pattern of peritoneal permeability in continuous ...

Proceedings of the First Asian Chapter Meeting — ISPD December 13 – 15, 2002, Hong Kong Peritoneal Dialysis International, Vol. 23 (2003), Supplement 2

0896-8608/03 $3.00 + .00 Copyright © 2003 International Society for Peritoneal Dialysis Printed in Canada. All rights reserved.

PATTERN OF PERITONEAL PERMEABILITY IN CONTINUOUS AMBULATORY PERITONEAL DIALYSIS PATIENTS IN BRUNEI

Ranganathan Dwarakanathan, Hjh Zarah Yaakob, and Hasnani Hadi

Department of Renal Medicine, RIPAS Hospital, Brunei Darussalam

B

Perit Dial Int 2003; 23(S2):S11–S13

PATIENTS

www.PDIConnect.com

KEY WORDS: Permeability characteristics; PET; Brunei. Correspondence to: R. Dwarakanathan, Department of Renal Medicine, Royal Brisbane Hospital, Herston, Queensland 4029 Australia. [email protected]

runei Darussalam is located in Southeast Asia and has a population of 320 000 (2001 census). The Government of His Majesty, Brunei Darussalam, provides free dialysis treatment for citizens and permanent residents suffering from end-stage renal disease (ESRD). Hemodialysis (HD) treatment started in 1968. Continuous ambulatory peritoneal dialysis (CAPD) commenced in 1993, although intermittent peritoneal dialysis (PD) was employed for many years as a short-term treatment. Most ESRD patients are on HD. Patients with ESRD are started on CAPD on selective basis. Patients with poor vascular access, with medical problems in which long-term heparin use is contraindicated, and with cardiovascular instability and or other problems that lead to intolerance of HD are initiated on CAPD. In Brunei, CAPD is an accepted modality, and 20% of the dialysis population was on CAPD in 2001. During CAPD, the magnitude of solute transport depends on the molecular weight of the given solute, the peritoneal permeability of the patient, and the volume of dialysis solution (1). For effective dialysis and to improve the long-term success of therapy, CAPD prescriptions must be individualized (2). The peritoneal equilibration test (PET) is the test most widely used to assess peritoneal transport. The PET was standardized in its present form by Twardowski et al. (3). Studies of the PET have been undertaken in CAPD patients in North America and in other countries. We undertook the present study to determine the pattern of peritoneal permeability among the Bruneian CAPD population. PATIENTS AND METHODS

Under the care of Department of Renal Medicine, RIPAS Hospital, Brunei Darussalam, 65 patients were on CAPD in 2001. Of those 65 patients, 4 were children and were excluded from the study. The age of the remaining patients ranged from 15 to 81 years. Of those 61 patients, 21 (34.43%) had diabetes. By S11

Downloaded from http://www.pdiconnect.com/ by guest on June 5, 2012

♦ Objective: Peritoneal permeability may be dissimilar in different populations. The present study identified the pattern of peritoneal permeability in continuous ambulatory dialysis (CAPD) patients treated at the Department of Renal Medicine, RIPAS Hospital, Brunei Darussalam. ♦ Methods: Data were collected from patients on CAPD in 2001 (n = 65). Four children were excluded from the study. The remaining 61 patients underwent a 4-hour peritoneal equilibration test (PET) as prescribed by Twardowski et al. For those patients, adequacy of dialysis (Kt/V) was estimated. A retrospective analysis of the peritoneal membrane characteristics of those CAPD patients was also conducted. The membrane characteristics were compared with the urea clearance results. ♦ Results: Of the 61 patients, 40 were non diabetic, and 21 (34.43%) were diabetic. More than half of our patients (55.74%) had membranes classified as high-average, followed by low-average (22.95%), high (18.03%), and low (3.28%). When the patient population was grouped separately into non diabetic and diabetic patients, peritoneal permeability differed between the groups (p = 0.000585). No relationship was observed between weekly Kt/V and transport characteristics in the group with diabetes (p = 0.219306), the group without diabetes (p = 0.74179), or the entire patient population ( p = 0.376832) ♦ Conclusion: We conclude that peritoneal permeability among Bruneian CAPD patients is probably different from that among patients from other regions of Asia (more than half of our Bruneian patients had a peritoneal membrane classified as high average). We believe that the observed difference may be related to a difference in ethnicity. In general, patients with diabetes have a highly permeable membrane. Adequacy of dialysis had no correlation to PET results in our study. A larger prospective study is required to confirm our findings.

