Malnutrition revisited

Criteria remain problematic from the clinical, coding, and regulatory perspectives and deserve more attention and discussion


The diagnosis of malnutrition continues to be controversial and confusing, despite the publication of a nutritional consensus statement, known as the ASPEN criteria, by the American Academy of Nutrition and Dietetics (the Academy) and the American Society for Parenteral and Enteral Nutrition (ASPEN) almost 5 years ago.

Even though malnutrition criteria were discussed in this column in June 2013, they remain problematic from the clinical, coding, and regulatory perspectives and deserve more attention and discussion.

Photo by Thinkstock
Photo by Thinkstock

The “traditional” concept of malnutrition has been a chronic condition with characteristic stigmata resulting from prolonged deficiency of calories and/or protein. The traditional diagnosis of malnutrition and its severity depended on the physician's own clinical determination, using a constellation of findings in four categories: physical findings, risk factors, biochemical markers, and body mass composition. (See sidebar on next page.) No particular finding has been 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.

As discussed in my June 2013 column, the ASPEN criteria redefined malnutrition as “undernutrition” classified in three distinct contexts: acute, chronic, and social-environmental. The distinction between acute and chronic illness is based on the National Center for Health Statistics' (NCHS) definition of “chronic” as a disease or condition that lasts three months or longer. The ASPEN criteria do not specifically define “social-environmental,” but it seems to be intended for those whose nutrition is chronically deficient because of such factors as living environment, debility, nonadherence, lack of social support, and similar circumstances. Once a patient meets the criteria for “undernutrition,” the term “malnutrition” is to be used in documentation.

At least two of the following six findings are also required to define malnutrition (the specific ranges of the six findings differ in each of the three contexts):

  1. 1. Insufficient energy intake
  2. 2. Weight loss parameters (or No. 5 below)
  3. 3. Loss of muscle mass
  4. 4. Loss of subcutaneous fat
  5. 5. Localized or generalized fluid accumulation that may sometimes mask weight loss (as an alternative to No. 2)
  6. 6. Diminished functional status as measured by hand grip strength

In general, the findings for the chronic and social-environmental contexts in these six areas are largely consistent with the traditional concept of malnutrition, but in the acute context, they are quite different. For example, according to the criteria for the acute context, 1% weight loss in one week with caloric intake less than 75% of needs constitutes malnutrition, while 2% weight loss in one week with caloric intake less than 50% of needs for five days would represent severe malnutrition. Clinicians might agree that this represents acute “undernutrition” requiring attention, but these findings would hardly lead any reasonable clinician to label a patient malnourished.

The traditional diagnostic criteria for malnutrition have been criticized by many experts as too subjective, yet most of the ASPEN criteria are also highly subjective. Estimations of energy intake involve an “educated guess” by nutritionists. Loss of muscle mass or subcutaneous fat is classified by the subjective terms “mild,” “moderate,” or “severe,” without objective guidance. The criteria do not specify how fluid accumulation (edema) should be quantitated to determine whether significant weight loss has been masked and to what degree. Calibrated hand grip strength is the most objective measure and is well correlated with malnutrition, but most hospital nutrition services don't have the devices available to measure it.

Severity of malnutrition is a very important consideration that has prognostic, management, coding, and regulatory implications. Malnutrition has traditionally been classified as mild, moderate, or severe based on commonly recognized parameters (Table). Albumin and prealbumin levels are highly nonspecific for malnutrition, but when malnutrition is known to be present, they may be useful indicators of severity. ICD-10 codes use the three traditional levels of severity, and selecting the correct one has quality and reimbursement implications. The ASPEN criteria only distinguish severe from nonsevere malnutrition and do not specifically identify mild or moderate malnutrition.

A diagnosis of severe malnutrition carries great weight and often results in higher reimbursement. It has been the focus of many U.S. Department of Justice investigations and sanctions for improper claims. For billing and payment compliance, a diagnosis that results in higher payment must be verifiable by independent professional audit using clinical criteria widely accepted by the medical community.

As noted, it might be difficult to justify a diagnosis of severe malnutrition in the acute context based on the ASPEN criteria. For example, if severe malnutrition is diagnosed and the ICD-10 code for this condition is assigned, the need for aggressive management, such as enteral or parenteral feeding, would be expected to substantiate the severity. Before diagnosing and treating severe malnutrition, clinicians should identify some of the traditional criteria associated with the condition, which are rarely found in the acute context. A potential solution to this dilemma would be substituting a diagnosis of “nutritional deficiency” or “severe nutritional deficiency” (ICD-10 code E63.9) for malnutrition in the acute context. This diagnosis has no revenue or regulatory implications and is indisputably clinically valid in this situation.

There seem to be other problems with the ASPEN criteria. For example, body mass index (BMI), one of the most important indicators of malnutrition and its severity, is not included. Also, nonsevere and severe energy intake deficiency in the chronic context have exactly the same definition without supporting evidence (less than 75% of caloric needs for one month) implying that there is no distinction between the two. Both the acute and social-environmental contexts require energy intake of less than 50% of caloric needs for severe malnutrition; it seems obvious that this should be the same in the chronic context as well.

Another potential problem is that clinicians may mistakenly count the weight loss criterion and the edema criterion as the needed two findings for diagnosing malnutrition. But the two must be considered mutually exclusive—if weight loss parameters are met, edema cannot be masking weight loss.

The ASPEN criteria can be credited with focusing attention, which has been sorely lacking, on the profound consequences of severe and nonsevere nutritional deficiency associated with acute illness and injury. Affected patients need early and aggressive intervention, which they have often not received. However, applying the term “malnutrition” to such patients is probably ill advised.

In summary, while the ASPEN malnutrition consensus statement has great merit in many respects, it is not entirely objective. The diagnostic criteria in the chronic and social-environmental contexts are generally consistent with the traditional concept of malnutrition but do have a few important problems: energy intake definitions, absence of a BMI measure, and practical application difficulties.

The inclusion of the nutritional deficiencies associated with acute illness and injury in the definition of malnutrition, redefined as undernutrition, is problematic. The ASPEN criteria for the acute setting are inconsistent with the traditional clinical concept of malnutrition and may have adverse billing, coding, regulatory, and compliance implications that can be avoided by using the term “nutritional deficiency” rather than “malnutrition” in the acute setting.

Finally, whenever a diagnosis of malnutrition is made and its severity determined, verifiable objective supporting findings must be present in the medical record that will pass muster on professional audit. Clinicians would be well served to identify both ASPEN criteria and findings consistent with the traditional concept of malnutrition to substantiate their diagnostic determination.