Role of peritoneal loss of albumin in the hypoalbuminemia of continuous ambulatory peritoneal dialysis patients: relationship to peritoneal transport of solutes

Multidisciplinary supportive care in systemic light chain amyloidosis

The immunoglobulin light-chain amyloidosis is a multisystemic disease which manifests by damage to the vital organs by light chain-derived amyloid fibril. Traditionally, the treatment has been directed to the underlying plasma cell clone with or without high dose chemotherapy followed by autologous stem cell transplantation using melphalan based conditioning. Now with the approval of highly tolerable anti-CD38 monoclonal antibody daratumumab based anti-plasma cell therapy in 2021, high rates of hematologic complete responses are possible even in patients who are otherwise deemed not a candidate for autologous stem cell transplantation. However, despite the progress, there remains a limitation in the strategies to improve symptoms particularly in patients with advanced cardiac involvement, those with nephrotic syndrome and autonomic dysfunction due to underlying systemic AL amyloidosis. The symptoms can be an ordeal for the patients and their caregivers and effective strategies are urgently needed to address them. The supportive care is aimed to counteract the symptoms of the disease and the effects of the treatment on involved organs’ function and preserve patients’ quality of life. Here we discuss multidisciplinary approach in a system-based fashion to address the symptom management in this dreadful disease. In addition to achieving excellent anti-plasma cell disease control, using treatment directed to remove amyloid from the vital organs can theoretically hasten recovery of the involved organs thereby improving symptoms at a faster pace. Ongoing phase III clinical trials of CAEL-101 and Birtamimab will address this question.

Supportive Care for Patients with Systemic Light Chain Amyloidosis

Light chain amyloidosis is a disease in which clonal plasma cells produce toxic immunoglobulin light chains that form amyloid fibrils with deposition in organs, most commonly the heart and kidneys, but also the nervous system, gastrointestinal tract, and soft tissues. Treatment directed at the clonal cells eliminates light chain production and further deposition and may enable organ improvement and decrease the risk of organ failure. Supportive care manages the symptoms of organ involvement and the side effects of treatment. Supportive care also addresses the psychological and social issues that may arise in patients with light chain amyloidosis.

Residual Renal Function Affects Lipid Profile in Patients Undergoing Continuous Ambulatory Peritoneal Dialysis

Objective

To determine whether lipoprotein abnormalities associated with continuous ambulatory peritoneal dialysis (CAPD) are influenced by residual renal function (RRF).

Design

Open, non randomized prospective and com -parative study.

Setting

Single university teaching hospital dialysis unit and outpatient clinic.

Patients

Twenty adult patients on standard CAPD (1 -38 months) were divided into two groups: group A (RRF ≤ 0.8 mL/min, n = 10) and group B (RRF ≥ 1.1 mL/ min, n = 10). Patients in the two groups were matched for age, time on dialysis, body weight, body mass index, serum urea and albumin levels, peritoneal and urinary albumin losses, and peritoneal transport characteristics such as overnight 8hour peritoneal creatinine and β2-microglobulin clearances and overnight 8-hour effluent glucose concentrations.

Results

The degree of uremia in patients with preserved RRF (group B) was obviously lower than in patients with negligible RRF (group A), that is, patients in group B had significantly lower serum creatinine and β2-microglobulin levels and significantly higher weekly KTN than group A patients. Despite the prevalence of allele 4 of apolipoprotein E genotype in group A patients, their levels of serum total cholesterol, low-density lipoprotein cholesterol, lipoprotein (a) [Lp(a)], apolipoprotein B (ApoB), and apolipoprotein A1 (ApoA1) were significantly lower than those of patients with preserved RRF (group B). The two groups did not differ significantly in the serum levels of triglyceride or high-density lipoprotein cholesterol. Serum concentrations of Lp(a) and ApoA1, as well as ratios of ApoA1 to ApoB, were correlated significantly with RRF (r = 0.63, r = 0.51, and r = 0.61, respectively).

Conclusions

The findings suggest that RRF affects the lipid profile of CAPD patients, especially serum levels of cholesterol-rich lipoproteins.

Effect of Dialysis Modality and Membrane Transport Characteristics on Dialysate Protein Losses of Patients on Peritoneal Dialysis

Objective

To determine if peritoneal dialysis modality has an impact on protein losses in dialysate.

Design

Retrospective, cross-sectional study.

