The number of patients with chronic kidney disease (CKD) is on the rise, and most of them have nutrition abnormalities.
At the same time, CKD and hemodialysis (HD) centers are cutting costs due to new government funding protocols, namely the bundling of payments for dialysis-related goods and services. This poses a dilemma. With the CKD population growing and tighter money for end-stage renal disease care, how can health care providers improve nutrition-related outcomes, which are strongly associated with quality of life measures, hospitalization rates, and mortality?
Assessing key nutrition parameters
Currently, dietitians across the country conduct complete assessments on each dialysis patient at least once a year. Additionally, a review of lab values typically occurs once a month depending on the facility and the dietitian’s time availability. Whether or not significant interventions—including intense education, counseling with motivational interviewing, and the introduction of aggressive nutrition support—occurs greatly depends on the composition of the health care team, the dietitian-to-patient ratio, and the dietitian’s skill set.
Despite the annual assessment process, evidence suggests that patient outcomes are not improving significantly. Therefore, an alternative process needs to be considered. The Centers for Medicare and Medicaid Services now mandate that each HD patient be reviewed for key nutrition parameters monthly. This could add considerably to the work burden of the dietitian or it could be seen as an opportunity to create and validate a monthly screening tool that would allow dietitians to target high-risk patients suffering from moderate or severe nutrition abnormalities.
Diet and bone metabolism
The phrase “nutrition abnormality” is important because nutrition in CKD goes way beyond protein-energy wasting. Nutrition screening, assessment, and interventions must encompass bone metabolism parameters (such as calcium, phosphorus, and parathyroid hormone) and cardiovascular risk factors (such as inflammation, obesity, and serum lipid concentrations, to name a few).
Many researchers have attempted, with minimal success, to validate screening tools that could be used to assist with triaging CKD patients. Such a screening tool would allow dietitians to allocate their time resource appropriately for preventive exercises and toward those patients who are at high risk and needing aggressive nutrition interventions.
This is not a new concept. In other populations many screening tools have been validated for hospitalized patients (e.g., the Malnutrition Universal Screening Tool [Eur J Clin Nutr. 2010; published online ahead of print]), elderly patients (e.g., Mini Nutritional Assessment [Clin Geriatr Med. 2002;18:737-757]), and other populations. However, these screening tools have yet to demonstrate high specificity and sensitivity in CKD when compared with the gold standard assessment tool, Subjective Global Assessment (SGA). This article is not meant to be an exhaustive review of potential screening tools and how they compare with SGA; instead, its intent is to highlight an issue that must be thought through as we move forward in optimizing renal nutrition.
More screening tools
The currently available screening tools look solely at protein-energy wasting. They do not include parameters for other extremely important nutrition abnormalities such as elevated serum phosphorus, serum potassium, and serum lipid levels. Finally, although the above mentioned screening tools may pick up the effect of inflammation they do not directly measure its presence.
The intent of screening is to identify individuals at “high nutritional risk” so that further assessment can be done to determine whether or not the person actually has nutritional loss or deficiency. The SGA is a great tool for nutrition assessment of protein energy wasting (J Ren Nutr. 2007;17:336-342) and it has been shown to predict mortality in HD patients (Am J Clin Nutr. 2009, 17, 336-342). However, similar to the currently available screening tools, it does not assess for bone, cardiovascular or electrolyte abnormalities.
Therefore, a screening tool ideally needs to be designed that would be brief, easy to administer, inexpensive, and have good specificity and sensitivity for key nutrition-related problems. To date, this author of unaware of any screening tools that meet these criteria and has been well validated in the CKD population. One screening tool that did meet all of the aforementioned criteria was presented in a poster presentation by Bowes et al. at the International Society of Renal Nutrition and Metabolism meeting in 2010. However, it only described minimal validity and therefore will need further testing before it can be used clinically in the CKD population. In the future, clinicians should be on the outlook for well validated tools that allows nutrition screening of CKD patients that includes parameters for protein-energy wasting, bone metabolism, cardiovascular risk, and electrolyte imbalance.