Jochen Raimann - Academia.edu (original) (raw)
Papers by Jochen Raimann
Despite significant progress in the fields of dialysis technology and medical therapy, mortality ... more Despite significant progress in the fields of dialysis technology and medical therapy, mortality of hemodialysis (HD) patients remains high. Chronic overhydration is a major contributor to the high cardiovascular morbidity and mortality observed in HD patients. The difficulty of measuring excess fluid accurately and the determination of 'dry weight' are reflected in the abundant literature on overhydration. Data indicate that a significant proportion of HD patients are not at 'dry weight'. Considering its impact on cardiovascular diseases, the relation between excess fluid, sodium, interdialytic weight gain, hypertension and cardiac diseases needs more attention. Clearly the reduction of sodium intake is of prime importance. This can be achieved by a reduction of dietary sodium intake, individualized dialysate sodium concentration, avoidance of sodium profiling and use of hypertonic saline during dialysis. These measures are expected to result in less thirst and consecutive water intake, thereby facilitating achieving dry weight (DW). In concert, the application of new tools for DW assessment such as continuous intradialytic bioimpedance spectroscopy measurement, means to prevent intradialytic symptoms (e.g. glucose bolus instead of hypertonic saline; improved hemodynamic stability by reduced dialysate temperature) may be operative in reducing morbidity and mortality in HD patients.
A noninvasive test for determining elevated levels of blood urea nitrogen (BUN) may be useful und... more A noninvasive test for determining elevated levels of blood urea nitrogen (BUN) may be useful under circumstances in which there is limited access to laboratories. Because saliva urea nitrogen (SUN) parallels BUN, we investigated the diagnostic performance of a semiquantitative SUN dipstick to test for elevated BUN levels in patients with chronic kidney disease (CKD). Patients with CKD Stages 1 to 5D were studied. 50 µl of saliva were transferred onto the SUN test strip (Integrated Biomedical Technology, Elkhart, Indiana, IN, USA). SUN was determined after 1 minute by visual comparison of the color of the moistened test pad with 6 calibrated color blocks. Interobserver reproducibility was evaluated by independent observers, masked to urea concentrations of 6 calibrated urea solutions. Correlation between SUN and BUN was quantified by Spearman's rank correlation coefficient (RS), Kappa Statistic was employed to evaluate within-sample reproducibility of duplicates. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic performance of SUN. 68 patients (31 females, 60 ± 14 years; 34 hemodialysis patients, 34 patients CKD Stages 1 - 4) were studied. Interobserver coefficient of variation was 4.9% at SUN levels > 50 mg/dl; within-sample reproducibility was 90%. SUN and BUN were correlated significantly (RS = 0.63; p < 0.01). Elevated BUN was diagnosed with high accuracy by SUN determination (area under the ROC curve: 0.90 (95% CI 0.85 - 0.95)). Semiquantitative dipstick measurements of SUN can reliably identify CKD patients with elevated BUN levels.
Increased salt intake is related to extracellular fluid expansion and a rise in blood pressure, a... more Increased salt intake is related to extracellular fluid expansion and a rise in blood pressure, and has been linked to cardiovascular disease. Several studies have also suggested that sodium can exert detrimental effects via blood pressure-independent mechanisms. Chronic kidney disease patients are particularly susceptible to the negative consequences of sodium loading. While individuals with normal kidney function are able to regulate their sodium balance, hemodialysis patients have to rely virtually entirely on the dialysis procedure for sodium elimination. Tragically, the dialysis procedure has, in many instances, turned into a de facto source of sodium loading rather than a means for sodium removal. The main sources of sodium related to the dialysis procedure are (1) diffusive influx from the dialysate, including inappropriate use of sodium profiling; (2) the use of saline solution for priming and rinsing; and (3) the treatment of intradialytic hypotension and cramps with saline solution. Creating a positive intradialytic sodium balance is effective in acutely reducing the incidence of intradialytic symptoms, but it also sustains a vicious cycle hampering the attainment of dry weight and predisposes the patient to an increased risk of intradialytic complications during the following dialysis session. Avoiding sodium loading in hemodialysis patients is a cornerstone of blood pressure and fluid status management and, therefore, deserves a conscious effort, bearing in mind not only short-term effects but also long-term goals. In the absence of routine means of quantifying sodium balance, sodium profiling should be viewed critically, as it has been shown to induce a positive sodium balance in the majority of cases. A preferred approach under these circumstances may be simple sodium alignment. In combination with the abdication of saline solution for priming, rinsing, and intradialytic infusions, these measures would go a long way to help reduce sodium overload and achieve a more physiologic sodium balance in this patient population.
Frequent hemodialysis can alter volume status, blood pressure and the concentration of osmoticall... more Frequent hemodialysis can alter volume status, blood pressure and the concentration of osmotically active solutes, each of which might affect residual kidney function (RKF). In the Frequent Hemodialysis Network Daily and Nocturnal Trials, we examined the effects of assignment to 6 compared to 3 times per week hemodialysis on follow up RKF. In both trials, baseline RKF was inversely correlated with number of years since onset of ESRD. In the Nocturnal Trial, 63 participants had non-zero RKF at baseline (mean urine volume 0.76 l/d, urea clearance 2.3 ml/min, and creatinine clearance 4.7 ml/min). In those assigned to frequent nocturnal dialysis, these indices were all significantly lower at month 4 and were mostly so at month 12 compared to controls. In the frequent dialysis group, urine volume had declined to zero in 52% and 67% of patients at months 4 and 12, respectively, compared to 18% and 36% in controls. In the Daily Trial, 83 patients had non-zero RKF at baseline (mean urine volume 0.43 l/d, urea clearance 1.2 ml/min, and creatinine clearance 2.7 ml/min). Here, treatment assignment did not significantly influence follow-up levels of the measured indices, although the range in baseline RKF was narrower, potentially limiting power to detect differences. Thus, frequent nocturnal hemodialysis appears to promote a more rapid loss of RKF, the mechanism of which remains to be determined. Whether RKF also declines with frequent daily treatment could not be determined.
