A new paper describing a new International Classification of Diseases (ICD)-11 code for Undernutrition in Adults has been simultaneously published in The American Journal of Clinical Nutritionby ASN, the Journal of Parenteral and Enteral Nutrition by the American Society for Parenteral and Enteral Nutrition (ASPEN), and the Journal of Nutrition and Dietetics by the Academy of Nutrition and Dietetics (the Academy). The paper provides guidance on how adult undernutrition should be identified, documented, and implemented in clinical practice ahead of the ICD-11 rollout in 2027.
Why ICD Codes and Standardization Matter
ICD codes are the standard system used worldwide to document diagnoses in healthcare. They provide a shared language that clinicians, hospitals, researchers, insurers, and public health agencies rely on to describe health conditions.
Standardization matters because it ensures that the same condition is identified and documented consistently across clinical settings. Without standardized codes, the same diagnosis may be recorded differently by different providers or institutions, making it difficult to compare data, track outcomes, understand disease prevalence, or support appropriate care and reimbursement.
For adult undernutrition, the lack of a relevant, standardized ICD code has contributed to inconsistent documentation and under recognition, particularly among adults with acute or chronic disease who may not have low body mass index (BMI). The new ICD-11 code addresses this gap by providing a consistent way to identify and document undernutrition across clinical settings.
What the New ICD-11 Code Includes
The new code reflects current clinical understanding of undernutrition in adults. Diagnosis is based on a combination of physical signs, such as unintentional weight loss, low muscle mass, or low BMI, and underlying causes such as reduced food intake, disease, inflammation, or starvation.
Clinicians can use population-specific, validated tools such as the Subjective Global Assessment (SGA), the Academy of Nutrition and Dietetics/American Society for Parenteral and Enteral Nutrition Indicators (AAIM), the Mini Nutrition Assessment (MNA), and the Global Leadership in Malnutrition (GLIM) to determine whether a patient has undernutrition.
Preparing for Implementation
Successful implementation will require outreach, education, collaboration, and support among clinicians, dietitians, health IT teams, and coding professionals. Key steps will also include integrating the new ICD-11 code into electronic health record (EHR) systems to support consistent documentation and data capture.
ASN is committed to supporting its members and the broader nutrition community through education and practical resources that help prepare for ICD-11 implementation. A key part of this effort is the practice tool, developed jointly by ASN, ASPEN, and the Academy, which provides guidance on applying the diagnostic criteria.
The joint publication of this paper across leading nutrition journals underscores the importance of standardized diagnosis of adult undernutrition. By adopting a shared approach through ICD-11, clinicians will be better equipped to recognize undernutrition, provide appropriate care, and contribute to improved data, research, and outcomes worldwide.
For additional background, see ASN’s earlier blog post: WHO Establishes First-Ever ICD Code for Undernutrition in Clinical Settings for Adults, which also provides a link to the practice tool developed by ASN, ASPEN, and the Academy.
