Urea Distribution Volume Research Articles

Adjusting dialysis dose (Kt) scaled to Body Surface Area (BSA) could be a more logical approach.

The dialysis dose, quantified as Kt, is conventionally scaled to the urea distribution volume (V) to calculate the Kt/V ratio as an indicator of dialysis adequacy. However, the body surface area (BSA) is recognized as a more accurate reflection of metabolic activity compared to V. This study presents evidence supporting the enhanced efficacy of the Kt/BSA ratio as an indicator of hemodialysis adequacy. The study population comprised 211 individuals undergoing hemodialysis, all of whom had Kt/V values determined. Body composition was assessed using bioimpedance techniques, and BSA was calculated employing the DuBois and DuBois formula. The ratio of V/BSA served as the conversion factor to derive Kt/BSA from the standard Kt/V. Participants were categorized by gender, and a comparative analysis was performed on dialysis-related parameters alongside body composition indicators. Concurrently, linear regression analysis was applied to Kt/V and Kt/BSA, as well as to pairs of V and BSA, to elucidate the relationships among these variables. The average Kt/V ratio was 1.50 with a standard deviation of 0.28. The Kt/V ratio was significantly higher in women (P < 0.01). Conversely, the Kt value, when not adjusted for body size, was significantly lower in women (P < 0.01). Upon scaling Kt to BSA to calculate Kt/BSA, the gender difference in dialysis dose adequacy was no longer statistically significant (P = 0.06). Men exhibited a significantly higher mean V/BSA ratio. Additionally, women had a slightly higher mean percentage of fat mass (P < 0.01). In contrast, women had a lower mean percentage of muscle mass (P < 0.01). Our findings suggest that the Kt/V ratio may underestimate the required hemodialysis dose for women. There was no gender difference when Kt scaling to BSA. Consequently, the Kt/BSA ratio, which accounts for body surface area, may play a significant role in more accurately scaling the hemodialysis dose.

#811 Effect of GLP-1 receptor agonists on the weight, urea distribution volume and blood pressure of hemodialysis (HD) patients

Abstract Background and Aims Glucagon-like-peptide-1 receptor agonists (GLP-1) drugs are a class of medications commonly used to treat type-2 diabetes. Diabetes is prevalent in almost 60% of the end stage kidney disease (ESKD) patients and an increasing number of dialysis patients use GLP-1 drugs. It is important to note that GLP-1 drugs may have additional benefits such as weight loss and potential cardiovascular benefits. However, little is known about the effects of these drugs in dialysis patients. We analysed the changes in body weight and blood pressure in hemodialysis (HD) patients who start using these drugs. We also analysed whether there are changes in patients’ urea distribution volume, a proxy of lean body mass, to understand whether these medications affect muscle mass. Method We retrospectively evaluated 236 ESKD patients who were prescribed GLP-1 drugs as part of routine clinical care in October of 2023 at clinics in a large dialysis organization. All patients received dialysis for at least 60 days before and after they started using the medication. We looked at the changes in the average post dialysis weight, urea distribution volume, and pre dialysis systolic blood pressure (pre-SBP) between the 60 days before using GLP-1 drugs (pre-GLP1 period) and 60 days after initiating the drug (post-GLP1 phase). For each metric, we performed a paired t-test to evaluate the changes between pre-GLP1 and post-GLP1. Results The average post dialysis weight pre-GLP1 was 103.98 kg and the average post dialysis weight post-GLP1 was 102.02 kg (difference: −1.96 kg, 95% CI :1.37 to 4.27, p-value &amp;lt;0.001). The average urea distribution volume was 36.0 L pre-GLP1, and 35.6 L post-GLP1 (difference: −0.47 L, 95% CI: −0.99 to 3.56, p-value=0.07). The mean pre-SBP was 147.83 mmHg pre-GLP1 and 149.67 mmHg post-GLP1 (difference: 1.85 mmHg, 95% CI: −5.49 to 24.93, p=0.29). Conclusion Our analysis showed a significant decrease in the average post dialysis weight of HD patients using GLP-1 drugs. While the decline in patients' urea distribution volume, which can be considered as a proxy for lean tissue mass, was not statistically significant, it may be clinically meaningful. We do not see a significant change in pre-SBP. Reductions in weight may suggest reduction in fat and muscle mass but can also be due to “regression to the mean” phenomena as patients who were on these medications tended to be larger. Further studies are necessary to evaluate this association.