Clinical Nephrology, 2014
Measurement of saliva urea nitrogen (SUN) may be valuable in the screening of kidney failure. Her... more Measurement of saliva urea nitrogen (SUN) may be valuable in the screening of kidney failure. Here we evaluate the diagnostic performance of SUN dipsticks in patients with acute kidney injury (AKI). We measured SUN and blood urea nitrogen (BUN) in hospitalized patients diagnosed with AKI based on Acute Kidney Injury Network (AKIN)-criteria. After collection, saliva was transferred to a colorimetric SUN dipstick. We then compared the resultant test-pad color to six standardized color fields indicating SUN of 5 - 14 (#1), 15 - 24 (#2), 25 - 34 (#3), 35 - 54 (#4), 55 - 74 (#5), and ≥ 75 (#6) mg/dL, respectively. We assessed the performance of SUN and BUN to discriminate AKIN 3 from earlier stages by the area under receiver operating characteristic curves (AUC ROC). We enrolled 44 patients (59.5 ± 18 years, 58% female; pre-renal AKI: 67%; renal 24%; post-renal 9%) in AKIN stages 1 (59%), 2 (16%), and 3 (25%). SUN and BUN levels were correlated (Spearman rank Rs = 0.69; p < 0.001, n = 44) with the highest correlation in AKIN 1 (Rs = 0.63, p = 0.001, n = 26). SUN allowed a significant discrimination of AKIN 3 from earlier stages (AUC ROC 0.91; 95% CI 0.80 - 1.0), which was comparable to the diagnostic performance of BUN (AUC ROC 0.90; 95% CI 0.78 - 1.0). SUN dipsticks allow the discrimination of AKIN 3 from earlier AKI stages. This low-technology approach may aid the screening of severe AKI in areas where laboratory resources are scarce.
Physiological Measurement, 2011
Prescription of an appropriate dialysis target weight (dry weight) requires accurate evaluation o... more Prescription of an appropriate dialysis target weight (dry weight) requires accurate evaluation of the degree of hydration. The aim of this study was to investigate whether a state of normal hydration (DW(cBIS)) as defined by calf bioimpedance spectroscopy (cBIS) and conventional whole body bioimpedance spectroscopy (wBIS) could be characterized in hemodialysis (HD) patients and normal subjects (NS). wBIS and cBIS were performed in 62 NS (33 m/29 f) and 30 HD patients (16 m/14 f) pre- and post-dialysis treatments to measure extracellular resistance and fluid volume (ECV) by the whole body and calf bioimpedance methods. Normalized calf resistivity (ρ(N)(,5)) was defined as resistivity at 5 kHz divided by the body mass index. The ratio of wECV to total body water (wECV/TBW) was calculated. Measurements were made at baseline (BL) and at DW(cBIS) following the progressive reduction of post-HD weight over successive dialysis treatments until the curve of calf extracellular resistance is flattened (stabilization) and the ρ(N)(,5) was in the range of NS. Blood pressures were measured pre- and post-HD treatment. ρ(N)(,5) in males and females differed significantly in NS. In patients, ρ(N)(,5) notably increased with progressive decrease in body weight, and systolic blood pressure significantly decreased pre- and post-HD between BL and DW(cBIS) respectively. Although wECV/TBW decreased between BL and DW(cBIS), the percentage of change in wECV/TBW was significantly less than that in ρ(N)(,5) (-5.21 ± 3.2% versus 28 ± 27%, p < 0.001). This establishes the use of ρ(N)(,5) as a new comparator allowing a clinician to incrementally monitor removal of extracellular fluid from patients over the course of dialysis treatments. The conventional whole body technique using wECV/TBW was less sensitive than the use of ρ(N)(,5) to measure differences in body hydration between BL and DW(cBIS).
Nephron. Clinical practice, 2014
Bioimpedance analysis (BIA) is well established to assess body composition. Agreements between si... more Bioimpedance analysis (BIA) is well established to assess body composition. Agreements between single- and multi-frequency bioimpedance (SF-BIA, MF-BIS) measurements in subjects undergoing 6 or 3 times/week hemodialysis (HD) were analyzed. Total body water (TBW) and intra- and extracellular fluid (ICF, ECF) of subjects enrolled in the Frequent Hemodialysis Network (FHN) Daily Trial (www.clinicaltrials.gov No. NCT00264758) were measured with a Hydra 4200 at baseline (BL) and at 5 months (M5). Volumes were computed using SF (at 50 kHz) and MF approaches. Agreement was assessed by means of linear regression and Bland-Altman analysis and treatment effects by t test. 35 subjects (17 on the more frequent regimen, 26 males, 20 African-American, 48 ± 9 years, pre-HD weight 84 ± 19 kg) were studied. Assessments with SF-BIA and MF-BIS correlated significantly at BL and M5 in both arms. No proportional errors, but systematic biases over the entire range of values were found at BL and M5. Agree...
Contributions to Nephrology, 2011
The high mortality of hemodialysis patients has served as a strong incentive to increasing knowle... more The high mortality of hemodialysis patients has served as a strong incentive to increasing knowledge of the possible approaches to optimizing treatment strategies in this patient population. The majority of patients worldwide usually receive hemodialysis thrice-weekly, according to calculations of dialysis adequacy. An abundance of literature and studies, starting as early as the late 1960s, has shown that an increase in dialysis frequency has beneficial impacts on outcomes such as left ventricular hypertrophy, anemia, calcium and phosphorus metabolism, and health- related quality of life. Reductions in left ventricular mass and improvements in quality of life (as measured by RAND-36) by frequent hemodialysis were recently confirmed by a large-scale randomized trial. This is the first trial on this topic which was sufficiently powered and compared the findings in patients receiving frequent hemodialysis to an adequate control group. The significant findings of this trial thus confirmed the evidence in the literature which had been accumulating over decades. This manuscript reviews previous studies on more frequent hemodialysis, including published results of the Frequent Hemodialysis Network Daily Trial.
