Association between residual renal function, inflammation and patient survival in new peritoneal dialysis patients.

BACKGROUND: The recent ADEMEX study (Paniagua R, Amato D, Vonesh E et al. J Am Soc Nephrol 2002; 13: 1307-1320) indicates that peritoneal small solute clearance is not as critical for the survival of peritoneal dialysis (PD) patients as thought previously. On the other hand, low residual renal function (RRF), inflammation and an increased peritoneal transport rate (PTR) as evaluated by the peritoneal equilibration test (PET) are reported to be associated with increased mortality in PD patients, but the relationships between these factors and their separate and combined impact on the survival of PD patients are not clear. In this retrospective analysis, we evaluated possible relationships between RRF, inflammation and initial PTR in patients starting PD and the impact of these factors on patient survival. METHODS: A total of 117 patients with initial assessments for RRF, serum C-reactive protein (CRP) and PET at a mean period of 0.4+/-0.2 months (range 0.1-1.0 months) after start of PD were included in this study. Based on RRF (cut-off point, 4 ml/min/1.73 m(2)), serum CRP (cut-off point, 10 mg/l), and the dialysate to plasma creatinine ratio at 4-h of dwell (mean+1 SD), the patients were divided into different groups: low RRF and high RRF group, high CRP and normal CRP group and high PTR and other PTR group, respectively. RESULTS: Of 117 patients, 54 patients (46%) were in low RRF (<4 ml/min/1.73 m(2)) group, 36 patients (31%) were in high serum CRP (> or = 10 mg/l) group and 17 patients (15%) were in high PTR group. Forty-nine patients (42%) had one of these characteristics, 26 patients (22%) had two of these characteristics, two patients (2%) had three, and 40 patients (34%) had none of these characteristics. Patients with low RRF were older and had a higher prevalence of high CRP, lower normalized protein equivalent of total nitrogen appearance (nPNA), lower total Kt/V(urea) and lower total creatinine clearance (CCr) whereas patients with high CRP were older and had a higher proportion of men, lower serum albumin, lower nPNA, lower RRF and lower total CCr. Patients with high PTR had lower serum albumin, higher RRF and higher total CCr compared with patients with other PTR. Upon logistic multiple regression analysis, age and RRF were identified as factors affecting inflammation. Overall patient survival was significantly lower in the patients with low RRF, with high CRP, and in patients with more than two of the following: low RRF, high CRP and high PTR. In contrast, in patients with none of the discriminators low RRF, high CRP and high PTR, the 5-year survival was 100%. A high PTR was associated with decreased survival during the initial year on PD, but not thereafter. Patients who died during the follow-up period had a higher prevalence of high CRP and lower serum albumin, lower RRF, lower Kt/V(urea) and lower total CCr. Upon Cox proportional hazards multivariate analysis, age and RRF were predictors of mortality. CONCLUSIONS: These results indicate that in patients starting PD, low initial RRF is associated with inflammation, and low RRF and inflammation are both associated with high overall mortality. A high PTR was associated with higher mortality, but only during the initial year on PD, whereas Kt/V(urea) did not predict mortality. These results indicate the importance of RRF and inflammation as predictors of mortality in PD patients whereas the predictive power of PTR as such may lose its significance if these two parameters are taken into consideration.     

Peritoneal dialysis catheters: a comparison between percutaneous and conventional surgical placement techniques

