.39 for SBP, p = 0.70 for diastolic B P, p = 0.24 for ECW/ICW).

Conclusions

We have shown that good blood pressure and volume control is achievable in a large contemporary APD population with liberal use of icodextrin and avoidance of long daytime glucose-based dwells. Neither low nor high sodium removal was associated with more frequent hypertension or volume expansion.

Peritoneal Dialysis in Ontario: A Natural Experiment in Physician Reimbursement Methodology

Background

The factors that determine dialysis modality selection and distribution are not well understood. Physician reimbursement incentives have been suggested to play an important role. Under the fee-for-service system in Ontario that existed prior to July 1998, nephrologists were paid about sevenfold more for a hemodialysis (HD) patient than for a patient on peritoneal dialysis (PD). However, since then, nephrologists have been reimbursed via a modality-independent capitation fee, whereby payment for any form of dialysis is the same. This was expected to markedly increase the use of PD.

Methods

When the capitation fee was introduced in 1998, a survey questionnaire of all Ontario nephrologists was done and repeated 3 years later (response rate 62.5%). Changes in dialysis modality incidence and prevalence rates in Ontario and in the rest of Canada were examined.

Results

On a scale of 1 to 7, nephrologists were convinced that the capitation fee was a good thing (mean rating 6.07); 75% said they had been seeing patients at every dialysis under the old system, compared to 41% now. Of significance, the proportion of prevalent patients on PD in Ontario declined from 27.3% in 1997 to 19.7% in 2000, increasing to 22.6% in 2002. Similarly, the incident PD rate seems to have stabilized, while the use of non-hospital-based HD has increased.

Conclusions

Following the introduction of the capitation fee, PD use in Ontario continued to decline for 2 years, and then began to increase. In the rest of Canada, there are continuing declines in PD use. This is consistent with the hypothesis that the new incentives caused by the altered physician reimbursement are acting in a subtle way to increase PD and non-hospital-based HD. A longer period of observation may be required to assess the complete effect.

Supportive care for end-stage kidney disease: an integral part of kidney services across a range of income settings around the world

A key component of treatment for all people with advanced kidney disease is supportive care, which aims to improve quality of life and can be provided alongside therapies intended to prolong life, such as dialysis. This article addresses the key considerations of supportive care as part of integrated end-stage kidney disease care, with particular attention paid to programs in low- and middle-income countries. Supportive care should be an integrated component of care for patients with advanced chronic kidney disease, patients receiving kidney replacement therapy (KRT), and patients receiving non-KRT conservative care. Five themes are identified: improving information on prognosis and support, developing context-specific evidence, establishing appropriate metrics for monitoring care, clearly communicating the role of supportive care, and integrating supportive care into existing health care infrastructures. This report explores some general aspects of these 5 domains, before exploring their consequences in 4 health care situations/settings: in people approaching end-stage kidney disease in high-income countries and in low- and middle-income countries, and in people discontinuing KRT in high-income countries and in low- and middle-income countries.