Appropriately Diagnosing Malnutrition to Improve Wound Healing
by Nancy Collins, PhD, RDN, LD, FAPWCA, FAND, & Liz Friedrich, MPH, RDN, CSG, LDN, FAND
Nutrition professionals now use an etiology-based definition of malnutrition rather than the standard concept of lab values. In order for proper diagnosis and coding, wound clinic providers must understand this new definition and the criteria required to meet the current definition of malnutrition.
It’s become quite common for providers and program directors in outpatient wound clinics across the country to promote, market, and advertise their successful healing rates. However, they often overlook highlighting one of the keys to successful outcomes — the patient’s nutritional status. Simply put, if the patient is malnourished, there is insufficient nutritional substrate from which to build new tissue to heal a wound. This can affect healing rates despite any innovative care modalities or products being offered in the clinic. Nutrition professionals now use an etiology-based definition of malnutrition rather than the standard concept of lab values. In order for proper diagnosis and coding, wound clinic providers must understand this new definition and the criteria required to meet the current definition of malnutrition.
The Malnutrition Paradigm
Merriam-Webster defines malnutrition as “the unhealthy condition that results from not eating enough food or not eating enough healthy food: poor nutrition.” This classic dictionary definition may still work for grade school and middle school science classes, but is no longer applicable for diagnosing adult patients. It’s become clear in recent years that malnutrition is a complex syndrome that manifests itself in different ways. As a result of this new understanding, the definition of the condition and how to diagnosis it have both been subject to intense scientific scrutiny. Many clinicians struggle to understand this change and wonder what parameters to use in order to assign a diagnosis of malnutrition. In an attempt to understand the whys and wherefores of recent changes in the malnutrition paradigm, a summary of the evidence follows.
Historically, a diagnosis of protein energy malnutrition (PEM) was made using serum albumin and/or prealbumin. Malnutrition was once classified as “mild,” “moderate,” or “severe” based on a scale of “how low” a patient’s serum hepatic protein levels were. Table 1 outlines the malnutrition parameters that were standard in medical, nursing, and nutrition textbooks for generations. Many patients were labeled with a diagnosis of “severe malnutrition” when their serum albumin level was < 2.0 and the appropriate International Statistical Classification of Diseases and Related Health Problems code was applied. Those with low serum albumin or prealbumin were often referred to a registered dietitian nutritionist (RDN) and/or prescribed a protein supplement in an effort to correct malnutrition. Requests for serial serum albumin and prealbumin levels were recommended to track nutritional status in patients living with pressure ulcers, surgical wounds, and a host of other medical conditions. Fast-forward to 2013, when evidence proved that while serum albumin and prealbumin may be good indicators of morbidity and mortality, they are not accurate indicators of malnutrition.1-4 It’s now believed the relevance of the entire class of hepatoprotein laboratory tests, including serum albumin, as indicators of malnutrition is limited.2 This information has been documented in the literature for nearly 10 years, but has admittedly been slow to “trickle down” to practicing doctors, nurses, and dietitians. Despite the volume of evidence to the contrary, it’s still common to see a diagnosis of malnutrition based on a low albumin or prealbumin in medical records. Many clinicians are still confused by the subject and rely on albumin and prealbumin in the absence of other clear indicators of malnutrition. An understanding of the science behind the experts’ opinions can help practitioners understand why serum proteins are not effective for a malnutrition diagnosis.
Understanding Protein Lab Data
Albumin and prealbumin are “negative acute-phase reactants,” meaning they decrease in the presence of inflammation in the body.1,3 Inflammation can be defined as “the aggregate of clinical, hematologic, and organ function abnormalities associated with sepsis, trauma, and a variety of other conditions such as pancreatitis.”1 The inflammatory response is a complex series of cellular reactions that results in catabolism and breakdown of lean body mass. Inflammatory conditions that affect serum albumin levels include (but aren’t limited to) dehydration, hepatic failure, infection, cancer, bed rest, and pregnancy.1,3 In reality, almost every chronic medical condition and most acute conditions can potentially result in a decrease in serum prealbumin and/or albumin because of the inflammatory response. This is one reason it’s common to see very low albumin and prealbumin levels in trauma patients, critical care patients, and those with living with chronic illnesses and open wounds. As a normal part of the recovery process, inflammation subsides and serum albumin and prealbumin increase, often returning to normal levels. Because they are negative acute-phase proteins, serum albumin and prealbumin levels better reflect the severity of the inflammatory process than they do nutritional status. So what’s the relationship between nutrition and serum albumin levels? Doesn’t adding protein to the diet increase serum albumin and/or prealbumin levels? Surprisingly, even though they have been the “gold standard” of defining nutrition for years, there are actually no prospective, randomized studies that have shown an increase in albumin and prealbumin in response to changes in protein and calorie intake.3 Evidence indicates acute-phase proteins do not consistently or predictably change with weight loss, calorie restriction, or nitrogen balance.5 However, there’s an indirect relationship between hepatic proteins and nutritional status. Inflammation contributes to an increase in net protein loss caused by catabolism, meaning a patient may need more calories and protein in the diet. It also can induce anorexia, reducing the possibility that a patient will consume adequate nutrients.1 Experts agree that patients with low serum albumin or prealbumin may indeed have compromised nutritional status for a number of reasons. However, the conventional wisdom of increasing protein in the diet while expecting to increase serum hepatic proteins is no longer considered valid.
