Diagnostic value of methane-hydrogen breath test combined with intestinal flora testing in screening for colorectal...

Diagnostic value of Methane and Hydrogen Breath Test (MHBT) combined with intestinal flora detection in colorectal polyp screening.

Retrospective inclusion of 196 patients who had completed MHBT with colonoscopy during the same period of time in the General Hospital of the People's Liberation Army (PLA), China, from January 2022 to December 2023, were divided into a control group (no polyps) and an observation group (with polyps, n = 109). A total of 196 patients who were examined were divided into control group (without polyps, n = 109) and observation group (with polyps, n = 87). Baseline data, intestinal barrier function (DAO, D-lac, LPS), tumor markers (AFP, CA19-9, CA-125, CEA), MHBT positivity rate and relative abundance of intestinal flora were analyzed in the two groups, and diagnostic efficacy was assessed by ROC curve.

The proportion of males (64.94 vs. 49.54%) and age (61.85 ± 12.38 vs. 52.47 ± 13.57 years) in the observation group were significantly higher than those in the control group (P < 0.05). After multifactorial correction, CH₄ (OR = 2.32, P = 0.019) and H₂ positivity (OR = 2.14, P = 0.027) remained significantly higher in the observation group. In the observation group, Bifidobacterium spp. (Bb, -15.91 ± 2.86 vs. -16.65 ± 2.13 in the control group, t = 2.075, P = 0.039), Lactobacillus spp. (Lb, -12.58 ± 3.67 vs. -15.87 ± 2.70, t = 6.988, P < 0.001), enterotoxin-producing Enterotoxin fragile mimics (ETBF, -6.02 ± 2.17 vs. 6.02 ± 2.17 vs. -6.69 ± 2.23, t = 2.122, P = 0.035), Clostridium nucleatum (Fn, -18.73 ± 2.88 vs. -21.28 ± 3.07, t = 5.984, P < 0.001) and anaerobic Streptococcus pepticus (Panaerobius, -16.23 ± 1.98 vs. - 20.30 ± 2.43, t = -2.916, P < 0.001) were significantly higher than the relative quantitative values of the control group. ROC analysis showed that the AUC for diagnosing colorectal polyps with CH₄, H₂ and the combined assay (CH₄+H₂) were 0.725, 0.640, and 0.768, respectively; and after combining the intestinal flora (Bb, Lb, Fn, etc.) AUC was elevated to 0.831, with a sensitivity of 79.27% and a specificity of 82.90%.

HBT provides a non-invasive strategy for colorectal polyp screening by capturing CH₄/H₂ metabolic gases with intestinal flora characteristics. Combining flora markers significantly improves diagnostic efficacy, suggesting its translational potential in optimizing screening pathways. Future exploration of the mechanisms of flora-metabolic gas dynamic interactions and individualized threshold setting is warranted.