Comparison of Dietary Compliance and Dietary Knowledge Between Older and Younger Korean Hemodialysis Patients

Objective

The numbers of older hemodialysis patients (OHPs) are increasing very rapidly worldwide, but few studies have focused on the compliance of OHPs. This study compared the compliance with, and the knowledge of, dietary restriction regimens between OHPs and younger hemodialysis patients (YHPs). Mortality was also compared between these two groups.

Patients and Setting

A total of 160 patients who were registered at the Asan Medical Center (Seoul, Korea) participated in the study, 64 of whom were classified as OHPs (age ≥65 years), and 96 as YHPs (age <65 years).

Main Outcome Measures

Data were collected between September 2003 and February 2004. General characteristics and dietary knowledge of potassium, phosphorus, and sodium and fluid restrictions were assessed by personal interview. Dietary compliance was determined by measuring serum levels of these nutrients and interdialytic weight gain. Subjective global assessments were used to evaluate nutritional status. Both OHPs and YHPs were followed until May 2007 for mortality analysis. The data were analyzed with descriptive statistics, Student's t test, χ² test, and Spearman correlation using the SPSS statistical package (SPSS, Inc., Chicago, IL).

Results

The OHPs had a lower appetite, lower physical activity, and lower educational level compared with the YHPs. Dietary compliance with phosphorus restriction and with sodium and fluid restriction was higher in the OHPs than in the YHPs (P < .01 and P < .05, respectively), whereas compliance with potassium restriction did not differ between groups. The knowledge scores concerning potassium (P < .05) and phosphorus (P < .01) restriction diets were lower in OHPs than in YHPs, whereas no differences were found for knowledge scores concerning sodium and fluid restriction diets. Mortality was higher in the OHPs than in the YHPs (P < .001). The OHPs with higher mortality had higher dietary compliance with sodium and fluid restriction (r = 0.248, P < .05), and lower nutritional status (r = −0.342, P < .05).

Conclusions

The OHPs were generally less knowledgeable and more compliant, and had a lower appetite and a higher mortality than the YHPs. Therefore, the current application of the same dietary education to both OHPs and YHPs may be problematic. Instead, developing age-specific strategies to increase dietary knowledge and nutritional intake is urgently needed to increase the survival rate of Korean hemodialysis patients.