Knowledge of dietary restrictions and the medical consequences of noncompliance by patients on hemodialysis are not predictive of dietary compliance.

To investigate whether knowledge of the diet and medical consequences of noncompliance influences dietary compliance among patients on hemodialysis. An interviewer-administered questionnaire assessed patients' knowledge of foods restricted in their diet (four separate scores for knowledge of foods restricted for: potassium, phosphorus, sodium, and fluid); overall knowledge of restricted foods (one composite knowledge score); and knowledge of medical complications of dietary noncompliance (one composite knowledge score). Patients' mean monthly serum phosphorus and potassium and weight charts provided an estimate of dietary compliance. Seventy-one of the eligible 82 patients on hemodialysis at Nottingham City Hospital, Nottingham, UK, participated in the study (87% response rate). Chi(2) tests determined associations between dietary compliance and knowledge scores. More than one third of patients were noncompliant with at least one dietary restriction. Phosphorus dietary restrictions were the most commonly abused and potassium the least. Patients' knowledge of the medical consequences of noncompliance was poorer than knowledge of renal dietary restrictions (mean scores 29.4%; 74.7%). There was no association between compliance with potassium or sodium/fluid restrictions and knowledge of these dietary restrictions. However, patients with better knowledge about phosphorus were less likely to be compliant (P=.03). Patients with better knowledge about the medical complications of noncompliance were less likely to be compliant for phosphorus (P=.002) and sodium/fluid (P=.008) restrictions. These findings question the value of current dietary education techniques in motivating patients to comply with dietary restrictions. Instead of the more traditional approach of information-giving, effective educational methods that focus on motivating patients to comply with dietary restrictions are needed to improve compliance.