Contrasting clinical outcomes between different modes of peritoneal dialysis regimens: two center experiences in China

Factors Contributing to Formation of Edema in Volume Overloaded Continuous Ambulatory Peritoneal Dialysis Patients

Background

Volume control is critical for the success of peritoneal dialysis (PD) but dry weight in PD has been difficult to obtain. Edema free is, in general, accepted clinically as a target for volume control in PD patients. However, PD patients can be free of edema despite significant volume overload. The present study investigates the possible factors that influence the formation of pitting edema in volume-overloaded PD patients.

Methods

In this cross-sectional study, patients’ fluid status was evaluated by multifrequency bioelectrical impedance spectroscopy analysis. Values for overhydration were obtained. Patients with overhydration ≥ 2.0 kg were considered volume overloaded and were eligible for inclusion. From 1 March 2009 to 1 December 2009, a total of 96 patients on continuous ambulatory PD were included. Endothelial function was evaluated by flow-mediated dilatation (FMD). Other clinical indicators, such as blood pressure, dialysis adequacy, nutrition status, and biochemical parameters, were recorded. Patients were divided into 2 groups based on edema status: the edema group ( n = 35 volume-overloaded patients with bilateral pitting edema) and the non-edema group ( n = 61 volume-overloaded patients without bilateral pitting edema).

Results

Overhydration in the edema group was significantly higher than in the non-edema group (4.28 ± 1.75 kg vs 3.12 ± 0.81 kg, p < 0.001), whereas both FMD and serum albumin in the edema group were significantly lower than in the non-edema group (6.65% ± 5.2% vs 10.3% ± 5.1%, p = 0.001; 37.6 ± 4.2 g/L vs 39.3 ± 3.5 g/L, p = 0.047, respectively). Edema status (edema = 1, non-edema = 0) was positively correlated with overhydration ( r = 0.341, p < 0.001), gender (male = 1, female = 2: r = 0.184, p = 0.072), and total fluid removal ( r = 0.188, p = 0.074) and negatively correlated with endothelial function, as assessed by FMD ( r = -0.33, p = 0.001), and serum albumin ( r = -0.18, p = 0.055). Logistic regression analysis showed that FMD [odds ratio (OR) 0.90, 95% confidence interval (CI) 0.81 - 0.99; p = 0.036], gender (male = 1, female = 2: OR 4.06, 95% CI 1.23 - 13.35; p = 0.021), overhydration (OR 3.06, 95% CI 1.53 - 6.13; p = 0.002), and serum albumin (OR 0.86, 95% CI 0.75 - 0.99; p = 0.035) were independent factors affecting the edema status of the study population.

Conclusion

Our study showed that endothelial function (assessed by FMD), gender, serum albumin, and over hydration are independent determinants of edema status in PD patients. This may explain why some PD patients can maintain free of edema despite significant volume overload.

Serum albumin changes and mortality risk of peritoneal dialysis patients

PURPOSE

Initial or single time point serum albumin levels have been shown to be important in predicting the prognosis of peritoneal dialysis (PD) patients. However, we assume the dynamic change and trend of albumin after PD are essential. We aimed to investigate the association between baseline albumin levels, albumin trajectories, and patient mortality in a retrospective cohort study.

METHODS

In this retrospective cohort study, 547 incident PD patients were enrolled from Peking University Third Hospital. Date were collected by medical records review, including age, gender, body mass index, primary disease, comorbidities, and laboratory tests. A joint model for longitudinal data and time-to-event data was used to establish the relationship between serum albumin trajectories and mortality risk of PD patients.

RESULTS

The albumin trajectories was negatively correlated with risk of death. The increase in the current value of albumin trajectories at time points t after PD was associated with decreased risk of death (HR = 0.881, p < 0.0001). There was no statistical association between initial albumin and risk of death (HR = 1.030, 95% CI 0. 995-1.066). The results showed that increased age, higher albumin-corrected Ca levels, and higher eGFR values were risk factors for death. In addition, predictors of low albumin levels are increased PD time, increased age, increased albumin-corrected Ca, and decreased BMI as well as initial albumin levels.

CONCLUSION

This study demonstrates that albumin trajectories after PD is better than initial serum albumin level in predicting mortality risk. Increasing albumin level over time can improve the prognosis of PD patients.

Hypervolemia, hypoalbuminemia and mitral calcification as markers of cardiovascular risk in peritoneal dialysis patients

INTRODUCTION

Mortality in patients with end-stage renal disease is higher than in the general population. This is linked to traditional and non-traditional cardiovascular (CV) risk factors, as well as with risk factors associated with end-stage renal disease itself. The aim of this study is to identify CV risk markers in patients beginning peritoneal dialysis (PD) and their association with CV events and CV mortality.

METHODS

This was a retrospective cohort study of 112 incident PD patients, in which demographic, clinical and laboratory parameters, valvular calcifications, types of PD solutions, hospitalizations, CV events and death were analyzed. Occurrence of CV events or death due to a CV event after PD initiation was defined as the primary endpoint. The use of icodextrin solution was taken as a marker of hypervolemia.

