A new chapter in malnutrition care: what the upcoming ICD-11 undernutrition code means for healthcare teams
After 5 years of multidisciplinary input, the way adult malnutrition is classified and documented will undergo an important change.1
Beginning in 2027, the World Health Organization (WHO) will implement a new International Classification of Diseases, Eleventh Revision (ICD-11) code for “the diagnosis of adult undernutrition in clinical settings.”1,2 This represents a major step forward in recognizing adult undernutrition as a distinct clinical condition and reflects a more modern understanding of how disease, inflammation, reduced intake, and other factors contribute to nutritional decline.1
While adoption timelines may vary globally, implementation of ICD-11 in the United States is expected to take additional time. The US will develop its own clinical modification (ICD-11-CM) to support healthcare reporting and billing requirements. Healthcare organizations, clinicians, and nutrition teams will need to prepare for eventual changes in documentation and coding practices.1,2 Over time, a shared language and consistent metrics for diagnosing undernutrition may also strengthen global collaboration and make large-scale clinical nutrition research more meaningful.1
From “malnutrition” to “undernutrition”: A shift in recognition
One of the most notable changes is the terminology itself. The WHO has chosen the term “undernutrition” for the new ICD-11 category, emphasizing the clinical characteristics associated with nutritional depletion, including unintentional weight loss, low body mass index (BMI), and low muscle mass.1,3
Under the ICD-11 framework, adult undernutrition is identified through a combination of criteria1,3:
Phenotypic criteria such as unintentional weight loss, low BMI, or reduced muscle mass
Etiologic criteria such as reduced food intake, impaired absorption, or disease-related inflammation
The new classification acknowledges that undernutrition can occur across a wide range of patient populations and care settings—not only in individuals who appear visibly underweight. Patients who are overweight or obese can also experience significant loss of muscle mass or weight associated with illness, inflammation, or inadequate intake.1
This evolution reinforces an important message: nutrition status is about recognizing undernutrition across patient populations and using standardized coding language so clinicians can document care consistently, compare findings, and support reimbursement as chronic disease and aging populations continue to grow.1
What could ICD-11 mean for healthcare organizations?
Although the US implementation timeline is still developing, healthcare organizations can begin considering how this transition may affect clinical workflows. The introduction of a dedicated adult undernutrition code may influence several areas, including:
Documentation practices: Electronic health records, templates, and clinical documentation processes may need to incorporate updated terminology and criteria to support identification and communication of adult undernutrition.1,3
Education and training: Care teams may need education on the updated diagnostic framework and how it differs from current practices.1
Data collection and research: A more specific classification system may improve the ability to identify patients with undernutrition, evaluate outcomes, and advance research related to nutrition care.1
Reimbursement considerations: Because coding systems play an important role in healthcare reporting and reimbursement, organizations will need to monitor how ICD-11-CM development impacts future billing processes.1-3
Need help preparing for ICD-11?
The American Society for Parenteral and Enteral Nutrition (ASPEN), the Academy of Nutrition and Dietetics (the Academy), and the American Society for Nutrition (ASN) are working together to support clinicians through the ICD-11 transition with educational resources, coding guidance, and payor advocacy.3
Preparing today for the future of nutrition care
The transition to ICD-11 will not happen overnight. However, the conversation begins now with awareness, education, and collaboration across healthcare teams.
As healthcare continues to evolve toward more personalized, outcomes-focused care, nutrition assessment and intervention will remain critical components of patient management. The ICD-11 update provides an opportunity to further elevate the role of nutrition in clinical practice and ensure patients receive the support they need throughout their healthcare journey.
During Malnutrition Awareness Week and beyond, healthcare professionals can take this opportunity to begin preparing for the next chapter in nutrition care.
When it comes to improving patient outcomes, identifying nutritional risk is not just a coding change—it’s a change that can help more patients get recognized, supported, and treated.