The Impact of Phenylketonuria on Body Composition in Adults

<b><i>Introduction:</i></b> Patients with phenylketonuria (PKU) must follow a lifelong phenylalanine (Phe)-restricted diet with additional amino acid supplementations, and this may put them at risk for nutritional disturbances. However, the body composition and nutritional status of adult patients with PKU has only been partially explored. The current study aims to assess the body composition of adult patients with PKU using multifrequency bioimpedance analysis (MF-BIA) and to reveal potential correlations between therapy adherence and body composition. Additionally, we compared body composition of patients with healthy controls. <b><i>Methods:</i></b> Fifty adult patients with early-treated PKU (27 female and 23 male) and 40 healthy, age- and gender-matched controls were included in this single-center, cross-sectional study. MF-BIA was performed on all subjects. Additionally, we determined serum nutritional markers for all patients. In the PKU patient group, correlation analyses were performed between body composition parameters and therapy adherence. We compared body composition of patients with PKU and controls using BIA. <b><i>Results:</i></b> The proportion of overweight was 56% among all patients with PKU. Female patients with PKU had significantly higher body fat percentage compared with controls. In parallel with higher fat content, we observed lower muscle mass, protein, and mineral content among female patients with PKU compared to controls. Such findings were not observed in male patients. Female patients with PKU had decreased therapy adherence and had significantly lower prealbumin levels compared with males. There was no significant correlation observed between body composition parameters and therapy adherence over the last 10 years in the PKU patient group. <b><i>Conclusion:</i></b> Although female patients had less optimal therapy adherence over the last 10 years compared with male patients, our results suggest that this does not influence body composition fundamentally. Our results suggest that obesity is an important comorbidity in young adult patients with PKU, especially in females. We advocate that nutritional assessments and weight management should be additional objectives of PKU management to provide optimal care.

The Diagnosis of Protein Energy Wasting in Chronic Peritoneal Dialysis Patients Is Influenced by the Method of Calculating Muscle Mass. A Prospective, Multicenter Study

Objective: To analyze the concordance and agreement between bioimpedance spectroscopy (BIS) and anthropometry for the diagnosis of protein energy wasting (PEW) in chronic peritoneal dialysis patients.Methods: Prospective, multi-center, observational study using multifrequency bioimpedance device (Body Composition Monitor -BCM®- Fresenius Medical Care) and anthropometry for the diagnosis of PEW as recommended by the International Society of Renal Nutrition and Metabolism (ISRNM). Cohen's kappa was the main test used to analyze concordance and a Bland-Altmann curve was built to evaluate the agreement between both methods.Results: We included 137 patients from three PD clinics. The mean age of the study population was 57.7 ± 14.9, 47.8% had diabetes, and 52.2% were male. We calculated the scores for PEW diagnosis at 3 and 6 months after the first collection (T3 and T6) and on average 40% of the study population were diagnosed with PEW. The concordance in the diagnosis of PEW was only moderate between anthropometry and BIS at both T3 and T6. The main factor responsible for our results was a low to moderate correlation for muscle mass in kilograms, with an r-squared (R2) of 0.35. The agreement was poor, with a difference of more than 10 kg of muscle mass on average and with more than a quarter of all cases beyond the limits of agreements.Conclusion: Current diagnosis of PEW may differ depending on the tools used to measure muscle mass in peritoneal dialysis patients.

The Impact of Obesity and Adiposity on Mortality Risk in Older Adults: A Ten-year Survival Analysis

There are not much information about the impact of obesity on all-cause, cardiovascular and cancer mortality in older adults. We have investigated the impact of obesity and adiposity on all-cause, cardiovascular and cancer mortality, in older adults after a 10-year follow-up. Prospective cohort study has been carried out with individuals ≥ 60 years. Sociodemographic characteristics, lifestyle, clinical history, laboratory tests and anthropometric data were collected. Adiposity was defined as tertiles of the percentage of body fat assessed by multifrequency bioimpedance. For obesity, three classifications were considered using the body mass index (BMI) as follows: ≥ 25.0 kg/m² in men and ≥ 26.6 kg/m² in women, ≥ 27.0 kg/m² and ≥ 30.0 kg/m². The BMI ≥ 30.0 kg/m² was associated a reduction in the all-cause mortality risk in non-ajusted Cox regression (HR: 0.65; 95% CI: 0.43 - 0.97) and in the Kaplan-Meier curves (p = 0.032). However, in multivariate Cox regression none of the diagnostic criteria for obesity and adiposity were significantly associated with all-cause, cardiovascular or cancer mortality. This 10-year survival analysis has showed that obesity and adiposity were not associated with an increased risk of all-cause, cardiovascular or cancer mortality in the older adults.

