Association of Protein Intake with Protein-Energy Wasting in Patients Undergoing Post-Dilution Online Hemodiafiltration.

BACKGROUND

Protein-energy wasting (PEW) is a frequent complication in patients receiving kidney replacement therapy and is associated with adverse clinical outcomes. Hemodiafiltration (HDF), a convective dialysis modality, enhances uremic toxin removal but may also increase nutrient losses, potentially contributing to nutritional impairment. This study evaluated the prevalence of PEW and its association with protein intake in patients undergoing post-dilution online HDF.

METHODS

This cross-sectional study included 98 adults receiving post-dilution online HDF at a tertiary care center between March 2024 and July 2025. Nutritional status was assessed using the Malnutrition Inflammation Score (MIS); PEW was defined as MIS ≥8. Body composition was evaluated by bioelectrical impedance analysis, and dietary intake was assessed using 3-day food records. Multivariable linear regression models were used to analyze the association between protein intake and MIS.

RESULTS

PEW was identified in 45% of patients. Compared with patients without PEW, those with PEW had lower body mass index, fat-free mass index, phase angle, handgrip strength, energy intake, and protein intake, as well as greater fluid overload. Patients with PEW also exhibited lower serum phosphorus and higher C-reactive protein concentrations. Individuals consuming <1.2 g/kg ideal body weight/day of protein had lower energy intake and tended to present higher MIS scores. In multivariable analysis, lower protein intake remained independently associated with poorer nutritional status, corresponding to an approximately 2-point higher MIS score.

CONCLUSIONS

PEW is highly prevalent among patients undergoing post-dilution online HDF and is independently associated with lower protein intake. These findings support the need for individualized nutritional assessment and prospective studies evaluating optimal nutritional strategies in HDF populations.