Residual Renal Function and Volume Control in Peritoneal Dialysis Patients

Soluble CD59 in peritoneal dialysis: a potential biomarker for peritoneal membrane function

INTRODUCTION

Various studies have reported the importance of complement regulators in preventing mesothelial damage during peritoneal dialysis (PD). Its assessment, however, is limited in clinical practice due to the lack of easy access to the peritoneal membrane. Recently, a soluble form of the complement regulatory protein CD59 (sCD59) has been described. We therefore aimed to investigate the role of sCD59 in PD.

METHODS

Plasma sCD59 was measured in 48 PD patients, 41 hemodialysis patients, 15 non-dialysis patients with chronic kidney disease and 14 healthy controls by ELISA (Hycult; HK374-02). Additionally, sCD59 and sC5b-9 were assessed in the peritoneal dialysate.

RESULTS

sCD59 and sC5b-9 were detectable in the peritoneal dialysate of all patients, and marginally correlated (r = 0.27, P = 0.06). Plasma sCD59 levels were significantly higher in PD patients than in patients with chronic kidney disease and healthy controls, but did not differ from hemodialysis patients. During follow-up, 19% of PD patients developed peritoneal membrane failure and 27% of PD patients developed loss of residual renal function. In adjusted models, increased sCD59 levels in the dialysate (HR 3.44, 95% CI 1.04-11.40, P = 0.04) and in plasma (HR 1.08, 95% CI 1.01-1.17, P = 0.04) were independently associated with the occurrence of peritoneal membrane failure. Higher plasma levels of sCD59 were also associated with loss of residual renal function (HR 1.10, 95% CI 1.04-1.17, P < 0.001).

CONCLUSIONS

Our study suggests that sCD59 has potential as a biomarker to predict peritoneal membrane function and loss of residual renal function in PD, thereby offering a tool to improve patient management.

Ultrafiltration volume by once-weekly hemodialysis is a predictor of technique survival of combination therapy with peritoneal dialysis and hemodialysis

Overhydration is a major cause of technique failure of peritoneal dialysis (PD). Hence, we investigated the impact of ultrafiltration (UF) volume by once-weekly hemodialysis (HD), excess volume beyond their dry weight, on technique survival of PD and HD combination therapy (PD+HD). Forty-six anuric PD+HD patients were divided into three groups according to baseline UF volume by HD: low-UF (<mean - 1SD), middle-UF (≥mean - 1SD and <mean + 1SD), and high-UF (≥mean + 1SD). High-UF group showed larger extracellular water normalized to height (P = .038) and longer HD sessions (P < .001) compared with low-UF group, whereas low-UF group was older than middle-UF group (P = .001). Technique survival rate was significantly lower in high-UF group than in low and middle-UF groups (P < .001), and the rates at 44 months were 80%, 90%, 20% in low, middle, and high-UF groups, respectively. Chronic overhydration was the leading cause of technique failure for all. This study suggests that fluid overload remains a major cause of technique failure of PD even after once-weekly HD is added.

Bioimpedance Spectroscopy-Based Fluid Status in Combined Dialysis Compared With Hemodialysis and Peritoneal Dialysis: A Cross-Sectional Study

Combination therapy with peritoneal dialysis and hemodialysis (PD+HD) is widely used in Japan for PD patients with decreased residual renal function. However, fluid status in PD+HD patients has not been well studied. In this cross-sectional study, we compared fluid status in 41 PD+HD patients with that in 103 HD and 92 PD patients using the bioimpedance spectroscopy. Extracellular water normalized to patient height (NECW, kg/m) was the highest in pre-HD (8.3 ± 1.6) followed by PD (7.9 ± 2.7), PD+HD (7.5 ± 2.5), and post-HD patients (6.9 ± 1.5) (P < 0.01). By multiple linear regression analysis, PD+HD was associated with a significantly lower NECW than pre-HD (β = -0.8, P = 0.03) and similar to PD (β = -0.5, P = 0.24) and post-HD (β = 0.6, P = 0.08) after adjustment for age, sex, diabetic nephropathy, ischemic heart disease, dialysis period, and daily urine volume. There was no correlation between NECW and daily urine volume in all dialysis groups. Average daily fluid removal (a sum of urine volume and ultrafiltration volume by dialysis) was positively correlated with NECW in PD+HD and pre-HD, but not in PD and post-HD patients. Our results suggest that fluid status in PD+HD patients with decreased residual renal function is acceptable as compared with that in HD and PD patients.