Percutaneous peritoneal dialysis catheter (PDC) placement isa well-tolerated, rapidly performed side-room procedure thatallows the rapid initiation of dialysis without the delay imposedin co-ordinating a surgeon, theatre time, and theatre staff.We retrospectively reviewed the clinical outcome of 230 PDCinserted over a 30-month period. Fifty were placed percutan-eously(group P) and 180 were placed using conventional surgical techniques,107 in patients commencing CAPD (group A) and 73 in patientspreviously established on CAPD (group B). Total experience accumulatedwas 2563 patient months: 270 patient months group P, 1381 patientmonths group A, 912 patient months group B. Percutaneous PDCinsertion was non-elective, and reserved for patients unfitfor general anaesthesia or haemodialysis. Group P patients wereolder (P<0.001) and had increased early mortality (P<0.005)due to underlying pathology. Death and early mechanical failurecontributed to a shorter mean duration of catheter use in groupP (9.0 ± 2.3 months compared to 15.3 ± 9.6 monthsgroup A and 17.3 ±9.7 group B) (P<0.05). The peritonitisrate was similar in group P (1 per 6.75 patient months) andgroup B (1 per 7.4 patient months) but significantly lower ingroup A (1 per 15.7 patient months) (P<0.01). We concludethat percutaneous PDC placement provides a safe, reliable accessfor peritoneal dialysis and is especially suitable for ill patientswho would not tolerate general anaesthesia.     

Peritoneal dialysis solutions and patient survival: does wishing make it so?

In this issue of Nephrology, Dialysis and Transplantation, Leeand colleagues [1] compare outcomes of Korean peritoneal dialysis(PD) patients who received standard dialysis fluid vs newer,‘biocompatible’dialysis solutions. This very interestingreport found no significant difference in outcome of PD techniquesurvival or its complications, such as peritonitis. However,those who received the new solution had a reduced risk of death.The authors suggest that the newer dialysis solutions may leadto sustained reduction in circulating levels of advanced glycosylationendproducts (AGEs), with a concomitant reduction in microvascularand macrovascular disease. Furthermore, the authors point todownstream effects of AGE binding with its receptors (RAGE),and suggest that reduced AGE production with new solutions couldbe followed by a parallel decline in the AGE–RAGE productionof mediators of inflammation and fibrosis. The authors     

Baseline and time-averaged fluid removal affect technique survival in peritoneal dialysis in a non-linear fashion

AIM: The longevity of peritoneal dialysis (PD) is limited by technique failure and patient mortality. The authors assessed the influence of baseline and time-averaged fluid removal on patient, technique and death-censored technique survival. METHODS: Peritoneal and total fluid removal was measured 1 month after commencing PD, then 6 monthly, in 225 incident patients (mean age 55.3+/-15.8 years, 52% male). A Cox proportional hazards model regression analysis was performed to identify variables independently predictive of technique and patient survival. RESULTS: Seventy (31.9%) patients were transferred to haemodialysis and 39 (17.63%) died. Technique survival was greatest in the middle tertile of baseline total fluid removal (mean survival time 3.5 vs 2.5 and 2.2 years for the lower and upper tertiles, respectively, log rank 6.5, P=0.039). The middle tertile of both baseline and time-averaged total fluid removal were significant predictors of PD survival (adjusted hazard ratio (HR) 0.476, 95% CI 0.286-0.795, P=0.005 relative to the upper tertile and HR 0.573, 95% CI 0.350-0.939, P=0.027 for baseline and time-averaged, respectively). Other significant variables on multivariate analysis were body mass index (HR 1.044 per kg/m2, 95% CI 1.005-1.084, P=0.028), creatinine (HR 0.999 per micromol, 95% CI 0.998-1.000, P=0.048) and residual Kt/V (HR 0.418, 95% CI 0.233-0.747, P=0.003). Patient survival was not affected by fluid removal. CONCLUSION: Patients with moderate total fluid removal both at baseline and throughout their PD career have improved technique survival. Attention should be paid to optimizing total fluid removal.     

Patient-related and centre-related factors influencing technique survival of peritoneal dialysis in The Netherlands.