#1615 Working without peritoneal dialysate and urine collections during the COVID-19 pandemic: how to assure sufficient small solute removal

Abstract Background and Aims The guidelines of the International Society of Peritoneal Dialysis suggest regular control of small solute removal. During the COVID-19 pandemic we did not perform additional controls of dialysis adequacy in our peritoneal dialysis patients. We judged patients according symptoms and serum urea levels. In this retrospective study, we aimed to evaluate whether the measurement of serum urea alone might indicate sufficient small solute removal in peritoneal dialysis patients. Method In 216 adult PD patients (139 males, 77 females, median age 64 years, median BMI 26.7) Kt/V urea (renal and peritoneal) was registered together with anthropometric and laboratory data during the first two years of PD therapy. Patients presenting urea values between 100 and 250 mg/dl were included in the statistical analysis, thus resulting in the evaluation of 410 measurements (265 in male, 145 in female patients). Urea distribution volume was calculated using the formula of Watson and Watson. The measurement of urea in blood and urine was performed by a standard kinetic test with urease. Results Serum urea correlated significantly to Kt/V urea (r = −0.28, p &amp;lt; 0.01), whereas significance was not reached in female patients (male patients: r = −0.35, p &amp;lt; 0.01; female patients; r = −0.14, p = 0.13). Kt/V urea of at least 1.7 is achieved in male patients presenting serum urea values lower than 160 mg/dl (95% confidence interval), whereas in female patients apparently presenting serum urea values lower than 200 mg/dl (95% confidence interval). This difference is due to the distinct sex specific urea distribution volume (median value: male patients 40.8 liters, female patients 31.8 liters) and to the absence of a significant correlation between serum urea and Kt/V urea in female patients. Conclusion Serum urea values below 160 mg/dl in male peritoneal dialysis patients are roughly indicating sufficient small solute removal, whereas a clear relation between serum urea and Kt/V urea was not present in female patients in our study population.

Validation of formulas calculating normalized protein catabolic rate in patients undergoing home hemodialysis.

Depner and Daugirdas developed a simplified formula to estimate the normalized protein catabolic rate in patients on twice- or thrice-weekly hemodialysis (JASN, 1996). The aim of our work was to establish formulas in more frequent schedules and validate them in home-based hemodialysis patients. We realized that the structure of Depner and Daugirdas' normalized protein catabolic rate formulas has a general meaning and can be expressed as PCRn = C0/[a + b*(Kt/V) + c/(Kt/V)] + d, where C0 is pre-dialysis blood urea nitrogen, Kt/V is dialysis dose,a, b, c, dare the specific coefficients for each combination of home-based hemodialysis schedules and the day of blood sampling. The same applies to the formula that adjusts C0 (C'0) for residual kidney clearance of blood water urea (Kru) and urea distribution volume (V): C'0 = C0*[1 + (a1 + b1/(Kt/V))*Kru/V]. On this basis, we computed the six coefficients (a, b, c, d, a1, b1) for each of the 50 possible combinations and simulated a total of 24,000 weekly dialysis cycles using the Daugirdas Solute Solver software recommended by the KDOQI 2015 guidelines. From the associated statistical analyses we obtained 50 sets of coefficient values, which were validated comparing the paired normalized protein catabolic rate values (i.e., those estimated with our formulas with those modeled with Solute Solver) in 210 datasets of27patients on home-based hemodialysis. The mean values ± SD were 1.06 ± 0.262 and 1.07 ± 0.283g/kg/day, respectively, with a mean difference of 0.004 ± 0.034g/kg/day (p = 0.11). The paired values were highly correlated (R2 = 0.99). In conclusion, even if the coefficient values were validated in a relatively small sample of patients, they allow an accurate estimation of normalized protein catabolic rate in home-based hemodialysis patients.

#5157 ESTIMATION OF RENAL KT/V FROM 24-HOUR URINE VOLUME AND UREA DISTRIBUTION VOLUME IN PERITONEAL DIALYSIS

Abstract Background and Aims Residual renal function is an important factor in peritoneal dialysis (PD) regarding technical survival and implementation of incremental therapy schemes. The aim of the retrospective study was to develop an estimation formula of renal Kt/Vurea in PD based on urine output and anthropometric data. Method In 235 adult PD patients (151 males, 84 females, median age 66 years, median BMI 26.0, diuresis &amp;gt;100 ml/day) urine output was registered together with anthropometric and lab data during the first peritoneal equilibration test. The dose of furosemide therapy was noted. Urea distribution volume calculated using the formula of DuBois. Measurement of urea in blood and urine was performed by a standard kinetic test with urease. Results 24-hour urine volume ranged from 100 to 3800 ml (median 1150 ml), similar in both sexes. Renal Kturea showed a significant linear correlation to daily urine volume (r=0.78, p&amp;lt;0.01) independent from sex and diuretic dose: renal Kturea = 5.116 + 0.0221 x 24-hour urine volume (renal Kturea in liters/week, 24-hour urine volume in ml). Urea distribution volume varied between 24 and 60 liters (median 36.4 liters), and calculated renal Kt/V ranged from 0.05 to 2.57 (median 0.84). Estimated renal Kt/V, based on the before mentioned equation divided by urea distribution volume, correlated significantly to calculated renal Kt/V (r=0.75, p&amp;lt;0.01). The goodness of fit analysis showed a mean absolute error of 0.24. The Bland-Altman Plot confirmed a tendency of over-estimation for renal Kt/V &amp;lt; 1.0 and under-estimation for higher renal Kt/V. A restriction of the analysis to 24-hour urine volume up to 1500 ml (n=142 patients, median age 69 years, BMI 25) resulted in an improvement of renal Kt/V estimation (goodness of fit analysis: mean absolute error 0.20). Conclusion The estimation of renal Kt/V in PD patients seems to be feasible utilizing 24-hour urine volume and anthropometric data.

