Effect Of Residual Renal Function Research Articles

#2704 MANAGEMENT OF HAEMODIALYSIS PATIENTS UNDERGOING RADIOACTIVE IODINE THERAPY FOR THYROID CANCER

Abstract Background and Aims Radioactive iodine (RAI) 131I is used in the adjuvant treatment of thyroid carcinoma following thyroidectomy. 131I is renally excreted, with reduced clearance in patients with end-stage kidney disease (ESKD). There are no established protocols for RAI dosing, timing of dialysis and safety in this population [1]. We describe a single-centre experience with a modified protocol and setup for RAI in haemodialysis (HD) patients including serum 131I measurements to monitor for red marrow toxicity. We present the outcomes in two HD patients. Method A protocol was developed for performing HD post-RAI administration. HD sessions were performed at 24, 72 and 144 hours post-treatment. Custom HD plumbing was installed within existing lead-lined infrastructure. Specific considerations were made for radiation safety including emergency protocols, handling of blood samples, nursing education, patient self-cannulation and dose-reduction of thyrogen pre-treatment. In addition to standard dose-rate meter measurements of radiation, serum 131I measurements were taken pre- and post-HD as a more accurate measurement of red marrow toxicity. Results The two patients included in the study were aged 41 and 60 years. Special considerations for these patients included anuric state in one patient (bilateral nephrectomy) and morbid obesity in the other. Both had early-stage papillary thyroid cancer treated with thyroidectomy. Retained radioactivity measured by dose-rate meter is shown in Figure 1. The largest reduction in radioactivity occurred after the first HD session (approximately 60%). The highest risk of radiation exposure was in the 24 hours prior to the first HD session. Pre-and post-HD serum 131I measurements estimated the radiation dose to red marrow to be below 0.2Gy (maximum tolerated radiation dose for red marrow is 2.0Gy2). Radiation received by HD nurses is shown in Figure 2. Overall exposure was well within national regulatory dose limit of 0.5mSv for members of the public. Conclusion HD at 24, 72 and 144 hours produced a radiation clearance profile similar to controls with normal renal function. The effect of residual renal function on 131I clearance was minimal and HD was the main determinant of 131I clearance in ESKD. Non-routine serum measurements of 131I can be used to assess toxicity to red marrow and guide HD session timing during RAI therapy. Performing HD at 24 and 72hrs post- 131I resulted in a radiation burden to the red marrow well below the accepted radiotoxicity threshold of 2Gy [2]. RAI can be given safely to HD patients with thyroid cancer in centres with the appropriate protocol and setup.

The Effect of Residual Renal Function on Clinical and Laboratory Parameters in Peritoneal Dialysis Patients

The Effect of Residual Renal Function on Clinical and Laboratory Parameters in Peritoneal Dialysis Patients

P1208TREATMENT OUTCOMES IN PERITONEAL DIALYSIS PERITONITIS ARE NOT AFFECTED BY DEGREE OF RESIDUAL RENAL FUNCTION

Abstract Background and Aims Early studies in peritonitis showed no difference in outcomes between anuric and non-anuric patients, despite pharmacokinetic studies showing the effect of residual renal function (RRF) on antibiotic clearance. Recent work identified a relationship between preserved RRF and treatment failure in gram-positive and culture-negative peritonitis. Our centre uses empiric vancomycin and gentamicin dosed by weight (both drugs) and by RRF (gentamicin). We sought to examine whether RRF is associated with treatment failure in our population. Method We retrospectively identified all episodes of PD peritonitis between January 2014 and July 2019 including demographic and clinical information. The RRF measured closest to the peritonitis episode was used. Treatment failure was defined as death, catheter removal or relapse. Results 189 peritonitis episodes occurred in 128 patients (43% female, mean age 61.3±17.9). 80 episodes were caused by gram-positive bacteria, 49 gram-negative, 51 culture-negative, 5 fungal and 4 polymicrobial. 21, 88 and 61 episodes occurred in patients with a creatinine clearance <0.5, 0.5-5, and >5ml/min respectively. Creatinine clearance data was unavailable in 21 patients. Treatment failure occurred in 72 cases (38%) (19 relapses, 52 catheter removals, 7 deaths). Treatment failure for all bacterial peritonitis episodes was not affected by RRF as compared to anuric patients: 0.5-5 (OR 0.41, 95% CI 0.12-1.35, p 0.14) or >5 (OR 0.90, 95% CI 0.22-3.67, p 0.88). There was no difference in outcome in sub-group analysis by type of organism. Antibiotic concentrations did not differ between the RRF groups. Conclusion Although limited by small numbers we found no association between the degree of RRF and outcome. We hypothesise this is because we monitor antibiotic concentrations and therefore dose antibiotics appropriate to the level of RRF. In PD peritonitis regimes that adjust for RRF there is no impact of RRF on treatment outcomes.