Seminars in Dialysis, 2011
Numerous reports in the general and the dialysis population have shown associations of sodium (Na... more Numerous reports in the general and the dialysis population have shown associations of sodium (Na(+)) intake, blood pressure, and survival. In addition to dietary Na(+) intake, positive Na(+) balance during dialysis needs to be considered as a source of Na(+). Dialysate Na(+) (DNa(+)) concentrations above the serum Na(+) concentration (SNa(+)) result in diffusive Na(+) flux from the dialysate into the patient, which has recently been reported to be associated with increased interdialytic weight gain and mortality. Individualization of the Na(+) prescription and Na(+) alignment (DNa(+) equal to SNa(+)) prevents positive Na(+) balance and improves patient outcomes. Alignment requires the knowledge of patients' SNa(+), which can be estimated from previous SNa(+) in the monthly routine laboratory measurements. Na(+) alignment was recently implemented in a dialysis clinic of Renal Research Institute. Preliminary results of this initiative have shown a trend of predialysis weight and blood pressure reduction. Expansion of this initiative to all clinics of RRI is currently underway and as of April 2011, four additional clinics have been included. Additional research on adequate Na(+) alignment is needed to account for Gibbs-Donnan effects, differences in charge across the dialyzer membrane, and variability in measurement methods. Regular calibration of DNa(+) delivery by dialysis machines is necessary to ensure that the dialysis prescription is followed. How to provide dialysis to severely hyponatremic patients remains an open question. Finally, long-term studies of the effects of Na(+) restriction on hospitalization and mortality are required to demonstrate the benefits of aligning DNa(+) with SNa(+).
Seminars in Dialysis, 2013
Seminars in Dialysis, 2013
Vitamin C has several well-established roles in physiology including synthesis of collagen, carni... more Vitamin C has several well-established roles in physiology including synthesis of collagen, carnitine and epinephrine, absorption of dietary iron, and mobilization of storage iron for erythropoeisis. Loss of several of these functions explains the pathology of scurvy, where defective collagen synthesis and anemia are major symptoms. Vitamin C deficiency is very common in dialysis patients and may arise from dialytic vitamin C clearance, restricted intake of vitamin C-rich foods, and increased vitamin C catabolism in vivo from inflammation. In the dialysis population, greater vitamin C intake may be needed for optimal health. Relationships between intake, body distribution, inflammation, and dialytic losses are complex and
Nephrology Dialysis Transplantation, 2012
Various biochemical and physiological variables are related to outcome in hemodialysis (HD) patie... more Various biochemical and physiological variables are related to outcome in hemodialysis (HD) patients. However, the prognostic implications of trends in body temperature (BT) in this population have not yet been studied. The aim of this study was to assess the relationship between trends in BT and outcome in incident HD patients. Six thousand seven hundred and forty-two incident HD patients without thyroid disease from the Renal Research Institute were followed for 1 year. Patients were divided into tertiles of initial pre-dialysis BT (Tertile 1: ≤ 36.47°C, Tertile 2: > 36.47 to 36.71°C and Tertile 3: > 36.7°C) and further classified according to the change in BT (increased: > 0.01°C/month, decreased: less than -0.01°C/month and stable, with change between - 0.01 and + 0.01°C/month) during the first year of treatment. The reference group is Tertile 2 of initial temperature with stable BT. Cox regression was used for survival analyses. Analyses were repeated for patients who survived the first year and were treated for ≥ 1 month in Year 2. BT decreased in 2903 patients, remained stable in 2238 patients and increased in 1601 patients. After adjustment for multiple risk factors, hazard ratios (HRs) for mortality were higher for those groups in whom, irrespective of the initial BT, BT increased or declined, as compared to the reference group during follow-up (HR between 1.46 and 2.27). The best survival was observed in the group with the highest BT at baseline and stable BT during the follow-up period (HR 0.50).
Nephrology Dialysis Transplantation, 2012
Background. There is no agreement concerning dialyzate glucose concentration in hemodialysis (HD)... more Background. There is no agreement concerning dialyzate glucose concentration in hemodialysis (HD) and 100 and 200 mg/dL (G100 and G200) are frequently used. G200 may result in diffusive glucose flux into the patient, with consequent hyperglycemia and hyperinsulinism, and electrolyte alterations, in particular potassium (K) and phosphorus (P). This trial compared metabolic effects of G100 versus G200. Methods. Chronic HD patients participated in this randomized, single masked, controlled crossover trial (www.clinicaltrials.gov: #NCT00618033) consisting of two consecutive 3-week segments with G100 and G200, respectively. Intradialytic serum glucose (SG) and insulin concentrations (SI) were measured at 0, 30, 60, 120, 180, 240 min and immediately post-HD; P and K were measured at 0, 120, 180 min and post-HD. Hypoglycemia was defined as an SG <70 mg/dL. Mean SG and SI were computed as area under the curve divided by treatment time. Results. Fourteen diabetic and 15 non-diabetic subjects were studied. SG was significantly higher with G200 as compared to G100, both in diabetic {G200: 192.8 6 48.1 mg/dL; G100: 154.0 6 27.3 mg/dL; difference 38.8 [95% confidence interval (CI): 21.2-56.4] mg/dL; P < 0.001} and non-diabetic subjects [G200: 127.0 6 11.2 mg/dL; G100 106.5 6 10.8 mg/dL; difference 20.6 (95% CI: 15.3-25.9) mg/dL; P < 0.001]. SI was significantly higher with G200 in non-diabetic subjects. Frequency of hypoglycemia, P and K serum levels, interdialytic weight gain and adverse intradialytic events did not differ significantly between G100 and G200. Conclusion. G200 may exert unfavorable metabolic effects in chronic HD patients, in particular hyperglycemia and hyperinsulinism, the latter in non-diabetic subjects.
Nephrology Dialysis Transplantation, 2013
Nephrology, 2012
The aim of this study was to demonstrate the ability of widely used bioimpedance techniques to as... more The aim of this study was to demonstrate the ability of widely used bioimpedance techniques to assess dry weight (DW) and to predict a state of normal hydration in haemodialysis patients whose post-dialysis weight had been gradually reduced from baseline in successive treatments over time. Calf bioimpedance spectroscopy (cBIS) was employed to determine DW (DW(cBIS) ) as defined by flattening of an intradialytic continuously measured resistance curve and by normalized resistivity (nRho) being in the gender-specific normal range. The wECV/TBW ratio was determined by &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;classical&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; wrist-to-ankle whole body bioimpedance spectroscopy (wBIS); in addition, a novel whole body model (WBM) based on wBIS was used to predict normal hydration weight (NHW(WBM) ). Twenty-one haemodialysis patients were studied; 11 ± 6 measurements were performed per patient. Nine patients reached DW(cBIS) (DW(cBIS) group), while 12 patients remained fluid-overloaded (non-DW(cBIS) group). Change in wECV as measured by wBIS accounted for 46 ± 23% in DW(cBIS) group, which was higher than in non-DW(cBIS) group (33 ± 48%, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) of actual weight loss at the end of study. In both groups the wECV/TBW ratio did not change significantly between baseline and study end. Mean predicted NHW(WBM) at baseline was 3.55 ± 1.6 kg higher than DW(cBIS) . The difference in DW(cBIS) and NHW(WBM) was 1.97 ± 1.0 kg at study end. WBM could be useful to predict a target range of normal hydration weight particularly for patients with substantial fluid overload. The cBIS provides an accurate reference for the estimation of DW so that combined use of cBIS and WBM is promising and warrants further studies.
