Silvia Carreira Ribeiro

Predictive Value of Malnutrition Markers for Mortality in Peritoneal Dialysis Patients

INTRODUCTION Alterations in nutritional status have been described as important predictors of mortality in patients with chronic kidney disease (CKD). However, the association between multiple markers for nutritional status and the mortality rates of patients with CKD on peritoneal dialysis (PD) has not yet been illustrated in previously published data, particularly by using the new definition of protein energy wasting (PEW). OBJECTIVE To evaluate the predictive value of malnutrition markers for mortality rates, on the basis of the PEW definition, of PD patients. MATERIALS AND METHODS At the start of PD treatment, the nutritional status of 199 patients (mean age, 56 ± 13.3 years; 53% females) was evaluated. Body mass index (BMI), arm circumference, mid-arm muscle circumference, protein and caloric intake (by using a 3-day food record), and serum albumin were all recorded, as well as a subjective global assessment (SGA) and presence of PEW. Cut-off points were defined on the basis of the consensus of the International Society for Renal Nutrition and Metabolism (albumin, <3.8 g/dL; BMI, <23 kg/m(2); mid-arm muscle circumference, >10% in comparison with the 50th percentile for the reference population; protein intake, <0.8 g/kg/daily; caloric intake, <25 kcal/kg/daily). The data were obtained retrospectively between the years 2001 and 2008 on the basis of routine nutritional evaluation. Patients were monitored for fatal events from all possible causes. RESULT The mean BMI for the population was 26.6 ± 5.0 kg/m(2). A median protein intake of 0.94 (0.18 to 4.57) g/kg/daily was reported and 60.3% of the patients reported a protein intake of <0.8 g/kg/daily. With respect to caloric intake, 38.7% of the patients consumed <25 kcal/kg/daily. A median of 3.5 (1.4 to 5.3) g/dL for serum albumin was observed and 29.3% of the patients presented values of <3.8 g/dL. PEW was diagnosed in 17.5% of patients. In the univariate model, being of age >65 years (P = .002), cardiovascular disease (P < .001), diabetes mellitus (P = .02), SGA (P = .02), and albumin (P = .002), were all significant markers for mortality. The presence of patients aged >65 years (P = .02), with diabetes mellitus (P = .057), cardiovascular disease (P = .005), and albumin were considered as independent factors for mortality in this study. CONCLUSION SGA, albumin, and PEW were the only nutritional markers found to be associated with mortality in this cohort of PD patients. In the multivariate analysis, after adjusting for classic mortality risk factors, only patients with hypoalbuminemia were found to be at a high risk for mortality at follow-up. These results may be limited by the number of observations and a necessity for confirmation in larger prospective studies.

Low Serum Potassium Levels Increase the Infectious-Caused Mortality in Peritoneal Dialysis Patients: A Propensity-Matched Score Study

Background and Objectives Hypokalemia has been consistently associated with high mortality rate in peritoneal dialysis. However, studies investigating if hypokalemia is acting as a surrogate marker of comorbidities or has a direct effect in the risk for mortality have not been studied. Thus, the aim of this study was to analyze the effect of hypokalemia on overall and cause-specific mortality. Design, Setting, Participants and Measurements This is an analysis of BRAZPD II, a nationwide prospective cohort study. All patients on PD for longer than 90 days with measured serum potassium levels were used to verify the association of hypokalemia with overall and cause-specific mortality using a propensity match score to reduce selection bias. In addition, competing risks were also taken into account for the analysis of cause-specific mortality. Results There was a U-shaped relationship between time-averaged serum potassium and all-cause mortality of PD patients. Cardiovascular disease was the main cause of death in the normokalemic group with 133 events (41.8%) followed by PD-non related infections, n=105 (33.0%). Hypokalemia was associated with a 49% increased risk for CV mortality after adjustments for covariates and the presence of competing risks (SHR 1.49; CI95% 1.01-2.21). In contrast, in the group of patients with K <3.5mEq/L, PD-non related infections were the main cause of death with 43 events (44.3%) followed by cardiovascular disease (n=36; 37.1%). For PD-non related infections the SHR was 2.19 (CI95% 1.52-3.14) while for peritonitis was SHR 1.09 (CI95% 0.47-2.49). Conclusions Hypokalemia had a significant impact on overall, cardiovascular and infectious mortality even after adjustments for competing risks. The causative nature of this association suggested by our study raises the need for intervention studies looking at the effect of potassium supplementation on clinical outcomes of PD patients.