Patients

190 patients who had selected peritoneal dialysis were classified into one of four transport categories (high, high-average, low-average, or low) based on standard peritoneal equilibration test results. Patients were then assigned to continuous ambulatory peritoneal dialysis (CAPD) or nightly intermittent peritoneal dialysis (NIPD) based on membrane transport characteristics and individual preferences.

Results

Patients with similar membrane transport characteristics had essentially no differences in dialysate protein and albumin losses whether treated with CAPD or NIPD.

Conclusions

Although high transporters may be better managed with short -dwell therapies such as nocturnal intermittent peritoneal dialysis or daily ambulatory peritoneal dialysis, consistent marked decreases in protein losses cannot be cited as a benefit of NIPD over CAPD.

Association between vitamin C deficiency and dialysis modalities

AIM

  We designed a cross-sectional study to investigate plasma vitamin C level in patients who underwent maintenance haemodialysis (MHD) and continuous ambulatory peritoneal dialysis (CAPD) to explore whether there is a difference in vitamin C deficiency between MHD patients and CAPD patients.

METHODS

  This investigation included 382 dialysis patients without vitamin C supplement before the study. Demographic characteristics, laboratory tests, ascorbic acid and total plasma vitamin C level were measured. A linear regression model was built to explore the association between vitamin C deficiency and dialysis modalities after adjusting for age, dialysis vintage, gender, Charlson index, modality of dialysis and hsCRP.

RESULTS

  The range of plasma vitamin C level was from 0.48 µg/mL to 31.16 µg/mL. 35.9% (n = 137) patients had severe vitamin C deficiency (<2 µg/mL). Plasma vitamin C level was inversely associated with age and dialysis vintage. After age and dialysis vintage were adjusted, vitamin C deficiency was associated with MHD. R square for model fitting was relatively low, which implied that there were other vitamin C influencing factors not included in the model.

CONCLUSIONS

  Vitamin C deficiency is common in dialysis patients, especially in patients treated with MHD.

Higher peritoneal transport status is associated with higher mortality and technique failure in the Australian and New Zealand peritoneal dialysis patient populations

Although early studies observed that peritoneal membrane transport characteristics were determinants of morbidity and mortality in peritoneal dialysis (PD) patients, more recent investigations, such as the Ademex trial, have refuted these findings. The aim of this study was to determine whether baseline peritoneal transport status predicted subsequent survival in Australian and New Zealand PD patients. The study included all adult patients in Australia and New Zealand who commenced PD between April 1, 1999, and March 31, 2004, and had a peritoneal equilibration test (PET) performed within 6 mo of PD commencement. Times to death and death-censored technique failure were examined by Kaplan-Meier analyses and multivariate Cox proportional hazards models. PET measurements were available in 3702 (72%) of the 5170 individuals who began PD treatment in Australia or New Zealand during the study period. In these patients, high transporter status was found to be a significant, independent predictor of death-censored technique failure (adjusted hazard ratio [AHR] 1.23; 95% confidence interval [CI] 1.02 to 1.49; P = 0.03) and mortality (AHR 1.34; 95% CI 1.05 to 1.79, P = 0.02) compared with low-average transport status. High-average transport class was also associated with mortality (AHR 1.21; 95% CI 1.00 to 1.48; P = 0.047) but not death-censored technique failure (AHR 1.04; 95% CI 0.90 to 1.21) compared with low-average transport status. When transport status was alternatively analyzed as a continuous variable, dialysate:plasma creatinine ratio at 4 h was independently predictive of both death-censored technique failure (AHR 1.07; 95% CI 1.01 to 1.295; P = 0.031) and death (AHR 1.09; 95% CI 1.01 to 1.373; P = 0.036 per 0.1 change in dialysate:plasma creatinine). Peritoneal transport rate is a highly significant risk factor for both mortality and death-censored technique failure in the Australian and New Zealand incident PD patient populations.

Serum prealbumin is higher in peritoneal dialysis than in hemodialysis: a meta-analysis

BACKGROUND

Although not widely appreciated, the reported concentration of serum prealbumin, like that of serum cholesterol, tends to be higher in patients on peritoneal dialysis (PD) than on hemodialysis (HD), despite the substantial loss of protein during PD.