Kidney International, 2012
The association between changes in systolic and diastolic blood pressure, and the use of cardiopr... more The association between changes in systolic and diastolic blood pressure, and the use of cardioprotective drugs on survival of incident hemodialysis patients, was examined in this retrospective cohort study. Pre-hemodialysis systolic and diastolic blood pressures were averaged over the first month of hemodialysis. Slopes, reflecting temporal changes, were computed by linear regression of systolic blood pressures and Cox regression was used for survival analyses. Patients were initially stratified into four cohorts (below 120, 120 to 150, 151 to 180, and above 180 mm Hg) and further subdivided into groups with stable (no more than a 1-mm Hg change per month), increasing (over 1-mm Hg per month), and decreasing (less than 1-mm Hg per month) slopes during the first year. Analyses were repeated for patients who were treated with cardioprotective drugs for 1 month or more in the second year. In 10,245 patients (59% prescribed cardioprotective drugs), both increases and decreases in all ranges of blood pressure were associated with worse outcomes, whereas stable blood pressure had a survival advantage at all levels of systolic and diastolic pressures. Use of cardioprotective drugs attenuated changes and improved survival. Validation and sensitivity analyses confirmed the primary findings. Therefore, previous temporal trends need to be considered in patient care, and the use of cardioprotective agents is associated with enhanced survival at all blood pressure levels.
Kidney International, 2014
Bioimpedance analysis (BIA) is accepted for the assessment of total-body water (TBW), intracellul... more Bioimpedance analysis (BIA) is accepted for the assessment of total-body water (TBW), intracellular fluid (ICF) and extracellular fluid (ECF). We aimed to compare precision and accuracy of single and multi-frequency-BIA to direct estimation methods (DEMs) of TBW, ECF, and ICF in hemodialysis patients. Linear regression analysis of volume estimates in 49 patients by single- and multi-frequency-BIA correlated significantly with DEMs. Bland-Altman analysis (BAA) found systemic bias for ECF single-frequency-BIA vs. ECF-DEMs. No other systematic biases were found. Proportional errors were found by BAA of ICF and ECF assessments with single- and multi-frequency bioimpedance spectroscopy compared to the DEMs. Comparisons of indirect methods (IEMs) to DEMs showed no significant differences and proportional errors. Root mean-squared-error analysis suggested slightly better accuracy and precision of ICF single-frequency-BIA vs. DEMs over ICF multi-frequency-BIA and IEMs to DEMs, and slightly better performance for ECF multi-frequency-BIA over both respective other methods. Compared to DEMs, there is slightly better accuracy for ECF multi- over single-frequency-BIA and ICF single- over multi-frequency-BIA. However the margin of differences between direct and indirect methods suggests that none of the analyzed methods served as a true &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;gold standard&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;, because indirect methods are almost equally precise compared to DEMs.
Kidney and Blood Pressure Research, 2012
In incident hemodialysis (HD) patients, the relationship between early systolic blood pressure (S... more In incident hemodialysis (HD) patients, the relationship between early systolic blood pressure (SBP) dynamics and mortality is unknown. Baseline SBP levels were stratified into 5 categories ranging from &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;120 and ≥180 mm Hg. Early pre-HD SBP change was defined as the slope of pre-HD SBP from week 1 to 12 and categorized in quartiles (Q1, lowest slope). SBP slopes were computed for each patient by simple linear regression. In 3,446 incident HD patients (42% females, 44% black, age 62 ± 15 years), the median pre-HD SBP slope was -1.7 (Q1) to +2.3 (Q4) mm Hg/week. In an adjusted multivariate Cox regression analysis, patients with declining SBP (slope Q1) had higher mortality compared to patients with increasing pre-HD SBP (slope Q4) at 12 months (hazard ratio 2.01, 95% confidence interval 1.35-3.01). In addition, patients with baseline pre-HD SBP &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;120 mm Hg showed higher mortality compared to the reference group (SBP ≥180 mm Hg) at 12 months (hazard ratio 1.89, 95% confidence interval 1.03-3.45). Baseline pre-HD SBP and early SBP dynamics are associated with mortality in the first year of dialysis. Patients who had low (pre-HD SBP &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;120 mm Hg) or declining SBP had the highest mortality rates. Particular attention is warranted in incident HD patients with low or declining SBP.
Journal of the American Society of Nephrology, 2013
The effects of high-flux dialysis and ultrapure dialysate on survival of hemodialysis patients ar... more The effects of high-flux dialysis and ultrapure dialysate on survival of hemodialysis patients are incompletely understood. We conducted a randomized controlled trial to investigate the effects of both membrane permeability and dialysate purity on cardiovascular outcomes. We randomly assigned 704 patients on three times per week hemodialysis to either high-or low-flux dialyzers and either ultrapure or standard dialysate using a two-by-two factorial design. The primary outcome was a composite of fatal and nonfatal cardiovascular events during a minimum 3 years follow-up. We did not detect statistically significant differences in the primary outcome between high-and low-flux (HR=0.73, 95% CI=0.49 to 1.08, P=0.12) and between ultrapure and standard dialysate (HR=0.90, 95% CI=0.61 to 1.32, P=0.60). Posthoc analyses suggested that cardiovascular event-free survival was significantly better in the high-flux group compared with the low-flux group for the subgroup with arteriovenous fistulas, which constituted 82% of the study population (adjusted HR=0.61, 95% CI=0.38 to 0.97, P=0.03). Furthermore, high-flux dialysis associated with a lower risk for cardiovascular events among diabetic subjects (adjusted HR=0.49, 95% CI=0.25 to 0.94, P=0.03), and ultrapure dialysate associated with a lower risk for cardiovascular events among subjects with more than 3 years of dialysis (adjusted HR=0.55, 95% CI=0.31 to 0.97, P=0.04). In conclusion, this trial did not detect a difference in cardiovascular event-free survival between flux and dialysate groups. Posthoc analyses suggest that high-flux hemodialysis may benefit patients with an arteriovenous fistula and patients with diabetes and that ultrapure dialysate may benefit patients with longer dialysis vintage.
