Hydration status according to impedance vectors and its association with clinical and biochemical outcomes and mortality in patients with chronic kidney disease.

Introduction: Background: the evaluation of hydration status and body composition in patients with kidney disease is vital for proper management, since overhydration is associated with cardiovascular complications. Patients with chronic kidney disease (CKD) begin to show perceptible alterations in hydration during the intermediate stages of the disease; however, there is little information regarding the evaluation of blood volume status through bioelectrical impedance vector analysis (BIVA) in this population. Objective: to determine the association between hydration status measured with BIVA and biochemical and clinical parameters and mortality in patients with stage G3a, G3b and G4 CKD. Material and methods: A cross-sectional study was conducted with patients with stage G3a, G3b and G4 CKD who underwent bioelectrical impedance analysis (BIA). The following biochemical and clinical parameters were determined: serum and urinary albumin, hematocrit, serum electrolytes and creatinine, estimated glomerular filtration rate (eGFR, using the CKD-EPI formula), 24-hour urine output and blood pressure. The clinical and biochemical variables were associated with the components of the BIA. According to the resistance/height (R/H) and reactance/height (Xc/H) values, the BIVA results were individually plotted on reference ellipses to identify patients with abnormal hydration states. The patients were classified by group according to hydration status and CKD stage z-scores, and differences in clinical, biochemical and BIA parameters were identified. Mortality was determined by hydration status. Results: a total of 138 subjects, 69 men and 69 women, were studied. An association was found between the BIVA components (R/H, Xc/H and phase angle (PA) and serum albumin (albumin and R/H, r = -0.38, p = 0.001; Xc, r = 0.59, p = 0.000; PA, r = 0.58, p ≤ 0.0010). When the biochemical and clinical parameters were compared by hydration status, significant differences were found in eGFR (p = 0.01), serum calcium (p ≤ 0.001), serum albumin (p ≤ 0.001), hemoglobin (p = 0.04), hematocrit, (p = 0.04) and mean arterial pressure (p = 0.03). The patients were followed for a median of 65.5 months (IQR: 53.0 to 207.0), and 12 (8.6 %) patients with CKD died. The Kaplan-Meier curves showed that patients with overhydration had a significantly higher risk of death than patients with normal hydration. Conclusions: there is an association between the hydration status evaluated by BIVA and clinical and biochemical variables. Patients with overhydration are significantly more likely to die than patients with normal hydration.

Introducción: Antecedentes: la evaluación del estado de hidratación y la composición corporal es imprescindible para los pacientes con enfermedad renal crónica en estadios intermedios, ya que en esta etapa inician con alteraciones hídricas perceptibles; sin embargo, existe poca información en dicha población sobre la evaluación del estado de volemia mediante el análisis de vectores de bioimpedancia eléctrica. Objetivo: asociar el estado de hidratación medido por BIVA con parámetros bioquímicos, clínicos y mortalidad en pacientes con ERC G3a G3b y G4 Material y métodos: estudio transversal en el cual se incluyó a pacientes con ERC en estadios G3a G3b y G4 a los que se les realizó un análisis de impedancia bioeléctrica y en los que se determinaron parámetros bioquímicos y clínicos. Las variables clínicas y bioquímicas se asociaron con los componentes de la IBE. Los valores de resistencia/estatura (R/H) y reactancia/estatura se graficaron individualmente sobre las elipses de referencia para identificar a pacientes con estados de hidratación anormales. Se ubicaron grupos según el estado de hidratación y estadio de ERC en z-score y se identificaron las diferencias de parámetros clínicos, bioquímicos y de IBE. Se determinó la mortalidad según el estado de hidratación. Resultados: se estudiaron 138 sujetos 69 hombres y 69 mujeres. Se encontró una asociación entre los componentes de los BIVA y albúmina sérica (albúmina y R/H, r = -0,38, p = 0,001; Xc, r = 0,59, p = 0,000; ángulo de fase, r = 0,58, p ≤ 0,00110). Al comparar los parámetros bioquímicos y clínicos por estado de hidratación se encontraron diferencias significativas en TFGe (p = 0,01), calcio sérico (p ≤ 0,001), albúmina sérica (p ≤ 0.001), hemoglobina (p = 0,04), hematocrito (p = 0.04) y presión arterial media (p = 0.03). Se identificó el fallecimiento de 12 (8,6 %) pacientes con ERC, con una mediana de seguimiento de 65,5 meses (RIC: 53,0 a 207,0). Las curvas de Kaplan-Meier mostraron que los pacientes con sobrehidratación tenían significativamente mayor riesgo de morir que los pacientes con normohidratación. Conclusiones: existe asociación entre el estado de hidratación evaluado por BIVA y variables clínicas y bioquímicas. Los pacientes con sobre hidratación son significativamente más propensos a morir que los pacientes con normohidratación.

