Objective: Interdialytic weight gain is an important prognostic factor in dialysis patients. Different eating patterns may affect interdialytic weight gain. The goal was to assess the effect of the Mediterranean type of diet on interdialytic weight gain of chronic hemodialysis patients.
Design: This study had a cross-sectional design.
Setting: Four hospital-based satellite hemodialysis units in different cities in Turkey.
Patients: A total of 702 patients (279 women, 423 men; mean age, 47.8 +/- 15.5 years) were included in the study. They were grouped according to the hemodialysis centers: Alanya-Izmir (group 1, n = 194) and Ankara-Adana (group 2, n = 508).
Intervention: Group 1 patients were consuming a Mediterranean type of diet, whereas group 2 patients had a diet rich in protein and carbohydrates. All of the patients were under the same dialysis and treatment protocols. The demographic data, the medications, interdialytic weight gains, and laboratory data such as serum albumin, C-reactive protein, hemoglobin, hematocrit, serum iron binding capacity, ferritin, and parathyroid hormone during the last 3 months for each patient were recorded.
Main outcome measure: The interdialytic weight gain differences between the groups were compared using the Student t-test and the Mann-Whitney U test.
Results: When the two groups were compared according to age, sex, blood pressure, serum albumin, hematocrit, and parathyroid hormone levels, there was no statistically significant difference. Mean interdialytic weight gain for group 1 and group 2 was 2.47 +/- 0.94 kg and 3.08 +/- 0.94 kg, respectively (P < .001). When the two groups were compared according to their iron requirements, group 1 showed an increased requirement for doses of iron and erythropoietin (P < .001 and P < .001, respectively).
Conclusions: A Mediterranean-type diet, rich in seafood and vegetables, was associated with less interdialytic weight gain compared with a diet rich in protein and carbohydrates. Although all of our patients had the same diet education and treatment protocols, the geographic region and culture influenced their compliance to diet and their therapeutic outcomes.