Vascular calcification and cardiac function according to residual renal function in patients on hemodialysis with urination

BackgroundVascular calcification is common and may affect cardiac function in patients with end-stage renal disease (ESRD). However, little is known about the effect of residual renal function on vascular calcification and cardiac function in patients on hemodialysis.MethodsThis study was conducted between January 2014 and January 2017. One hundred six patients with residual renal function on maintenance hemodialysis for 3 months were recruited. We used residual renal urea clearance (KRU) to measure residual renal function. First, abdominal aortic calcification score (AACS) and brachial-ankle pulse wave velocity (baPWV) were measured in patients on hemodialysis. Second, we performed echocardiography and investigated new cardiovascular events after study enrollment.ResultsThe median KRU was 0.9 (0.3–2.5) mL/min/1.73m2. AACS (4.0 [1.0–10.0] vs. 3.0 [0.0–8.0], p = 0.05) and baPWV (1836.1 ± 250.4 vs. 1676.8 ± 311.0 cm/s, p = 0.01) were significantly higher in patients with a KRU < 0.9 mL/min/1.73m2 than a KRU ≥ 0.9 mL/min/1.73m2. Log-KRU significantly negatively correlated with log-AACS (ß = -0.29, p = 0.002) and baPWV (ß = -0.19, P = 0.05) after factor adjustment. The proportion of left ventricular diastolic dysfunction was significantly higher in patients with a KRU < 0.9 mL/min/1.73m2 than with a KRU ≥ 0.9 mL/min/1.73m2 (67.9% vs. 49.1%, p = 0.05). Patients with a KRU < 0.9 mL/min/1.73m2 showed a higher tendency of cumulative cardiovascular events compared to those with a KRU ≥ 0.9 ml/min/1.73m2 (P = 0.08).ConclusionsResidual renal function was significantly associated with vascular calcification and left ventricular diastolic dysfunction in patients on hemodialysis.

Effect of residual renal function on quality of life of patients with uremic peritoneal dialysis

Objective To explore the effect of residual renal function(RRF) on the quality of life in uremia patients with peritoneal dialysis (PD). Methods 64 patients with uremia who underwent PD for 3 months or more were selected.According to the residual glomerular filtration rate(rGFR), the patients were divided into RRF group[35 cases with rGFR≥1mL· min-1·(1.73m2)-1] and non-RRF group[29 cases with rGFR≤1mL· min-1 ·(1.73m2) -1]. The patients were followed up at 3-month intervals.The quality of life was assessed using the SF-36. Results The calcium, phosphorus, parathyroid hormone, serum creatinine, C-reactive protein, serum albumin, total urea removal, serum potassium, total urea clearance in the non-RRF group were (2.29±0.25)mmol/L, (1.68±0.42)mmol/L, 275.68 ng/L, (1 121.58±215.36)μmol/L, (11.02±14.35)mg/L, (31.01±3.26)g/L, (100±50)mL/d, (3.48±0.78)mmol/L, (1.71±0.28), respectively, which in the RRF group were (2.21±0.19)mmol/L, (1.59±0.35)mmol/L, 147.43ng/L, (872.56±264.68) μmol/L, (5.34±8.97)mg/L, (3.43±0.59)mmol/L, (33.21±4.62)g/L, (5.34±8.97)mg/L, (33.21±4.62) g/L, (800±200)mL/d, (3.79±0.59) mmol/L, (2.01±0.41), respectively, the differences between the two groups were significant (t=2.316, 2.149, 2.353, 3.881, 2.229, 7.213, 2.243, 2.212, 4745, all P 0.05). Univariate linear regression analysis showed that rGFR was not associated with SF-36 overall score.Multivariate linear regression analysis found that SF-36 overall score and serum calcium, phosphorus, parathyroid hormone, serum creatinine, C-reactive protein, peritoneal ultrafiltration volume had relevance(t=4.102, 2.412, 2.174, 4.259). Conclusion There was no significant difference in overall quality of life scores and mental health scores between the RRF group and the non-RRF group.RRF was not directly related to the quality of life of the patients. Key words: Uremia; Peritoneal dialysis; Quality of life

Sleep Disorders in Hemodialysis Patients: Does RKF Matter?

