Measurement of fecal volatile organic compounds (VOC) was effective in identifying inflammatory bowel disease (IBD) biomarkers, but not for monitoring disease activity, according to study results published in Digestive and Liver Disease.
Researchers recruited adult patients, who had a scheduled consultation or colonoscopy at 3 hospitals or 2 outpatient clinics in the Netherlands, between 2009 and 2017. During these visits, participants provided stool samples from which VOC were analyzed by gas chromatography ion mobility spectrometry. Disease state was defined as fecal calprotectin (FCP) ≥250 mg/g and remission <100 mg/g. Crohn’s disease (CD) was defined by a Harvey Bradshaw Index <4 and ulcerative colitis (UC) was defined by a Simple Clinical Colitis Activity Index <3. The researchers identified healthy controls (HC) by a lack of mucosal abnormalities during colonoscopy. In total, 107 participants had active CD, 84 had CD in remission, 80 had active UC, 63 had UC in remission, and 227 were HC.
The VOC analysis was able to discriminate IBD from HC with a high degree of accuracy, even in individuals who were in remission for the disease. Specifically, active UC or CD vs HC had an area under the receiving operator curve (AUC) of 0.96 (95% CI, 0.94-0.99), while UC or CD remission vs HC had an AUC of 0.95 (95% CI, 0.93-0.98).
The researchers reported few differences between the UC and CD samples (AUC, 0.55; 95% CI, 0.50-0.60) and no difference between remission and active UC (AUC, 0.63; 95% CI, 0.44-0.82) or CD (AUC, 0.52; 95% CI, 0.39-0.65).
A limitation of this study was the use of FCP as a diagnostic tool instead of colonoscopy. The study designers questioned the ethics of requiring all participants to undergo invasive procedures, so colonoscopy was avoided for this study. Furthermore, fecal samples were collected between 2009 and 2017, and it remains unclear whether the age of the samples introduced bias to the analysis.
The study authors concluded that fecal VOC analysis could be used as a non-invasive tool for detecting biomarkers of IBD, but that neither UC vs CD nor active vs remission states could be deciphered, making monitoring disease activity or progression infeasible.
Disclosures: Some authors declared receiving consulting or funding from the pharmaceutical industry. A complete list of disclosures can be found in the original study.
Bosch S, Wintjens D S J, Wicaksono A, et al. The faecal scent of inflammatory bowel disease: detection and monitoring based on volatile organic compound analysis. [available online May 10, 2020]. Dig Liver Dis. doi:10.1016/j.dld.2020.03.007