EVALUATION OF THE ROYAL FREE HOSPITAL CIRRHOSIS GLOMERULAR FILTRATION RATE FORMULA IN HISPANIC PATIENTS WITH CIRRHOSIS: AN EXTERNAL VALIDATION.

BACKGROUND AND AIMS: Glomerular filtration rate (GFR) measurement in patients with liver cirrhosis (LC) is the ideal method for adequate evaluation of kidney function. However, it is invasive, costly, and not widely accessible. Moreover, GFR estimation in patients with cirrhosis has been inaccurate. The aim of the present study was to evaluate and validate the recently described Royal Free Hospital (RFH) formula in a Hispanic cohort of patients with LC and compare it with other formulas, including the CKD-EPI cystatin C equation. METHODS: GFR was measured through the renal clearance of Tc-99m DTPA; it was cross-sectionally evaluated and compared with GFRs that were estimated utilizing the following formulas: RFH, Cockcroft-Gault, 6-variable Modification of Diet in Renal Disease-6, CKD-EPI cystatin C, CKD-EPI Creatinine, and CKD-EPI Cystatin C-Creatinine. RESULTS: We included 76 patients (53% women). The mean measured GFR in the entire cohort was 64 ml/min/1.73m2; 54% of the patients had a GFR < 60 ml/min/1.73 m2 at the time of evaluation. The RFH formula and the CKD-EPI cystatin C formula showed the best performance, with a p30 of 62% and 59%, respectively. All formulas performed poorly when GFR was < 60 ml/min/1.73 m2. CONCLUSIONS: The RFH formula showed a better performance than the other formulas based on serum creatinine in a Hispanic population with LC. There was no difference in performance between the RFH formula and the CKD-EPI cystatin C formula.

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.

Association between Serum Uric Acid Levels, Nutritional and Antioxidant Status in Patients on Hemodialysis.

PURPOSE: To determine the relationship between uric acid (UA) and nutritional and antioxidant status in hemodialysis (HD) patients, given that hyperuricemia could be an indicator of good nutritional status possibly because of the antioxidant properties of UA. METHODS: Cross-sectional study with 93 patients on HD. Hyperuricemia was considered as UA ≥6.0 mg/dL in females and ≥7.0 mg/dL in males. Nutritional variables were registered. Blood samples were taken before the dialysis session to determine oxidative damage as plasma malondialdehyde (MDA) content, and antioxidant capacity measuring 2,2-diphenyl-piclrylhidrazil radical (DPPH●) scavenging activity and oxygen radical absorbance capacity (ORAC) value. RESULTS: Patients with hyperuricemia had higher creatinine (11.9 vs. 10.5 mg/dL; p = 0.004), potassium (5.5 vs. 5.0 mg/dL; p = 0.014) levels; phase angle (5.8 vs. 4.9; p = 0.005), protein consumption (normalized protein nitrogen appearance, nPNA, 1.03 vs. 0.83; p = 0.013) than normouricemic patients. DPPH● scavenging activity was higher in hyperuricemic subjects (1.139 vs. 1.049 mM Trolox equivalents; p = 0.007); likewise, hyperuricemic subjects had less oxidant damage measured by MDA (10.6 vs. 12.7 nmol/mL; p = 0.020). Subjects with normouricemia were at higher risk of having a reactance to height (Xc/H) ratio less than 35 (OR 2.79; 95% CI, 1.1-7.017, p = 0.028); nPNA < 1.0 (OR 3.78; 95% CI, 1.4-10.2, p = 0.007), diagnosis of cachexia (OR 2.95; 95% CI, 1156-7.518, p = 0.021), potassium levels <5 (OR 2.97; 95% CI, 1.136-7.772, p = 0.023) and PA < 5.5° (OR 3.38; 95% CI, 1.309-8.749, p = 0.012.) Conclusions: Patients with hyperuricemia had higher antioxidant capacity and better nutritional status. Purines and protein restrictions in HD patients with hyperuricemia need to be reviewed individually for each patient. More studies are needed to stablish a cut point of UA levels in renal population.

Evaluation of the royal free hospital cirrhosis glomerular filtration rate formula in hispanic patients with cirrhosis: an external validation

Abstract Background and Aims Glomerular filtration rate (GFR) measurement in patients with liver cirrhosis (LC) is the ideal method for adequate evaluation of kidney function. However, it is invasive, costly, and not widely accessible. Moreover, GFR estimation in patients with cirrhosis has been inaccurate. The aim of the present study was to evaluate and validate the recently described Royal Free Hospital (RFH) formula in a Hispanic cohort of patients with LC and compare it with other formulas, including the CKD-EPI cystatin C equation. Methods GFR was measured through the renal clearance of Tc-99m DTPA; it was cross-sectionally evaluated and compared with GFRs that were estimated utilizing the following formulas: RFH, Cockcroft-Gault, 6-variable Modification of Diet in Renal Disease-6, CKD-EPI cystatin C, CKD-EPI Creatinine, and CKD-EPI Cystatin C-Creatinine. Results We included 76 patients (53% women). The mean measured GFR in the entire cohort was 64 ml/min/1.73m2; 54% of the patients had a GFR < 60 ml/min/1.73 m2 at the time of evaluation. The RFH formula and the CKD-EPI cystatin C formula showed the best performance, with a p30 of 62% and 59%, respectively. All formulas performed poorly when GFR was < 60 ml/min/1.73 m2. Conclusions The RFH formula showed a better performance than the other formulas based on serum creatinine in a Hispanic population with LC. There was no difference in performance between the RFH formula and the CKD-EPI cystatin C formula.

Performance of MDRD-IDMS and CKD-EPI equations in Mexican individuals with normal renal function.

BACKGROUND:  The performance of the CKD-EPI and MDRD formulae for estimating glomerular filtration rate (GFR) in patients of Hispanic origin with normal renal function has been poorly explored and requires validation in Mexico.  MATERIAL AND METHOD:  We included previously healthy Mexican adults. We obtained clinical variables and determined serum creatinine to calculate the CKD-EPI and MDRD-IDMS formulae. These results were compared with the gold standard (GFR measured by Tc99DTPA). We evaluated other clinical variables that could affect the performance of the CKD-EPI formula.  RESULTS:  A total of 97 healthy volunteers were included, 55 males and 42 females; the mean age was 35.8 years old (18 to 73). Mean creatinine was 0.76mg/dl (±0.18). CKD-EPI performance was significantly better than MDRD-IDMS in all comparisons (bias, correlation and accuracy). The bias difference between the formulae was 6.08ml/min/1.73m2 (95% CI 2.58 to 9.58) (p<.001). Individuals with a body mass index (BMI) above 25kg/m2 displayed a better performance than the group with a lower BMI (difference of means 7.39ml/min/1.73m2; 95% CI 1.17 to 13.6 p<.02). Both formulae overestimated the GFR. BMI was significantly associated with the performance of the CKD-EPI formula (β 0.82; 95% CI 0.085 to 1.56 p=.029).  CONCLUSIONS:  In healthy Mexican adults, the CKD-EPI formula is a better predictor of the mGFR than the MDRD-IDMS formula. BMI is significantly associated with the performance of the CKD-EPI formula and is better in those with a BMI greater than 25kg/m2. Both formulae overestimate mGFR.