The uric acid-urea distribution volume ratio is a potential marker of hydration status in patients on hemodialysis.

The distribution volume of uric acid is affected by the amount of extracellular water (ECW), while urea distribution volume can be considered as total body water (TBW). Thus, the ratio of distribution volumes of uric acid and urea can be paralleled to and be considered as the proxy of ECW/TBW. A total of 108 patients at our facility was included. The uric acid and urea distribution volume ratio (UUVdR) calculated from the single-pool model, which was measured within 1month of the time when the bioimpedance index was measured. ECW/TBW at the end of the HD session was measured by InBody S10. We investigated the association between the UUVdR and the ECW/TBW values and the factors affecting the residuals of the regression equation. We also evaluated the predictive ability of overhydration or dehydration in randomly selected two groups, i.e., the training group and the validation group. ECW/TBW correlated highly with UUVdR. Multivariate analysis demonstrated that only creatinine and ECW/TBW were significantly associated with regression residuals. The cutoff values of UUVdR for overhydration and dehydration were 0.666 and 0.579, respectively, in the training group. Their AUC were 0.872 and 0.898, respectively. The sensitivity and specificity values in the validation group were 0.571 and 0.868 for overhydration, and 0.444 and 0.953 for dehydration, respectively. UUVdR might be a proxy of hydration status in hemodialysis patients. It may be possible to predict hydration status without dedicated devices in the epidemiological study.

Correlation between serum SIRT1 and EZH2 expressions and peritoneal function in patients with diabetic nephropathy undergoing peritoneal dialysis.

To determine the correlation between the expression of silent information regulator 1 (SIRT1) and enhancer of zeste two polycomb repressive complex two subunit (EZH2) and peritoneal function in patients with diabetic nephropathy (DN) and peritoneal dialysis. One hundred forty patients with DN underwent peritoneal dialysis in Hanchuan People's Hospital from April 2016 to January 2019 were divided into four groups according to the duration of peritoneal dialysis. The levels of SIRT1 and EZH2 in serum were measured. The ratio of dialysate to plasma creatinine (D/Pcr) and the concentration of cancer antigen 125 (CA125) in peritoneal dialysate were determined. The ratio of urea clearance to urea distribution volume (Kt/V) of dialyzer was calculated. The correlations between SIRT1 and EZH2 expressions and peritoneal function were analyzed. With the prolongation of peritoneal dialysis, serum SIRT1 expression, Kt/V, Ccr and CA125 decreased, while EZH2 expression and D/Pcr increased in patients with DN undergoing peritoneal dialysis. Pearson's correlation analysis showed that SIRT1 expression was negatively correlated with D/Pcr while positively correlated with Kt/V and CA125, and serum EZH2 expression was negatively correlated with Kt/V and CA125 while positively correlated with D/Pcr. ROC analysis demonstrated that SIRT1 and EZH2 expressions had certain diagnostic value for the poor prognosis of patients with DN undergoing peritoneal dialysis. Serum SIRT1 and EZH2 expressions in patients with DN undergoing peritoneal dialysis are closely related to their peritoneal function. They have certain diagnostic value for the poor prognosis of patients with DN undergoing peritoneal dialysis.

