Variables associated with reduced dietary intake in hemodialysis patients.

Background: Among the causes of malnutrition in hemodialysis (HD) patients, inadequate dietary intake (IDI) seems to be one of the most frequent and important. Although it has been hypothesized that IDI might be secondary to uremia, anorexia, underlying illness, psychosocial conditions, loss of dentures, depression, aging, or chronic inflammation, definite data on the etiology of IDI in HD patients are still lacking. The goal of this study was to measure the actual dietary energy and protein intakes in stable HD patients and to evaluate which demographic, clinical, dialytic, and humoral variables were associated with a dietary intake lower than recommended by international guidelines.

Methods: Thirty-seven patients maintained on regular HD, 3 times per week for 4 hours per session, were included in the study. In addition to epidemiologic data, patients were scrutinized for dry weight, weight change in the last 6 months, height, Body Mass Index, Kt/V, serum leptin, leptin-BMI ratio, presence of anorexia, and dietary energy and protein intake. Anorexia was assessed by means of a questionnaire in which the presence of major symptoms, namely meat aversion, taste and smell alterations, nausea and/or vomiting, and early satiety, was investigated. Dietary intake was recorded for 3 days after questionnaire administration by means of 3-day diet diaries.

Results: Overall, the mean (+/- standard deviation) dietary energy and protein intakes were 24.9 +/- 10.1 kcal/kg/day and 0.64 +/- 0.4 g protein/kg/day, respectively. Twenty-six patients (70.2%) had energy and protein intakes lower than recommended, 7 (18.9%) had adequate energy intake but inadequate protein intake, 1 (2.7%) had adequate protein intake and inadequate energy intake, and 3 (8.1%) had both adequate energy and adequate protein intakes. Anorexia was present in 14 of the 26 (53%) patients with low protein and energy intakes, and was absent in the other groups ( P =.003). The age of patients with inadequate energy and protein intakes was significantly higher than the age of patients with adequate energy and protein intakes (62.1 +/- 10.4 versus 37 +/- 20.8, P <.001) and the age of patients with only adequate energy intake (40.5 +/- 10.4, P <.001). Twenty-seven patients (73%) had an energy intake <30 kcal/kg/day, and 10 (27%) had an energy intake > or =30 kcal/kg/day. Compared with patients with energy intakes > or =30 kcal/kg/day, patients with energy intakes <30 kcal/kg/day were significantly older ( P =.0001) and more frequently were anorexic (P <.05). Compared with patients with protein intakes > or =1.2 g/kg/day, patients with protein intakes <1.2 g/kg/day were significantly older (P <.001). Limiting the analysis to the 33 patients with protein intakes <1.2 g/kg/day, we found a significant negative correlation between age and energy intake ( r =-0.612; P <.001) and between age and protein intake ( r =-0.723; P <.001). Correlations between both energy and protein intakes and age, dialytic age, Kt/V, C-reactive protein, parathyroid hormone, and leptin-BMI were not statistically significant.

Conclusions: This study shows that dietary energy and protein intakes are inadequate in the majority of HD patients and are negatively related to the presence of anorexia and age. These data may be potentially useful in the identification of nutritional strategies as well as in improving food intake in HD patients.