PROCEEDINGS OF THE FIRST ASIAN CHAPTER MEETING— ISPD DWARAKANATHAN et al.

ethnic origin, 47 patients (77.05%) were Malay, 8 patients (13.11%) were Chinese, and 6 patients (9.84%) came from other ethnic backgrounds. METHODS

RESULTS Of our 65 patients on CAPD, 61 underwent a PET and Kt/V estimation. Most of our patients (55.74%) had membranes classified as high average (Table 1), followed by low average (22.95%), high (18.03%), and low (3.28%). When the patient population was grouped separately into patients without diabetes and with diabetes (Tables 2 and 3), the peritoneal permeability differed between the groups (p = 0.000585). Only 5.00% of non diabetic patients had a membrane classified as high, as compared with 42.86% of diabetic patients. Because no patient in the diabetic group had a membrane characterized as low, the low and lowS12

PDI

PERITONEAL PERMEABILITY IN CAPD PATIENTS IN BRUNEI

TABLE 1 Peritoneal Equilibration Test in Bruneian Continuous Ambulatory Peritoneal Dialysis Patients Membrane permeability

Patients [n (%)]

High High average Low average Low Total

11 (18.03) 34 (55.74) 14 (22.95) 2 (3.28) 61 (100)

TABLE 2 Peritoneal Equilibration Test (PET) and Dialysis Adequacy (Kt/V) in Patients With and Without Diabetes (DM) Patients [n (%)] Mean weekly Kt/V Membrane Without Without permeability (PET) DM With DM DM With DM High High average Low average Low Total

2 (5.00) 9 (42.86) 24 (60.00) 10 (47.62) 12 (30.00) 2 (9.52) 2 (5.00) 0 40 21

2.08 2.23 2.14 2.00

2.058 2.199 2.11

TABLE 3 Relationship Between Membrane Permeability and Dialysis Adequacy (Kt/V) in Patients With and Without Diabetes (DM) Kt/V

p Value

HA vs. H with DM 2.199±0.183 2.058±0.146 0.0416 HA vs. LA without DM 2.23±0.417 2.14±0.226 0.246 With DM vs. without DM 2.13±0.18 2.18±0.35 0.257 HA = high average; H = high; LA = low average.

average groups were analyzed together. That analysis showed a significant difference in PET between the diabetic patients and the non diabetic patients (p = 0.000633). In the group of diabetic patients, no relationship was observed between the high-average and high membrane groups with regard to weekly Kt/V and transport characteristics (Tables 2 and 3). When the unpaired t-test was used, p = 0.0416. Using the single-factor ANOVA, and taking all groups into consideration, p = 0.219306. In the non diabetic group, the difference between patients with a high-average and a low-average membrane was p = 0.246 using the unpaired t-test. Using the single-factor ANOVA, and taking all groups into consideration, p = 0.74179. When the groups were combined, p = 0.376832. Also, no significant relationship was observed with regard to Kt/V when diabetic patients were compared to non diabetic patients (p = 0.257).


All of the patents, excepting the 4 children, underwent a PET. Continuous ambulatory peritoneal dialysis was initiated 2 weeks after insertion of a PD catheter. The PD fluid volume was then slowly increased. During the break-in period, the peritoneal membrane acclimatized to the PD solution. In the initial 1 – 2 weeks of PD, significant changes in small-solute transport occur; with continued therapy, small-solute transport stabilizes (4). The PET was conducted at least 2 weeks after the patient could hold 2 L of PD fluid in the abdominal cavity. The procedure used the standard 4-hour PET as prescribed by Twardowski et al. Patients were categorized based on their dialysate-to-plasma ratio of creatinine (D/P Cr: high > 0.81, high average = 0.65 – 0.81, low average = 0.50 – 0.64, low < 0.50) and dialysate ratio of glucose at the start and at 4 hours of the dwell (D4/D0: high < 0.26, high average = 0.26 – 0.38, low average = 0.39 – 0.49, low > 0.49). Adequacy of dialysis (Kt/V) was estimated for all patients. The chi-square test was used for statistical analysis of various permeability groups. Correlations between Kt/ V and membrane permeability used the unpaired t-test. The number of patients with low membrane permeability characteristics is small among patients with diabetes, and the number of patients with high membrane permeability characteristics is small among patients without diabetes. Those numbers were therefore are excluded from our calculations. When all the groups were taken into consideration, the p value was calculated using a single-factor analysis of variance (ANOVA). All statistical analyses were carried out using Microsoft Excel for Windows (2000 Me edition)

DECEMBER 2003 – VOL. 23, SUPPL 2

PDI

DECEMBER 2003 – VOL. 23, SUPPL 2

PROCEEDINGS OF THE FIRST ASIAN CHAPTER MEETING — ISPD

DWARAKANATHAN et al.

