[Can the hemodialysis strategy influence the nutritional status of hemodialysis patients?]

Malnutrition is frequent in hemodialysis (HD) patients. The HEMO study has shown a progressive decline of nutritional markers, such as body weight, albuminemia and protein intake, in prevalent hemodialysis patients during a 3-year follow-up. In incident dialysis patients, nutritional status usually improves during the first year of HD treatment. Opposite to the HEMO findings, we have shown that nutritional stability was achieved during a 5 year follow-up with sequential long hour dialysis (3 x 6-8 hours/week). Energy and protein intakes are related to the dialysis dose. Moreover, several studies show the nutritional consequences of changing the dialysis prescriptions. The switch from conventional HD to short daily dialysis improves significantly protein and energy intake and albuminemia. Also, increasing treatment time increases significantly the body weight after several months. One of the hypothesis for this effect is that uremia-related middle molecules compromise the patient appetite. Increasing dialysis time or frequency may decrease the level or the time of exposition to these molecules. However, the beneficial effect of hemodiafiltration on HD patients' nutritional status is not spectacular. Another hypothesis is the role of extra-cellular fluid excess and its relationship with inflammation that is deleterious for nutrition. In conclusion, dialysis adequacy is a mandatory prerequisite when facing a malnourished HD patient. Increasing time or frequency must be part of the therapeutic thought in such situation.