Despite significant progress in the fields of dialysis technology and medical therapy, mortality ... more Despite significant progress in the fields of dialysis technology and medical therapy, mortality of hemodialysis (HD) patients remains high. Chronic overhydration is a major contributor to the high cardiovascular morbidity and mortality observed in HD patients. The difficulty of measuring excess fluid accurately and the determination of 'dry weight' are reflected in the abundant literature on overhydration. Data indicate that a significant proportion of HD patients are not at 'dry weight'. Considering its impact on cardiovascular diseases, the relation between excess fluid, sodium, interdialytic weight gain, hypertension and cardiac diseases needs more attention. Clearly the reduction of sodium intake is of prime importance. This can be achieved by a reduction of dietary sodium intake, individualized dialysate sodium concentration, avoidance of sodium profiling and use of hypertonic saline during dialysis. These measures are expected to result in less thirst and consecutive water intake, thereby facilitating achieving dry weight (DW). In concert, the application of new tools for DW assessment such as continuous intradialytic bioimpedance spectroscopy measurement, means to prevent intradialytic symptoms (e.g. glucose bolus instead of hypertonic saline; improved hemodynamic stability by reduced dialysate temperature) may be operative in reducing morbidity and mortality in HD patients.
A noninvasive test for determining elevated levels of blood urea nitrogen (BUN) may be useful und... more A noninvasive test for determining elevated levels of blood urea nitrogen (BUN) may be useful under circumstances in which there is limited access to laboratories. Because saliva urea nitrogen (SUN) parallels BUN, we investigated the diagnostic performance of a semiquantitative SUN dipstick to test for elevated BUN levels in patients with chronic kidney disease (CKD). Patients with CKD Stages 1 to 5D were studied. 50 µl of saliva were transferred onto the SUN test strip (Integrated Biomedical Technology, Elkhart, Indiana, IN, USA). SUN was determined after 1 minute by visual comparison of the color of the moistened test pad with 6 calibrated color blocks. Interobserver reproducibility was evaluated by independent observers, masked to urea concentrations of 6 calibrated urea solutions. Correlation between SUN and BUN was quantified by Spearman&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s rank correlation coefficient (RS), Kappa Statistic was employed to evaluate within-sample reproducibility of duplicates. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic performance of SUN. 68 patients (31 females, 60 ± 14 years; 34 hemodialysis patients, 34 patients CKD Stages 1 - 4) were studied. Interobserver coefficient of variation was 4.9% at SUN levels &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 50 mg/dl; within-sample reproducibility was 90%. SUN and BUN were correlated significantly (RS = 0.63; p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). Elevated BUN was diagnosed with high accuracy by SUN determination (area under the ROC curve: 0.90 (95% CI 0.85 - 0.95)). Semiquantitative dipstick measurements of SUN can reliably identify CKD patients with elevated BUN levels.
Increased salt intake is related to extracellular fluid expansion and a rise in blood pressure, a... more Increased salt intake is related to extracellular fluid expansion and a rise in blood pressure, and has been linked to cardiovascular disease. Several studies have also suggested that sodium can exert detrimental effects via blood pressure-independent mechanisms. Chronic kidney disease patients are particularly susceptible to the negative consequences of sodium loading. While individuals with normal kidney function are able to regulate their sodium balance, hemodialysis patients have to rely virtually entirely on the dialysis procedure for sodium elimination. Tragically, the dialysis procedure has, in many instances, turned into a de facto source of sodium loading rather than a means for sodium removal. The main sources of sodium related to the dialysis procedure are (1) diffusive influx from the dialysate, including inappropriate use of sodium profiling; (2) the use of saline solution for priming and rinsing; and (3) the treatment of intradialytic hypotension and cramps with saline solution. Creating a positive intradialytic sodium balance is effective in acutely reducing the incidence of intradialytic symptoms, but it also sustains a vicious cycle hampering the attainment of dry weight and predisposes the patient to an increased risk of intradialytic complications during the following dialysis session. Avoiding sodium loading in hemodialysis patients is a cornerstone of blood pressure and fluid status management and, therefore, deserves a conscious effort, bearing in mind not only short-term effects but also long-term goals. In the absence of routine means of quantifying sodium balance, sodium profiling should be viewed critically, as it has been shown to induce a positive sodium balance in the majority of cases. A preferred approach under these circumstances may be simple sodium alignment. In combination with the abdication of saline solution for priming, rinsing, and intradialytic infusions, these measures would go a long way to help reduce sodium overload and achieve a more physiologic sodium balance in this patient population.
Frequent hemodialysis can alter volume status, blood pressure and the concentration of osmoticall... more Frequent hemodialysis can alter volume status, blood pressure and the concentration of osmotically active solutes, each of which might affect residual kidney function (RKF). In the Frequent Hemodialysis Network Daily and Nocturnal Trials, we examined the effects of assignment to 6 compared to 3 times per week hemodialysis on follow up RKF. In both trials, baseline RKF was inversely correlated with number of years since onset of ESRD. In the Nocturnal Trial, 63 participants had non-zero RKF at baseline (mean urine volume 0.76 l/d, urea clearance 2.3 ml/min, and creatinine clearance 4.7 ml/min). In those assigned to frequent nocturnal dialysis, these indices were all significantly lower at month 4 and were mostly so at month 12 compared to controls. In the frequent dialysis group, urine volume had declined to zero in 52% and 67% of patients at months 4 and 12, respectively, compared to 18% and 36% in controls. In the Daily Trial, 83 patients had non-zero RKF at baseline (mean urine volume 0.43 l/d, urea clearance 1.2 ml/min, and creatinine clearance 2.7 ml/min). Here, treatment assignment did not significantly influence follow-up levels of the measured indices, although the range in baseline RKF was narrower, potentially limiting power to detect differences. Thus, frequent nocturnal hemodialysis appears to promote a more rapid loss of RKF, the mechanism of which remains to be determined. Whether RKF also declines with frequent daily treatment could not be determined.
