What Are the GLIM Criteria for Malnutrition?

Malnutrition is a condition caused by a nutrient deficiency with wide-ranging health consequences. A persistent challenge in healthcare has been the lack of a single, globally accepted method for its diagnosis. This inconsistency makes it difficult to compare data across regions and populations, hindering efforts to understand its prevalence and manage it. A standardized diagnostic framework was needed to ensure clinicians could identify and treat malnutrition uniformly.

Understanding the GLIM Initiative

The Global Leadership Initiative on Malnutrition (GLIM) was a collaborative effort convened in 2016 by major clinical nutrition societies. Participating organizations included the American Society for Parenteral and Enteral Nutrition (ASPEN), the European Society for Clinical Nutrition and Metabolism (ESPEN), the Latin American Federation of Parenteral and Enteral Nutrition (FELANPE), and the Parenteral and Enteral Nutrition Society of Asia (PENSA). Before GLIM, various diagnostic tools were used globally, leading to inconsistencies in how malnutrition was defined. The objective was to develop consensus-based diagnostic criteria that could be applied by clinicians worldwide. This framework was designed to be practical, using methods readily available in most clinical environments.

Key Diagnostic Criteria of GLIM

The GLIM framework uses two categories of criteria: phenotypic and etiologic. Phenotypic criteria are the physical manifestations of malnutrition, while etiologic criteria relate to its underlying causes. A diagnosis requires at least one criterion from each category, ensuring a comprehensive assessment.

The three phenotypic criteria are non-volitional weight loss, low Body Mass Index (BMI), and reduced muscle mass. Weight loss is defined as losing more than 5% of body weight in the past six months or more than 10% over a longer period. A low BMI, a measure of body fat based on height and weight, is another indicator, with thresholds adjusted for age and ethnicity; for adults under 70, a BMI below 20 is a marker, while for those of Asian descent, it is 18.5. Reduced muscle mass, assessed using various techniques from physical exams to advanced imaging, is the third physical sign.

The etiologic criteria focus on the causes of nutritional decline and include two factors: reduced food intake or assimilation and inflammation or disease burden. Reduced food intake can be due to consuming less than half of required energy for over a week, or any reduction for more than two weeks. It also includes chronic gastrointestinal conditions that impair nutrient absorption. The second factor, inflammation, recognizes that acute or chronic diseases can increase the body’s nutritional needs or interfere with its ability to use nutrients.

Diagnosing Malnutrition with GLIM

Diagnosing malnutrition with GLIM criteria involves two steps. The first is risk screening, where healthcare providers use a validated tool to identify patients who may be at risk. This initial phase helps focus more intensive assessment on those most likely to have the condition. Any validated tool is acceptable for this screen.

If a patient is identified as “at risk,” the second step is a detailed assessment for diagnosis and severity grading. A diagnosis is made based on the presence of at least one phenotypic and one etiologic criterion. For example, a patient with significant unintentional weight loss (phenotypic) and a chronic illness causing poor appetite (etiologic) would be diagnosed with malnutrition.

Once a diagnosis is made, severity is determined by the intensity of the phenotypic criteria. The framework outlines two stages: Stage 1 (moderate malnutrition) and Stage 2 (severe malnutrition). For instance, weight loss between 5-10% in six months might indicate moderate malnutrition, whereas weight loss exceeding 10% could classify the condition as severe. This grading system helps clinicians tailor interventions to the patient’s needs and provides a clear benchmark for monitoring progress.

Impact of GLIM on Malnutrition Care

The introduction of the GLIM criteria has affected clinical practice and research related to malnutrition. By providing a globally accepted diagnostic framework, it has promoted greater consistency in how malnutrition is identified and documented. This standardization allows for more reliable comparisons of malnutrition prevalence, intervention strategies, and patient outcomes across different hospitals and countries.

This unified approach enhances communication among healthcare professionals, ensuring a diagnosis of malnutrition means the same thing regardless of location. It also facilitates more robust and comparable clinical research. The ability to collect data using a common set of variables strengthens the evidence base for nutritional interventions.

The GLIM framework supports improved patient care by enabling earlier and more consistent identification of individuals who require nutritional support. By clearly defining malnutrition and its severity, clinicians are better equipped to advocate for the necessary resources and implement timely interventions. This standardized approach helps elevate the importance of nutritional status in patient management and public health policy.