RESULTS

Mean age was 53.7±16.1 years. Patients were treated with PD for 29.3±17.4 months. Eighteen patients (16.1%) had valvular calcifications at baseline, 15 patients (13.4%) had major CV events and 11 patients (9.8%) died from CV-related causes. Cox proportional hazards analysis of CV events or CV-related mortality revealed that mitral calcification, use of icodextrin solution and low albumin were independent predictors of CV events or mortality.

CONCLUSIONS

Traditional CV risk factors appear to have little impact on CV complications in PD patients. Nevertheless, hypervolemia, hypoalbuminemia and mitral calcifications were independent predictors of CV events or mortality in this group of patients.

The Effect of Fluid Overload on Clinical Outcome in Southern Chinese Patients Undergoing Continuous Ambulatory Peritoneal Dialysis

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BACKGROUND

Fluid overload is frequently present in dialysis patients and one of the important predictors of patient outcome. This study aimed to investigate the influence of fluid overload on all-cause mortality and technique failure in Southern Chinese continuous ambulatory peritoneal dialysis (CAPD) patients. ♦

METHODS

This was a post hoc study from a cross-sectional survey originally designed to investigate the prevalence and associated risk factors of fluid overload defined by bioimpedance analysis (BIA) in CAPD patients from January 1, 2008, to December 31, 2009. All 307 CAPD patients completing the original study were followed up until December 31, 2012. ♦

RESULTS

With a median follow-up period of 38.4 (19.2 - 47.9) months, 52 patients died. Patients with fluid overload (defined by extracellular water/total body water [ECW/TBW] ≥ 0.40) had a significantly higher peritonitis rate (0.016 vs 0.011 events/month exposure, p = 0.018) and cerebrovascular event rate (3.9 vs 1.1 events/100 patient years, p = 0.024) than the normal hydrated patients. Moreover, the results showed a significant rising of all-cause mortality (log-rank test = 5.59, p = 0.018), and a trend of increasing cardiovascular disease (CVD) mortality (log-rank test = 2.90, p = 0.089) and technique failure (log-rank test = 3.78, p = 0.052) in the patients with fluid overload. Fluid overload independently predicted all-cause mortality (hazard ratio [HR] = 12.98, 95%, confidence interval [CI] = 1.06 - 168.23, p = 0.042) and technique failure (HR = 13.56, 95% CI = 2.53 - 78.69, p = 0.007) in CAPD patients after adjustment for confounders. ♦

CONCLUSIONS

Fluid overload defined by BIA was an independent predictor for all-cause mortality and technique failure in CAPD patients. Continuous ambulatory peritoneal dialysis patients with fluid overload had a higher peritonitis rate, cardiovascular event rate, and poorer clinical outcome than those patients with normal hydration.

Prevalence and risk factors of fluid overload in Southern Chinese continuous ambulatory peritoneal dialysis patients

Background

Fluid overload is frequently present in CAPD patients and one of important predictors of mortality. The aim of this study is to investigate the prevalence and associated risk factors in a cohort study of Southern Chinese CAPD patients.

Methods

The patients (receiving CAPD 3 months and more) in our center were investigated from January 1, 2008 to December 31, 2009. Multi-frequency bioelectrical impedance analysis was used to assess the patient’s body composition and fluid status.

Results

A total of 307 CAPD patients (43% male, mean age 47.8±15.3 years) were enrolled, with a median duration of PD 14.6 (5.9–30.9) months. Fluid overload (defined by Extracellular water/Total body water (ECW/TBW)≥0.40) was present in 205 (66.8%) patients. Univariate analysis indicated that ECW/TBW were inversely associated with body mass index (r = −0.11, P = 0.047), subjective global assessment score (r = −0.11, P = 0.004), body fat mass (r = −0.15, P = 0.05), serum albumin (r = −0.32, P<0.001), creatinine (r = −0.14, P = 0.02), potassium (r = −0.15, P = 0.02), and residual urine output (r = −0.14, P = 0.01), positively associated with age (r = 0.27, P<0.001), Chalrlson Comorbidity Index score (r = 0.29, P<0.001), and systolic blood pressure (r = 0.22, P<0.001). Multivariate linear regression showed that lower serum albumin (β = −0.223, P<0.001), lower body fat mass (β = −0.166, P = 0.033), old age (β = 0.268, P<0.001), higher systolic blood pressure (β = 0.16, P = 0.006), less residual urine output (β = −0.116, P = 0.042), and lower serum potassium (β = −0.126, P = 0.03) were independently associated with higher ECW/TBW. After 1 year of follow-up, the cardiac event rate was significantly higher in the patients with fluid overload (17.1% vs 6.9%, P = 0.023) than that of the normal hydrated patients.

Conclusions

The prevalence of fluid overload was high in CAPD patients. Fluid overload in CAPD patients were independently associated with protein-energy wasting, old age, and decreased residual urine output. Furthermore, CAPD patients with fluid overload had higher cardiac event rate than that of normal hydrated patents.