Is Kauppila method able to detect the progression of vascular calcification and predict cardiovascular events in patients undergoing hemodialysis?

BACKGROUND: Cardiovascular disease (CVD) is the main cause of death in hemodialysis (HD) patients. Vascular calcification (VC) is common in these patients. The main objective of this study was to evaluate if a semiquantitative radiographic method is able to detect VC progression in a prospective cohort of patients and predict the risk of cardiovascular events. Secondarily, we intend to identify predictors of the presence and progression of VC. METHODS: 49 patients undergoing HD for ≥ 90 days were included. At the beginning and after 12 months, the VC score (VCS) was determined by the Kauppila method, and clinical, nutritional, and laboratory markers were measured. The rates of fatal and nonfatal cardiovascular events were analyzed from months 13 to 24. RESULTS: Of 49 patients, 55.1% were male, 46.9% diabetic, and the mean age was 59.5 ± 14.4 years. At the beginning of the follow-up, 65.3% of the patients exhibited VC with a median VCS of 4 points. The intracellular water was negatively associated with VC and its intensity. The presence of VC was the only independent predictor of VC progression. Among patients with VC, 17 showed rapid progression, and 15 showed slow progression. The VCS was independently associated with rapid progression, while ΔCS (final VCS - initial VCS) was an independent predictor of cardiovascular events. CONCLUSIONS: The Kauppila method was able to detect VC, its progression, and predict cardiovascular events. These results suggest an association of VC with nutritional status.

Most consumed processed foods by patients on hemodialysis: Alert for phosphate-containing additives and the phosphate-to-protein ratio.

BACKGROUND AND AIMS: Hyperphosphatemia is common in patients with chronic kidney disease (CKD) stages IV and V because of decreased phosphorus excretion. Phosphatemia is closely related to dietary intake. Thus, a better understanding of sources of dietary phosphate consumption, absorption and restriction, particularly inorganic phosphate found in food additives, is key to prevent consequences of this complication. Our aims were to investigate the most commonly consumed processed foods by patients with CKD on hemodialysis, to analyze phosphate and protein content of these foods using chemical analysis and to compare these processed foods with fresh foods. METHODS: We performed a cross-sectional descriptive analytical study using food frequency questionnaires to rank the most consumed industrialized foods and beverages. Total phosphate content was determined by metavanadate colorimetry, and nitrogen content was determined by the Kjeldahl method. Protein amounts were estimated from nitrogen content. The phosphate-to-protein ratio (mg/g) was then calculated. Processed meat protein and phosphate content were compared with the nutritional composition of fresh foods using the Brazilian Food Composition Table. Phosphate measurement results were compared with data from the Food Composition Table - Support for Nutritional Decisions. An α level of 5% was considered significant. RESULTS: Food frequency questionnaires were performed on 100 patients (mean age, 59 ± 14 years; 57% male). Phosphate additives were mentioned on 70% of the product labels analyzed. Proteins with phosphate-containing additives provided approximately twice as much phosphate per gram of protein compared with that of fresh foods (p < 0.0001). CONCLUSIONS: Protein and phosphate content of processed foods are higher than those of fresh foods, as well as phosphate-to-protein ratio. A better understanding of phosphate content in foods, particularly processed foods, may contribute to better control of phosphatemia in patients with CKD.

Validity of malnutrition scores for predicting mortality in chronic hemodialysis patients.

PURPOSE: Malnutrition is a strong predictor of mortality in hemodialysis patients. Several scoring systems for evaluating nutritional status have been proposed. However, they rely on different sets of anthropometric and laboratory markers to make a diagnosis of malnutrition and assess its impact on prognosis. To validate them, nutritional scores should be compared with clinical outcomes. Thus, the purpose of this study was to assess malnutrition by three different nutrition scoring systems and determine which best predicts mortality in hemodialysis patients. METHODS: This prospective study included 106 adult chronic hemodialysis patients. Their mean age was 56.3 ± 14.9 years and mean body mass index 24.8 (21.8-28.9); 52 % were men and they had been on dialysis for 24 (5-55) months. Nutritional status was classified according to the diagnostic systems proposed by Wolfson et al. (Am J Clin Nutr 39(4):547-555, 1984), International Society of Renal Nutrition and Metabolism (ISRNM) (Fouque et al. in Kidney Int 73(4):391-398, 2008), and Beberashvili et al. (Nephrol Dial Transplant 25(8):2662-2671, 2010). During about 2 years of follow-up, mortality was assessed by Kaplan-Meier curves, log-rank, and Cox's models adjusted for diabetes, sex, C-reactive protein, time on dialysis, age, and fractional urea clearance. RESULTS: Twenty-three deaths (21.5 %) occurred during the study period. According to the systems of Wolfson, Beberashvili, and the ISRNM, 54, 32, and 20 % of patients, respectively, had malnutrition. Both univariate and multivariate analyses showed that the ISRNM system was the only one that predicted poorer survival (fourfold higher death risk) in malnourished patients. CONCLUSIONS: The scoring system proposed by the ISRNM most accurately identifies patients at higher risk of death.

