Background: Malnutrition is a common problem in hemodialysis (HD) patients and one of the most important factors influencing morbidity and mortality. More frequent HD has been shown to improve nutritional status in HD patients.
Methods: The London Daily/Nocturnal Hemodialysis Study compared the nutritional status of patients receiving quotidian HD, either short daily HD (n = 11) or long nocturnal HD (n = 12), with that of 22 matched control patients receiving conventional thrice-weekly HD. A number of biochemical parameters indicative of nutritional status were measured, including protein equivalent of total nitrogen appearance (nPNA), serum albumin, serum prealbumin, dietary calcium, serum lipids, and water-soluble vitamin levels.
Results: nPNA tended to increase throughout the study for both quotidian HD groups and remained unchanged in the control group, which had the lowest values (1 to 1.1 g/kg/d). Daily HD patients showed a significant increase in mean serum albumin levels at 3, 12, and 18 months. The nocturnal HD group showed a significant decrease in albumin levels at month 9, and control patients maintained relatively stable albumin levels throughout the study. Serum prealbumin levels averaged 0.04 g/dL for daily HD patients, whereas serum prealbumin levels decreased in nocturnal HD patients during the study period. Half the nocturnal HD patients had vitamin C levels lower than the reference range. Body composition data showed increased arm muscle area and maintenance of 100% to 110% of relative body weight (RBW) after several months of daily HD, whereas patients on nocturnal HD therapy showed a significant decline in RBW. There were no significant differences in lean body mass, percentage of body fat, or body mass index among the 3 study groups.
Conclusion: Increased nPNA, serum albumin levels, and arm muscle area suggest that daily HD patients experienced improved nutritional status.