Comparative analysis of lipid and glucose metabolism biomarkers in non-diabetic hemodialysis and peritoneal dialysis patients

OBJECTIVE To investigate and compare glucose and lipid metabolism biomarkers in non-diabetic peritoneal dialysis and hemodialysis patients. METHODS The study followed a prospective and cross-sectional design. PARTICIPANTS Participants included all prevalent end-stage renal disease patients under renal replacement therapy treated in a university-based clinic. INTERVENTIONS There were no interventions. MAIN OUTCOMES MEASURES Blood samples were taken after 8 hours of fasting. Insulin serum levels were determined by chemiluminescence. Insulin resistance were assessed by the insulin sensitivity check index (QUICKI) determined as follow: 1/[log(Io) + log(Go)], where Io is the fasting insulin, and Go is the fasting glucose. HOMA index was also measured: (FPG × FPI)/22.5; FPG = fasting plasma glucose (mmol/L); FPI = fasting plasma insulin (mU/mL). The others biochemical exams were measured utilizing the routine tests. RESULTS We screened 154 patients (80 on hemodialysis and 74 on peritoneal dialysis). Seventy-four diabetic patients were excluded. Of the remaining 80 patients (55% males, mean age 52 ± 15 years), 35 were on peritoneal dialysis and 45 on hemodialysis. Fasting glucose of peritoneal dialysis patients compared to hemodialysis patients were 5.0 ± 0.14 versus 4,58 ± 0.14 mmol/L, p<0.05; glycated hemoglobin 5.9 ± 0.1 versus 5.5 ± 0.1%, p < 0.05; total cholesterol 5.06 ± 0.19 versus 3.39 ± 0.20 mmol/L, p < 0.01; LDL-c 2.93 ± 0.17 versus 1.60 ± 0.17 mmol/L, p < 0.01; and index HOMA 3.27 versus 1,68, p < 0,05. Importantly, all variables were adjusted for age, gender, dialysis vintage, calcium-phosphorus product, albumin and C-reactive protein levels. CONCLUSION We observed a worst profile of lipid and glucose metabolism biomarkers in peritoneal dialysis patients (lower insulin sensitivity and higher fasting glucose, HbA1c, total cholesterol and LDL-c) when compared to hemodialysis, potentially due to the glucose-based dialysis solutions utilized in the peritoneal dialysis population.

Low-calcium peritoneal dialysis solution is effective in bringing PTH levels to the range recommended by current guidelines in patients with PTH levels < 150 pg/dL

INTRODUCTION/OBJECTIVE Adinamic bone disease (ABD) is a common finding in peritoneal dialysis (PD) and is associated with higher risk of developing cardiovascular and bone disease. Data from BRAZPD indicates that 3.5 mEq/L calcium PD solutions represents the majority of PD prescriptions in the country. A positive calcium balance can contribute to ABD development. Currently guidelines suggest that PTH-i levels in end stage renal disease should be kept from 150-300 pg/mL. The purpose of this study is to evaluate 6 month PTH-i response after conversion to 2.5 mEq/L calcium PD solution in patients with baseline PTH-i levels < 150 pg/mL. METHODS Prospective, observational study of all prevalent patients (at least 90 days on therapy) on PD of a single Brazilian center from January 2008 to May 2009. Inclusion criteria (1) be in use of a PD solution with 3.5 mEq/L of calcium; (2) baseline PTH levels < 150 pg/ mL. According to clinical practice patients could be switched to PD solutions with 2.5 mEq/L of calcium. RESULTS 35 patients (age 62 ± 17 years) were included. Of these 22 were converted to 2.5 mEq/L calcium solutions. Diabetic nephropathy (36%) was the main cause of renal disease followed by nephrosclerosis (25%) and glomerulonephritis (14%). Converted group presented a greater increase in PTH levels when compared with the control group (Δ194 pg/dL versus Δ 92/dL; p < 0,05). Among patients switched to low calcium solution, 41% reached the target values (PTH 150-300 pg/mL) compared to 14% whose remain with normal calcium solutions (p < 0.05). There were no differences between groups regarding calcium, phosphorus and alkaline phosphatase. CONCLUSION In patients with PTH < 150 pg/mL conversion to low calcium solutions (2.5 mEq/L) appears to be a simple and effective strategy to bring PTH levels to the range determined by current guidelines when compared with 3.5 mEq/L calcium PD solutions.

