Inflammatory bowel diseases (IBDs) are a group of chronic inflammatory diseases that affect the gastrointestinal tract, including Crohn's disease (CD) and ulcerative colitis. Surgery is a treatment option, and more than half of the patients with CD will undergo surgical interventions over the course of the disease. Postoperative complications are common in IBD patients, the most frequent being intra-abdominal sepsis, infection of the surgical site, and adynamic ileum, and nutritional status is a factor that can influence postoperative outcome. Recent studies have shown that malnutrition, obesity, sarcopenia, and myosteatosis are predictors of surgical complications. However, most were retrospective studies with small patient samples and heterogeneity of clinical and nutritional assessment methods, which limit the extrapolation of data. Therefore, knowing the pathophysiological mechanisms of IBD and identifying the best parameters for assessing nutritional status are essential for prompt implementation of adequate nutritional interventions.

Background Evidence indicates that inflammation in Inflammatory Bowel Disease (IBD) is associated with increased systemic levels of reactive oxygen species. Systemic oxidative stress has been associated with reduced levels of plasma thiols. Less invasive tests capable of reflecting and predicting IBD activity are increasingly sought after. In this sense, we sought to systematically review the evidence inherent in serum thiol levels as a marker of Crohn's Disease and Ulcerative Colitis activity (PROSPERO: CRD42021255521). Methods The highest quality documents for systematic reviews and meta-analyses standards were used as reference. The highest quality documents for systematic reviews and meta-analyses standards were used as reference. Articles were searched on Medline via PubMed and via Central, VHL, LILACS, WOS, EMBASE, SCOPUS, COCHRANE, CINAHL, OVID, CTGOV, WHO/ICTRP, OPENGREY, BDTD and CAPES, between August and September/2021. Descriptors were defined according to the Medical Subject Heading.The articles were searched between August and September/2021. Of the 11 articles selected for full reading, 7 were included in the review. Of these, 4 were combinable studies and were included in the meta-analysis. Results The findings of the individual studies included suggest an association between disease activity and systemic oxidation, as measured by serum thiol levels, however, the pooled analysis did not identify a significant association between the parameters evaluated. The limitations identified in this meta-analysis made it impossible to weigh the results of individual studies, which, associated with potential confounding factors, may have interfered with the results of the grouped assessment. Conclusions We recommend conducting randomized clinical trials, with individuals of both phenotypes and in different stages of IBD, involving larger numbers of participants, using standardization of the technique for measuring serum thiols, in order to confirm whether thiols can be a good parameter of monitoring the clinical course of these intestinal diseases and the degree of clinical applicability.

Background Evidence indicates that inflammation in Inflammatory Bowel Disease (IBD) is associated with increased systemic levels of reactive oxygen species. Systemic oxidative stress has been associated with reduced levels of plasma thiols. Less invasive tests capable of reflecting and predicting IBD activity are increasingly sought after. We sought to systematically review the evidence inherent in serum thiol levels as a marker of Crohn's Disease and Ulcerative Colitis activity (PROSPERO: CRD42021255521). Methods The highest quality documents for systematic reviews standards were used as reference. Articles were searched on Medline via PubMed, VHL, LILACS, WOS, EMBASE, SCOPUS, COCHRANE, CINAHL, OVID, CTGOV, WHO/ICTRP, OPENGREY, BDTD and CAPES, between August, 03 and September, 03 on 2021. Descriptors were defined according to the Medical Subject Heading. Of the 11 articles selected for full reading, 8 were included in the review. It was not possible to perform a pooled analysis of the studies, as there were no combinable studies between subjects with active IBD and controls/inactive disease. Results Findings from the individual studies included in this review suggest an association between disease activity and systemic oxidation, as measured by serum thiol levels, however, there are limitations that preclude weighting the study results in a meta-analysis. Conclusions We recommend conducting better-designed and controlled studies, that include individuals of both phenotypes and at different stages of IBD, involving a larger number of participants, using the standardization of the technique for measuring serum thiols, to confirm whether thiols can be a good parameter for monitoring the clinical course of these intestinal diseases and the degree of clinical applicability.