Target weight gain during the first year of hemodialysis therapy is associated with patient survival.

Background: Hemodialysis (HD) patients are exposed to a high risk of death. Nutritional status has been recognized as a key factor for patient survival. Nutritional markers have been shown to improve after HD onset. In this study we have analyzed the dynamics of target weight (TGW) change and the evolution of other nutritional parameters during the first year of HD treatment and their influence on patients' outcomes.

Methods: We have analyzed a retrospective cohort of incident patients starting HD therapy between January 2000 and January 2009, and studied the values and changes in TGW, interdialytic weight gain (IDWG), predialysis systolic blood pressure, serum albumin, protein intake, C-reactive protein (CRP) from the start and first week (W1), W8, W12, W26 and W52 in patients who survived the first year of therapy. We have analyzed the relationship between TGW changes with other nutritional parameters and the patient survival.

Results: Among the cohort including 363 patients starting HD therapy, 251 (age 65.8 ± 14.8 years, 93 female/158 male, diabetes 36%) survived at least 1 year after dialysis onset and were followed for 44.9 months. During the first 8 weeks, the TGW decreased by 6.5 ± 5.6% (initial TGW change). The initial TGW change was correlated with IDWG at W12 and W26, and with changes in serum albumin and nPNA (normalized protein equivalent of nitrogen appearance) between HD W1 and W52 (respectively +7.8 and +11.4%). From W8 to W52, the TGW increased by +1.9 ± 7.4% (secondary TGW change). The Kaplan-Meier analysis displayed a significantly better survival in patients above the median (+2.3%) of the secondary TGW change (respectively -3.6 ± 5.2% and +7.6 ± 4.5%). The two groups above and below this median were not different according to age, diabetes or cardiovascular event history but the patients above the median had a significant higher IDWG and protein intake. In the Cox model analysis the patient overall mortality was related to age (p < 0.0001), to the secondary TGW change (p = 0.0001), and to the CRP level at W52 (p < 0.0001).

Conclusions: The initial fluid removal was related to nutritional markers. The secondary TGW change during the first year of HD treatment calculated after the initial phase of fluid removal was identified as a strong predictor of survival. It was associated with a better food intake whereas the patient case mix was not different. These data highlight the importance of nutrition and food intake in the first year of dialysis therapy and the need for nutritional follow-up and support in incident HD patients. It stresses the need in understanding the key factors associated with food intake in this setting.