Residual Renal Function and Effect of Low-Sodium Solution on Blood Pressure in Peritoneal Dialysis Patients

Background:Residual renal function (RRF) affects sodium and fluid balance. The aim of this analysis was to examine the impact of RRF on the effect of a sodium-reduced peritoneal dialysis fluid (PDF) on blood pressure (BP).Methods:This is a post-hoc analysis of a prospective, randomized, controlled double-blind clinical trial with 82 patients on continuous ambulatory PD (CAPD) treated with a low-sodium (125 mmol/L Na) or a standard-sodium (134 mmol/L Na) PDF. Subgroups according to glomerular filtration rate (GFR) at baseline (≤ / > 6 mL/min/1.73 m²) were analyzed for BP and antihypertensive medication.Results:In the low-GFR group on low-sodium PDF (N = 26), systolic BP was reduced from 152 ± 24 mmHg at baseline to 137 ± 21 mmHg at week 12, diastolic BP from 90 ± 16 mmHg to 83 ± 11 mmHg. In the low-GFR group on standard-sodium PDF and in the high-GFR group on both PDF types, only minor changes were observed. For the low-GFR subgroup, the confounder-adjusted mean study group difference in systolic BP at week 12 between low-sodium and standard-sodium PDF was -16.9 (95% confidence interval [CI] -27.2 to -6.6) mmHg, for diastolic BP, it was -7.0 (95% CI -12.6 to -1.4) mmHg. In both GFR subgroups, more patients had a reduced daily dose of antihypertensive medication and fewer patients an increased daily dose in the low-sodium compared with the standard-sodium group at week 12.Conclusions:The reduction of BP with a sodium-reduced PDF seems to be more effective in patients with no or low RRF than in patients with residual capacity of renal sodium and fluid control.

Does Residual Renal Function Have a Beneficial Effect on Patient and Technique Survival in Peritoneal Dialysis Patients?

Objectives:

Residual renal function (RRF) at the initiation of peritoneal dialysis (PD) therapy can be a predictor of survival in stable PD patients. The aim of the present study was to investigate PD patients regarding the effect of baseline RRF on patient and technique survival.

Methods:

Urine output at the beginning of PD therapy was evaluated retrospectively in 202 PD patients. Patients were divided into two groups: patients with anuria (urine output ≤100 ml/day) and patients without anuria (urine output >100 ml/day).

Results:

The number of patients with anuria was 58 in which 38 patients were females. The mean age of the patients was 42.8±14.9 years. The mean follow-up period was 44.2±35 months. Twelve percent of patients with anuria had history of hemodialysis (HD).

One hundred forty-four had no anuria (68 females, mean age 43.7±14.5 years, mean follow-up period 39.6±26.1 months, mean urine volume 592±442 ml). Twenty-three patients had received HD therapy before. Sixty-five had anuria in the following 22.5±19.6 months.

At the beginning of therapy, systolic and diastolic blood pressures were lower in patients with oliguria than in patients without oliguria (p<0.001), but C-reactive protein (p=0.004) and ferritin (p<0.001) levels were higher. There was no difference between two groups regarding the other parameters (age, follow-up periods, presence of diabetes, ultrafiltration volumes, albumin, hemoglobin, calcium phosphorus product, parathormone, and Kt/V levels) (p>0.05).

The peritonitis rate was one episode per 28.2 versus 30 patient-months for the anuric and non-anuric groups, respectively (p>0.05).

For Kaplan–Meier survival analysis, the mean technique survival rates at 1 and 3 years were 97% and 86.6% in patients without anuria and 94% and 85.3% in patients with anuria, respectively. The 5-year technique survival rates according to residual volume states were not statistically significant with log-rank test (p>0.05).

