Nutrition assessment of IBD patients
Emma Halmos, D-ECCO Member
© Emma Halmos
It has long been acknowledged that Inflammatory Bowel Disease (IBD) carries a risk of malnutrition, leading to fatigue, infection, poor wound healing and poor health-related quality of life . Historically, most attention has been devoted to undernutrition; however, there is now evidence that overnutrition in the form of visceral fat is associated with raised tumour necrosis factor (TNF) and poorer responses to anti-TNF agents , indicating that central adiposity can be just as detrimental to disease outcomes as undernutrition. Furthermore, under- and overnutrition are not mutually exclusive and nutrient deficiencies and excesses often co-exist. In the last few years, there has been a shift away from the historical approach of using rudimentary markers of malnutrition, such as weight or body mass index (BMI), which can often be misleading as assessment tools in that they may falsely detect abnormalities or miss them completely, towards more detailed body composition measures of muscle and fat mass, which reflect nutritional abnormalities more sensitively. Indeed, GLIM (Global Leadership Initiative on Malnutrition) recognises the importance of body composition in the diagnosis of malnutrition . The key question now is how should we best assess our IBD patients for nutritional status in order to identify risk of poor clinical outcomes?
Both myopenia (depletion of lean muscle mass) and sarcopenia (muscle wasting associated with loss of muscle function), but not BMI, are associated with poor clinical outcomes in IBD patients, including major postoperative complications, osteopenia and poor health-related quality of life [4–6]. It is undisputed that radiological imaging techniques, such as dual-energy X-ray absorptiometry (DXA) and abdominal CT and MRI, are the best means of determining body composition, but these techniques have the limitations of restricted accessibility, need for administration by highly trained staff and high cost. Nevertheless, they are often applied in IBD patients as part of routine care, albeit usually without the additional body composition analysis. While in most cases it is not feasible to use such methods for monitoring of nutrition, they can have value as a point of reference. Handgrip strength devices correlate well with imaging for the identification of myopenia and sarcopenia, and offer cheap and easily administered point-of-care testing .
Myosteatosis (infiltration of fat into inter- and intramuscular compartments) represents a good marker of muscle dysfunction and fatigue  and is associated with poor IBD disease outcomes, as is visceral adiposity (adipose tissue surrounding intra-abdominal organs), at least in Crohn’s Disease patients . As with undernutrition, imaging has proven to be the gold standard in indicating body composition abnormalities and can feasibly be incorporated into IBD management, if used for the assessment of IBD disease burden. There are currently no point-of-care tests to indicate myosteatosis; however, waist circumference is independently associated with visceral adiposity adjusted for height, and its assessment is cheap and requires minimal training in administration .
Recommendations for nutrition assessment in clinical practice :
- In addition to standard screening for micronutrient deficiencies, nutrition assessment, preferably by a dietitian, should be applied to all IBD patients.
- BMI should be abandoned as a tool to indicate body composition abnormalities.
- Body composition analysis should additionally be undertaken in IBD patients undergoing imaging for disease assessment.
- Point-of-care handgrip strength and waist circumference measures should be used to monitor body composition abnormalities.
- Patients with malnutrition should be referred to the dietitian for dietary assessment to identify and manage eating patterns and nutritional intake.
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