BACKGROUND: Although technique failure occurs relatively frequently in peritoneal dialysis (PD), few data have been published on differences in technique failure between centres. METHODS: Using data from RENINE, the comprehensive dialysis registry of The Netherlands, we analysed PD technique failure rates in the period 1994-1999, with life table methods and Cox multiple regression analysis. Patient age, sex, and the presence or absence of diabetes were included in the analysis, as well as time of initiation of PD and the following centre characteristics: number of PD patients treated in the centre and percentage of patients on PD. RESULTS: Technique failure was higher in older patients: 2-year technique survival was 75% in those younger than 45 years, 68% in the group aged 45-64 years, and 60% in those over 64 years (P<0.0001). Sex and diabetes made no difference in technique survival. Mean annual technique failure rates varied greatly between centres (10-59%) and correlated with the number of patients on PD in the centre (r=-0.396, P=0.009) and with the fraction of patients on PD (r=-0.410, P=0.006). Low technique survival rates occurred mainly in centres with less than 20 patients on PD: relative risk for technique failure 1.68 as compared with larger centres. Patients starting PD in the period 1997-1999 had better technique survival than those starting in 1994-1996 (P=0.001). CONCLUSION: PD technique survival in The Netherlands has increased in recent years. Having less than 20 PD patients in a centre or having a small fraction of patients on PD carries an increased risk of technique failure. The variability in PD technique survival between centres indicates that in many centres further improvements should be possible.     

Increases in peritoneal small solute transport in the first month of peritoneal dialysis predict technique survival

BACKGROUND: Peritoneal transport of small solutes generally increases during the first month of peritoneal dialysis (PD). The aim of this study was to prospectively evaluate the ability of the peritoneal equilibration test (PET), carried out 1 and 4 weeks after the commencement of PD, to predict subsequent technique survival. METHODS: Fifty consecutive patients commencing PD at the Princess Alexandra Hospital between 1 February 2001 and 31 May 2003 participated in the study. Paired 1 week and 1 month PET data were collated and correlated with subsequent technique survival. RESULTS: A significant increase was observed in the dialysate : plasma creatinine ratio at 4 h (D/P Cr) between 1 and 4 weeks after the onset of PD (0.55 +/- 0.12 vs 0.66 +/- 0.11, P <0.001). Mean death-censored technique survival was superior in patients who experienced > or =20% rise in D/P Cr during the first month of PD compared with those who did not (2.3 +/- 0.2 vs 1.6 +/- 0.2 years, P <0.05). Using a multivariate Cox proportional hazards model analysis, the significant independent predictors of death-censored technique survival were an increase in D/P Cr of greater than 20% during the first month (adjusted hazard ratio [HR] 0.20, 95% CI 0.05-0.75), the absence of diabetes mellitus, the absence of ischaemic heart disease, body mass index and baseline peritoneal creatinine clearance. CONCLUSIONS: A 20% or greater rise in D/P Cr during the first month of commencing PD is independently predictive of PD technique survival. Further investigations of the mechanisms underlying this phenomenon are warranted.     

Peritoneal dialysis practice in Australia and New Zealand: A call to sustain the action

This paper updates a previous ‘Call to Action’ paper (Nephrology 2011; 16: 19–29) that reviewed key outcome data for Australian and New Zealand peritoneal dialysis patients and made recommendations to improve care. Since its publication, peritonitis rates have improved significantly, although they have plateaued more recently. Peritoneal dialysis patient and technique survival in Australian and New Zealand have also improved, with a reduction in the proportion of technique failures attributed to ‘social reasons’. Despite these improvements, technique survival rates overall remain lower than in many other parts of the world. This update includes additional practical recommendations based on published evidence and emerging initiatives to further improve outcomes.     

Peritoneal albumin leakage: 2 year prospective cardiovascular event occurrence and patient survival analysis