The 1-, 3-, and 5-year survival rates were 96.9%, 89.6%, and 86.5% in patients without anuria, respectively, whereas they were 87.3%, 77.3%, and 53.7% in patients with anuria, respectively. The 5-year survival rates according to residual volume states were statistically significant (p<0.05).

Conclusion:

RRF at the beginning of PD has an important and positive impact on patient survival in PD patients. Peritonitis rates and technique survival were not different for patients with anuria and without anuria.

Correlation of Residual Diuresis with MIS Score and Nutritional Status in Peritoneal Dialysis Patients: A Croatian Nationwide Study

Introduction. Residual diuresis (RD) is an important predictor of mortality and cardiovascular (CV) deaths in peritoneal dialysis (PD) patients, and contributes more to overall survival compared to PD clearance. In this study we investigated the correlation between RD and CV outcomes in PD patients.

Methods. A total of 190 PD patients from 13 dialysis centers, a national representation, were included in this analysis. Biomarkers of anemia, nutritional status [malnutrition inflammation score (MIS), subjective global assessment (SGA), serum albumin, anthropometric measurements including body mass index (BMI)], dialysis dose (Kt/V) and laboratory measurements were determined. RD was estimated using the volume of daily urine.

Results. There were 78(41.05 %) females and 112 (58.95 %) males; aged 57.35±14.41 years, on PD for 24.96±24.43 months. Fifty-six patients had diabetes type II (44 as primary kidney disease). The mean RD was 1170±673.6 ml (range 0-3000 mL). Statistically significant correlations between RD and BMI, hip circumference, time on PD, Kt/V, MIS, SGA, erythrocytes (E), Hemoglobin (Hb), PTH, and serum albumin were observed.

Conclusions. We demonstrated a significant correlation between RD and MIS score, SGA, anthropometry and albumin. Every effort should be invested to maintain RD for as long as possible to achieve optimal treatment results and to decrease CV mortality in PD population.

Advances in Understanding and Management of Residual Renal Function in Patients with Chronic Kidney Disease

BACKGROUND

Residual renal function (RRF), defined as the ability of native kidneys to eliminate water and uremic toxins, is closely correlated with mortality and morbidity rates among patients receiving either peritoneal dialysis (PD) or hemodialysis (HD) via continuous clearance of middle-sized molecules and protein-bound solutes. Therefore, preserving RRF is considered to be one of the primary goals in managing patients with end-stage renal disease (ESRD).

SUMMARY AND KEY MESSAGES

In this article, we provide a review on the understanding and management of RRF in patients on dialysis. RRF may be estimated and measured by calculating the mean 24-hour urine creatinine level and urea clearance. Currently, several middle-sized molecules are reported but rarely used in practice. Many risk factors such as original renal diseases, dietary intake, and nephrotoxic agents impair RRF. Targeting such factors may halt the decline in RRF and offer better outcomes for patients on PD or HD. Except for in PD patients, RRF is a powerful predictor of survival in HD patients. RRF requires more clinical and research attention in the care of patients with ESRD on dialysis.

The Impact of Fluid Overload and Variation on Residual Renal Function in Peritoneal Dialysis Patient

BACKGROUND

The effect of fluid overload and variation on residual renal function (RRF) in peritoneal dialysis (PD) patients is controversial.

METHODS

Retrospective cohort study was designed. One-hundred and ninety PD patients with measured glomerular filtration rate (mGFR) ≧ 3 ml/min/1.73 m2 were recruit. Fluid status of every participant was assessed by bioelectrical impedance analysis (BIA) every 3 months for 1 year. The cohort was divided into three hydration groups, namely persistent overhydration (PO) group, intermittent overhydration (IO) group and normal hydration (NH) group. Additionally, participants were also divided into high or low fluid variation groups. The decline rate of RRF and the event of anuria were followed up for 1 year. The association of fluid overload with RRF loss was evaluated by Cox proportional hazard models adjusted for confounders.

