Objective: To assess knowledge of phosphorus compared with other nutrients in patient undergoing maintenance dialysis (MD).
Design:We compared knowledge of phosphorus versus other nutrients important to the MD diet (potassium, sodium, protein) in hemodialysis (HD) and peritoneal dialysis (PD) patients. We further measured gender, age, education level and functional health literacy to assess correlations in patient nutrient knowledge. Nutrient knowledge was measured using a 25-item chronic kidney disease knowledge assessment tool for nutrition (CKDKAT-N), and functional health literacy was measured using the short-form of the test of functional health literacy in adults (STOFHLA). Results: Forty-seven MD patients participated in the study (29 HD, 18 PD, 30 males and 17 females, average age 58.6 (SD 13.8) years, average grade level 1.4 (SD 2.6) years of post-secondary education). 35 participants had adequate, 4 marginal and 8 inadequate health literacy. CKDKAT-N scores ranged from 6 to 21 of 25 items, mean score of 13 (SD 2.91). Knowledge of phosphorus compared with knowledge of other nutrients was poor (0.38 versus 0.72, p = 0.003). Comparing HD to PD patient knowledge, both phosphorus (0.37 versus 0.42, p=0.231) and other nutrients (0.69 versus 0.80, p=0.115) were the same.
Conclusion:Despite regular dietary instruction, patients undergoing MD have a poor knowledge of dietary phosphorus content, compared with knowledge of other nutrients important in chronic kidney disease. Interestingly, there was no difference in nutrition knowledge when comparing PD and HD patients, despite differences in education level and health literacy between the groups.