Dialysis Adequacy, Nutritional Target Attainment, and Intradialytic Amino Acid Loss in Maintenance Hemodialysis Patients: Implications for Clinical Management

Background: Malnutrition and protein-energy wasting (PEW) are prevalent in maintenance hemodialysis (HD) patients and pose significant challenges to clinical care. Although adequate dietary protein intake is essential for maintaining nutritional status, phosphorus control often complicates nutritional management. In addition, HD is associated with dialysis-related amino acid (AA) loss, which may further aggravate nutritional vulnerability. This study examined the associations of dialysis adequacy with nutritional target attainment, biochemical parameters, and intradialytic AA reduction in maintenance HD patients. Methods: This cross-sectional study included 45 stable maintenance HD patients. Dietary intake was assessed using a 2-day pre-dialysis dietary record, and protein and energy intake attainment were calculated relative to recommended targets. Pre-HD and post-HD plasma AA concentrations were measured to determine intradialytic AA reduction. Correlation analyses, group comparisons, and multivariable regression analyses were performed. Results: Serum albumin was not significantly associated with protein intake, suggesting that it may not adequately reflect current dietary protein adequacy when used as an isolated marker. Patients with adequate protein intake attainment had lower serum phosphorus levels; however, after adjustment, dialysis adequacy assessed by spKt/V, rather than protein intake attainment itself, remained independently associated with serum phosphorus levels. Dialysis adequacy was significantly associated with both protein and energy intake attainment. HD was associated with significant reductions in most plasma AAs. Patients with adequate protein intake attainment showed lower intradialytic reductions in total amino acids, essential amino acids, branched-chain amino acids, and aromatic amino acids. Conclusions: Dialysis adequacy was associated with nutritional target attainment, phosphorus control, and intradialytic plasma AA reduction in maintenance HD patients. Adequate protein intake attainment was associated with lower category-specific AA reduction, whereas serum albumin alone did not reflect current dietary protein adequacy. These findings should be interpreted as associations and confirmed in larger prospective studies.