Huang H, Li H Z, Wang Y R, Song Y, Wang B M, Cao H L, Jiang K
Department of Gastroenterology,General Hospital,Tianjin Medical University,Tianjin 300052,China.
Department of Gastroenterology,Second Teaching Hospital of Tianjin University of Traditional Chinese Medicine,Tianjin 300150,China.
Zhonghua Nei Ke Za Zhi. 2023 Nov 1;62(11):1335-1340. doi: 10.3760/cma.j.cn112138-20221111-00843.
To investigate the diagnostic value of a single hydrogen-methane breath test (SHMBT) for small intestinal bacterial overgrowth (SIBO). The current investigation was a cross-sectional study. Questionnaires and SHMBTs were administered to 162 patients with gastrointestinal symptoms (case group) and 69 healthy volunteers (control group). Differences in SHMBT results between the two groups were assessed,and cut-off values of CH (methane) and H (hydrogen) were analyzed via receiver operating characteristic (ROC) curves. Lastly,archived SHMBT data from 2 655 patients with gastrointestinal symptoms (validation set) were used to evaluate the diagnostic value of the SHMBT with respect to SIBO. The Chi-square test,the Mann-Whitney test,Spearman's Rank correlation analysis,and the test were used for statistical analysis. Based on the international recommended diagnostic criteria for SIBO,which are fasting CH ≥10 ppm (parts per million) or H ≥20 ppm,the SHMBT-positive rate in the case group was significantly higher than that of control group (35.2% vs. 21.7%, =4.08, =0.043). Levels of CH and H were higher in the case group than in the control group [CH: 3(2,7) vs. 3(1,3) ppm, H: 11(4,22) vs. 10(5,15) ppm],and the difference in CH levels was statistically significant (=6.22,=0.001). ROC curves were generated based on whether the subjects had gastrointestinal symptoms. The areas under the ROC curves were 0.633 for CH alone,0.531 for H alone, and 0.620 for CH combined with H. The cut-off values were fasting CH≥4 ppm,fasting H≥13 ppm,and fasting CH ≥5 ppm (or CH≥4 ppm and H≥24 ppm),respectively. Measuring CH alone and CH combined with H was effective for determining the presence of gastrointestinal symptoms (<0.05). When CH alone or CH combined with H were used as diagnostic indicators of SIBO, the respective SHMBT-positive rates in the validation set were 34.2% and 30.4%. These rates did not significantly differ from the SIBO-positive rate of 32.0% obtained via the international recommended diagnostic criteria (>0.05). The specificity of CH alone was 79.9%,and the accuracy of CH alone was 68.8%. The specificity of CH combined with H was 85.0%,and the accuracy of CH combined with H was 71.7%. Rapid one-time determination of CH and H in exhaled breath may a viable diagnostic method for SIBO, and using CH combined with H (,fasting CH≥5 ppm, or CH ≥4 ppm and H ≥24 ppm) as cutoff values may be feasible.
探讨单次氢甲烷呼气试验（SHMBT）对小肠细菌过度生长（SIBO）的诊断价值。本研究为横断面研究。对162例有胃肠道症状的患者（病例组）和69名健康志愿者（对照组）进行问卷调查和SHMBT检测。评估两组SHMBT结果的差异，并通过受试者工作特征（ROC）曲线分析甲烷（CH）和氢气（H）的截断值。最后，使用2655例有胃肠道症状患者的存档SHMBT数据（验证集）评估SHMBT对SIBO的诊断价值。采用卡方检验、曼-惠特尼检验、Spearman秩相关分析和t检验进行统计分析。根据国际推荐的SIBO诊断标准，即空腹CH≥10 ppm（百万分之一）或H≥20 ppm，病例组的SHMBT阳性率显著高于对照组（35.2%对21.7%，χ²=4.08，P=0.043）。病例组CH和H水平高于对照组[CH：3（2，7）对3（1，3）ppm，H：11（4，22）对10（5，15）ppm]，且CH水平差异具有统计学意义（t=6.22，P=0.001）。根据受试者是否有胃肠道症状绘制ROC曲线。单独CH的ROC曲线下面积为0.633，单独H的为0.531，CH与H联合的为0.620。截断值分别为空腹CH≥4 ppm、空腹H≥13 ppm以及空腹CH≥5 ppm（或CH≥4 ppm且H≥24 ppm）。单独检测CH以及CH与H联合检测对判断胃肠道症状的存在有效（P<0.05）。当单独使用CH或CH与H联合作为SIBO的诊断指标时，验证集中SHMBT的阳性率分别为34.2%和30.4%。这些率与通过国际推荐诊断标准获得的SIBO阳性率32.0%无显著差异（P>0.05）。单独CH的特异性为79.9%，单独CH的准确性为68.8%。CH与H联合的特异性为85.0%，CH与H联合的准确性为71.7%。快速一次性测定呼出气体中的CH和H可能是一种可行的SIBO诊断方法，以CH与H联合（即空腹CH≥5 ppm，或CH≥4 ppm且H≥24 ppm）作为截断值可能是可行的。