Aim: High peritoneal transport status is a determinant of morbidity and mortality in peritoneal dialysis (PD) patients. It was hypothesized that 24 h peritoneal albumin leakage predicted 2 year prospective cardiovascular outcome and survival in patients receiving PD. Methods: Sixty‐six patients were included. A simplified peritoneal equilibration test was performed and 24 h peritoneal albumin leakage was calculated. Patients were followed up for 2 years. Patient outcome (alive or dead) and occurrence of a cardiovascular event were recorded. Results: During a 2 year follow‐up period, 10 (15.2%) patients had suffered from a cardiovascular event and seven (10.6%) patients had died. Patients who had suffered from a cardiovascular event during the follow up period were older (54.0 ± 9.4 years vs 44.3 ± 14.5 years, P = 0.025), had lower serum pre‐albumin concentrations (29.3 ± 10.0 g/dL vs 36.0 ± 9.2 g/dL, P = 0.034) and had higher 24 h peritoneal albumin leakage (median, 3.4 g/day (1.66–15.4 g/day) vs 2.4 g/day (0.76–7.31 g/day), P = 0.011) than patients who did not suffer from a cardiovascular event. In the Cox proportional hazards multivariate analysis of factors which differed significantly between patients with and without a cardiovascular event (age, serum pre‐albumin and 24 h peritoneal albumin leakage), only advanced age (hazards ratio, 1.083; 95% confidence interval, 1.023–1.147, P = 0.006) was an independent predictor of a cardiovascular event. Conclusion: In contrast to the hypothesis, 24 h peritoneal albumin leakage is not a predictor of 2 year prospective cardiovascular outcome and patient survival. Only advanced age independently predicts the occurrence of a cardiovascular event in patients receiving PD.     

Risk factors for mortality in patients undergoing peritoneal dialysis: a systematic review and meta-analysis

AimInconsistent investigations of the risk factors for all-cause mortality in patients undergoing peritoneal dialysis (PD) were reported. The present meta-analysis aimed to assess the impact of some clinical characteristics on the risk of mortality in PD patients.MethodsPubMed and Embase were systematically searched for studies evaluating the risk factors for all-cause mortality in PD patients. Hazard ratio (HR) and 95% confidence interval (CI) were derived using a random-effect or fixed-effect model considering the heterogeneity across studies.ResultA total of 26 studies were included in this meta-analysis in accordance with the inclusion and exclusion criteria. Age, primary cardiovascular diseases, diabetes mellitus, and high level of alkaline phosphatase showed significant positive associations with elevated risk of all-cause and cardiovascular mortality in PD patients, while hemoglobin acted as a benefit factor. Furthermore, early onset of peritonitis, high peritoneal transport status, elevated body mass index and high-sensitivity C-reactive protein could also considerably increase the risk of all-cause mortality. The absolute serum level of magnesium, potassium, and uric acid required to improve survival in PD patients should be verified further.ConclusionsMultiple factors could affect the risk of mortality in PD patients.     

Quality of life on chronic dialysis: comparison between haemodialysis and peritoneal dialysis.

BACKGROUND: Quality of life (QOL) assessment in patients on chronic haemodialysis (HD) or peritoneal dialysis (PD) has only rarely been carried out with the generic Euroqol-5D questionnaire. METHODS: All chronic HD and PD patients in the 19 centres of western Switzerland were requested to fill in the validated Euroqol-5D generic QOL questionnaire, assessing health status in five dimensions and on a visual analogue scale, allowing computation of a predicted QOL value, to be compared with the value measured on the visual analogue scale. RESULTS: Of the 558 questionnaires distributed to chronic HD patients, 455 were returned (response rate 82%). Fifty of 64 PD patients (78%) returned the questionnaire. The two groups were similar in age, gender and duration of dialysis treatment. Mean QOL was rated at 60+/-18% for HD and 61+/-19% for PD, for a mean predicted QOL value of 62+/-30 and 58+/-32% respectively. Results of the five dimensions were similar in both groups, except for a greater restriction in usual activities for PD patients (P = 0.007). The highest scores were recorded for self-care, with 71% HD and 74% PD patients reporting no limitation, and the lowest scores for usual activities, with 14% HD and 23% PD patients reporting severe limitation. Experiencing pain/discomfort (for HD and PD) or anxiety/depression (for PD) had the highest impact on QOL. CONCLUSIONS: QOL was equally diminished in HD and PD patients. The questionnaire was well accepted and performed well. Improvement could be achievable in both groups if pain/discomfort and anxiety/depression could be more effectively treated.     