Clinical Nephrology, 2014
Measurement of saliva urea nitrogen (SUN) may be valuable in the screening of kidney failure. Her... more Measurement of saliva urea nitrogen (SUN) may be valuable in the screening of kidney failure. Here we evaluate the diagnostic performance of SUN dipsticks in patients with acute kidney injury (AKI). We measured SUN and blood urea nitrogen (BUN) in hospitalized patients diagnosed with AKI based on Acute Kidney Injury Network (AKIN)-criteria. After collection, saliva was transferred to a colorimetric SUN dipstick. We then compared the resultant test-pad color to six standardized color fields indicating SUN of 5 - 14 (#1), 15 - 24 (#2), 25 - 34 (#3), 35 - 54 (#4), 55 - 74 (#5), and ≥ 75 (#6) mg/dL, respectively. We assessed the performance of SUN and BUN to discriminate AKIN 3 from earlier stages by the area under receiver operating characteristic curves (AUC ROC). We enrolled 44 patients (59.5 ± 18 years, 58% female; pre-renal AKI: 67%; renal 24%; post-renal 9%) in AKIN stages 1 (59%), 2 (16%), and 3 (25%). SUN and BUN levels were correlated (Spearman rank Rs = 0.69; p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001, n = 44) with the highest correlation in AKIN 1 (Rs = 0.63, p = 0.001, n = 26). SUN allowed a significant discrimination of AKIN 3 from earlier stages (AUC ROC 0.91; 95% CI 0.80 - 1.0), which was comparable to the diagnostic performance of BUN (AUC ROC 0.90; 95% CI 0.78 - 1.0). SUN dipsticks allow the discrimination of AKIN 3 from earlier AKI stages. This low-technology approach may aid the screening of severe AKI in areas where laboratory resources are scarce.
Physiological Measurement, 2011
Prescription of an appropriate dialysis target weight (dry weight) requires accurate evaluation o... more Prescription of an appropriate dialysis target weight (dry weight) requires accurate evaluation of the degree of hydration. The aim of this study was to investigate whether a state of normal hydration (DW(cBIS)) as defined by calf bioimpedance spectroscopy (cBIS) and conventional whole body bioimpedance spectroscopy (wBIS) could be characterized in hemodialysis (HD) patients and normal subjects (NS). wBIS and cBIS were performed in 62 NS (33 m/29 f) and 30 HD patients (16 m/14 f) pre- and post-dialysis treatments to measure extracellular resistance and fluid volume (ECV) by the whole body and calf bioimpedance methods. Normalized calf resistivity (ρ(N)(,5)) was defined as resistivity at 5 kHz divided by the body mass index. The ratio of wECV to total body water (wECV/TBW) was calculated. Measurements were made at baseline (BL) and at DW(cBIS) following the progressive reduction of post-HD weight over successive dialysis treatments until the curve of calf extracellular resistance is flattened (stabilization) and the ρ(N)(,5) was in the range of NS. Blood pressures were measured pre- and post-HD treatment. ρ(N)(,5) in males and females differed significantly in NS. In patients, ρ(N)(,5) notably increased with progressive decrease in body weight, and systolic blood pressure significantly decreased pre- and post-HD between BL and DW(cBIS) respectively. Although wECV/TBW decreased between BL and DW(cBIS), the percentage of change in wECV/TBW was significantly less than that in ρ(N)(,5) (-5.21 ± 3.2% versus 28 ± 27%, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). This establishes the use of ρ(N)(,5) as a new comparator allowing a clinician to incrementally monitor removal of extracellular fluid from patients over the course of dialysis treatments. The conventional whole body technique using wECV/TBW was less sensitive than the use of ρ(N)(,5) to measure differences in body hydration between BL and DW(cBIS).
Nephron. Clinical practice, 2014
Bioimpedance analysis (BIA) is well established to assess body composition. Agreements between si... more Bioimpedance analysis (BIA) is well established to assess body composition. Agreements between single- and multi-frequency bioimpedance (SF-BIA, MF-BIS) measurements in subjects undergoing 6 or 3 times/week hemodialysis (HD) were analyzed. Total body water (TBW) and intra- and extracellular fluid (ICF, ECF) of subjects enrolled in the Frequent Hemodialysis Network (FHN) Daily Trial (www.clinicaltrials.gov No. NCT00264758) were measured with a Hydra 4200 at baseline (BL) and at 5 months (M5). Volumes were computed using SF (at 50 kHz) and MF approaches. Agreement was assessed by means of linear regression and Bland-Altman analysis and treatment effects by t test. 35 subjects (17 on the more frequent regimen, 26 males, 20 African-American, 48 ± 9 years, pre-HD weight 84 ± 19 kg) were studied. Assessments with SF-BIA and MF-BIS correlated significantly at BL and M5 in both arms. No proportional errors, but systematic biases over the entire range of values were found at BL and M5. Agree...
Contributions to Nephrology, 2011
The high mortality of hemodialysis patients has served as a strong incentive to increasing knowle... more The high mortality of hemodialysis patients has served as a strong incentive to increasing knowledge of the possible approaches to optimizing treatment strategies in this patient population. The majority of patients worldwide usually receive hemodialysis thrice-weekly, according to calculations of dialysis adequacy. An abundance of literature and studies, starting as early as the late 1960s, has shown that an increase in dialysis frequency has beneficial impacts on outcomes such as left ventricular hypertrophy, anemia, calcium and phosphorus metabolism, and health- related quality of life. Reductions in left ventricular mass and improvements in quality of life (as measured by RAND-36) by frequent hemodialysis were recently confirmed by a large-scale randomized trial. This is the first trial on this topic which was sufficiently powered and compared the findings in patients receiving frequent hemodialysis to an adequate control group. The significant findings of this trial thus confirmed the evidence in the literature which had been accumulating over decades. This manuscript reviews previous studies on more frequent hemodialysis, including published results of the Frequent Hemodialysis Network Daily Trial.
Seminars in Dialysis, 2011
Numerous reports in the general and the dialysis population have shown associations of sodium (Na... more Numerous reports in the general and the dialysis population have shown associations of sodium (Na(+)) intake, blood pressure, and survival. In addition to dietary Na(+) intake, positive Na(+) balance during dialysis needs to be considered as a source of Na(+). Dialysate Na(+) (DNa(+)) concentrations above the serum Na(+) concentration (SNa(+)) result in diffusive Na(+) flux from the dialysate into the patient, which has recently been reported to be associated with increased interdialytic weight gain and mortality. Individualization of the Na(+) prescription and Na(+) alignment (DNa(+) equal to SNa(+)) prevents positive Na(+) balance and improves patient outcomes. Alignment requires the knowledge of patients&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; SNa(+), which can be estimated from previous SNa(+) in the monthly routine laboratory measurements. Na(+) alignment was recently implemented in a dialysis clinic of Renal Research Institute. Preliminary results of this initiative have shown a trend of predialysis weight and blood pressure reduction. Expansion of this initiative to all clinics of RRI is currently underway and as of April 2011, four additional clinics have been included. Additional research on adequate Na(+) alignment is needed to account for Gibbs-Donnan effects, differences in charge across the dialyzer membrane, and variability in measurement methods. Regular calibration of DNa(+) delivery by dialysis machines is necessary to ensure that the dialysis prescription is followed. How to provide dialysis to severely hyponatremic patients remains an open question. Finally, long-term studies of the effects of Na(+) restriction on hospitalization and mortality are required to demonstrate the benefits of aligning DNa(+) with SNa(+).