Peritoneal dialysis-related peritonitis due to Staphylococcus aureus: a single-center experience over 15 years.

Peritonitis caused by Staphylococcus aureus is a serious complication of peritoneal dialysis (PD), which is associated with poor outcome and high PD failure rates. We reviewed the records of 62 S. aureus peritonitis episodes that occurred between 1996 and 2010 in the dialysis unit of a single university hospital and evaluated the host and bacterial factors influencing peritonitis outcome. Peritonitis incidence was calculated for three subsequent 5-year periods and compared using a Poisson regression model. The production of biofilm, enzymes, and toxins was evaluated. Oxacillin resistance was evaluated based on minimum inhibitory concentration and presence of the mecA gene. Logistic regression was used for the analysis of demographic, clinical, and microbiological factors influencing peritonitis outcome. Resolution and death rates were compared with 117 contemporary coagulase-negative staphylococcus (CoNS) episodes. The incidence of S. aureus peritonitis declined significantly over time from 0.13 in 1996-2000 to 0.04 episodes/patient/year in 2006-2010 (p = 0.03). The oxacillin resistance rate was 11.3%. Toxin and enzyme production was expressive, except for enterotoxin D. Biofilm production was positive in 88.7% of strains. The presence of the mecA gene was associated with a higher frequency of fever and abdominal pain. The logistic regression model showed that diabetes mellitus (p = 0.009) and ß-hemolysin production (p = 0.006) were independent predictors of non-resolution of infection. The probability of resolution was higher among patients aged 41 to 60 years than among those >60 years (p = 0.02). A trend to higher death rate was observed for S. aureus episodes (9.7%) compared to CoNS episodes (2.5%), (p = 0.08), whereas resolution rates were similar. Despite the decline in incidence, S. aureus peritonitis remains a serious complication of PD that is associated with a high death rate. The outcome of this infection is negatively influenced by host factors such as age and diabetes mellitus. In addition, ß-hemolysin production is predictive of non-resolution of infection, suggesting a pathogenic role of this factor in PD-related S. aureus peritonitis.

Peritonitis in recent years: clinical findings and predictors of treatment response of 170 episodes at a single Brazilian center.

PURPOSE: Peritonitis continues to be a major cause of dropout in peritoneal dialysis (PD) patients. Changes in the prevalence of peritonitis etiologies and an increase in the frequency of methicillin-resistant coagulase-negative staphylococci (CoNS) and Gram-negative species resistant to commonly used antibiotics have been reported. As a consequence, the current clinical presentation and patient outcome may differ from classical descriptions. The objectives of this study were to describe the clinical and microbiological characteristics of PD-related peritonitis episodes that occurred over a period of 6 years at a single Brazilian dialysis center and to identify predictors of outcome. METHODS: A total of 170 peritonitis episodes that occurred in 92 PD patients between January 2004 and December 2009 were reviewed. Multivariate analysis was used to identify demographic, clinical, and microbiological factors predicting endpoints (resolution and peritonitis-related death). Patients' characteristics and peritonitis incidence, etiology and outcomes were compared with a series of 232 episodes that occurred in the first 6 years (1995-2000) of the PD program at the same center. RESULTS: The overall peritonitis rate was 0.65 episodes/patient-year. Gram-positive cocci were identified in 79 (46.5%) episodes, whereas Gram-negative bacilli were isolated from 48 (28.2%). CoNS were the main Gram-positive species identified in 48 episodes. Of these, 56.3% were resistant to methicillin. Among Gram-negative species, amikacin resistance was observed in 60% of non-fermentative Gram-negative bacilli (NFGNB) and in only 3.6% of Enterobacteriaceae. The overall resolution rate was 44.1%. Oxacillin resistance and NFGNB etiology were strong predictors of non-resolution, whereas older age was the only predictor of death. Antibiotic protocols did not influence outcome. Comparison with the results obtained for the 1990-1995 period showed a lower peritonitis rate, a strong decline in the proportion of Staphylococcus aureus episodes, a significant increase in the frequency of oxacillin-resistant CoNS and amikacin-resistant NFGNB, and a significantly lower resolution and higher death rate. CONCLUSIONS: The current clinical characteristics and outcome suggest a greater severity of peritonitis episodes and higher risk of death, possibly due to bacterial resistance. Older age is a risk factor for death.