[Development of a screening tool for a high sodium intake in an adult Mexican population]. / Desarrollo de una herramienta de tamizaje para consumo elevado de sodio en una población adulta mexicana.

BACKGROUND: twenty-four-hour urinary sodium excretion is the reference method to assess sodium intake; however, tools that can be more easily applied in the clinical and population setting are needed. OBJECTIVES: to develop and evaluate a self-administered high-sodium food frequency questionnaire (abbreviated to CFCA-S in Spanish) as a screening tool for high sodium intake in an adult Mexico City population. METHODS: a CFCA-S including 28 sodium-rich food categories and a scoring system were developed. The 75 percentile for the total score was tested as cut-off point to classify high sodium consumers at two different levels (≥ 2,000 and ≥ 3,000 mg/day) against 24-h urinary sodium excretion as reference method. RESULTS: ninety-five participants were included (median age: 39 [25th-75th percentiles: 26-46] years; men: 39 [41.1%]). A total score of 51.2 in the CFCA-S showed a sensitivity of 31.6% (95% confidence interval [CI]: 19.1-47.5), specificity of 78.9 (95% CI: 66.7-87.5), positive predictive value of 50% (95% CI: 31.4-68.6) and negative predictive value of 63.4% (95% CI: 51.8-73.6) to classify high-sodium consumers at a level of intake ≥ 3,000 mg/day. A total score ≥ 51.2 was significantly associated with a sodium intake ≥ 3,000 mg/day, observing an odds ratio of 3.12 (CI 95%: 1.03-9.44, p = 0.04), after adjusting by sex, age, and body mass index. CONCLUSIONS: the sodium CFCA-S developed in this study is a practical, feasible and useful tool to identify individuals at greater risk of having a high sodium intake.

INTRODUCCIÓN: la excreción de sodio en orina de 24 horas es el método de referencia para evaluar la ingesta de sodio; sin embargo, se  requieren herramientas que puedan aplicarse de manera más práctica tanto en el ámbito clínico como en el poblacional. OBJETIVOS: desarrollar y evaluar un cuestionario autoadministrable de frecuencia de consumo de alimentos ricos en sodio (CFCA-S) como herramienta de tamizaje para consumo elevado de sodio en una población adulta de la Ciudad de México. MÉTODOS: se desarrolló un CFCA-S con 28 categorías de alimentos ricos en sodio y su sistema de puntuación respectivo. El percentil 75 del puntaje total del CFCA-S se probó como punto de corte para clasificar a las personas con alto consumo de sodio a dos niveles (≥ 2.000 y ≥ 3.000 mg/día), considerando la excreción urinaria de sodio en 24 horas como método de referencia. RESULTADOS: se incluyeron 95 participantes (mediana de edad: 39 [percentiles 25-75: 26-46] años; hombres: 39 [41,1%]). Un puntaje total de 51,2 en el CFCA-S mostró una sensibilidad del 31,6% (intervalo de confianza [IC] 95%: 19,1-47,5), una especificidad del 78,9% (IC 95%: 66,7-87,5), valor predictivo positivo del 50% (IC 95%: 31,4-68,6) y valor predictivo negativo del 63,4% (IC 95%: 51,8-73,6), para clasificar a las personas con consumo de sodio ≥ 3.000 mg/día. Un puntaje ≥ 51,2 se asoció significativamente con una ingesta de sodio ≥ 3.000 mg/día, resultando en una razón de momios de 3,12 (IC 95%: 1,03-9,44, p = 0,04), después de ajustar por sexo, edad e índice de masa corporal (IMC). CONCLUSIONES: el CFCA-S es una herramienta práctica, factible de aplicarse y útil para identificar a personas en riesgo de tener un consumo elevado de sodio.

Anthropometric variables and physical activity as predictors of cardiac cachexia.

BACKGROUND: This study explored the frequency of cardiac cachexia in Mexican patients, the role of anthropometric variables as predictors of its development and its association with food intake and physical activity. METHODS: Seventy three patients with systolic heart failure were included in the study. Cardiac cachexia was defined as weight loss of >6.0% in 6 months. Anthropometric data, physical activity and dietary intake were evaluated by a 3-day questionnaire at the beginning of the study and 6 months later. RESULTS: After 6 months of follow up, 14 (19%) patients developed cachexia with a mean weight loss of 12.1+/-3.4%. Significant decrease in the anthropometric variables were observed in patients which developed cachexia except in the waist to hip ratio, which increased in these patients due to bigger diminish of hip circumference than in the waist one. The subjects which developed cachexia had significant less physical activity after 6 months (-6.9%) in comparison with the non cachexic group. Reported energy intake did no differ among groups. Patients with cardiac cachexia showed greater prevalence of obesity and overweight, a high body fat percentage and a low arm circumference. CONCLUSIONS: Cardiac cachexia development was not related with low energy intake or increase in the total energy expenditure (explained by the physical activity). The only variable related to cachexia development was lower physical activity.