Background: Sleep disorders are common in ESRD. Residual kidney function contributes significantly to the overall health and well-being of dialysis patients. The importance of RKF in patients on peritoneal dialysis is widely known, but only a few studies have examined RKF in patients on hemodialysis. Methods: Our study aimed to evaluate sleep disorders in hemodialysis patients and the effect of residual renal function on them. A cross sectional study was conducted on 80 HD patients who were divided into 2 groups. Group I included 30 HD patients with RKF and group II included 50 HD patients without RKF. RKF (Kru) was calculated using the equation: Interdialytic urine volume x Urine urea concentration/Interdialytic period/Mean BUN. Where Mean BUN= (BUN 1 + BUN 2)/2. BUN 1 was measured after first dialysis of week and BUN 2 was measured prior to second dialysis of week. Routine laboratory investigations were done to all patients. We assessed the following sleep disorders in both group: insomnia through insomnia severity index, the restless leg syndrome through international restless leg syndrome study group (IRLSSG) and the excessive Daytime sleepiness through the Italian version of Epworth sleepiness scale. Results: In group I, 43.3% were female and 56.7% were male with mean age 40.47 ± 13.96 years and mean dialysis duration 4.38 ± 2.86 years. In group II, 38% were female and 62% were male with mean age 54.68 ± 9.36 years and mean dialysis duration 6.90 ± 3.82 years. There was highly significant difference between both groups regarding age and dialysis duration (p=0.000, 0.002 respectively). There was highly significant difference between the two groups regarding iPTH (106.71 ± 57.34 pg/ml, 175.36 ± 15.71 pg/ml, p=0.000). The prevalence of insomnia was 62% followed by IRLS 18.7% and EDS 12.5%. There was no statistically significant difference between group I and group II regarding insomnia severity index, while there was statistically significant difference between them regarding international restless limb syndrome and epworth sleepiness (p=0.040, 0.004 respectively). There was no significant correlation between Kru and total score of insomnia severity index, total score of limb syndrome and total score of epworth sleepiness scale. In our study there was positive correlation between Phosph and total score of limb syndrome (p=0.010). Also the level of iPHT was correlated with the total score of limbs syndrome and total score of Epworth sleepiness scale (p=0.027, 0.038 respectively). Conclusion: Sleep disorders are quite common in the HD patients. Patients with high level of iPTH and phosphorus are at major risk of sleep disorders. Residual kidney function is very important to control Ca, phosphorus and iPTH level but its effect on the sleep disorders is not obvious in our study.

Effects of residual renal function on uremic toxicity level of patients undergoing high-flux dialysis

Effects of residual renal function on uremic toxicity level of patients undergoing high-flux dialysis

Effects of Residual Renal Function on Left Ventricle and Analysis of Related Factors in Patients with Hemodialysis

Background: Left ventricular hypertrophy (LVH) and systolic dysfunction would predict the mortality of patients undergoing maintenance hemodialysis. The cause of LVH is usually related to the increase of total peripheral vascular resistance and overloading volume. The presence of residual diuresis enables greater control of the volume. This study evaluated the effects of residual renal function (RRF) on the left ventricle and analyzed the related factors involved in hemodialysis patients. Methods: A total of 59 hemodialysis patients were classified into two groups. The patients in the RRF (RRF+) group had a urine volume greater than 200 mL/24 h, and the patients in the non-RRF (RRF−) group had a urine volume less than 200 mL/24 h. B-type natriuretic peptide (BNP), blood total homocysteine (tHcy), and blood biochemical indexes were determined for the patients in both groups. Echocardiography and Doppler tests were performed to determine the cardiac indexes. Results: LVH and systolic dysfunction in the RRF+ group were less severe than those in the RRF− group. The concentration of tHcy and BNP in patients with RRF was decreased in comparison with those without RRF. The concentration of tHcy and BNP was positively correlated with the residual diuresis. Conclusions: There were distinct ventricular geometric patterns and different functional performances between RRF+ and RRF− groups. The presence of residual diuresis had a beneficial effect on the left ventricular function in hemodialysis patients.