RESULTS

Thirty-six (18.9%) patients developed anuria. The decline rate of mGFR in both PO and IO groups were significantly faster than that of NH group (PO vs NH: -0.2 vs -0.1 ml/min/1.73 m2/month, p < 0.01; IO vs NH: -0.2 vs -0.1 ml/min/1.73 m2/month, p < 0.01). Kaplan-Meier analysis showed poorer RRF outcome in both PO and IO groups compared with that of NH group (PO vs NH: p < 0.001; IO vs NH: p = 0.006). Patients with high fluid variation had worse RRF survival than those with low fluid variation (p = 0.04). Adjusted Cox regression models indicated the hazard ratio of RRF loss in PO group was 8.90-folds higher (95% confidence interval 3.07-31.89) than that in NH group.

CONCLUSIONS

These findings suggested fluid overload was independently associated with the decline of RRF in PD patients.

Volume-Based Peritoneal Dialysis Prescription Guide to Achieve Adequacy Targets

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BACKGROUND

The use of automated and continuous ambulatory peritoneal dialysis (APD and CAPD) prescriptions (Rxs) to achieve adequate uremic toxin and fluid removal targets is important for attaining optimal patient outcomes. One approach for predicting such Rxs is the use of kinetic modeling. ♦

METHODS

Demographic data and peritoneal membrane characteristics derived from a peritoneal equilibration test (PET) were available from 1,005 patients in North American centers who participated in a national adequacy initiative in 1999. Twelve patient subgroups were identified according to peritoneal membrane transport type and tertiles of total body water, assumed equal to urea distribution volume (Vurea). Each patient was then modeled using PD Adequest 2.0 to be treated by 12 CAPD and 34 APD Rxs using both glucose and icodextrin solutions to achieve adequacy targets of weekly urea Kt/V of 1.7 and 1 L of daily ultrafiltration (UF). Residual kidney function (RKF) was assumed to be 0, 2, 4, and 6 mL/min. Feasible peritoneal dialysis (PD) Rxs were identified where: 1) the 95% confidence limit achieved the goal of meeting the targets for urea Kt/V, daily UF, and both in 85%, 75%, and 70% of patients, respectively; 2) average PD solution dextrose concentration was < 2.5%; and 3) the number of daytime exchanges was minimized. ♦

RESULTS

Feasible PD Rxs were similar when RKF was ≥ 2 mL/min, allowing condensed recommendations based on RKF ≥ 2 mL/min or < 2 mL/min. Individuals with lower or slower membrane transport required relatively greater 24-h solution volumes to achieve adequacy targets when RKF fell below 2 mL/min. With increasing Vurea, there was disproportionately greater dependence on RKF to achieve targets. While multiple Rxs achieving urea Kt/V and daily UF goals were identified for all membrane transport types, use of icodextrin in the long dwell reduced the need for a midday exchange in APD, glucose exposure, required fill and 24-h dwell volumes, irrespective of RKF and Vurea. While these benefits were most notable in high and high-average transporters, similar results were also seen in low and low-average transporters. ♦

CONCLUSIONS

Kinetic modeling identified multiple APD and CAPD Rxs that achieved adequate uremic solute and fluid removal for patients, irrespective of RKF and Vurea. Use of icodextrin rather than glucose in the long dwell reduced the complexity of the PD regimen, total glucose exposure, and 24-h total treatment solution volumes. Irrespective of modeling, adequacy of any PD prescription should be based upon individual clinical evaluation both for volume and solute removal.

Body composition of chronic renal patients: anthropometry and bioimpedance vector analysis

OBJECTIVE

to compare the body composition of patients undergoing hemodialysis with that of healthy individuals using different methods.

METHOD

cross-sectional study assessing male individuals using anthropometric markers, electrical bioimpedance and vector analysis.

RESULTS

the healthy individuals presented larger triceps skinfold and arm circumference (p<0.001). The bioimpedance variables also presented significant higher values in this group. Significant difference was found in the confidence interval of the vector analysis performed for both the patients and healthy individuals (p<0.0001). The tolerance intervals showed that 55.20% of the patients were dehydrated, 10.30% presented visible edema, and 34.50% were within normal levels of hydration. Bioimpedance and vector analysis revealed that 52% of the patients presented decreased cell mass while 14.00% presented increased cell mass.