Seminars in Dialysis, 2013
Seminars in Dialysis, 2013
Vitamin C has several well-established roles in physiology including synthesis of collagen, carni... more Vitamin C has several well-established roles in physiology including synthesis of collagen, carnitine and epinephrine, absorption of dietary iron, and mobilization of storage iron for erythropoeisis. Loss of several of these functions explains the pathology of scurvy, where defective collagen synthesis and anemia are major symptoms. Vitamin C deficiency is very common in dialysis patients and may arise from dialytic vitamin C clearance, restricted intake of vitamin C-rich foods, and increased vitamin C catabolism in vivo from inflammation. In the dialysis population, greater vitamin C intake may be needed for optimal health. Relationships between intake, body distribution, inflammation, and dialytic losses are complex and
Nephrology Dialysis Transplantation, 2012
Various biochemical and physiological variables are related to outcome in hemodialysis (HD) patie... more Various biochemical and physiological variables are related to outcome in hemodialysis (HD) patients. However, the prognostic implications of trends in body temperature (BT) in this population have not yet been studied. The aim of this study was to assess the relationship between trends in BT and outcome in incident HD patients. Six thousand seven hundred and forty-two incident HD patients without thyroid disease from the Renal Research Institute were followed for 1 year. Patients were divided into tertiles of initial pre-dialysis BT (Tertile 1: ≤ 36.47°C, Tertile 2: &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 36.47 to 36.71°C and Tertile 3: &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 36.7°C) and further classified according to the change in BT (increased: &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.01°C/month, decreased: less than -0.01°C/month and stable, with change between - 0.01 and + 0.01°C/month) during the first year of treatment. The reference group is Tertile 2 of initial temperature with stable BT. Cox regression was used for survival analyses. Analyses were repeated for patients who survived the first year and were treated for ≥ 1 month in Year 2. BT decreased in 2903 patients, remained stable in 2238 patients and increased in 1601 patients. After adjustment for multiple risk factors, hazard ratios (HRs) for mortality were higher for those groups in whom, irrespective of the initial BT, BT increased or declined, as compared to the reference group during follow-up (HR between 1.46 and 2.27). The best survival was observed in the group with the highest BT at baseline and stable BT during the follow-up period (HR 0.50).
Nephrology Dialysis Transplantation, 2012
Background. There is no agreement concerning dialyzate glucose concentration in hemodialysis (HD)... more Background. There is no agreement concerning dialyzate glucose concentration in hemodialysis (HD) and 100 and 200 mg/dL (G100 and G200) are frequently used. G200 may result in diffusive glucose flux into the patient, with consequent hyperglycemia and hyperinsulinism, and electrolyte alterations, in particular potassium (K) and phosphorus (P). This trial compared metabolic effects of G100 versus G200. Methods. Chronic HD patients participated in this randomized, single masked, controlled crossover trial (www.clinicaltrials.gov: #NCT00618033) consisting of two consecutive 3-week segments with G100 and G200, respectively. Intradialytic serum glucose (SG) and insulin concentrations (SI) were measured at 0, 30, 60, 120, 180, 240 min and immediately post-HD; P and K were measured at 0, 120, 180 min and post-HD. Hypoglycemia was defined as an SG <70 mg/dL. Mean SG and SI were computed as area under the curve divided by treatment time. Results. Fourteen diabetic and 15 non-diabetic subjects were studied. SG was significantly higher with G200 as compared to G100, both in diabetic {G200: 192.8 6 48.1 mg/dL; G100: 154.0 6 27.3 mg/dL; difference 38.8 [95% confidence interval (CI): 21.2-56.4] mg/dL; P < 0.001} and non-diabetic subjects [G200: 127.0 6 11.2 mg/dL; G100 106.5 6 10.8 mg/dL; difference 20.6 (95% CI: 15.3-25.9) mg/dL; P < 0.001]. SI was significantly higher with G200 in non-diabetic subjects. Frequency of hypoglycemia, P and K serum levels, interdialytic weight gain and adverse intradialytic events did not differ significantly between G100 and G200. Conclusion. G200 may exert unfavorable metabolic effects in chronic HD patients, in particular hyperglycemia and hyperinsulinism, the latter in non-diabetic subjects.
Nephrology Dialysis Transplantation, 2013
Nephrology, 2012
The aim of this study was to demonstrate the ability of widely used bioimpedance techniques to as... more The aim of this study was to demonstrate the ability of widely used bioimpedance techniques to assess dry weight (DW) and to predict a state of normal hydration in haemodialysis patients whose post-dialysis weight had been gradually reduced from baseline in successive treatments over time. Calf bioimpedance spectroscopy (cBIS) was employed to determine DW (DW(cBIS) ) as defined by flattening of an intradialytic continuously measured resistance curve and by normalized resistivity (nRho) being in the gender-specific normal range. The wECV/TBW ratio was determined by &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;classical&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; wrist-to-ankle whole body bioimpedance spectroscopy (wBIS); in addition, a novel whole body model (WBM) based on wBIS was used to predict normal hydration weight (NHW(WBM) ). Twenty-one haemodialysis patients were studied; 11 ± 6 measurements were performed per patient. Nine patients reached DW(cBIS) (DW(cBIS) group), while 12 patients remained fluid-overloaded (non-DW(cBIS) group). Change in wECV as measured by wBIS accounted for 46 ± 23% in DW(cBIS) group, which was higher than in non-DW(cBIS) group (33 ± 48%, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) of actual weight loss at the end of study. In both groups the wECV/TBW ratio did not change significantly between baseline and study end. Mean predicted NHW(WBM) at baseline was 3.55 ± 1.6 kg higher than DW(cBIS) . The difference in DW(cBIS) and NHW(WBM) was 1.97 ± 1.0 kg at study end. WBM could be useful to predict a target range of normal hydration weight particularly for patients with substantial fluid overload. The cBIS provides an accurate reference for the estimation of DW so that combined use of cBIS and WBM is promising and warrants further studies.
