Clinical Nutrition in Focus

Defining and regulating medical nutrition: Study calls for harmonised approach

By Nathan Gray contact

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Medical nutrition terminology is not consistently defined - with frequent inconsistencies between definitions and regulations relating to specific terms and practices, warn researchers who argue that standardised terminology is needed.

Standardised definitions of medical nutrition terms, aligned with regulatory definitions, are needed to help boost research outcomes and aid the ‘economic evaluation’ of interventions with medical nutrition, say the team, writing in Value in Health​.

Led by Karen Freijer from Maastricht University in the Netherlands, the team noted that the term ‘medical nutrition’ encompasses a range of products used as a clinical nutrition therapy to manage disease- and condition-related nutritional needs, while ‘clinical nutrition’ refers to the discipline as a whole – which deals with the prevention, diagnosis, and management of nutritional and metabolic changes related to acute and chronic diseases caused by a lack or excess of energy and nutrients.

“MN is indicated in clinical situations, such as for infants with special needs, disease-related malnutrition, and other medical conditions in which there is an increased risk of malnutrition, including surgery and trauma,”​ they explained. “In all circumstances, regulatory bodies require that MN is administered under the supervision of a medical professional, such as a physician, dietitian, or nurse.”

However, they noted that there are a number of definitions and ways in which medical nutrition, and specific terms used within medical nutrition, are used. Furthermore, that many of these specific definitions of terms are not aligned with regulations.

Different definitions

The team identified a total of 459 full-text and website records associated with medical nutrition terminology or regulations.

Of these, they noted that just 22% defined at least one medical nutrition term – with almost half of the records found to mentioned an MN term without providing a definition for it.

“Altogether 156 definitions for 71 MN terms were identified,”​ said the team.

According to Freijer and her colleagues, the most frequently mentioned and defined terms were enteral nutrition and malnutrition, while less than 5% of the records referenced any form of medical nutrition regulation.

Furthermore, the health economic impact of MN was rarely and insufficiently assessed, although an increase in economic analyses was observed, they added.

They noted that medical nutrition was defined in only two records—either as a commercially available product for nutritional support, including oral nutritional supplements, enteral tube feeds, and PN, or as any form of nutritional support that implies the use of food for special medical purposes (FSMPs).

However, multiple definitions were found for malnutrition (58), enteral nutrition (9), undernutrition (7), early enteral nutrition (6), parenteral nutrition (5), and oral nutritional supplements (3), the team noted.

“Definitions for malnutrition were highly heterogeneous, covering various health states and quantitative diagnostic criteria,”​ noted the authors. “Furthermore, many articles included only qualitative definitions of malnutrition, defining it either synonymously with undernutrition (…)} or as a more complex term covering undernutrition, disproportional nutrient intake, and/or overnutrition.”

Aligned to regulations?

Parenteral nutrition (PN) was consistently defined as intravenous feeding. As such, it is considered medication, which is in line with the existing regulations for PN, noted Freijer and colleagues.

Indeed, the team noted that PN is regulated within the same legislative framework as injectable pharmaceuticals, with clear rules pertaining to the production, distribution, and administration of legally controlled substances.

In contrast, however, enteral nutrition (EN) - generally defined as products delivered to the gastrointestinal tract - are legislated as food.

“Although these types of MN are not considered medication, a set of strict regulatory rules are in place for these products because they are intended for use by a vulnerable patient population as opposed to an otherwise healthy consumer,”​ they noted. “Unfortunately, MN regulations vary from country to country. This makes it difficult to standardise or act in an uniform manner.”

Freijer and her team concluded that medical nutrition terminology is not consistently defined, that relevant European and US regulations are rarely cited, and economic evaluations are infrequently conducted.

“Without a common understanding of MN terms and definitions, clear medical nutrition economic analyses are not feasible,”​ they said.

“The two major nutrition societies in Europe (ESPEN) and the United States (ASPEN) have prioritised, and are calling for, continuing constructive discussions to reach a consensus statement for the benefit of the global nutrition community,”​ they added – noting that their findings ‘fully supports’ the ongoing initiative and emphasises that adopting standardised medical nutrition terminology is essential to develop reliable and harmonised methods.

Source: Value in Health
Volume 22, Issue 1, January 2019, Pages 1-12, doi: 10.1016/j.jval.2018.07.879
“Medical Nutrition Terminology and Regulations in the United States and Europe—A Scoping Review: Report of the ISPOR Nutrition Economics Special Interest Group”
Authors: Karen Freijer, et al

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