Understanding hemodialysis (HD) patients' individual health beliefs may help clinicians better match their communication strategies and interventions for greater adherence to a low-phosphorus diet, according to a new study. 

Dietary restriction of phosphorus is challenging for most patients with end-stage renal disease (ESRD). For the study, lead researcher John O. Elliott, PhD, of OhioHealth Riverside Methodist Hospital in Columbus, and colleagues asked 95 HD patients at 3 Ohio centers to answer questions that gauged their health beliefs and readiness to maintain a low-phosphorus diet. The researchers then correlated the responses with demographic factors and serum phosphorus levels.

Dr. Elliott's group found that 62% of the patients endorsed adherence to a low-phosphorus diet, but only 34% had average serum phosphorus levels of 5.5 mg/dL or less, according to a report published online ahead of print in the Journal of Renal Nutrition.

The authors stated that ESRD educators may obtain better results with phosphorus control “if their focus is directed not only toward disease and dietary education, but also to identifying and understanding individual health beliefs like perceived benefits and self-efficacy when addressing dietary adherence.”

Better adherence to a low-phosphorus diet was achieved by people who were Caucasian, highly educated, and enjoyed a good quality of life with fewer disabilities. The researchers also found that the longer a patient was on dialysis, the greater his or her self-reported dietary adherence. It might reflect greater motivation or point to a social bias whereby a veteran patient tells clinicians “what they want to hear.”

Serum phosphorus control was achieved by patients who were long-time dialysis recipients and ethnic minorities. They were also younger, highly educated, and knowledgeable about CKD.

In light of the findings, the investigators offer some suggestions for patient communication:

• Health literacy: Convey simple, non-medical messages. This especially may benefit patients with lower levels of education and minorities, some of whom may be non-native English speakers.
• Quality of life: Counsel the patient who is feeling well on the importance of making dietary changes to prevent future complications.
• Patient motivation: Focus on the benefits of following a low-phosphorus eating plan to overcome any ambivalence.
• Self-efficacy: Build the patient's confidence by describing the eating plan as a series of achievable steps.
• Older age: Recognize that age is a significant barrier to phosphorus control for reasons that remain unclear.
• Knowledge of CKD: Unlike previous research, this study found increased odds for optimal phosphorus levels for each point improvement in knowledge. Continue to educate patients about the disease.
• Length of time on dialysis: Long-time patients may perceive greater benefit and fewer barriers to a low-phosphorus diet, or may be more willing to follow recommendations.

Finally, the researchers recommend motivational interviewing techniques. This communication style uses open-ended questions to discover patients' incentives for change, demonstrates empathy, addresses resistance, and avoids arguments.

1. Elliott, JO, et al. Journal of Renal Nutrition, March 2015; doi: 10.1053/j.jrn.2014.08.006.

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