Racial and social disparities in the access to automated peritoneal dialysis - results of a national PD cohort

The prevalence of patients on automated peritoneal dialysis (APD) is increasing worldwide and may be guided by clinical characteristics, financial issues and patient option. Whether socioeconomic factors at the patient level may influence the decision for the initial peritoneal dialysis (PD) modality is unknown. This is a prospective cohort study. The primary outcome of interest was the probability to start PD on APD. The inclusion criteria were adult patients incident in PD. Exclusion criteria were missing data for either race or initial PD modality. We used a mixed-model analysis clustering patients according to their PD center and region of the country. We included 3,901 patients of which 1,819 (46.6%) had APD as their first modality. We found a significant disparity for race and educational level with African American patients less likely to start on APD (Odds ratio 0.74 CI95% 0.58–0.94) compared to Whites whilst those with greater educational levels were more likely to start on APD (Odds ratio 3.70, CI95% 2.25–6.09) compared to illiterate patients. Limiting the use of APD in disadvantaged population may be unethical. Demographics and socioeconomic status should not be necessarily part of the decision-making process of PD modality choice.

Impact of Renin-Angiotensin Aldosterone System Inhibition on Serum Potassium Levels among Peritoneal Dialysis Patients

Background: The chronic use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blocker has been associated with hyperkalemia in patients with reduced renal function even after the initiation of hemodialysis. Whether such medications may cause a similar effect in peritoneal dialysis patients is not well established. So, the aim of our study was to analyze the impact of renin-angiotensin-aldosterone inhibitors on the serum levels of potassium in a national cohort of peritoneal dialysis patients. Method: A prospective, observational, nationwide cohort study was conducted. We identified all incident patients on peritoneal dialysis that had angiotensin converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB) prescribed for at least 3 months and a similar period of time without these medications. Patients were divided into 4 groups: Groups I and III correspond to patients using, respectively, an ACEi or ARB and then got the drug suspended; Groups II and IV started peritoneal dialysis without the use of any renin-angiotensin aldosterone system inhibitor and then got, respectively, an ACEi or ARB introduced. Changes in potassium serum levels were compared using 2 statistical approaches: (1) the non-parametric Wilcoxon test for repeated measures and (2) a crossover analysis. Results: Mean potassium serum levels at the first phase of the study for Groups I, II, III, and IV were, respectively, 4.46 ± 0.79, 4.33 ± 0.78, 4.41 ± 0.63, and 4.44 ± 0.56. Changes in mean potassium serum levels for Groups I, II, III, and IV were -0.10 ± 0.60, 0.02 ± 0.56, -0.06 ± 0.46, and 0.03 ± 0.50, respectively. Conclusion: The use of ACEi and ARB was not associated with a greater risk for hyperkalemia in stable peritoneal dialysis patients independently of residual renal function.

Dialysis modality and quality of life

Qualidade de vida (QV) pode ser definida nao por um estado de ausencia de doenca ou qualquer outra enfermidade, mas por uma sensacao de bem-estar fisico, mental e social. Ela se encontra consideravelmen-te alterada nos pacientes com doenca renal cronica em dialise (DRC-5d) e os motivos desse comprometimento sao os mais diver-sos, incluindo, mas nao se restringindo, a presenca de sintomas uremicos como nau-seas e vomitos, desnutricao, cansaco, impo-sicao de severas restricoes dieteticas e a pre-senca de outras importantes comorbidades como hipertensao arterial e diabetes.O aumento na prevalencia de pacientes em dialise, aliado a preocupacao em ofere-cer o melhor tratamento possivel, torna os estudos comparando as modalidades de te-rapia renal substitutiva imprescindiveis. Ha mais de 20 anos existem relatos comparando hemodialise intermitente (HD) e dialise pe-ritoneal (DP). Essas comparacoes tomaram particular importância quando diferentes estudos reportaram que nao existe diferenca nas taxas de mortalidade entre as modalida-des, fazendo com que um potencial beneficio na qualidade de vida pudesse direcionar a escolha da modalidade de dialise inicial.