Guidelines for the diagnosis of malnutrition were published in the May 2012 Journal of the Academy of Nutrition and Dietetics, representing a consensus statement of the American Academy of Nutrition and Dietetics (the Academy) and the American Society for Parenteral and Enteral Nutrition (ASPEN).
The guidelines indicate that malnutrition (defined as “nutritional imbalance”) should be diagnosed when at least two of the following six characteristics are identified: insufficient energy intake; weight loss; loss of muscle mass; loss of subcutaneous fat; localized or generalized fluid accumulation that may sometimes mask weight loss; and diminished functional status as measured by hand grip strength.
The document further states that context (e.g., acute illness or injury, chronic illness, and social or environmental circumstances) should be used to determine whether malnutrition is present and whether it is severe or non-severe.
The guidelines are an effort to identify evidence-based, objective criteria comprising a broad range of acute and chronic circumstances. They focus attention on the profound consequences of severe nutritional imbalance associated with acute illness and injury. The criteria are consistent with and indicative of the acute or chronic state but are specific for neither.
However, the consensus has its own conceptual disadvantages. It expands on the more limited “classic” medical definition and application of the term “malnutrition” with its associated degrees (mild, moderate and severe). This classic definition describes a sustained period of chronic nutritional imbalance manifested by observable, measurable clinical consequences. “Chronic” is defined as a duration of three months or more.
The diagnosis of classic chronic malnutrition and its severity depends on clinical judgment, using several findings:
- Physical findings, such as emaciation or muscle/adipose wasting (e.g. temporal wasting, thenar atrophy).
- Risk factors, such as cancer, chemotherapy, AIDS, alcoholism, end-stage disease processes, debilitation, residence in a skilled nursing facility, malabsorption syndromes, or other gastrointestinal and pancreatic disorders.
- Biochemical markers, including low albumin, prealbumin, cholesterol, transferrin, blood urea nitrogen/creatinine ratio, and/or anemia.
- Body mass composition, such as low body mass index and recent or progressive unintended weight loss or low body weight.
No particular finding is required or definitive. Biochemical markers should be considered with caution because many other conditions, especially inflammatory states, acute illness and trauma, may cause acutely low biomarkers.
The degree of classic chronic malnutrition can be more precisely defined by quantitative measures shown in Table. Two or more in the most severe category are required. Albumin and/or prealbumin should be considered as only one variable.
However, these classic findings do not identify patients with acute nutritional imbalance and risk for malnutrition, hence the guidelines' effort to expand the definition to include these circumstances. But acute nutritional imbalance without preexisting classic malnutrition is not identical to the chronic malnourished state and is likely to entail different risks, implications and consequences. The new criteria cannot distinguish among mild, moderate and severe malnutrition because, in the context of acute nutritional imbalance, these are meaningless terms.
Another problem is that ICD-9/10 codes, definitions and concepts have been based entirely on the classic criteria for chronic malnutrition. What will happen if the new broad definition of malnutrition as “nutritional imbalance,” incorporating the concept of acute undernutrition, is imposed? Assigning malnutrition codes for acute “nutritional imbalance” may be problematic.
Perhaps a cautious practical approach to coding would be to distinguish between classic chronic malnutrition and acute nutritional imbalance in patients without preexisting malnutrition. The diagnosis of malnutrition and its degree should perhaps be limited to the classic chronic type.