In all patients, malnutrition can refer to either undernutrition or overnutrition, and chronic kidney disease (CKD) patients face several challenges when it comes to nutritional balance. To help assist both patients and their healthcare teams, The Renal Association has compiled a set of guidelines with nutritional recommendations for adults with stage 4 or stage 5 CKD.*

What is malnutrition?

As defined by the National Institute for Health (NIH) in the U.K., malnutrition is “a state in which a deficiency of nutrients, such as energy, protein, vitamins and minerals, causes measurable adverse effects on body composition, function, or clinical outcome.”

What this means is that there is an imbalance between the amount of nutrients a person needs and the amount he or she is taking in. More often than not, this results in undernutrition, as investigated in this study, which leads to a deficit in:

• energy;
• protein; and/or
• micronutrients.

Screening CKD patients for undernutrition

CKD patients should have regular screenings to identify and monitor their nutrient levels to pinpoint those who are at risk of undernutrition. 

The recommended screening schedule is as follows: 

• A patient’s first screening should be upon admission.
• After that the first screening, follow-up screenings should be weekly for those in inpatient care.
• For those in outpatient care or stable hemodialysis patients, screenings should be performed two to three times a month.

Effects of uremia on nutrition

Many CKD patients have uremia—or elevated levels of urea (primary component of urine) and other nitrogenous wastes in the blood. 

• The kidneys, when healthy, normally remove these substances. 
• When a patient has uremia, it inhibits his or her appetite and decreases his or her nutrient intake.

Protein energy wasting

Protein energy wasting is when the body has decreased levels of protein and energy stored up. Twenty to 40% of stage 4-5 CKD patients waste energy derived from protein, and in patients on dialysis, these numbers jump to 28-54%. 

• The effects of protein energy wasting include reduced survival, poor healing, infection risk, impaired functional ability, and reduced quality of life.

• CKD patients should be assessed by a dietitian before starting dialysis (at least one month prior) and/or considering transplantation. A dietitian should also be seen if there are any changes made to a patient’s dialysis schedule.

Additional reading can be found in the following Journal of Renal Nutrition articles: “Global Prevalence of Protein-Energy Wasting in Kidney Disease: A Meta-analysis of Contemporary Observational Studies From the International Society of Renal Nutrition and Metabolism” and “Subjective Global Assessment for the Diagnosis of Protein-Energy Wasting in Nondialysis-Dependent Chronic Kidney Disease Patients.”

*Wright, M.; Southcott, E.; MacLaughlin, H.; & Wineberg, S. (2019, June). “Clinical Practice Guideline: Undernutrition in Chronic Kidney Disease.” The Renal Association.