Defining & Diagnosing Malnutrition
As knowledge of the inflammatory process increased over time, experts began to realize the existing definition of malnutrition did not account for this variable. In 2010, an international consensus group acknowledged widespread confusion among experts and worked to establish a more comprehensive definition for adults. This group proposed an etiology-based diagnosis for malnutrition, settling on the following three types of malnutrition:6
1) Pure chronic starvation without inflammation (for example, anorexia).
2) Chronic diseases or conditions that impose sustained inflammation of a mild to moderate degree (eg, organ failure, pancreatic cancer, rheumatoid arthritis, sarcopenic obesity).
3) Acute disease or injury states with marked inflammatory response (eg, major infection, burns, trauma, closed head injury).
Despite this proposed definition, there is still no single, universally accepted approach to the diagnosis and documentation of adult malnutrition. Use of the Nestlé Mini Nutrition Assessment,® Subjective Global Assessment, or other nutritional screening tools have become customary in many settings,7 but most don’t acknowledge the concept of the inflammatory response. The good news is there’s an effort underway to identify and document malnutrition. In 2012, the Academy of Nutrition and Dietetics (Academy) and the American Society for Parenteral and Enteral Nutrition (ASPEN) released the joint consensus statement “Characteristics Recommended for the Identification and Documentation of Adult Malnutrition (Undernutrition).” The authors proposed a three-pronged, etiology-based definition of malnutrition that was adopted by the international consensus committee: starvation-related, chronic disease-related, and acute disease- or injury- related. Table 2 outlines and defines the categories. The Academy/ASPEN consensus statement goes well beyond defining malnutrition and suggests six characteristics for diagnosis: 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. Patients meet the guidelines for malnutrition when they exhibit two or more of these criteria. Using specific parameters under each of these criteria, the proposal recommends labeling malnutrition as “nonsevere” or “severe.” The basic characteristics used to make a malnutrition diagnosis are detailed in Table 3. The characteristics and criteria to identify malnutrition outlined by ASPEN and the Academy rely on the age-old methods of medical history, physical examination/clinical signs, anthropometric data, food and nutrient intake, and functional assessment. Laboratory markers of inflammation (C-reactive protein, white blood cell count, and blood glucose levels) may be used to help determine if the condition is related to starvation, chronic disease, or acute disease or injury. Identification of malnutrition clearly becomes more complex with adoption of an etiology-based diagnosis. A comprehensive assessment requires more time than a simple blood draw, but can also give more clues as to how to best intervene for each type of malnutrition.
Clinicians are seeking a simple, clear way to diagnose malnutrition. Unfortunately, there’s no single biological marker (like albumin or prealbumin) that can provide that information. Albumin and prealbumin, although still commonly used to diagnose malnutrition, are no longer considered reliable ways to do so. These laboratory tests alone should not be used as a basis for nutrition interventions. Clinicians should recognize the need to use comprehensive diagnostic criteria to asses and document nutritional status in adults. Medical professionals in all healthcare settings must work together to begin implementing new ways to identify and classify malnutrition using the Academy/ASPEN criteria as a template.
Nancy Collins is a registered dietitian nutritionist based in Las Vegas, NV, who serves as a consultant to healthcare institutions and as a medico-legal expert to law firms involved in healthcare litigation. Correspondence may be sent to NCtheRD@aol.comLiz Friedrich is president of Friedrich Nutrition Consulting, Salisbury, NC.
This article originally appeared in Today’s Wound Clinic here. All credit to Today’s Wound Clinic and Author.
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4. Pressure Ulcer Prevention and Treatment Clinical Practice Guideline. European Pressure Ulcer Advisory Panel and National Pressure Ulcer Advisory Panel. Accessed online at www.npuap.org
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7. Tsai AC, Wang JY, Change TL, Li TY. A comparison of the full Mini Nutritional Assessment, short-form Mini Nutritional Assessment, and the Subjective Global Assessment to predict the risk of protein-energy malnutrition in patients on peritoneal dialysis: a cross-sectional study. Int J Nurs Stud. 2013;50(1):83-9.