MO907: Predictors of Negative Outcomes in HDF-OL Patients: A Cohort Study

BACKGROUND AND AIMSHaemodiafiltration on-line (HDF-ol), an effective mode of replacement therapy for stage 5 chronic kidney disease (CKD 5D), cannot be considered sufficiently studied in terms of its effect on the outcomes. Our main aim was to identify a possible association between individual anthropometric, laboratory data and parameters of the prescribed treatment regimen with the best survival rate when using the HDF-ol mode.METHODA retrospective1 year analysis of the EuCliD database of 9986 patients treated with HDF-ol in 27 Fresenius Medical Care centres in Russia was carried out. All patients got post-dilution HDF-ol procedures at least 3 times a week, for at least 12 h a week with Kt/V at least 1.4. Data on alive (9616) and deceased (370) patients were compared by gender, age, treatment experience, body weight (BW), body mass index (BMI), body surface area (BSA), total body water volume (TBW), volume of urea distribution (V Urea BCM), presence of diabetes mellitus (DM), ischemic heart disease (CHD), chronic heart failure (CHF), as well as parameters of the procedure: effective weekly dialysis time, Kt/V, effective infusion volume (EIV) and effective convection volume (ECV).RESULTSDifferences in groups were found only for a part of parameters (Table 1).Table 1.Group of patientsStatisticAliveDeceasedP-valueBasic demographic characteristicsSex: f n (%)4422 (46.0%)140 (37.8%).0024Sex: m n (%)5194 (54.0%)230 (62.2%).0024Age (years) N 9616370<.0001Mean (SD)53.4 (13.6)58.8 (12.1)Median5560Min–max17.0–86.030.0–83.095% CI53.1–53.757.5–60.0BW (kg) N 9616370<.0001Mean (SD)75.2 (17.5)71.7 (16.5)Median73.470Min–max30.6–194.635.3–133.295% CI74.8–75.570.0–73.4BMIMean (SD)26.7 (5.7)25.5 (5.7)<.0001Median2625Min–max14.1–53.213.4–47.295% CI26.6–26.924.9–26.1CHD: yes n (%)1565 (16.3%)98 (26.5%)<.0001CHD: no n (%)8051 (83.7%)272 (73.5%)<.0001HF: yes n (%)1878 (19.5%)94 (25.4%).0065HF: no n (%)7738 (80.5%)276 (74.6%).0065diabetes: yes n (%)1213 (12.6%)72 (19.5%).0002diabetes: no n (%)8403 (87.4%)298 (80.5%).0002Parameters of the HDF ol proceduresEffective week dialysis time (min)Mean (SD)784.2 (140.2)731.6 (372.2)<.0001Median790733,5Min–max150.0–4979.0197.0–4017.095% CI781.3–787.1689.6–773.6EIV (L)Mean (SD)24.6 (4.3)23.0 (4.7)<.0001Median23.722.4Min–max0.5–69.41.9–43.895% CI24.5–24.722.6–23.5ECV (L)Mean (SD)27.0 (4.4)25.3 (5.0)<.0001Median2624.7Min–max0.5–71.22.0–46.095% CI26.9–27.124.8–25.8OCM Kt/VMean (SD)1.7 (0.3)1.7 (0.3)<.0001Median1.71.6Min–max0.5–6.40.7–3.095% CI1.7–1.71.7–1.7The main laboratory parametersCalcium (mmol/L)Mean (SD)2.2 (0.2)2.3 (0.2)<.0001Median2.22.2Min–max1.0–3.71.5–3.095% CI2.2–2.22.2–2.3Albumin (g/L)Mean (SD)40.6 (3.2)38.7 (4.3)<.0001Median4139Min–max13.0–71.018.2–49.095% CI40.5–40.638.4–38.9b2-microglobulin (mg/L)Mean (SD)23.8 (7.0)25.2 (8.1)<.0001Median23.323.7Min–max1.5–80.05.4–85.195% CI23.8–23.924.7–25.7Haemoglobin (g/L)Mean (SD)110.4 (14.9)105.6 (17.9)<.0001Median111106Min–max12.0–176.034.0–167.095% CI110.2–110.5104.5-106.7CRP (mg/L)Mean (SD)7.8 (15.7)19.7 (43.3)<.0001Median3.46.6Min–max0.0–500.00.1–521.195% CI7.6–7.917.0–22.4Table 2.Hospitalization of ESKD patients before and after the onset of the COVID-19 pandemic in a tertiary University Hospital of Thessaloniki, GreeceBefore COVID-19 pandemicAfter COVID-19 pandemicP-valueTime period1 March 2019–29 February 20211 March 2020–28 February 2021-Hospitalizationsa (n)14990-Age (years)67.7 ± 13.665.3 ± 16.7247Gender (M/F)105/44 (70.5%/29.5%)62/28 (68.9%/31.1%)884Duration of hospitalization (days)7 (2–83)9 (2–67)0.423Outcome (n, %)0.837 Improvement127 (85.2%)76 (84.4%) Stable medical condition10 (6.7%)6 (6.7%) In-hospital death12 (8.1%)8 (8.9%) aHospitalizations due to SARS-CoV-2 infection over the pandemic period were not included in this comparative analysis.CONCLUSIONAssociation of risk of death in patients with CKD 5D treated with HDF-ol included male gender, older age, concomitant diseases (CHD, CHF, DM), lower BW and BMI, shorter effective weekly dialysis time, lower values of EIV and ECV, Kt/V, higher values of hypercalcemia, hypoalbuminemia, lower haemoglobin levels, higher levels of b2-microglobulin and CRP. Such indicators as TBW, VUrea BCM, BSA and the length of treatment on dialysis did not reached statistical significance when comparing alivе and deceased patients.

Inflammation and hemodialysis adequacy: are C-reactive protein levels influenced by the dose of dialysis?

IntroductionChronic inflammation and the underlying cardiovascular comorbidity are still current problems in chronic hemodialysis patients. There are few studies comparing the "dialysis dose" with the degree of inflammation in the patient. Our main objective was to determine whether there is a relationship between serum C-reactive protein (CRP) levels and the “dialysis dose” (Kt / V) using ionic dialysance. MethodsMulticenter cross-sectional study. 536 prevalent chronic hemodialysis patients were included. CRP levels, neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) were collected. Kt was obtained by ionic dialysance and urea distribution volume was calculated from the Watsonˈs formula. The sample was divided into two groups, taking the median CRP as the cut-off point. Dialysis adequacy obtained in each group was compared. Finally, a logistic regression model was carried out to determine the variables with the greatest influence. ResultsMedian CRP was 4.10 mg/L (q25-q75: 1.67-10) and mean Kt/V was 1.48 ± 0.308. Kt/V was lower in the patients included in the high inflammation group (p = 0.01). In the multivariate logistic regression, the "high" levels of CRP were directly correlated with the Log INL (p < 0.001) and inversely proportional with serum albumin values (p = 0.014), Kt/V (p = 0.037) and serum iron (p < 0.001). ConclusionThe poorer adequacy in terms of dialysis doses, lower Kt / V values, may contribute to a higher degree of inflammation in chronic hemodialysis patients