Cystatin C in children on chronic hemodialysis

Cystatin C (CyC) concentration has been suggested as a marker of middle-molecule accumulation, hemodialysis (HD) adequacy and for estimating residual renal function (RRF), but it has not been studied in pediatric HD. High CyC is associated with increased cardiovascular disease (CVD). We investigated CyC kinetics and the effect of RRF on CyC in a pediatric HD population. A total of 21 HD sessions and 20 interdialytic periods were analyzed in seven patients, age 5-19 years, of whom four were anuric (A) and three were non-anuric (NA). CyC was measured before (preHD) and after (postHD) three standard HD sessions in 1 week and prior to the first session of the following week. We found no difference (p=0.67) in CyC concentration between preHD CyC (9.85 ± 2.15 mg/l; A vs. NA, p=0.37) and postHD CyC (10.04 ± 2.83 mg/l; A vs NA, p=0.28). The weekly average preHD CyC median concentration was 10.14 mg/l (A vs. NA, p=0.87) and correlated with age (r=0.808, p=0.03) and height measurement (r=0.799, p=0.03), but not with RRF, single-pool Kt/V, ultrafiltration, HD duration or blood liters processed. Cystatin C is very elevated in children on HD. It does not rise between HD sessions, is not removed by standard HD and remains at steady state; therefore, elimination is extrarenal. Low RRF does not affect CyC elimination. CyC increases with age and height. If a high CyC concentration can be proven to have a causative role in the development of CVD, routine intensified HD regimens in children may be indicated for its removal.

Late Dialysis Start Did Not Affect Long‐Term Outcome in Japanese Dialysis Patients: Long‐Term Prognosis From Japanese Society of Dialysis Therapy Registry

Early initiation of dialysis had been considered one of the most important methods for better prognosis of dialysis patients. One of the reasons for this was that long-term as well as short-term prognosis was poor with late initiation of dialysis. In this study, we analyzed the effects of residual renal function and comorbidity on both short- and long-term outcomes of ESRD patients. The subjects of this study were 20 854 patients who started renal replacement therapy (RRT) in 1989 and 1990, when we conducted national surveillance for new ESRD patients. The effects of glomerular filtration rate (GFR) at dialysis start and comorbidity conditions on survival were measured. Mortality hazard ratio (HR) was calculated using a Cox proportional hazard model. Multivariate analysis included pre-dialysis estimated GFR, age, sex, and underlying renal disease. The mean age of the subjects was 57.7 years old. Mean GFR at dialysis initiation was 5.00 mL/min per 1.73 m(2) and GFR was significantly higher in patients with diabetes. The median survival time from the start of dialysis was 69 months, excluding subjects who died within 3 months; 1-year survival was 89.7%, while 2-year, 3-year, 5-year, 10-year, and 15-year cumulative survival rates were 79.3%, 71.1%, 57.8%, 37.3%, and 26.1%, respectively. For mortality risks, the higher the GFR at dialysis initiation, the worse the HR for mortality in both short-term and long-term prognoses by unadjusted analysis. However, after adjustments for age, gender, underlying renal diagnosis, and symptom at dialysis initiation, both late and early initiation of RRT did not affect long-term prognosis.

The Effect of Residual Renal Function at the Initiation of Dialysis on Patient Survival

Background/AimsThe optimal time point for initiating renal replacement therapy in patients with end-stage renal disease remains controversial. The primary objective of our study was to determine the effects of residual renal function at the beginning of renal replacement therapy on the mortality of patients with end-stage renal disease.MethodsWe retrospectively studied the clinical outcomes in patients (n=210) with end-stage renal disease who underwent renal replacement therapy at our hospital between 2000 and 2005; all patients were followed for more than 1 year. We used the Modification of Diet in Renal Disease equation to estimate residual renal function.ResultsOf the 210 patients who received renal replacement therapy, 108 were treated with hemodialysis and 102 were treated with peritoneal dialysis. Thirty-three patients died, and the mean survival period was 37.3±17.7 months. The survival rates were compared based on the estimated glomerular filtration rate; no difference in survival rates was observed (p=0.27). Subgroup analysis in the hemodialysis group showed that patients who began chronic dialysis at a lower estimated glomerular filtration rate had higher mortality rates (p<0.05); patients treated with peritoneal dialysis showed no significant difference in mortality rate (p=0.50).ConclusionsAlthough there was no difference in the mortality rate based on residual renal function, hemodialysis patients with a lower estimated glomerular filtration rate showed a higher mortality rate than those with a higher estimated glomerular filtration rate.

