While nephrologists wait for the ideal, non invasive, inexpensive, precise, and reproducible tool to evaluate extracellular volume (ECV), they need to exert their clinical acumen in the quest of that holy grail, dry weight (DW). Estimation of DW using a clinical approach based on blood pressure (BP) and ECV is feasible and reliable as shown by successful experiences in various dialysis modes over more than three decades. But a need still exists to resolve difficulties associated with accurate assessment of BP (methods and circumstances of measurement, and the confounding effects of antihypertensive drugs) and ECV (evaluation of weight changes unrelated to ECV, lack of specificity and sensitivity of clinical symptoms, lag time, confusion in terminology). An essential point in clinical assessment of DW is that a normal BP is at the same time the target and the crucial index of DW achievement. For this reason, a trialand-error "probe" process has to be used at intervals to make sure that the dry weight target point is correctly estimated. The various "non clinical" methods proposed for dry weight assessment increase the complexity and the cost of hemodialysis. They are, in the present state of things, more clinical research than practice tools. They do not replace clinical judgment.

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Hence, plasma BNP levels decreased during the first months of HD treatment during the dry weight quest. Whereas initial BNP values were not associated with increased mortality risk, the BNP level at Q2 was independently predictive of mortality. Hence, BNP is a useful tool to follow patient dehydration after dialysis start. Initial fluid overload may act as a confounding factor for its value as a prognostic marker because of cardiac disease.

Hence, despite adequate dialysis dose and protein intake, patients treated with HD for a long period of time became malnourished, whereas the classical nutritional markers remained in normal ranges. Among the potential causes leading to malnutrition, inadequate energy intake and micronutrient deficiencies were found in these patients.

Background: The relationship between predialysis blood pressure (BP) and hemodialysis (HD) patient outcomes is controversial. We report the evolution of predialysis BP in incident patients treated with the dry weight method and its relationship with patients’ outcomes. Methods: Between January 2000 and 2009, 308 patients started HD treatment. Fluid was progressively removed. The patients were encouraged to accept long-hour dialysis session and to follow a salt-restricted diet. BP and body weight (BW) were recorded and analyzed at start (week 1, W1) and weeks 8, 12, 26 and 52. Results: The predialysis systolic BP decreased from 142.1 at W1 to 130.7 mm Hg at W52. Postdialysis BW decreased from W1 to W8 (–5.0 ± 4.5%). It was correlated with the decrease of the predialysis systolic BP at W26 and W52. Whereas the patient survival was significantly lower in the lower predialysis systolic BP tertile at W1 like in previous reports calling this phenomenon ‘reverse epidemiology’, no relationship between predialysis BP levels and outcomes was found at W12, W26 and W52. The patients in the tertile of the greater predialysis systolic BP decrease at W12 had significantly better survival in the whole group and in hypertensive patients. This relationship remained significant in the Cox proportional-hazards analysis. Conclusions: Hence the dry weight method is efficient in decreasing the predialysis BP in incident HD patients. The initial BW decrease was correlated with BP decrease at W26 and W52. Early correction of BP by fluid removal erases the reverse epidemiology for BP and influences positively the patient survival.