Geographic and educational factors and risk of the first peritonitis episode in Brazilian Peritoneal Dialysis study (BRAZPD) patients.

BACKGROUND AND OBJECTIVES: Peritonitis remains as the most frequent cause of peritoneal dialysis (PD) failure, impairing patient's outcome. No large multicenter study has addressed socioeconomic, educational, and geographic issues as peritonitis risk factors in countries with a large geographic area and diverse socioeconomic conditions, such as Brazil. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Incident PD patients recruited from 114 dialysis centers and reporting to BRAZPD, a multicenter observational study, from December 2004 through October 2007 were included. Clinical, dialysis-related, demographic, and socioeconomic variables were analyzed. Patients were followed up until their first peritonitis. Cox proportional model was used to determine independent factors associated with peritonitis. RESULTS: In a cumulative follow-up of 2032 patients during 22.026 patient-months, 474 (23.3%) presented a first peritonitis episode. In contrast to earlier findings, PD modality, previous hemodialysis, diabetes, gender, age, and family income were not risk predictors. Factors independently associated with increased hazard risk were lower educational level, non-white race, region where patients live, shorter distance from dialysis center, and lower number of patients per center. CONCLUSIONS: Educational level and geographic factors as well as race and center size are associated with risk for the first peritonitis, independent of socioeconomic status, PD modality, and comorbidities.

Desenvolvimento de um modelo experimental de hemodiálise em cães / Development of a dog model of hemodialysis

To develop a model of hemodialysis (HD), 18 healthy dogs, without a defined breed, males, weighing 7-14 kg, were studied. A double lumen catheter was inserted into the jugular vein for vascular access. HD sessions, totalizing 5 for each dog, were performed with a proportional HD machine, controlled isovolemic ultrafiltration, standard dialysis solution and bicarbonate buffer. Sodium profile and sodium heparin were used. During HD sessions the dogs were kept anesthetized (levomepromazine and propofol). Hematological and biochemistry data, blood gas analysis, systemic arterial blood pressure, and activated clotting time were evaluated. Serum biochemistry e blood gas analysis showed, respectively, sodium and SO2 maintenance. Systemic blood pressure kept sustained during HD sessions. It could be concluded that it was possible to develop a HD dog model that is a safe and viable technique to be used in chronic renal failure patients.

Com o objetivo de desenvolver um modelo de hemodiálise (HD) em cães, foram estudados 18 animais, sem raça definida, machos, clinicamente sadios, com peso corporal variando entre sete e 14 kg. O acesso vascular foi obtido através de implantação do cateter de duplo lúmen em veia jugular externa. As sessões de HD, em número de cinco por animal, com até três horas de duração, foram realizadas em hemodialisadora de sistema proporcional com ultrafiltração (UF) controlada, com solução dialisante padrão e tampão bicarbonato. A UF foi ajustada para HD isovolêmica, utilizou-se perfil de sódio, e para anticoagulação heparina sódica. Os animais foram mantidos anestesiados com cloridrato de levomepromazina e propofol. Foram avaliados dados hematológicos, bioquímicos, hemogasometria, pressão arterial sistêmica e tempo de coagulação ativado. Foi observada diminuição do número global de hemácias, volume globular, hemoglobina e leucócitos. Em relação aos exames bioquímicos, houve manutenção nos níveis de sódio sérico, e quanto à hemogasometria, a manutenção da SO2. A pressão arterial sistêmica manteve-se constante. Os resultados obtidos no presente trabalho permitiram concluir que foi possível o desenvolvimento do modelo proposto e mostrou que a HD em cães é um método viável e seguro, que poderá contribuir para o tratamento clínico da insuficiência renal nesta espécie.

The role of virulence factors in the outcome of staphylococcal peritonitis in CAPD patients.

