Metabolic acidosis and its association with nutritional status in hemodialysis.

INTRODUCTION: Metabolic acidosis is a common problem in dialysis patients and plays an important role in the pathogenesis of protein-energy malnutrition in these patients. OBJECTIVES: To assess the prevalence of metabolic acidosis in hemodialysis and search their association with nutritional status. METHODS: A cross-sectional study was performed in hemodialysis patients at a single center. Nutritional status was assessed by anthropometric, biochemical and multifrequency bioelectrical impedance analysis. Metabolic acidosis was defined as serum bicarbonate (BIC) < 22 mEq/L and patients were divided into 3 groups according to BIC (< 15.15 to 21.9 and ≥ 22). The association between BIC and continuous variables was investigated using the Kruskal Wallis test. The linear correlation between BIC and the variables of the study was also tested. RESULTS: We studied 95 patients, 59% male, mean age 52.3 years. The prevalence of metabolic acidosis was 94.7%. BMI, interdialytic weight gain and PTH were significantly different among the 3 groups of BIC. The BIC was negatively correlated with urea, phosphorus and interdialytic weight gain. There was no significant correlation with albumin, phase angle and lean body mass index. CONCLUSION: The prevalence of metabolic acidosis was high in this population, and a lower BIC correlated with higher levels of urea, PTH, phosphorus, interdialytic weight gain and lower BMI. The evaluation of acid-basic status should be routinely implemented in dialysis patients by considering the negative effects of acidosis on the nutritional status, inflammation and bone disease.

Acidose metabólica e sua associação com o estado nutricional em hemodiálise / Metabolic acidosis and its association with nutritional status in hemodialysis

Resumo Introdução: A acidose metabólica é frequente em pacientes dialíticos e participa na patogênese da desnutrição energético-proteica destes pacientes. Objetivos: Avaliar a prevalência de acidose metabólica em hemodiálise e pesquisar sua associação com o estado nutricional. Métodos: Foi realizado um estudo transversal em pacientes em hemodiálise em um único centro. O estado nutricional foi avaliado por meio de indicadores antropométricos, bioquímicos e da bioimpedância elétrica multifrequencial. Acidose metabólica foi definida como bicarbonato sérico (BIC) < 22 mEq/L, e os pacientes foram divididos em 3 grupos, segundo o BIC (< 15,15-21,9 e ≥ 22). A associação entre o BIC e as variáveis contínuas foi pesquisada com o teste de Kruskal Wallis. A correlação linear entre o BIC e as variáveis do estudo também foi testada. Resultados: Foram avaliados 95 pacientes, 59% masculinos, idade média 52,3 anos. A prevalência de acidose metabólica foi 94,7%. O IMC, o ganho de peso interdialítico e o PTH foram significativamente diferentes entre os 3 grupos de BIC. O BIC apresentou correlação negativa significativa com ureia, fósforo e ganho de peso interdialítico. Não houve correlação significativa com albumina, ângulo de fase e índice de massa magra. Conclusão: A prevalência de acidose metabólica foi elevada na população em estudo, e um BIC mais baixo correlacionou-se com valores maiores de ureia, PTH, fósforo, ganho de peso interdialítico e menores de IMC. A avaliação do estado metabólico em hemodiálise deve ser implementada rotineiramente, considerando-se os efeitos negativos da acidose no estado nutricional, inflamatório e na doença óssea.

Abstract Introduction: Metabolic acidosis is a common problem in dialysis patients and plays an important role in the pathogenesis of protein-energy malnutrition in these patients. Objectives: To assess the prevalence of metabolic acidosis in hemodialysis and search their association with nutritional status. Methods: A cross-sectional study was performed in hemodialysis patients at a single center. Nutritional status was assessed by anthropometric, biochemical and multifrequency bioelectrical impedance analysis. Metabolic acidosis was defined as serum bicarbonate (BIC) < 22 mEq/L and patients were divided into 3 groups according to BIC (< 15.15 to 21.9 and ≥ 22). The association between BIC and continuous variables was investigated using the Kruskal Wallis test. The linear correlation between BIC and the variables of the study was also tested. Results: We studied 95 patients, 59% male, mean age 52.3 years. The prevalence of metabolic acidosis was 94.7%. BMI, interdialytic weight gain and PTH were significantly different among the 3 groups of BIC. The BIC was negatively correlated with urea, phosphorus and interdialytic weight gain. There was no significant correlation with albumin, phase angle and lean body mass index. Conclusion: The prevalence of metabolic acidosis was high in this population, and a lower BIC correlated with higher levels of urea, PTH, phosphorus, interdialytic weight gain and lower BMI. The evaluation of acid-basic status should be routinely implemented in dialysis patients by considering the negative effects of acidosis on the nutritional status, inflammation and bone disease.