CONCLUSIONS

the differences in the body composition of patients and healthy individuals were revealed through bioimpedance and vector analysis but not through their measures of arm circumference and arm muscle area.

Assessment of fluid status in CAPD patients using the body composition monitor

AIMS AND OBJECTIVES

To assess the degree of overhydration in our peritoneal dialysis patients and to examine the factors contributing to overhydration.

BACKGROUND

Volume control is critical for the success of peritoneal dialysis, but dry weight has been difficult to ascertain accurately. Chronic fluid overload and hypertension are among the leading causes of mortality in dialysis patients.

DESIGN

A cross-sectional observational study.

METHODS

The body composition monitor (Fresenius Medical Care, Bad Homburg, Germany) is a bioimpedance spectroscopy device that has been validated for the assessment of overhydration. We used this body composition monitor device on all patients on continuous ambulatory peritoneal dialysis at our institution who met the inclusion criteria to assess their degree of overhydration.

RESULTS

Thirty four (17 men, 17 women; mean age 44·5 ± 14·2 years) of a 45 continuous ambulatory peritoneal dialysis patients were enrolled. The mean overhydration was 2·4 ± 2·4 l. Fifty per cent of the patients were ≥2 l overhydrated. Overhydration correlated with male gender, low serum albumin, increasing number of antihypertensive agents and duration of dialysis. There was no difference in overhydration between diabetic and non-diabetic patients. Men were more overhydrated than women, had lower Kt/V and were older. Although, there was no difference in blood pressure between the genders, men had a trend towards a higher usage of antihypertensive agents.

CONCLUSION

Our study demonstrates that overhydration is common in peritoneal dialysis patients. Blood pressure should ideally be controlled with adherence to dry weight and low salt intake rather than adding antihypertensive agents even in the absence of clinical oedema.

RELEVANCE TO CLINICAL PRACTICE

Body composition monitor is a simple, reliable and inexpensive tool that can be routinely used in the outpatient clinic setting or home visit to adjust the dry weight and avoid chronic fluid overload in between nephrologists review.

Effluent free radicals are associated with residual renal function and predict technique failure in peritoneal dialysis patients

OBJECTIVE

Residual renal function (RRF) is associated with low oxidative stress in peritoneal dialysis (PD). In the present study, we investigated the relationship between the impact of oxidative stress on RRF and patient outcomes during PD.

METHODS

Levels of free radicals (FRs) in effluent from the overnight dwell in 45 outpatients were determined by electron spin resonance spectrometry. The FR levels, clinical parameters, and the level of 8-hydroxy-2'-deoxyguanosine were evaluated at study start. The effects of effluent FR level on technique and patient survival were analyzed in a prospective cohort followed for 24 months.

RESULTS

Levels of effluent FRs showed significant negative correlations with daily urine volume and residual renal Kt/V, and positive correlations with plasma β(2)-microglobulin and effluent 8-hydroxy-2'-deoxyguanosine. A highly significant difference in technique survival (p < 0.05), but not patient survival, was observed for patients grouped by effluent FR quartile. The effluent FR level was independently associated with technique failure after adjusting for patient age, history of cardiovascular disease, and presence of diabetes mellitus (p < 0.001). The level of effluent FRs was associated with death-censored technique failure in both univariate (p < 0.001) and multivariate (p < 0.01) hazard models. Compared with patients remaining on PD, those withdrawn from the modality had significantly higher levels of effluent FRs (p < 0.005).

CONCLUSIONS

Elevated effluent FRs are associated with RRF and technique failure in stable PD patients. These findings highlight the importance of oxidative stress as an unfavorable prognostic factor in PD and emphasize that steps should be taken to minimize oxidative stress in these patients.