Preservation of residual renal function and factors affecting its decline in patients on peritoneal dialysis

SUMMARY:     The decline of residual renal function (RRF) in peritoneal dialysis (PD) patients was analysed and assessed, and risk factors affecting its decline were identified. Residual glomerular filtration rate (GFR) was calculated from averaging the urea and creatinine clearance by 24-h urine collection, and peritoneal solute removal was evaluated by creatinine clearance calculated from 24-h effluent collection. Both GFR and peritoneal solute removal were chronologically examined in 34 PD patients from the time of initiation, and risk factors associated with rapid GFR decline were investigated. The RRF contributed to 43.1 ± 17.6% of total (peritoneal and renal) weekly creatinine clearance at 1 month after initiation of PD. Residual GFR, however, declined continuously with time (−0.19 ± 0.14 mL/min per month), and the reduction rate was high with a higher GFR, higher normalized dietary protein intake, higher urine volume and higher urine protein excretion at the initiation of PD. Other factors related to the rapid decline of GFR were: being older than 60 years of age, automated peritoneal dialysis (APD) rather than continuous ambulatory peritoneal dialysis, mean blood pressure higher than 110 mmHg, and serum human atrial natriuretic peptide level higher being than 60 pg/dL. These data suggest that while RRF plays an important role in the removal of uraemic solute in PD patients, they show a significant decrease over 2 years. The factors related to the rapid decline of GFR corresponded to older age, modality of PD (APD), higher GFR and higher amount of urine protein at initiation, higher dietary protein intake, and inadequate control of hypertension and body fluid volume.     

Long-term blood pressure control in a cohort of peritoneal dialysis patients and its association with residual renal function.

BACKGROUND: Hypertension is the prime contributor for cardiovascular mortality in the dialysis population. Peritoneal dialysis (PD) has been thought to improve blood pressure (BP) control in the short term, but the long-term benefits are not conclusively proven. We aimed to evaluate the degree of BP control in PD patients in the long term and analyse the factors associated with poor control. METHODS: Data of all patients who were initiated on PD at one centre between July 1994 and July 1998 and completed at least 1 year of PD were analysed retrospectively at initiation of PD, at 6 months, and annually thereafter until 5 years or until discontinuation of therapy. Hypertension was defined as per WHO/ISH criteria. A 'Blood Pressure Control Index' was empirically defined to account for the effect of antihypertensives on measured BP. Factors associated with poor BP control were analysed. RESULTS: Out of 207 patients (age 57.0+/-16.0 years, 103 male, 104 female) 91.3% were hypertensive at the start of PD. About 33.8% had diabetic nephropathy. Systolic and mean arterial pressure index improved in early phase reaching a nadir between 6 months and 1 year followed by steady progressive worsening through out the rest of follow up. On multiple linear regression analysis age (P<0.001), duration of hypertension prior to dialysis (P<0.001), and declining residual renal function, expressed as both average of urea and creatinine clearance (P=0.002) and residual urine output (P<0.001) were independently associated with poor BP control. Diabetes (P=0.836), peritoneal transport (D/P 4 of creatinine at start) (P=0.218), peripheral oedema (P=0.479) and dose of erythropoetin (P=0.488) were not associated. CONCLUSIONS: Initiation of PD results in early improvement of hypertension in end-stage renal disease (ESRD). BP control thereafter deteriorates steadily with time and this is associated with age, duration of hypertension, and declining residual renal function. This suggests that hypertension in ESRD patients is a progressive disease primarily related to falling glomerular filtration rate, the preservation of which might improve BP control and possibly modify cardiovascular risk.     