METHODS

The mean difference in serum prealbumin was quantified by meta-analysis of the mean differences found in six cohorts with both PD and HD patients (set 1; N = 639) using a fixed-effects model, and meta-analysis of the mean prealbumin values reported in 23 cohorts of unselected dialysis patients on a single modality (set 2; 9 PD cohorts, 14 HD cohorts; N = 12,256) using a mixed model. For comparison, the mean difference in serum albumin concentration between PD and HD also was estimated in sets 1 and 2 using the same methods.

RESULTS

In set 1, the mean prealbumin difference (PD-HD) in the individual cohorts ranged from 3.6 to 14.7 mg/dL (P < 0.05 in five cohorts), and the weighted mean difference was 5.4 mg/dL (95% CI, 3.8 to 7.0 mg/dL). In set 2, weighted mean prealbumin was 8.1 mg/dL (95% CI, 5.2 to 10.9 mg/dL) higher in PD than in HD in the entire data set, and 6.9 mg/dL (95% CI, 5.2 to 8.6 mg/dL) higher in a sensitivity analysis that excluded two outlying HD studies. By contrast, weighted mean serum albumin concentration was significantly lower in PD than in HD in both sets 1 and 2; the mean difference was 0.25 g/dL (95% CI, 0.14 to 0.36 g/dL) in set 1 and 0.28 g/dL (95% CI, 0.14 to 0.42 g/dL) in set 2.

CONCLUSIONS

Serum prealbumin level is approximately 6 mg/dL higher in PD than HD, perhaps due to the stimulation of hepatic synthesis by PD albumin loss, while serum albumin is approximately 0.3 g/dL lower in PD. Different reference ranges and clinical targets (such as, K/DOQI guidelines) are needed for PD and for HD.

Pathogenic effects of a high peritoneal transport rate

Recent studies have shown that patients with high peritoneal transport characteristics have substantially increased morbidity and mortality. This finding is counter-intuitive, since HTs will a priori achieve higher clearances. There are many possible causes: increased protein losses with consequent hypoalbuminemia; poor ultrafiltration capacity causing fluid retention, ventricular hypertrophy and hypertension; increased glucose absorption leading to anorexia, hyperinsulinism, and local AGE formation; and the development of an atherogenic lipid profile. While common pathogenic causes of high peritoneal transport and atherosclerosis have been hypothesized, it is more likely that CAPD as currently practiced is unsuitable for HTs, who should be switched to HD or NIPD. Renal and peritoneal clearances have different clinical effects and should be assessed separately. Current measures of dialysis adequacy, such as total Kt/V, do not therefore describe the patient's clinical situation accurately and are insufficient.

Peritoneal transport properties and dialysis dose affect growth and nutritional status in children on chronic peritoneal dialysis. Mid-European Pediatric Peritoneal Dialysis Study Group

To evaluate a possible effect of peritoneal transport properties and dialysis dose on the physical development of children on chronic peritoneal dialysis, a cohort of 51 children was prospectively followed for 18 mo. Peritoneal transport characteristics were assessed by serial peritoneal equilibration tests (PET), dialysis efficacy by dialysate and residual renal clearance measurements, and growth and nutritional status by the longitudinal changes (delta) of height SD score (SDS), body mass index (BMI) SDS, and serum albumin. delta height SDS was negatively correlated with the creatinine equilibration rate observed in the initial PET (r = -0.31, P < 0.05). Multiple regression analysis confirmed the negative effect of the high transporter state (partial r2 = 0.07), and disclosed an additional positive effect of dialytic C(Cr) (partial r2 = 0.11) and a weak negative effect of daily dialysate volume (partial r2 = 0.04) on delta height SDS. delta BMI SDS was strongly age-dependent (r = -0.48, P < 0.001); while relative body mass gradually increased below 4 yr of age, it remained stable in older children. Positive changes in BMI SDS were associated with rapid PET creatinine equilibration rates (univariate r = 0.35, P < 0.05) and/or large dialysate volumes (multivariate partial r2 = 0.11), suggesting a role of dialytic glucose uptake in the development of obesity. The change in serum albumin concentrations was positively correlated with dialysate volume (partial r2 = 0.14), and negatively affected by dialytic protein losses (partial r2 = 0.06). In conclusion, the peritoneal transporter state is a weak but significant determinant of growth and body mass gain in children on chronic peritoneal dialysis. Rapid small solute equilibration contributes to impaired growth but enhanced acquisition of body mass. Dialytic small solute clearance has a weak positive effect on statural growth independent of the transporter state, but does not affect body mass gain.