Clinical and nutritional factors associated with dialysis initiation and mortality in chronic kidney disease

BACKGROUND: Chronic kidney disease is worldwide recognized as a public health problem due to high rates of morbidity and mortality. At the end stage of the disease, which the glomerular filtration rate is equal or less than15 ml/min/1.73 m2, dialysis initiation is usually indicated. In the absence of a consensus on the best time of beginning, the aim of this study was to identify clinical and nutritional factors associated with clinical outcomes with the start of dialysis and death. METHODS: In a prospective cohort of 82 patients, clinical (underlying renal disease, renal survival time, systolic and diastolic blood pressure, estimated glomerular filtration rate) and nutritional data (protein intake, anthropometry, bioelectrical impedance test, and strength handgrip) were collected. We used mean and standard deviation ormedian and association of the variables with the outcome entry into dialysis or death, and a Cox regression model was applied. Statistical significance wasp< 0.05.RESULTS: Fifty-eight patients were included in group 1­G1 (without dialysis)­and 24 patients in group 2­G2(dialysis). The groups were different in blood urea nitrogen (p= <0.001), serum creatinine (p= 0.003), estimated glomerular filtration rate (p= 0.002), and serum phosphorus (p= 0.002). After multivariate analysis, only serumalbumin (HR 0.342,p= 0.004) and glomerular filtration rate (HR 0.001,p= 0.001) were associated with entry into dialysis and death. CONCLUSIONS: We concluded that lower levels of serum albumin and glomerular filtration rate values are associated with entry into dialysis or death.

Evaluation of energy metabolism in septic patients with and without AKI

BACKGROUND: The determination of resting energy expenditure (REE) in critically ill patients could prevent complications such as hypo- and hyper alimentation. This study aims to describe the REE in septic patients with and without acute kidney injury (AKI) and compare the REE estimated by the Harris-Benedict equation (HB) with the REE measured by indirect calorimetry (IC). METHODS: Prospective and observational study was performed. Septic patients older than 18 years, undergoing mechanical ventilation, with or without AKI defined by KDIGO criteria, and admitted to the Intensive Care Unit of University Hospital from Brazil were included. The REE was estimated by HB equation and measured by the IC within72 h after the diagnosis of sepsis and 7 days after the initial measure. RESULTS:Sixty-eight patients were evaluated, age was 62.5 ± 16.6 years, 64.7% were male, 63.2% had AKI, and SOFA was9.8 ± 2.35. The measured REE was 1857.5 ± 685.32 kcal, while the estimated REE was 1514.8 ± 356.72 kcal, with adequacy of 123.5 ± 43%. Septic patients without AKI (n= 25) and with AKI (n= 43) had measured REE statistically higher than the estimated one (1855.0 (1631.75­2052.75) vs. 1551.0 kcal (1349.0­1719.25),p= 0.007 and 1868.0(1219.5­2364.75) vs. 1388.0 kcal (1254.0­1665.5),p= 0.026, respectively). There was no significant difference between the two groups (with and without AKI) in measured and estimated REE (p= 0.63 and 0.64, respectively). There was no significant difference in evolutional REE (1845.95 ± 658.27 kcal vs. 1809.54 ± 755.08 kcal, p=0.86).CONCLUSIONS: The REE measured by IC was significantly higher than that estimated by HB equation in both septic with and without AKI. There was no significant difference in REE between the septic patients with and without AKI, suggesting that AKI does not influence the energy metabolism of septic patients.

Daily variability of resting energy expenditure in acute kidney injury patients on dialysis / Variabilidade diária do gasto energético de repouso em pacientes com lesão renal aguda em tratamento dialítico

Abstract Introduction: It is needed for nutrition prescription correct estimate of resting energy expenditure (REE), which is a challenge given the possible daily variation in critically ill patients with acute kidney injury (AKI). Objective: To evaluate the daily variability of REE measured by indirect calorimetry (IC) in patients with AKI and dialysis indication and identify clinical variables associated with REE. Methods: The REE was measured on the time of dialysis indication and the subsequent four days. We also evaluated parameters that can influence the REE. The daily differences were analyzed by generalized linear model for repeated measures. We also used Spearman correlation and multiple linear regression. Results: There were 301 IC measurements in 114 patients, mean age of 60.65 ± 16.9 years and 68.4% were male. The average REE was 2081 ± 645 kcal, rising on day 5 (2270 ± 556 kcal) compared to the days 2 and 3 (2022 ± 754; 2022 ± 660 kcal, respectively, p = 0,04). When normalized to weight, there was no significant difference in REE (kcal/kg/day) during follow-up. REE was positively correlated with total leukocyte count, C-reactive protein, minute volume (MV), fraction of inspired oxygen (FiO2) urea nitrogen appearance (UNA), weight and height and inversely with age. After multiple regression, MV, FiO2, weight and age are correlated independently with REE. Conclusion: Patients with AKI have REE stable. The REE was associated independently with FiO2, MV, body weight and age. Thus, ventilatory parameters should be evaluated each day for the necessary dietary changes may be made.

