Systematic review of sarcopenia in inflammatory bowel disease

There is growing evidence of increased muscle atrophy in IBD patients, likely resulting in a higher sarcopenia prevalence in IBD. The aims of this systematic review are A1; to estimate sarcopenia prevalence in IBD patients, A2; to investigate its impact on IBD patients, and A3; the effectiveness of nutritional interventions on muscle mass and/or strength in IBD patients.

On 28 July 2021, three electronic databases were used to identify eligible studies, including peer-reviewed studies (randomised controlled trials [RCTs], non-RCTs, observation studies) in adult (⩾ 18 years) IBD patients. For A1 and A2 only, studies defined low muscle mass and/or strength cut-off points. For A2, studies assessed association between sarcopenia and IBD complication. For A3, studies assessed the nutrition effect among IBD patients.

35 studies were included, 34 for A1, 20 for A2, and three for A3. 42% of adult IBD patients have myopenia, 34% have pre-sarcopenia, and 17% sarcopenia. Myopenic IBD was significantly associated with therapy failure including IBD-related surgery risk in six studies, risk of medical therapy failure in four studies, risk of hospitalisation in one study. A significant association existed with postoperative complications risk in IBD patients in four studies, reduction in BMD in two studies, and increased incidence of non-alcoholic fatty liver disease (NAFLD) in one study. Sarcopenia in IBD was significantly associated with a reduction in BMD in one study. Two studies found a personalised nutrition plan (high protein) in IBD patients significantly improved muscle mass. One study found a significant positive association between muscle mass and dietary intake including high protein intake.

Over one third of adult IBD patients have myopenia and pre-sarcopenia, and nearly a fifth have sarcopenia. Myopeninc IBD is significantly associated with increased risk of IBD therapy failure, postoperative complications, and low BMD, with possible association with increased NAFLD risk. Nutritional therapy may play a role in reversing low muscle mass though yet unclear if this is through disease activity reversal. Further studies on adult IBD patients focusing on sarcopenia/myopenia are needed with recommended study designs of 1) standardised population-based definitions with recommended standard methods used to measure skeletal muscle mass, 2) prospective studies with IBD patients stratified by Montreal classification, disease activity, disease duration and concomitant medication to observe muscle changes, 3) mechanistic studies on sarcopenia aetiology, specifically focusing on protein handling atrophy and absorption, 4) properly designed RCT to assess nutrition intervention in sarcopenic IBD patients.