Independent effects of residual renal function and dialysis adequacy on dietary micronutrient intakes in patients receiving continuous ambulatory peritoneal dialysis

Dialysis patients are at risk of vitamin and mineral deficiencies, not only because of losses during chronic hemodialysis or peritoneal dialysis but also because of low intakes. The objective was to determine the importance of urea clearance (calculated as K(t)/V) and residual renal function (RRF) in predicting micronutrient intakes in a large cohort of patients receiving continuous ambulatory peritoneal dialysis (CAPD). We conducted a survey of dietary intakes in 242 CAPD patients and divided them into 3 groups according to their weekly urea clearance and RRF: WD group (n = 84), a urea clearance >/= 1.7 and a glomerular filtration rate (GFR) >/= 1 mL x min(-1) x 1.73 m(-2); DD group (n = 71), a urea clearance >/= 1.7 and a GFR < 1 mL x min(-1) x 1.73 m(-2); and ID group (n = 87), a urea clearance < 1.7. Most of the patients had intakes of water-soluble vitamins and minerals that were lower than the recommended dietary allowance; most intakes were significantly higher in the WD group than in the DD and ID groups, except those of niacin and calcium. After age, sex, body weight, and the presence of diabetes were controlled for, total weekly urea clearance and the GFR (but not peritoneal dialysis urea clearance) were significantly associated with intakes of vitamins A and C, the B vitamins, and minerals (calcium, phosphate, iron, and zinc). Low intakes of vitamins and minerals with low RRF and urea clearance were the result of reduced overall food intakes, except for thiamine, vitamin B-6, and folic acid, which were deficient in the diet. Supplementation with most water-soluble vitamins and minerals, including iron and zinc, should be considered in CAPD patients, especially those with low RRF and low urea clearance. The optimal dose needs to be determined.

Independent effects of residual renal function and dialysis adequacy on actual dietary protein, calorie, and other nutrient intake in patients on continuous ambulatory peritoneal dialysis.

Previous studies have suggested that the cross-sectional relationship observed between total solute clearance (Kt/V) and dietary protein intake (DPI) in patients undergoing dialysis is possibly mathematical in origin. A cross-sectional study on 242 patients undergoing continuous ambulatory peritoneal dialysis (CAPD) was performed to determine the differential effects of dialysis adequacy and residual renal function (RRF) on actual dietary intake. All patients underwent a 7-d food frequency questionnaire to quantify daily dietary protein, calorie (DCI), and other nutrient intake, subjective global assessment (SGA), and collection of 24-h dialysate and urine for total (PD and renal) Kt/V and RRF. Patients were categorized into three groups: I (n = 94), total Kt/V >/=1.7 and GFR >0.5 ml/min per 1.73 m(2); II (n = 58), total Kt/V >/=1.7 but GFR <0.5 ml/min per 1.73 m(2); and III (n = 90), total Kt/V <1.7. Sixty-nine percent versus 62% versus 42% of group I versus II versus III patients were well nourished according to SGA (P = 0.004). DPI (1.23 [0.47] versus 1.12 [0.49] versus 0.99 [0.40] g/kg per d; P = 0.002) and DCI (27.3 [8.9] versus 23.8 [8.6] versus 23.0 [8.2] kcal/kg per d; P = 0.002) showed significant decline across the three groups. Intake of other nutrients, including carbohydrate, fat, fatty acids, and cholesterol was higher for group I compared with groups II and III. Adjusting for age, gender, weight, and diabetes, every 1 ml/min per 1.73 m(2) increase in GFR was associated with a 0.838-fold increase in DCI (95% confidence interval to interval, 0.279 to 1.397; P = 0.003) and a 0.041-fold increase in DPI (95% confidence interval, 0.009 to 0.072; P = 0.012), whereas every 0.25-unit increase in total (PD and renal) Kt/V was associated with a 0.570-fold increase in DCI (95% confidence interval, 0.049 to 1.092; P = 0.032) and a 0.052-fold increase in DPI (95% confidence interval, 0.023 to 0.081; P = 0.001). Greater small-solute clearances are associated with better dietary intake and better nutrition. The study confirmed significant and independent effect of RRF, but not PD solute clearance, on actual DPI, DCI, and other nutrient intake in patients on CAPD.