Software for Gene-Biosensor based on PCR and Electrical Bioimpedance

Gene detection by the use of bioimpedance measurements is an emerging technical proposal from the last two decades. Our recent studies have shown the feasibility to use multifrequency bioimpedance to detect specific label-free Deoxyribonucleic Acids (DNA) sequence in the final product of Polymerase Chain Reaction (PCR). We have developed a gene-biosensor integrated by a thermocycler block for final point PCR process and a relative bioimpedance meter at every PCR cycle in the sample. The system demands a dynamic software for all gene-biosensor modules control. This work reports a control program design for a gene-biosensor based on PCR product and bioimpedance measurements, the general structural philosophy, operating routines and subroutines as well as its interaction with the hardware in every module are described. The program was designed on the basis of Python language version 3.8.3 with the support of the Visual Studio Code as Integrated Development Environment (IDE), and using Windows 10 as the operating system. Results indicate the control program allows a suitable governing of the bioimpedance meter and PCR thermocycler block, both as a well-integrated system. Bioimpedance and temperature measurements are in agreement with the control operating structural design. Additional amendments regarding an on-line monitoring system are warranted.

Bioimpedance Spectroscopy as a potential technique to detect label-free PCR products

PCR is a molecular technique that multiplies DNA fragments in a logarithmical way. qPCR uses fluoroscopic dyes or probes to quantify amplicons but it is a complex and expensive technique that should be performed by highly trained personnel. PCR has been used in a wide variety of disciplines such as in food sciences, organ transplant, odontology, oncology and lately, as the standard diagnostic technique for COVID-19. Even when qPCR is a reliable and robust technique, it is hardly accessible for developing countries for its complex labelling procedures and expensive instrumentation, for that, it is of big relevance to search for simpler and cheaper alternative technologies for the detection and analysis of DNA. In this work, we explore the feasibility of using multifrequency bioimpedance measurements to detect label-free PCR products as a proof of principle for the future development of a gene biosensor on the basis of PCR and bioimpedance measurements.

MO712EVALUATION OF VOLUME OVERLOAD STATUS MARKERS IN PERITONEAL DIALYSIS PATIENTS

Background and Aims N-terminal fragment of B-type natriuretic peptide (NT-proBNP) can reflect changes in hydration status and may help the nephrologist to estimate it. Fluid volume overload is a major concern in dialysis patients, and it is associated with increased cardiovascular risk and death. This study evaluated the relationship between serum NT-proBNP levels and left ventricular (LV) dysfunction and extra-cellular excess water in peritoneal dialysis patients. Method We conducted a cross-sectional study of 60 peritoneal dialysis (PD) patients. Incident and prevalent patients were included. Echocardiography was performed using HDI 5000, allowing M-mode, two-dimensional measurement. A multifrequency bioimpedance (BIA) analyzer was used. Overhydration (OH) was defined as an extra-cellular water (ECW)/total body water (TBW) over 15%. Clinical and biochemical variables were also analysed. Results A total of 60 patients were evaluated (male 60% (n=36), mean age was 55,8 ± 15,3 years, BMI 25.9 ± 3.9 kg/m2 and 31.7% (n=19) had diabetes mellitus (DM). Median PD vintage was 21 months, automated PD 30%, 8.3% (n=5) were anuric and 10% (n=6) were overhydrated. The median serum NT-proBNP level was 1071 pg/mL. LV mass index and LV ejection fraction were 129.0 ± 51.1 g/m2 and 62.8 ± 13.0%, respectively. The median excess volume overload was 0.9L. Serum NT-proBNP levels correlated positively with, diabetes (r=0.27, p=0.04), isquemic cardiopathy (r=0.37, p=0.01), LV mass index (r=0.48, p=0.001) and extracellular water (r=0.31, p=0.02) and negatively with LV ejection fraction (r= -0.81, p=0.01). In a multivariable analysis, in a model adjusted to time in DP, diabetes, residual diuresis, isquemic cardiopathy and left ventricle mass index, NT-proBNP &gt; 1600 pg/mL was associated with patient overhidratation (exp (B) 1,44, 95% CI 0,15-2.73). No statistical difference was observed considering nutritional parameters, peritoneal transport, dialysis efficacy and NT-proBNP. Conclusion In this population, higher levels of NT-proBNP were associated with overhydration status and left ventricular dysfunction. Therefore, BIA and NT-proBNP may be complementary to clinical evaluation of PD patients. BIA results can be affected by malnutrition with loss of cell mass according to some studies. In our population NT-proBNP is not affected by nutritional status and therefore can also be used as a congestive marker in malnourished patients. Longitudinal application of BIA could be a useful clinical tool to evaluate adequacy in PD patients.