Time-dependent associations between total sodium removal and mortality in patients on peritoneal dialysis

PURPOSE

To determine if the time-dependent association between total sodium removal and mortality in patients on continuous ambulatory peritoneal dialysis (CAPD) is confounded by markers of diet and nutrition.

METHODS

The study enrolled 305 incident patients who started CAPD between July 2002 and February 2007. All patients were followed until death or censoring in February 2008. Demographics, blood pressure, and markers of volume and inflammation were collected at baseline. Biochemistry, fluid and solute removal, and diet and nutrition parameters were collected quarterly and thus calculated as time-averaged values.

RESULTS

Mean age of the study patients was 59.4 years, 42.3% were men, and 40.3% had diabetes. During the 31.4-month follow-up, 74 patients died. The time-averaged daily total sodium removal (TSR) in the overall cohort was 2.67 g (range: 2.02 g-3.47 g). Participants with a high time-averaged TSR tended to experience higher fluid, sodium, urea, and creatinine removal, mainly as a result of better residual renal function (RRF). They also had a higher nutrient intake and a higher lean body mass. Time-dependent TSR was an independent predictor of death, including when adjusted for age, Charlson index, time-dependent hemoglobin, RRF, and peritoneal transport rate (hazard ratio: 0.84; 95% confidence interval: 0.70 to 1.00; p=0.05), but the predictive effect disappeared in multivariate models after further individual adjustment for time-dependent total energy intake, total protein intake, serum albumin, and lean body mass. By contrast, the predictive effect did not disappear if the only adjustment was for time-dependent RRF.

CONCLUSIONS

The time-dependent association between TSR and mortality in patients on peritoneal dialysis can be largely explained by diet and nutrition parameters.

Low-GDP fluid (Gambrosol trio) attenuates decline of residual renal function in PD patients: a prospective randomized study

BACKGROUND

Residual renal function (RRF) impacts outcome of peritoneal dialysis (PD) patients. Some PD fluids contain glucose degradation products (GDPs) which have been shown to affect cell systems and tissues. They may also act as precursors of advanced glycosylation endproducts (AGEs) both locally and systemically, potentially inflicting damage to the kidney as the major organ for AGE elimination. We conducted a clinical study in PD patients to see if the content of GDP in the PD fluid has any influence on the decline of the residual renal function.

METHODS

In a multicentre approach, 80 patients (GFF > or = 3 mL/min/1.732 or creatinine clearance > or =3 mL/min/1.73 m(2)) were randomized to treatment with a PD fluid containing low levels of GDP or standard PD fluid for 18 months. RRF was assessed every 4-6 weeks. Fluid balance, mesothelial cell mass marker CA125, peritoneal membrane characteristics, C-reactive protein (CRP), total protein, albumin, electrolytes and phosphate were measured repeatedly.

RESULTS

Data from 69 patients revealed a significant difference in monthly RRF change: -1.5% (95% CI = -3.07% to +0.03%) with low GDP (43 patients) vs -4.3% (95% CI = -6.8% to -2.06%) with standard fluids (26 patients) (P = 0.0437), independent of angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker medication. Twenty-four-hour urine volume declined more slowly with low-GDP fluid compared to standard fluids (12 vs 38 mL/month, P = 0.0241), and monthly change of phosphate level was smaller (+0.013 vs +0.061 mg/dL, P = 0.0381).

CONCLUSIONS

Our prospective study demonstrates for the first time a significant benefit concerning preservation of RRF and urine volume of using a PD fluid with low GDP levels. These findings suggest that GDPs might affect patient outcome related to RRF.

Comparison of fluid status in patients treated by different modalities of peritoneal dialysis using multi-frequency bioimpedance

BACKGROUND AND AIMS

Patients treated by peritoneal dialysis, especially those using automatic cyclers, are frequently found to be hypervolemic. To determine whether there are significant differences between the currently available modalities of peritoneal dialysis, we analyzed whether differences in transporter status and treatment modality had a discernible effect on extracellular fluid volumes as measured by multi-frequency bioimpedance.