Residual Renal Function in a Large Cohort of Peritoneal Dialysis Patients: Change over Time, Impact on Mortality and Nutrition

Residual renal function contributes importantly to total solute clearance in peritoneal dialysis (PD) patients. This study was designed to examine the progression of residual renal function over time and its impact on nutrition and mortality in PD patients in the six New England states (ME, NH, VT, CT, MA, RI) comprising End Stage Renal Disease (ESRD) Network 1. As part of the ESRD Clinical Indicators Project, data on 990 PD patients in Network 1 were abstracted from data supplied by dialysis units in the fourth quarter of 1997. This included demographic information; dose of PD in L/day; weekly renal, dialysis, and total Kt/V urea; weekly renal, dialysis, and total creatinine clearance (CCr); serum albumin level; and mortality and transplantation information. Data collection was repeated in the second and fourth quarters of 1998 and in the second quarter of 1999. 990 PD patients in Network 1. The change in total and renal solute clearances over time, the relationship between renal clearance and mortality, and the relationship between renal clearance and nutritional status, as represented by serum albumin. Over the 2-year period, mean weekly renal Kt/V urea and weekly renal CCr dropped significantly. To examine the effect of residual renal function on mortality, patients were divided into high and low (above and below the median) weekly renal Kt/V urea and weekly renal CCr groups. Patients above the median levels of both weekly renal Kt/V urea and weekly renal CCr had a significantly decreased risk of dying during the observation period, after controlling for age, gender, serum albumin level, and diabetic status [OR for high vs low renal Kt/V urea 0.54 (CI 0.34 - 0.84), OR for high vs low renal CCr 0.61 (CI 0.40 - 0.94)]. The mean weekly renal Kt/V urea was significantly and directly correlated with the mean serum albumin level by Spearman rank correlation (R = 0.133, p < 0.001), as was the mean weekly renal CCr (R = 0.115, p < 0.001). Residual renal function is an important contributor to total solute clearance in PD patients. Even at low levels it is linked to decreased mortality and better nutritional status.

Independent effects of residual renal function and dialysis adequacy on nutritional status and patient outcome in continuous ambulatory peritoneal dialysis.

Dialysis adequacy has a major impact on outcome of continuous ambulatory peritoneal dialysis (CAPD) patients. However, there is a substantial confounding effect by residual renal function in most studies. We differentiated the effects of dialysis adequacy from those of residual renal function on nutritional status and outcome of CAPD patients. We identified 168 CAPD patients treated in our center between September 1995 and December 1996 and categorized them into three groups: 49 patients with an average total Kt/V of 1.93 +/- 0.18 and a median residual glomerular filtration rate (GFR) of 0. 07 mL/min/1.73 m(2) in the dialysis-dependent (DD) group; 48 patients with an average total Kt/V of 2.03 +/- 0.25 and a residual GFR of 2. 33 mL/min/1.73 m(2) in the residual renal function (RRF) group; and 71 patients with an average total Kt/V of 1.38 +/- 0.22 and a residual GFR of 0.05 mL/min/1.73 m(2) in the control (CTL) group. They were followed-up for 1 year to compare baseline nutritional status and 1-year morbidity. Baseline normalized protein catabolic rates (NPCR) are 1.00 +/- 0.20 and 0.96 +/- 0.19 (for RRF and DD, respectively) versus 0.89 +/- 0.16 g/kg/d for CTL (P < 0.01). Percentage lean body mass (%LBM) was 71.6 +/- 9.8 and 71.5 +/- 10.0 (for RRF and DD, respectively) versus 65.2 +/- 8.5% for CTL (P < 0. 001). No difference was seen in the nutritional status between RRF and DD groups. Duration of hospitalization for 1 year was 6.9 +/- 11. 8 days in the RRF group versus 14.9 +/- 25.1 in the DD and 10.6 +/- 11.6 days in the CTL groups (P < 0.05). The peritonitis rate was 44. 4 patient-months for the RRF group, versus 13.6 for the DD and 12.9 for the CTL groups (P < 0.05). There also was a trend toward superior 1-year technique survival in the RRF group, but the number of observations was small. There was no difference in duration of hospitalization, peritonitis rate, and technique survival between the DD and CTL groups. Short-term morbidity in patients without residual renal function appears to be independent of total Kt/V, although Kt/V may have some effects on nutritional status. The assumption that renal and peritoneal clearances are equivalent must be carefully reexamined. Further studies on the effect of dialysis adequacy in patients without residual renal function are urgently needed.