Comparison of Body Fluid Volumes Determined by Kinetic Modeling and by Bioimpedance Spectroscopy

Introduction: The bioimpedance spectroscopy (BIS) method is used in individual patients requiring body fluid volume measurement. In a hemodialysis facility, however, regular screening of body fluid volumes is also necessary. Such screening, by kinetic modeling, may become possible by calculating distribution volumes of urea and uric acid from regular blood test results. Objective: The aim is to compare uric acid distribution volumes with BIS-extracellular volume, urea distribution volume with BIS-total body water, and difference between urea and uric acid distribution volumes with BIS-intracellular volume. Methods: We reanalyzed stored blood test data of 53 hemodialysis patients obtained together with BIS data of the same patients in our previous study. Results: Significant correlations were found between urea distribution volume and total body water predicted by the BIS method, between uric acid distribution volume and extracellular volume predicted by the BIS method, and between the difference of uric acid distribution volume from urea distribution volume and intracellular volume predicted by the BIS method. In Bland-Altman analysis, comparison of each pair showed no systematic error. The mean difference between each pair was minimal. Conclusion: Fluid volumes in different body compartments can be estimated by kinetic modeling as well as by the BIS method.

Inflamación y adecuación de la hemodiálisis: ¿están los niveles de proteína C reactiva influidos por la dosis de diálisis recibida?

IntroductionChronic inflammation and the underlying cardiovascular comorbidity are still current problems in chronic hemodialysis patients. There are few studies comparing the “dialysis dose” (Kt/V) with the degree of inflammation in the patient. Our main objective was to determine whether there is a relationship between serum C-reactive protein (CRP) levels and the Kt/V using ionic dialysance. MethodsMulticenter cross-sectional study. A total of 536 prevalent chronic hemodialysis patients were included. CRP levels, neutrophil-lymphocyte ratio and platelet-lymphocyte ratio were collected. Kt was obtained by ionic dialysance and urea distribution volume was calculated from the Watson's formula. The sample was divided into 2 groups, taking the median CRP as the cut-off point. Dialysis adequacy obtained in each group was compared. Finally, a logistic regression model was carried out to determine the variables with the greatest influence. ResultsMedian CRP was 4.10mg/L (q25-q75: 1.67-10) and mean Kt/V was 1.48±0.308. Kt/V was lower in the patients included in the high inflammation group (P=.01). In the multivariate logistic regression, the “high” levels of CRP were directly correlated with the Log neutrophil-lymphocyte ratio (P<.001) and inversely proportional with serum albumin values (P=.014), Kt/V (P=.037) and serum iron (P<.001). ConclusionThe poorer adequacy in terms of dialysis doses (lower Kt/V values) may contribute to a higher degree of inflammation in chronic hemodialysis patients.

MO599COMPARISON OF TOTAL BODY WATER MEASURED BY BIOIMPEDANCE SPECTROSCOPY TO UREA DISTRIBUTION VOLUME ESTIMATED FROM UREA KINETIC MODELING IN HEMODIALYSIS PATIENTS

Abstract Background and Aims Monitoring of fluid, body composition and nutritional changes is important in clinical nephrology. The Body Composition Monitor (BCM; Fresenius Medical Care, Bad Homburg, Germany) measures whole-body bioimpedance and determines extracellular and intracellular resistance by using the Cole-model to estimate total body water (TBW-BCM) and its partition into extracellular and intracellular water. Both can then be used to define body composition and separate body weight into lean tissue mass, adipose tissue mass, and fluid overload. Urea kinetic modeling (UKM) allows the estimation of dialysis dose (double-pooled Kt/V), urea distribution volume (V-UKM) and dietary protein intake. We studied the bias between estimated V-UKM to anthropometric and measured TBW-BCM (Vant, TBW-BCM). Method Pre-hemodialysis (HD), electrodes for the BCM assessments were placed on the non-arteriovenous access arm and ipsilateral leg, respectively, with the patient in a supine position. Vant was calculated using the Watson equation. In addition to these assessments we entered the specified values from the most recent urea kinetic modeling (UKM) treatment into the online solute-solver calculator (http://ureakinetics.org). We chose a baseline ratio of modeled/anthropometric volume of 0.6 to 1.3 L to exclude values with data entry errors and/or UKM sampling errors. We calculated the post HD TBW-BCM by subtracting the intradialytic weight loss and adjusted these estimates by the differences in post HD weight between sessions to make both estimates comparable. We depicted the comparison between the estimated V-UKM versus the TBW-BCM in a scatter- and Bland-Altman (BA) plot (Figure). For the purpose of error investigation we studied the computed bias (V-UKM minus TBW-BCM) as a function of body mass index (BMI) and stray capacitance (td) in a BA plot. We then calculated the difference between Vant and V-UKM and illustrated the comparison in a scatter and BA plot. Results In a cross-sectional design, we studied 161 stable prevalent HD patients (61.3±14.7 years, 98 (60.9%) males, height of 167.5±10.7 cm) prior to their treatment. The regression plot showed slight agreement (R2= 0.69) and the Bland-Altman plot no systematic trends or proportional error in the main analysis (Figure 1a and b). Neither BMI or td explained bias and variance in the bias between both estimates. Vant and V-UKM plots showed agreement (R2 of 0.68) with a mean bias of -2.3±5.1 and no proportional error. Conclusion Both TBW-BCM and the V-UKM as the “bronze standard” of TBW estimation seemed to agree reasonably well. Neither body composition measurement or kinetic modeling approach showed any significant influence on the accuracy and precision of the estimate. According to BCM availability, estimated V-UKM or measured TBW-BCM could be used alternatively in practice to support clinical decision when pharmacokinetic considerations are concerned.