Kidney International, 2012
The association between changes in systolic and diastolic blood pressure, and the use of cardiopr... more The association between changes in systolic and diastolic blood pressure, and the use of cardioprotective drugs on survival of incident hemodialysis patients, was examined in this retrospective cohort study. Pre-hemodialysis systolic and diastolic blood pressures were averaged over the first month of hemodialysis. Slopes, reflecting temporal changes, were computed by linear regression of systolic blood pressures and Cox regression was used for survival analyses. Patients were initially stratified into four cohorts (below 120, 120 to 150, 151 to 180, and above 180 mm Hg) and further subdivided into groups with stable (no more than a 1-mm Hg change per month), increasing (over 1-mm Hg per month), and decreasing (less than 1-mm Hg per month) slopes during the first year. Analyses were repeated for patients who were treated with cardioprotective drugs for 1 month or more in the second year. In 10,245 patients (59% prescribed cardioprotective drugs), both increases and decreases in all ranges of blood pressure were associated with worse outcomes, whereas stable blood pressure had a survival advantage at all levels of systolic and diastolic pressures. Use of cardioprotective drugs attenuated changes and improved survival. Validation and sensitivity analyses confirmed the primary findings. Therefore, previous temporal trends need to be considered in patient care, and the use of cardioprotective agents is associated with enhanced survival at all blood pressure levels.
Kidney International, 2014
Bioimpedance analysis (BIA) is accepted for the assessment of total-body water (TBW), intracellul... more Bioimpedance analysis (BIA) is accepted for the assessment of total-body water (TBW), intracellular fluid (ICF) and extracellular fluid (ECF). We aimed to compare precision and accuracy of single and multi-frequency-BIA to direct estimation methods (DEMs) of TBW, ECF, and ICF in hemodialysis patients. Linear regression analysis of volume estimates in 49 patients by single- and multi-frequency-BIA correlated significantly with DEMs. Bland-Altman analysis (BAA) found systemic bias for ECF single-frequency-BIA vs. ECF-DEMs. No other systematic biases were found. Proportional errors were found by BAA of ICF and ECF assessments with single- and multi-frequency bioimpedance spectroscopy compared to the DEMs. Comparisons of indirect methods (IEMs) to DEMs showed no significant differences and proportional errors. Root mean-squared-error analysis suggested slightly better accuracy and precision of ICF single-frequency-BIA vs. DEMs over ICF multi-frequency-BIA and IEMs to DEMs, and slightly better performance for ECF multi-frequency-BIA over both respective other methods. Compared to DEMs, there is slightly better accuracy for ECF multi- over single-frequency-BIA and ICF single- over multi-frequency-BIA. However the margin of differences between direct and indirect methods suggests that none of the analyzed methods served as a true &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;gold standard&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;, because indirect methods are almost equally precise compared to DEMs.
Kidney and Blood Pressure Research, 2012
In incident hemodialysis (HD) patients, the relationship between early systolic blood pressure (S... more In incident hemodialysis (HD) patients, the relationship between early systolic blood pressure (SBP) dynamics and mortality is unknown. Baseline SBP levels were stratified into 5 categories ranging from &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;120 and ≥180 mm Hg. Early pre-HD SBP change was defined as the slope of pre-HD SBP from week 1 to 12 and categorized in quartiles (Q1, lowest slope). SBP slopes were computed for each patient by simple linear regression. In 3,446 incident HD patients (42% females, 44% black, age 62 ± 15 years), the median pre-HD SBP slope was -1.7 (Q1) to +2.3 (Q4) mm Hg/week. In an adjusted multivariate Cox regression analysis, patients with declining SBP (slope Q1) had higher mortality compared to patients with increasing pre-HD SBP (slope Q4) at 12 months (hazard ratio 2.01, 95% confidence interval 1.35-3.01). In addition, patients with baseline pre-HD SBP &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;120 mm Hg showed higher mortality compared to the reference group (SBP ≥180 mm Hg) at 12 months (hazard ratio 1.89, 95% confidence interval 1.03-3.45). Baseline pre-HD SBP and early SBP dynamics are associated with mortality in the first year of dialysis. Patients who had low (pre-HD SBP &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;120 mm Hg) or declining SBP had the highest mortality rates. Particular attention is warranted in incident HD patients with low or declining SBP.
Journal of the American Society of Nephrology, 2013
The effects of high-flux dialysis and ultrapure dialysate on survival of hemodialysis patients ar... more The effects of high-flux dialysis and ultrapure dialysate on survival of hemodialysis patients are incompletely understood. We conducted a randomized controlled trial to investigate the effects of both membrane permeability and dialysate purity on cardiovascular outcomes. We randomly assigned 704 patients on three times per week hemodialysis to either high-or low-flux dialyzers and either ultrapure or standard dialysate using a two-by-two factorial design. The primary outcome was a composite of fatal and nonfatal cardiovascular events during a minimum 3 years follow-up. We did not detect statistically significant differences in the primary outcome between high-and low-flux (HR=0.73, 95% CI=0.49 to 1.08, P=0.12) and between ultrapure and standard dialysate (HR=0.90, 95% CI=0.61 to 1.32, P=0.60). Posthoc analyses suggested that cardiovascular event-free survival was significantly better in the high-flux group compared with the low-flux group for the subgroup with arteriovenous fistulas, which constituted 82% of the study population (adjusted HR=0.61, 95% CI=0.38 to 0.97, P=0.03). Furthermore, high-flux dialysis associated with a lower risk for cardiovascular events among diabetic subjects (adjusted HR=0.49, 95% CI=0.25 to 0.94, P=0.03), and ultrapure dialysate associated with a lower risk for cardiovascular events among subjects with more than 3 years of dialysis (adjusted HR=0.55, 95% CI=0.31 to 0.97, P=0.04). In conclusion, this trial did not detect a difference in cardiovascular event-free survival between flux and dialysate groups. Posthoc analyses suggest that high-flux hemodialysis may benefit patients with an arteriovenous fistula and patients with diabetes and that ultrapure dialysate may benefit patients with longer dialysis vintage.