Significance of residual renal functions of patients with end-stage renal failure undergoing continuous ambulatory peritoneal dialysis

It is generally accepted that residual renal function remains well-preserved longer with CAPD than with hemodialysis. However, consideration and impact of the contributory effects of residual renal function on the adequacy of renal replacement therapy has not been well defined. In this report, creatinine clearance (Ccr), Kt/V, normalized protein catabolic rate (nPCR) and urinary excretion of uremic solutes were studied in 26 stable CAPD patients with a four-bag exchange. Weekly Ccr, weekly Kt/V and nPCR were 62.3 +/- 20.2 l/week/1.73 m2, 1.77 +/- 0.35, and 0.90 +/- 0.13 g/kg/day, respectively. These parameters correlated significantly with the daily urine volume. The weekly Ccr and Kt/V of anuric patients seemed to be inadequate. Urinary excretion of urea nitrogen, Cr, Na, Cl, Pi and beta 2-microglobulin (beta 2-MG) were dependent upon the daily urine volume. Significant phosphorus and beta 2-MG excretion seemed to have an effect on the prevention of bone and joint complications, because serum iPTH and beta 2-MG levels increased after the patients fell into an anuric state. It was suggested from this study that CAPD should be started before the patient loses residual renal function because four bag exchange as the standard CAPD prescription might not be adequate once the patient loses urine excretion.

Effects of residual renal function in haemodialysis patients

Thirty-six haemodialysis patients on treatment for more than six months were studied for residual renal function (RRF). Twenty patients were anuric. The remaining 16 patients with RRF excreted 35-1600 ml urine/day with creatinine clearance ranging 0.17-6.95 ml/min. Patients with RRF were on dialysis therapy for shorter periods than those with anuria (25.5 +/- 18.5 vs. 101.7 +/- 14.2 months, p = 0.001). Twelve out of 20 anuric patients had had previous renal transplantation, whereas none of those with RRF had been transplanted (p = 0.0006). Interdialytic weight gain, serum potassium and phosphate were lower in patients with RRF. Serum phosphate and uric acid were correlated with their respective urinary excretion rates (p = 0.013 and 0.005, respectively), but interdialytic weight gain could not be correlated with urinary output. Creatinine clearance significantly correlated with urinary excretion of potassium, sodium, phosphate and uric acid. In this series of patients a previous unsuccessful renal transplantation was an important factor in the loss of RRF. The presence of RRF contributed to the regulation of the blood levels of phosphate and the excretion rate of potassium, sodium and uric acid.

Serum Low-Molecular-Weight Proteins in Haemodialysis Patients: Effect of Residual Renal Function

Serum low-molecular-weight proteins, beta-2-microglobulin and alpha-1-microglobulin, were measured in 34 patients undergoing maintenance haemodialysis. There was a strong positive correlation between beta 2M and alpha 1M and predialysis serum creatinine and strong negative correlations between these proteins and 24-h urine volume and creatinine clearance. Good correlation was also demonstrated with total duration of haemodialysis, which also correlated with residual renal function. It is suggested that the elevated beta 2M and alpha 1M in haemodialysis patients merely reflect the severity of renal failure and are not directly influenced by the duration of dialysis or type of dialysis membrane.

The middle molecule hypothesis in perspective.

The middle molecule (MM) hypothesis states that molecules in the molecular weight range of 500 to 2000 daltons/molecule accumulate in uremia and are one cause of peripheral neuropathy. Evidence for and against this hypothesis is reviewed and evaluated. The course of events in the core of early hemodialysis patients who developed neuropathy provides important support ofr the hypothesis. Failure of early peritoneal dialysis patients to develop neuropathy suggested that the peritoneum is more permeable to MM's than early hemodialysis membranes, a fact that was later hemodialysis membranes, a fact that was later confirmed by appropriate investigations. Several investigators have demonstrated that MM's actually do accumulate in uremia and disappear rapidly following a renal transplant, which suggests a high clearance by the human kidney. Retrospective and prospective studies have demonstrated a protective effect of residual renal function against MM intoxication. Our prospective studies to produce MM intoxication are reviewed and their strengths and weaknesses delineated. Similarly, the investigations of others that are cited as evidence against the MM hypothesis are reviewed. It is the opinion of hte authors that the weight of evidence supports the validity of the MM hypothesis; but that final proof still is lacking. A protocol for more definitive studies is discussed.