Resumo Introdução: É imprescindível a correta estimativa do gasto energético de repouso (GER), que pode apresentar considerável variação diária no paciente crítico com lesão renal aguda (LRA). Objetivo: Avaliar a variabilidade diária do GER medido por calorimetria indireta (CI) em pacientes com LRA e indicação dialítica e identificar as variáveis clínicas associadas ao GER. Métodos: O GER foi medido no dia da indicação do procedimento dialítico e nos quatro dias subsequentes. Também foram avaliados parâmetros que podem influenciar o GER. As diferenças diárias foram analisadas pelo modelo linear generalizado para medidas repetidas, com distribuição gama, além da correlação de Spearman e regressão linear múltipla. Resultados: Foram 301 medidas de CI realizadas em 114 pacientes, com idade de 60,65 ± 16,9 anos e 68,4% do sexo masculino. O GER médio foi de 2081 ± 645 Kcal, com aumento no dia 5 (2270 ± 556 Kcal), quando comparado aos dias 2 e 3 (2022 ± 754; 2022 ± 660 kcal, respectivamente, p = 0,04); quando normalizado para peso, não houve diferença significante no GER (kcal/kg/dia) durante o acompanhamento. GER correlacionou-se positivamente com temperatura corporal, contagem total de leucócitos, proteína C reativa, volume minuto (VM), fração inspirada de oxigênio (FiO2), aparecimento de nitrogênio ureico (UNA), peso corporal e estatura e inversamente com idade. Após a regressão linear múltipla, somente VM, FiO2 e peso corporal e idade se correlacionaram independentemente. Conclusão: Pacientes com LRA dialíticos apresentam GER estável. O GER foi associado independentemente com FiO2, VM, peso e idade. Assim, requisitos ventilatórios precisam ser avaliados diariamente para que alterações necessárias na prescrição dietética sejam feitas.

Resting energy expenditure in critically ill patients: Evaluation methods and clinical applications / Gasto energético de repouso em pacientes críticos: métodos de avaliação e aplicações clínicas

Summary Patients on intensive care present systemic, metabolic, and hormonal alterations that may adversely affect their nutritional condition and lead to fast and important depletion of lean mass and malnutrition. Several factors and medical conditions can influence the energy expenditure (EE) of critically ill patients, such as age, gender, surgery, serious infections, medications, ventilation modality, and organ dysfunction. Clinical conditions that can present with EE change include acute kidney injury, a complex disorder commonly seen in critically ill patients with manifestations that can range from minimum elevations in serum creatinine to renal failure requiring dialysis. The nutritional needs of this population are therefore complex, and determining the resting energy expenditure is essential to adjust the nutritional supply and to plan a proper diet, ensuring that energy requirements are met and avoiding complications associated with overfeeding and underfeeding. Several evaluation methods of EE in this population have been described, but all of them have limitations. Such methods include direct calorimetry, doubly labeled water, indirect calorimetry (IC), various predictive equations, and, more recently, the rule of thumb (kcal/kg of body weight). Currently, IC is considered the gold standard.

Resumo Os pacientes em cuidados intensivos apresentam alterações sistêmicas, metabólicas e hormonais, que podem afetar adversamente a condição nutricional e levar à rápida e importante depleção da massa magra e desnutrição. Vários fatores e situações clínicas podem exercer influência sobre o gasto energético (GE) de pacientes críticos, como idade, sexo, cirurgias, infecções graves, medicamentos, modalidade ventilatória e disfunção de órgãos. Dentre as condições clínicas que podem cursar com alteração do GE, encontra-se a lesão renal aguda (LRA), distúrbio complexo comumente observado em pacientes críticos, com manifestações que podem variar de mínimas elevações na creatinina sérica até insuficiência renal com necessidade dialítica. Dessa forma, essa população crítica apresenta necessidades nutricionais complexas e a determinação do gasto energético de repouso (GER) torna-se essencial para o ajuste da oferta nutricional e para o planejamento de uma nutrição adequada, assegurando que as necessidades energéticas sejam atingidas e evitando as complicações associadas à hiper ou hipoalimentação. Diversos métodos de avaliação do GE nessa população foram descritos, mas todos apresentam limitações. Dentre eles, destacam-se a calorimetria direta, a água duplamente marcada, a calorimetria indireta (CI), diversas equações preditivas e, mais atualmente, a regra de bolso (kcal/kg de peso). Atualmente, a CI é eleita o método padrão-ouro.