Validação concorrente dos métodos compostos de avaliação do estado nutricional em pacientes idosos com doença renal crônica em hemodiálise

Abstract

The nutritional status of patients on hemodyalisis (HD) deserves attention, due to conditions inherent to Chronic Kidney Disease (CKD) and aging. Nutritional status can be assessed by objective and subjective methods. Among the subjective methods, the composite questionnaires of nutritional status have gained importance. The subjective global assessment (SGA) and malnutrition inflammation score (MIS) comprise the more applied compounds questionnaires to assess the nutritional status of patients with CKD in HD. In healthy elderly subjects, the mini-nutritional assessment short form (MNA-SF) has been recommended as a screening method for identifying individuals at nutritional risk. However, there is still no consensus on the best method to apply. Thus, the aim of this study is to perform the concurrent validity of SGA, MIS and MNA-SF with objective measurements of nutritional status, as well as to assess the prevalence of protein-energy wasting (PEW) by these 3 questionnaires. In a sample of 101 elderly (age> 60 years) on HD for at least 3 months, three questionnaires (SGA, MIS and MNA-SF) were applied. For concurrent validity, we used objective measures of anthropometry, bioelectrical impedance (BIA), handgrip strength (HGS) assessment, protein equivalent of nitrogen appearance (PNA) in addition to serum creatinine and albumin. The statistical package SPSS (version 17.0) was used for statistical analysis, considering p <0.05 for statistical significance. Considering the total sample, 76% of the patients were male, mean age 70.8 ± 7.0 years (mean ± SD), on HD for 2.25 (1.04, 5.32) years (median and interquartile limits) and body mass index (BMI) of 25.5 ± 4.9 kg/m2. By SGA, 40% of the patients were classified as well nourished, 61% with mild to moderate malnutrition and no patients as severe malnutrition. By MIS, 18% were well nourished, 55% with mild to moderate malnutrition, and 27% with severe malnutrition. By MNA-SF, 40% were well nourished, 60% at risk of malnutrition, and 1% classified as malnourished. Regarding the concurrent validity with objective measures, for SGA, 5 parameters were significantly higher in the group of well nourished patients than in those with mild to moderate malnutrition. For MIS, 6 were the objective parameters of nutritional status that differed significantly between the group of well nourished and severely malnourished patients. For the MNA-SF, 3 parameters differed between groups of nutritional status. The agreement between the methods showed that the best agreement was observed between SGA and MIS (Kappa = 0.31, P <0.001), followed by SGA and MNA-SF (Kappa = 0.27, P <0.001), and with the worst agreement, MNA-SF and MIS (Kappa = 0.09, P = 0:08). With these findings, it can be concluded that a wide variation in the prevalence of PEW was found depending on the questionnaire applied to assess the nutritional status. The concurrent validity of MIS and SGA were satisfactory for identifying the PEW.However, as we have no gold standard, we can not infere over which questionnaire is the most reliable one. This study suggests that the MIS and SGA can be applied to assess the nutritional status of elderly patients on HD, but should be complemented by other nutritional markers in order to assess more accurately the nutritional status of these patients