MO663THE UTILITY OF SMART SCALES TO MONITOR BODY COMPOSITION IN HEMODIALYSIS PATIENTS

Abstract Background and Aims Overhydration (OH) is an independent predictor of mortality on hemodialysis (HD). The gold standard to assess OH is BCM monitor from Fresenius®, however BCM is a hospital hold device limiting its use. New smart scales have emerged as household devices reporting daily body composition data. Objective To determine if Renpho ES-CS20M® could be useful on a 52 HD patient to estimate body composition data. Method 72 body composition assessments (BCA) during mid-week HD session were performed. Each BCA included: (1) Predialysis Renpho measurement, (2) Predialysis BCM monitor measurement, (3) Postdialysis Renpho measurement. To track the fluid balance during the HD session: (1) we recorded ultrafiltration, (2) food or fluid intake was not allowed, and (3) none of the HD patients urinated during the HD session. If any intravenous fluids were needed during the HD session, we subtracted them off from UF. Results Data from 52 HD patients were studied (age 58.8 ± 16.8 years, 56.9 % males, 14.7% diabetics), with a mean pre-HD weight of 70.0 ± 13. 4 Kg, overhydration of 1.7 ± 1.5 L and urea distribution volume of 31.7 ± 5.7 L. The mean ultrafiltration during HD session was -1.8 ± 0.9 L. Renpho estimated a Pre – HD hydration of 34.25 ± 6.02 Kg vs 33.4 ± 5.7 Kg by BCM, showing a good concordance between methods (ICC 0.788 [0.67-0.86], B -0.58, p &amp;lt;0.01). Renpho poorly estimated pre – HD lean tissue mass at 45.4 ± 6.9 Kg compared with 33.8 ± 8.0 Kg by BCM. Although Renpho was able to provide a moderate concordant estimation of fat tissue mass (33.8 ± 8.0 % with Renpho vs 34.7 ± 9.6%), the bias proportion was unacceptable. Post- HD hydration by Renpho was not able to reproduce the ultrafiltracion achieved during the HD session (pre-HD 34.25 ± 6.02 Kg vs post-HD 34.08 ± 6.00 Kg). Conclusion Renpho has a proportional bias estimating predialysis hydration compared with BCM monitor, but is not able to assess changes produced with ultrafiltration or other parameters of body composition (as lean or fat tissue mass). Although smart scales are unacurate to assess body composition on HD patients, they could be useful on the follow up of them changing the accuracy for frequency.

Routine assessment of kidney urea clearance, dialysis dose and protein catabolic rate in the once-weekly haemodialysis regimen.

The dialysis dose (Kt/V) and normalized protein catabolic rate (PCRn) are the most useful indices derived from the urea kinetic model (UKM) in haemodialysis (HD) patients. The kidney urea clearance (Kru) is another important UKM parameter which plays a key role in the prescription of incremental HD. Ideally, the three kinetic parameters should be assessed using the complex software Solute Solver based on the double pool UKM. In the clinical setting, however, the three indices are estimated with simplified formulae. The recently introduced software SPEEDY assembles the aforementioned equations in a plain spreadsheet, to produce quite accurate results of Kru, Kt/V and PCRn. Unfortunately, specific equations to compute Kt/V and PCRn for patients on a once-weekly HD regimen (1HD/wk) were not available at the time SPEEDY was built-up. We devised a new version of SPEEDY (SPEEDY-1) and an even simpler variant (SPEEDY-1S), using two recently published equations for the 1HD/wk schedule . Moreover, we also added a published equation to estimate the equivalent renal clearance (EKR) normalized to urea distribution volume (V) of 35 L (EKR35) from Kru and Kt/V . Aim of the present study was to compare the results obtained using the new methods (SPEEDY-1 and SPEEDY-1S) with those provided by the reference method Solute Solver. One hundred historical patients being treated with the once-weekly HD regimen were enrolled. A total of 500 HD sessions associated to the availability of monthly UKM studies were analysed in order to obtain Kru, single pool Kt/V (spKt/V), equilibrated Kt/V (eKt/V), V, PCRn and EKR35 values by using Solute Solver, SPEEDY-1 and SPEEDY-1S. When comparing the paired values of the above UKM parameters, as computed by SPEEDY-1 and Solute Solver, respectively, all differences but one were statistically significant at the one-sample t-test; however, the agreement limits at Bland-Altman analysis showed that all differences were negligible. When comparing the paired values of the above UKM parameters, as computed by SPEEDY-1S and Solute Solver, respectively, all differences were statistically significant; however, the agreement limits showed that the differences were negligible as far as Kru, spKt/V and eKt/V are concerned, though much larger regarding V, PCRn and EKR35. We implemented SPEEDY with a new version specific for the once-weekly HD regimen, SPEEDY-1. It provides accurate results and is presentlythe best alternative to Solute Solver. Using SPEEDY-1S led to a larger difference in PCRn and EKR35, which could be acceptable for clinical practice if SPEEDY-1 is not available.