MO604DIFFERENCES IN THE EXTRACELLULAR BODY WATER/TOTAL BODY WATER (EBW/TBW) IN HEMODIALYSIS AND CHRONIC KIDNEY DISEASE PATIENTS. RELATIONSHIP WITH NUTRITIONAL PARAMETERS

Background and Aims Knowing the hydration status of CKD patients is one of the basic objectives in CKD patients considering the Ratio of EBW(TBW) as indicator of them. Aim Determine the cut-off point of the EBW/TBW ratio using Bioimpedance in patients with global CKD and divided into advanced CKD and hemodialysis (HD) as a hydration marker in relation to MIS scale (malnutrition inflammation score), cut-off point 5. Method We value 199 CKD patients by setting the EBW/TBW cut-off points using Inbody S10 multifrequency bioimpedance with global ROC curve and for advanced CKD (ACKD) and HD analyzing differences according to age ranges (&lt;65,65,1-75 and &gt;75 years) and differences in nutritional parameters (visceral proteins, MIS scale and body composition). Results We have evaluated 199 patients with ACKD, 143 male and 56 female, 74 in CKD xage72.27 ?11.98years and 125 in HD, xage 70.76 ?12.73 years. Overall EBW / TBW ratio: AUC 0.657, p0.006, cut-off point 0.3965 60% sensitivity, 64% specificity. Advanced CKD: AUC 0.648, p0.071, cutoff point 0.397, 64% sensitivity, 61% specificity. HD: AUC 0.706, p0.012, cutoff point 0.391, 71% sensitivity, 63% specificity. The results in relation to age strata and MIS with 5 as the cut-off point in the table. No greater hydration in men than in women overall. The nutrition-inflammation parameters according to the cut-off point are different: Advanced CKD: age 0.001, albumin 0.024, prealbumin 0.013, trasferrin 0.078, CRP 0.432. HD: albumin 0.014, prealbumin 0.001, transferrin 0.939, lymphocytes 0.030, CRP 0.342, age 0.000. Conclusion 1. We have found slightly higher cut-off points between ACKD and hemodialysis in the assessed sample. 2. The EBW / TBW ratio appears higher in patients &gt; 65 years in both ACKD and HD, in contrast to what is observed in the healthy population. 3. A greater malnutrition appairs in a greater hyperhydration in HD and ACKD.

Multifrequency Bioimpedance Phase Angle as a Tool to Predict Maturation Failure of Native Fistulae for Hemodialysis

Background and objectives: An arteriovenous fistula is considered to be an ideal vascular access for patients receiving hemodialysis, its main limitation is its high failure rate to achieve maturation and long-term functionality loss. Multiple strategies have attempted to identify patients at risk. Bioelectrical impedance has shown to be a valuable resource in the determination of the hydration status, and the measurement of the phase angle through this method has demonstrated to be a good indicator of the nutritional state and it’s related as a general marker of survival. The objective of this study is to analyze the role of plasma albumin and phase angle measured through bioelectrical impedance as tools useful for predicting failure of arteriovenous fistulas.

Does Pulse Wave Velocity Increase Over Time in Hemodialysis Patients?

<b><i>Objectives:</i></b> Arterial stiffness, measured by pulse wave velocity (PWV), is reported to be increased in hemodialysis (HD) patients and increases cardiovascular mortality. Previous studies have reported an association between extracellular water (ECW) and PWV. We wished to review whether PWV increases over time and whether this is associated with ECW. <b><i>Methods:</i></b> We reviewed repeat aortic PWV measurements using an oscillograph method along with corresponding ECW measured by multifrequency bioimpedance in HD patients a minimum of 5 years apart. <b><i>Results:</i></b> Twenty-four patients (16 [66.7%] male and 11 [45.8%] diabetic, mean age 61.7 ± 15.2 years) had PWV and ECW initially measured after 46 (26–124) months of HD and then after 112 (97–202) months. Overall, there was no change in PWV or ECW (9.4 ± 2.2 vs. 8.1 ± 2.5 cm/s; 14.7 ± 2.5 vs. 15.2 ± 2.9 L, respectively), whereas the ECW/total body water ratio increased (0.399 ± 0.015 vs. 0.408 ± 0.021, <i>p</i> &#x3c; 0.05). We found no association between changes in PWV and ECW (<i>r</i> = −0.05, <i>p</i> = 0.84), whereas there was an association with the change in peri-dialytic systolic blood pressure (SBP) (<i>r</i> = 0.59, <i>p</i> = 0.007). <b><i>Conclusion:</i></b> In our small observational study, there was no overall change in PWV, after 5 years of HD, with PWV increasing in 50% and falling in 50%. Changes in PWV were not associated with changes in ECW but were associated with changes in peri-dialytic SBP. Our study demonstrates that PWV does not increase in all HD patients with time, and interventional studies are required to determine whether targeted blood pressure control reduces PWV in HD patients.