DISCUSSION

CONCLUSIONS We conclude that the pattern of peritoneal permeability among Bruneian CAPD patients is probably different from that seen in other Asian regions, with more than half of patients having a high-average peritoneal membrane. We believe that the ob-

served difference may be related to a difference in ethnicity. In general, diabetic patients are classified as having a highly permeable membrane. Adequacy of dialysis had no correlation with PET in our study. A larger prospective study is required to confirm our findings. ACKNOWLEDGMENTS We wish to thank Drs. Ishrat Kamal, Alwi Krishnan, Hla Aung, and the other members of the nursing staff of the CAPD center, Department of Renal Medicine, RIPAS Hospital, Brunei Darussalam for their contributions. Dr. Vasudevan Mangalam, Senior Lecturer, University of Brunei Darussalam, provided statistical assistance. This article was presented at the 1st Asian Chapter meeting of International Society for Peritoneal Dialysis, which was held in Hong Kong, December 2002.

REFERENCES 1. Ronco C, Feriani M, Chiaramonte S, Brendolan A, Bragantini L, Conz P, et al. Pathophysiology of ultrafiltration in peritoneal dialysis. Perit Dial Int 1990; 10: 119–26. 2. Blake P, Burkart JM, Churchill DN, Daugirdas J, Depner T, Hamburger RJ, et al. Recommended clinical practices for maximizing peritoneal dialysis clearances. Perit Dial Int 1996; 16:448–56. 3. Twardowski ZJ, Nolph KDA, Khanna R, Prowant BF, Ryan LP, Moore HL, et al. Peritoneal equilibration test. Perit Dial Bull 1987; 7:138–47. 4. Rocco MV, Jordan JR, Burkart JM. Changes in peritoneal transport during the first month of peritoneal dialysis. Perit Dial Int 1995; 15:12–17. 5. Chakravarthy R, Surjit S, Prakash KC, Subba RS, Gupta VC, Mani MK. Pattern of peritoneal permeability in Indian CAPD population. J Indian Soc Perit Dial 2002; 4:19–23. 6. Wong FK, Li CS, Mak CK, Chau KF, Choi KS. Peritoneal equilibration test in Chinese patients. Adv Perit Dial 1994; 10:38–41. 7. Lin JJ, Wadhwa NK, Suh H, Cabralda T, Patlak CS. Increased peritoneal solute transport in diabetic peritoneal dialysis patients. Adv Perit Dial 1995; 11:63–6.

S13


Most of the data available on peritoneal permeability comes from North American countries. Twardowski et al. found that most of the patients were classified as high average (53%) or low average (31%) according to the PET. In contrast, Chakravarty et al. (5) from South India found that most of their patients were classified as having membranes with high (55.8%) or low (35.8%) permeability. Wong et al. (6) studied 100 Chinese patients. They found a pattern different from that reported by Twardowski et al., but similar to that reported for the Indian CAPD population. Most of our patients had membranes that were classified as high average, followed by low average. When high-average and low-average patients were combined, 78.69% of our patients fell into the “average” group. Only 18.03% of our patients had membranes that were classified as high, compared with 55.8% of patients in the Indian CAPD population. That difference is probably attributable to the ethnic diversity that exists among various patient populations. Most of our patients are Malay. When our patient population was classified into diabetic and non diabetic groups, the diabetic patients were found to have high membrane permeability. Other researchers (6,7) have reported the same observation. We found no correlation between membrane permeability and adequacy of dialysis as measured by Kt/V. Our retrospective study is a small, comprising only 61 patients. Long-term larger prospective studies are required to substantiate our results.

PERITONEAL PERMEABILITY IN CAPD PATIENTS IN BRUNEI