The lacking equation that estimates the protein catabolic rate in patients on once-weekly haemodialysis.

The normalized protein catabolic rate (PCRn) is one of the key indices derived from the urea kinetic model (UKM) in haemodialysis (HD) patients. Ideally, it should be assessed using the double pool UKM (KDOQI clinical practice guidelines, AIKD, 2015), as the web-based software Solute-Solver (SS) does (Daugirdas et al., AJKD, 2009). Simple formulae exist to compute PCRn for patients on thrice- or twice-weekly HD schedule, but not for patients on once-weekly HD schedule (1HD/wk). Aim of the present technical note was to introduce the lacking equation that estimates PCRn in the 1HD/wk regimen. Data of a single HD session associated to monthly UKM studies were retrieved from the electronic database of our dialysis unit for 80 historical patients on 1HD/wk regimen. The UKM parameters, as calculated with SS, were used in a subgroup of 40 randomly selected patients (group 1) to build-up a multiple regression model of PCRn. The latter was used to predict PCRn (PCRnPred) values in the cohort of the remaining 40 patients (group 2). The Bland-Altman plot was used to analyse the agreement between PCRnPred and the paired "observed" (PCRnObs) values, as measured with SS. The following equation was established by means of the multiple regression analysis: PCRn =-0.46 + 0.01 × C0 + 0.09 × eKt/V + 3.94 × Kru/V, where C0 is pre-dialysis blood urea nitrogen concentration, eKt/V is the equilibrated Kt/V, Kru is the residual renal urea clearance and V is the post-dialysis urea distribution volume. The PCRnPred values were 0.99 ± 0.24g/kg/day; the PCRnObs values were 0.96 ± 0.23g/kg/day (mean difference 0.03 ± 0.05g/kg/day). Their difference at the Bland-Altman analysis ranged from -0.08 to + 0.13g/kg/day. Finally, a nomogram was drawn: it can be used to estimate not only PCRn from Kru/V and C0, but also C0 as a function of Kru/V and PCRn. The equation here introduced allows a simple and accurate estimate of PCRn in patients on once-weekly HD regimen. The availability of the nomogram relating C0 to PCRn and Kru/V could be a further step to make safer and safer the once-weekly HD regimen. The following equation was established by means of the multiple regression analysis [Formula: see text] where PCRn is the normalized protein catabolic rate (PCRn), C0 is pre-dialysis blood urea nitrogen concentration (BUN), eKt/V is the equilibrated Kt/V, Kru is the residual renal urea clearance and V is the post-dialysis urea distribution volume. A nomogram relating pre-dialysis BUN to PCRn and Kru/V could be drawn: it can be used to estimate not only PCRn from Kru/V and pre-dialysis BUN, but also pre-dialysis BUN as a function of Kru/V and PCRn.

Temporal Change in Formula-Derived Creatinine Index as a Surrogate for Lean Muscle Mass Correlates Well with Change in Post-Hemodialysis Weight but Not with the Volume of Urea Distribution

Temporal Change in Formula-Derived Creatinine Index as a Surrogate for Lean Muscle Mass Correlates Well with Change in Post-Hemodialysis Weight but Not with the Volume of Urea Distribution

High Levels of Physical Activity May Promote a Reduction in Bone Mineral Density in Peritoneal Dialysis.

Background and objectives: Peritoneal dialysis (PD) patients are expected to present lower levels of physical activity, unhealthy changes at the body composition level, and low levels of strength. Firstly, this study aimed to report the sex differences in physical activity, body composition and muscle strength and the relations among these variables. Secondly, we analyze the relationship between physical activity and biochemical parameters. Materials and Methods: Thirty-four patients (13 women and 21 men) participated in this study. Body composition was assessed by bioimpedance and dual-energy X-ray absorptiometry (DXA), and maximum isokinetic unilateral strength, analytical parameters and physical activity levels were evaluated. Results: The men showed higher values for weight, height, lean body mass, bone mineral content, bone mineral density (BMD) and total body water, while women showed higher values for the percentage of fat mass and hydration of lean body mass (p < 0.05). No differences between the sexes were found in different levels of physical activity; however, males registered significantly higher values for isokinetic strength variables except for knee extensor strength. BMD was positively related to sedentary activity and negatively related to moderate and vigorous activity (r = 0.383 and r = −0.404, respectively). Light physical activity was negatively correlated with albumin (r = −0.393) and total protein (r = −0.410) levels, while moderate/vigorous activity was positively correlated with urea distribution volume (r = 0.446) and creatinine clearance (r = 0.359) and negatively correlated with the triglyceride level (r = −0.455). Conclusions: PD patients with higher levels of physical activity present better results in terms of body composition and biochemical parameters. Additional studies should be conducted to clarify the relation between physical activity level and BMD.