BACKGROUND: Peritonitis continues to be the most frequent cause of peritoneal dialysis (PD) failure, with an important impact on patient mortality. Gram-positive cocci such as Staphylococcus epidermidis, other coagulase-negative staphylococci (CoNS), and Staphylococcus aureus are the most frequent etiological agents of PD-associated peritonitis worldwide. The objective of the present study was to compare peritonitis caused by S. aureus and CoNS and to evaluate the factors influencing outcome. METHODS: Records of 86 new episodes of staphylococcal peritonitis that occurred between 1996 and 2000 in the Dialysis unit of a single university hospital were studied (35 due to S. aureus, 24 to S. epidermidis and 27 to other CoNS). The production of slime, lipase, lecithinase, nuclease (DNAse), thermonuclease (TNAse), alpha- and beta-hemolysin, enterotoxins (SEA, SEB, SEC, SED) and toxic shock syndrome toxin-1 (TSST-1) was studied in S. aureus and CoNS. Antimicrobial susceptibility was evaluated based on the minimal inhibitory concentration determined by the E-test. Outcome predictors were evaluated by two logistic regression models. RESULTS: The oxacillin susceptibility rate was 85.7% for S. aureus, 41.6% for S. epidermidis, and 51.8% for other CoNS (p = 0.001). Production of toxins and enzymes, except for enterotoxin A and alpha-hemolysin, was associated with S. aureus episodes (p < 0.001), whereas slime production was positive in 23.5% of CoNS and 8.6% of S. aureus strains (p = 0.0047). The first model did not include enzymes and toxins due to their association with S. aureus. The odds of resolution were 9.5 times higher for S. epidermidis than for S. aureus (p = 0.02) episodes, and were similar for S. epidermidis and other CoNS (p = 0.8). The resolution odds were 68 times higher for non-slime producers (p = 0.001) and were not influenced by oxacillin resistance among vancomycin-treated cases (p = 0.89). In the second model, the resolution rate was similar for S. aureus and S. epidermidis (p = 0.70), and slime (p = 0.001) and alpha-hemolysin (p = 0.04) production were independent predictors of non-resolution. CONCLUSION: Bacterial species and virulence factors rather than antibiotic resistance influence the outcome of staphylococcal peritonitis.

Associations between nutritional markers and inflammation in hemodialysis patients.

The purpose of this study is to evaluate associations between clinical, laboratory, demographic, and nutritional markers with inflammatory state and malnutrition in hemodialysis (HD) patients. Fifty-two patients on regular HD were evaluated by clinical, demographic, laboratory, and nutritional parameters (food intake, anthropometric measurements, bioelectric impedance, subjective global assessment--SGA and appetite characteristics). Inflammation (serum C-reactive protein >or= 0.9 mg/dl) was present in 13 (25%) and malnutrition (SGA) in 16 (30.7%) patients. Body mass index (BMI), total lymphocytes count, and phase angle were negative and independently associated with malnutrition. Values of BMI >or= 25 kg/m2 were associated with diabetes, positively associated with adipose tissue percentage (BIA) and negatively associated with diastolic blood pressure. Phase angle was positively associated with hematocrit, total lymphocytes count and serum creatinine, and was negatively associated with age. A negative and independent association between muscle mass percentage (BIA) and inflammation was observed. These results suggested that inflammatory state induces muscle mass depletion, while high BMI is associated with diabetes and with lower diastolic blood pressure, a recognized cardiovascular risk factor in uremic patients. Phase angle and SGA were associated with traditional nutritional markers, reinforcing their validity for HD patients.

Peritonitis in Latin America.

Peritoneal dialysis has a high acceptance rate in Latin America, thus the knowledge concerning complication patterns is of great relevance. This work reviews Latin American data on peritonitis, the most serious complication of peritoneal dialysis. The incidence of peritonitis has been reduced over time, concomitantly with the incorporation of safer exchange systems and the use of prophylactic measurements. Today, rates lower than 1 episode per 24 patient-months are commonly reported. Furthermore, changes in causative organisms have been observed, with predominance of Staphylococcus aureus up through the mid-1990s, as well as increases in coagulase-negative staphylococcus and participation of gram negatives. However, the prevalence of S. aureus is still high, due possibly to climatic conditions and the elevated prevalence of carriers. Resolution rate varies from 55% to 78%, transfer to hemodialysis from 10.9% to 15.4%, and death in 3% to 9.9% of cases. Outcome is worse in S. aureus episodes compared to those with coagulase-negative staphylococcus, despite the higher percentage of oxacillin-resistant strains among the former. In general, despite socioeconomic or climatic conditions, our results are similar to those in developed countries, perhaps as a consequence of technological improvements and/or center expertise.