METHODS

Two hundred prevalent peritoneal dialysis patients, 48% male, mean age 54.9 yr (SD+/-15.6), were studied using multi-frequency bioimpedance following a standard peritoneal equilibration test; 63 patients were treated by CAPD, 29 by APD, 96 by CCPD and 12 by OCCPD.

RESULTS

There were no differences in extracellular volumes, or extracellular volume adjusted for height, or as a ratio to total body water between the groups. As expected, extracellular volume adjusted for height depended upon bodyweight (r=0.412, p<0.001), sex (r=0.457, p<0.001) and systolic blood pressure (r=0.162, p=0.023), and extracellular volume to total body water related to the reciprocal of total daily peritoneal ultrafiltration losses (r=-0.0254, p=0.003) and urine output (-0.254, p=0.003). More importantly, on logistical regression analysis the ratio of extracellular fluid to total body fluid increased with falling albumin, F=21.5 p<0.001, increasing age, F=18.5 p<0.001, urine output F=6.46, p=0.014, total daily ultrafiltration, F=3.52 and protein intake p=0.003. Extracellular fluid adjusted for total body fluid was associated with CRP (males F=6.03, p=0.03, females F=4.438, p=0.04).

CONCLUSION

Patients were more likely to have an expanded extracellular fluid volume if they had reduced daily fluid losses, but also with biomarkers typically associated with poor nutrition and inflammation.

A Role for the Asian Peritoneal Dialysis Community in Renal Replacement Therapy Worldwide

Prevalence and incidence of peritoneal dialysis (PD) in Asia are both increasing, but the increase is not homogenous. In some countries and regions, PD is not used as one of the standard therapeutic modalities, because of either insufficient medico-economic infrastructure or a lack of clinical experience and knowledge—or sometime both. In the present article, we would like to introduce a little “Asian heat” with regard to PD utilization and academic and scientific contributions to the PD community in the world.

Why is there significant overlap in volume status between hypertensive and normotensive patients on dialysis?

BACKGROUND/AIM

Volume overload is believed to play a pivotal role in the pathogenesis of hypertension in dialysis patients. Although the extracellular water (ECW) content in hypertensive dialysis patients was significantly higher than in normotensive dialysis patients on the whole, there was considerable overlap in ECW between the two groups. Little is known about the hemodynamic characteristics in subgroups of patients with normotension but a high volume (HV) status or with hypertension but a normal volume (NV) status. We investigate the overlap in ECW between controlled and uncontrolled hypertension in dialysis patients.

METHODS

Fifty-two patients (mean age 62 years, 26 males and 26 females) on peritoneal dialysis were enrolled into this study. The ECW was assessed by bioimpedance analysis and normalized by individual height in meters (NECW). The mean value of NECW in both sexes was arbitrarily set to define NV status (lower than mean value) or HV status (higher than mean value). All patients were thus divided into four subgroups: controlled hypertension with NV (CHT-NV), controlled hypertension with HV (CHT-HV), uncontrolled hypertension with NV (UHT-NV) and uncontrolled hypertension with HV (UHT-HV). The stroke volume, cardiac output and total peripheral resistance were echocardiographically measured and their respective indices were calculated.

RESULTS

There were 12 (23%), 8 (15%), 14 (27%) and 18 (35%) patients in the CHT-NV, CHT-HV, UHT-NV and UHT-HV subgroups, respectively. The four subgroups were matched for sex, diabetes and age. The NECW in the CHT-HV group was higher than that in CHT-NV and UHT-NV groups (p < 0.01), but was comparable with that in the UHT-HV group. The stroke volume and cardiac output indices in the CHT-HV group were not significantly different from those in the CHT-NV and UHT-NV groups. The total peripheral resistance index in the CHT-HV group was lower than that in UHT-NV and CHT-NV groups (p < 0.05), but was comparable to that in the UHT-HV group. There was no difference in heart rate among the four groups.

CONCLUSIONS

The overlap in ECW between controlled hypertension and uncontrolled hypertension in dialysis patients was related to a significant difference in total peripheral resistance index, but not to significant differences in stroke volume and cardiac output indices. The CHT-HV patients were characterized by lower total peripheral resistance indices.