Comparison of Clinical Performance of VectorFlow and Palindrome Symmetric-Tip Dialysis Catheters: A Multicenter, Randomized Trial

PurposeTo compare clinical performance of 2 widely used symmetric-tip hemodialysis catheters. Materials and MethodsPatients with end-stage renal disease initiating or resuming hemodialysis were randomized to receive an Arrow–Clark VectorFlow (n = 50) or Palindrome catheter (n = 50). Primary outcome was 90-d primary unassisted catheter patency. Secondary outcomes were Kt/V ([dialyzer urea clearance × total treatment time]/total volume of urea distribution), urea reduction ratio (URR), and effective blood flow (QB). ResultsPrimary unassisted patency rates with the VectorFlow catheter at 30, 60, and 90 d were 95.5% ± 3.3, 87.2% ± 7.3, and 80.6% ± 9.8, respectively, compared with 89.1% ± 6.2, 79.4% ± 10.0, and 71.5% ± 12.6 with the Palindrome catheter (P = .20). Patients with VectorFlow catheters had a mean Kt/V of 1.5 at 30-, 60-, and 90-day time points, significantly higher than the mean Kt/V of 1.3 among those with Palindrome catheters (P = .0003). URRs were not significantly different between catheters. Catheter QB rates exceeded National Kidney Foundation–recommended thresholds of 300 mL/min at all time points for both catheters and were similar for both catheters (median, 373 mL/min). Catheter failure, ie, poor flow rate requiring guide-wire exchange or removal, within the 90-day primary outcome occurred in 3 VectorFlow subjects and 5 Palindrome subjects (P = .72). Infection rates were similar, with 0.98 infections per 1,000 catheter days for VectorFlow catheters compared with 2.62 per 1,000 catheter days for Palindrome catheters (P = .44). ConclusionsThe 90-day primary patency rates of Palindrome and VectorFlow catheters were not significantly different, and both achieved sustained high QB through 90 day follow-up. However, dialysis adequacy based on Kt/V was consistently better with the VectorFlow catheter versus the Palindrome.

Accuracy of the estimation of V and the implications this has when applying Kt/Vurea for measuring dialysis dose in peritoneal dialysis.

Current guidelines for the prescription of peritoneal dialysis dose rely on a single cut-off 'minimal' value of Kt/V. To apply this in the clinic, this requires an accurate estimation of V, the volume of urea distribution that equates to the total body water (TBW). This analysis sought to determine the accuracy to which V can be estimated. A literature search was undertaken of studies comparing TBW estimation using two or three of the following methods: isotopic dilution (gold standard), anthropometric equations (e.g. Watson formula) and bioimpedance analysis. Studies of healthy and dialysis populations of all ages were included. Mean differences and 95% limits of agreement (LOA) were extracted and pooled. In 44 studies (31 including dialysis subjects), the between-method population means were typically within 1-1.5 L of each other, although larger bias was seen when applying anthropometric equations to different racial groups. However, the 95% LOA for all comparisons were consistently wide, typically ranging ±12-18% of the TBW. For a typical individual whose TBW is 35 L with a measured Kt/V of 1.7, this translates into a range of Kt/V 1.4-2.05. There are limitations to the accuracy of estimation of V which call into question the validity of applying a single threshold Kt/V value as indicative of adequate dialysis. This should be taken into account in guideline development such that if a target Kt/V was deemed appropriate that this should be expressed as a range; alternatively single targets should be avoided and dialysis dose should be determined according to patient need.

Relationship between the filter type and blood flow rate and, dialysis adequacy in hemodialysis patients

Context: One of the main factors associated with the death of chronic renal failure patients is dialysis adequacy. Aims: The present study aimed to investigate the relationship between filter type and blood flow rate with dialysis adequacy in hemodialysis patients referring to educational hospitals of Mazandaran University of Medical Sciences in 2016. Setting and Design: This correlational study was performed in 2016 in educational hospitals of Mazandaran University of Medical Sciences. Materials and Methods: This study was performed on 185 hemodialysis patients. Sampling was done using simple random sampling. The inclusion criteria included at least 6 months of hemodialysis history and two sessions of dialysis per week. Demographic data, as well as information on the filter type and blood flow rate, were collected using a questionnaire. Dialysis adequacy is generally measurable by two methods of urea reduction ratio (URR) and K or urea clearance, T or time of dialysis, and V, or volume of urea distribution in the body (KT/V) (K or urea clearance). Statistical Analysis Used: Data were described with mean, standard deviation, and frequency and analyzed using Chi-square and Fisher's exact tests. Results: Out of a total of 185 patients, 101 patients were male and 84 were female, with a mean age of 57.2 ± 0.7 years. The dialysis adequacy in high-flux and low-flux filters was, respectively, 79% and 1.5% based on the KT/V index and 70.6% and 0% according to the URR index. A statistically significant relationship was found between the filter type and blood flow rate with both KT/V and URR criteria (P Conclusion: It is recommended to use high-flux filters with high blood flow rate to improve dialysis adequacy in patients with hemodialysis. However, other factors affecting dialysis adequacy should be considered.