Sarcopenia in Cirrhosis and Chronic Inflammatory Bowel Disease: An Austrian Biobanking Study

As the average age of societies rises, so too does the onset of debilitating diseases. Among these, sarcopenia, which is defined as a progressive decline in muscle mass, quality and strength, affects over one third and of people above 70 and half of patients with chronic diseases- such as liver cirrhosis or chronic inflammatory bowel disease (IBD). Sarcopenia remains an unmet clinical need with wide reaching implications affecting patients, their families and the health care system as a whole whereby patients lose independence due to their frailty which consequently decreases overall life quality and increases the risk of severe injuries, and complication thereof, due to falls.The pathogenesis of sarcopenia in cirrhosis is incompletely understood: Decreased protein synthesis and increased protein degradation mediated by inflammation contribute to sarcopenia in cirrhosis. In chronic inflammatory bowel disease, sarcopenia often results from a complex interplay of various factors, including inflammation, malabsorption, limited physical activity, and nutrient deficiencies.

Despite the high prevalence of sarcopenia among the aging and diseased populations, its diagnosis remains challenging as generally accepted international standards are lacking. Combined with the low agreement of available diagnosis criteria, this further complicates diagnostic methods. (8) To date, the diagnosis of sarcopenia relies on the quantification of muscle mass and a clinical assessment of muscle strength. For the estimation of muscle mass, costly computed tomography (CT) or magnetic resonance imaging (MRI) are the methods of choice to quantify the muscled area of a cross section on the level of the L3 vertebra- these methods also require skilled personnel and specialized software solutions for image evaluation. Methods used to assess muscle function, such as hand grip strength, gait speed and knee flexion/extension also require skilled personnel and present an additional layer of complexity to the overall diagnosis as they are difficult to standardize and heavily dependent patient compliance. Furthermore, the interpretation of the outlined diagnostic measures remains ambiguous, since different consensus definitions show conflicting results in different patient populations. Biomarker of muscle function and inflammation, as well as hormone assessments have been considered as useful diagnostic alternatives, however they are not part of clinical routine yet. Taken together, current diagnostic options for sarcopenia remain grossly insufficient which, often, allows this detrimental condition to be missed in clinical practice thereby hindering adequate and timely intervention.

In addition, currently there is no medical treatment available for sarcopenia. The current recommendation therefore is to improve nutrition, especially regarding the protein content, and physical activity.

Acquiring large enough datasets is of utmost importance to validate diagnostic tools or develop novel biomarker and therapies.