Predictive value of dialysis adequacy and nutritional indices for mortality and morbidity in CAPD and HD patients. A longitudinal study

BACKGROUND: The effects of dialysis inadequacy on patient survival and nutritionalstatus and that of malnutrition on survival have not been clearlyassessed. Studies comparing dose/mortality and morbidity curveson continuous ambulatory peritoneal dialysis (CAPD) and on haemodialysis(HD) are also needed, to assess adequate treatment on CAPD. METHODS: We have evaluated the effects of age, 13 pretreatment risk factors,serum albumin, transferrin, normalized protein catabolic rate,Kt/V, normalized weekly creatinine clearance, residual renalfunction and subjective global assessment of nutritional statuson survival and morbidity, in a 3-year prospective study of68 CAPD and 34 HD patients. RESULTS: Survivals did not differ for CAPD and HD patients. In the Coxhazard regression model, age, peripheral vasculopathy, serumalbumin <3.5 g/dl and Kt/V < 1.0/treatment on HD and <1.7/weekon CAPD were independent factors negatively affecting survival.On the contrary, adjusted survivals were not affected by gender,modality, other comorbid factors, normalized protein catabolicrate, or subjective global assessment of nutritional status.Persistence of residual renal function significantly improvedsurvival. Observed and adjusted survival did not significantlydiffer for CAPD and HD patients with either low (HD, <1.0/treatment;CAPD, < 1.7/week) or high ( 1.0 and 1.7) Kt/V. On HD, adjustedsurvivals were similar for 1.0 Kt/V < 1.2 or 1.2. On CAPD,Kt/V 1.96/week was associated with definitely better survival,with only one death/23 patients versus 19/45, with Kt/V 1.96.Survival was not different for 1.96 Kt/V < 2.03 and 2.03.Normalized weekly creatinine clearance and wKt/V were positivelyrelated on CAPD (r 0.39, P<0.01) and wKt/V=1.96 correspondedto 58 litres of normalized weekly creatinine clearance. CONCLUSION: Indices of adequacy were predictors of mortality and morbidity,both on CAPD and HD, whereas normalized protein catabolic rateand subjective global assessment of nutritional status werenot. Serum albumin did not decrease during dialysis; hence itspredictive effect for survival is due to the predialysis conditionand not to dialysis-induced malnutrition.     

Peritoneal transport status and first episode of peritonitis: a large cohort study

BackgroundPeritonitis is one of the most serious complications of peritoneal dialysis (PD). This study aimed to explore the relationship between peritoneal transport status and the first episode of peritonitis, as well as the prognosis of patients undergoing continuous ambulatory peritoneal dialysis (CAPD).MethodA retrospective cohort study was conducted, analyzing data of CAPD patients from 1st January 2009, to 31st December 2017. Baseline data within 3 months after PD catheter placement was recorded. Cox multivariate regression analysis was performed to determine the risk factors for the first episode of peritonitis, technique failure and overall mortality.ResultsA total of 591 patients were included in our analysis, with a mean follow-up visit of 49 months (range: 27–75months). There were 174 (29.4%) patients who had experienced at least one episode of peritonitis. Multivariate Cox regression analysis revealed that a higher peritoneal transport status (high and high-average) (HR 1.872, 95%CI 1.349–2.599, p = 0.006) and hypoalbuminemia (HR 0.932,95% CI 0.896, 0.969, p = 0.004) were independent risk factors for the occurrence of the first episode of peritonitis. In addition, factors including gender (male) (HR 1.409, 95%CI 1.103, 1.800, p = 0.010), low serum albumin (HR 0.965, 95%CI 0.938, 0.993, p = 0.015) and the place of residence (rural) (HR 1.324, 95%CI 1.037, 1.691, p = 0.024) were independent predictors of technique failure. Furthermore, low serum albumin levels (HR 0.938, 95%CI 0.895, 0.984, p = 0.008) and age (>65years) (HR 1.059, 95%CI 1.042, 1.076, p < 0.001) were significantly associated with the risk of overall mortality of PD patients.ConclusionsBaseline hypoalbuminemia and a higher peritoneal transport status are risk factors for the first episode of peritonitis. Factors including male gender, hypoalbuminemia, and residing in rural areas are associated with technique failure, while hypoalbuminemia and age (>65years) are predictors of the overall mortality in PD patients. Nevertheless, the peritoneal transport status does not predict technique failure or overall mortality of PD patients.