No abstract

To our knowledge, this study is the first one that compares three different strategies to predict mortality in haemodialysed patients. The lung comet score emerged as the best predictor for the relationship hydration status-mortality, independently of bioimpedance-derived parameters in this population.

Background and objectivesChronic subclinical volume overload occurs very frequently and may be ubiquitous in hemodialysis (HD) patients receiving the standard thrice-weekly treatment. It is directly associated with hypertension, increased arterial stiffness, left ventricular hipertrophy, heart failure, and eventually, higher mortality and morbidity. We aimed to assess for the first time if the relationship between bioimpedance assessed overhydration and survival is maintained when adjustments for echocardiographic parameters are considered.Design, setting, participants and measurementsA prospective cohort trial was conducted to investigate the impact of overhydration on all cause mortality and cardiovascular events (CVE), by using a previously reported cut-off value for overhydration and also investigating a new cut-off value derived from our analysis of this specific cohort. The body composition of 221 HD patients from a single center was assessed at baseline using bioimpedance. In 157 patients supplemental echocardiography was performed (echocardiography subgroup). Comparative survival analysis was performed using two cut-off points for relative fluid overload (RFO): 15% and 17.4% (a value determined by statistical analysis to have the best predictive value for mortality in our cohort).ResultsIn the entire study population, patients considered overhydrated (using both cut-offs) had a significant increased risk for all-cause mortality in both univariate (HR = 2.12, 95%CI = 1.30–3.47 for RFO>15% and HR = 2.86, 95%CI = 1.72–4.78 for RFO>17.4%, respectively) and multivariate (HR = 1.87, 95%CI = 1.12–3.13 for RFO>15% and HR = 2.72, 95%CI = 1.60–4.63 for RFO>17.4%, respectively) Cox survival analysis. In the echocardiography subgroup, only the 17.4% cut-off remained associated with the outcome after adjustment for different echocardiographic parameters in the multivariate survival analysis. The number of CVE was significantly higher in overhydrated patients in both univariate (HR = 2.46, 95%CI = 1.56–3.87 for RFO >15% and HR = 3.67, 95%CI = 2.29–5.89 for RFO >17.4%) and multivariate (HR = 2.31, 95%CI = 1.42–3.77 for RFO >15% and HR = 4.17, 95%CI = 2.48–7.02 for RFO >17.4%) Cox regression analysis.ConclusionsThe study shows that the hydration status is associated with the mortality risk in a HD population, independently of cardiac morphology and function. We also describe and propose a new cut-off for RFO, in order to better define the relationship between overhydration and mortality risk. Further studies are needed to properly validate this new cut-off in other HD populations.

Within the framework of the LUST trial (LUng water by Ultra-Sound guided Treatment to prevent death and cardiovascular events in high-risk end-stage renal disease patients), the European Renal and Cardiovascular Medicine (EURECA-m) working group of the European Renal Association-European Dialysis Transplant Association established a central core lab aimed at training and certifying nephrologists and cardiologists participating in this trial. All participants were trained by an expert trainer with an entirely web-based programme. Thirty nephrologists and 14 cardiologists successfully completed the training. At the end of training, a set of 47 lung ultrasound (US) videos was provided to trainees who were asked to estimate the number of B-lines in each video. The intraclass correlation coefficient (ICC) for the whole series of 47 videos between each trainee and the expert trainer was high (average 0.81 ± 0.21) and >0.70 in all but five cases. After further training, the five underperforming trainees achieved satisfactory agreement with the expert trainer (average post-retraining ICC 0.74 ± 0.14). The Bland-Altman plot showed virtually no bias (difference between the mean 0.03) and strict 95% limits of agreement lines (-1.52 and 1.45 US B-lines). Only four cases overlapped but did not exceed the same limits. Likewise, the Spearman correlation coefficient applied to the same data series was very high (r = 0.979, P < 0.0001). Nephrologists and cardiologists can be effectively trained to measure lung congestion by an entirely web-based programme. This web-based training programme ensures high-quality standardization of US B-line measurements and represents a simple, costless and effective preparatory step for clinical trials targeting lung congestion.

This study shows that a LUS-bioimpedance-guided dry weight adjustment protocol, as compared to clinical evaluation, does not reduce all-cause mortality and/or CVE in HD patients. A fluid management protocol based on bioimpedance with LUS on indication might be a better strategy.