硫化氢呼气试验在小肠细菌过度生长诊断中的应用价值初探

The diagnostic value of hydrogen sulfide breath test for small intestinal bacterial overgrowth

目的探究硫化氢呼气试验(hydrogen sulfide breath test,SBT)在小肠细菌过度生长(small intestinal bacterial overgrowth,SIBO)诊断中的应用价值。方法纳入2019年4—12月某高校学生,进行消化道症状和1周膳食问卷调查,以及乳果糖氢-甲烷呼气试验(lactulose hydrogen-methane breath test,LHMBT)和SBT。分析呼气中氢、甲烷及硫化氢浓度并绘制硫化氢的受试者工作特征(ROC)曲线,确定SBT的阳性判断标准。结果共纳入300名受试者,男84名、女216名,年龄17~32(21.6±2.4)岁。203名报告SIBO样症状,其中LHMBT阳性99名(48.8%);无症状97名中,LHMBT阳性38名(39.2%)。摄入乳果糖90 min时呼气中硫化氢升高值和氢气升高值显著正相关(r=0.516,P<0.01);硫化氢绝对值和甲烷浓度显著正相关(r=0.632,P<0.01)。以服用乳果糖后90 min时硫化氢绝对值≥62.5 ppb(×10-9)或较基线值升高25.0 ppb为阳性判断值,敏感度、特异度和准确率分别为66.4%、79.1%和73.3%。硫化氢丰度与维生素B12的摄入量显著相关(P=0.011),阳性者便秘更为突出。结论乳果糖硫化氢呼气试验与氢-甲烷具有较高的一致性,对便秘患者具有更高的检出率,可作为诊断SIBO的重要补充。

Objective To evaluate the diagnostic value of hydrogen sulfide breath test(SBT)for small intestinal bacterial overgrowth(SIBO).Methods College students were enrolled to complete gastrointestinal symptom scale,food frequency questionnaire,lactulose hydrogen-methane breath test(LHMBT)and SBT.Based on the correlation between hydrogen sulfide(H2S)and hydrogen or methane gas,the receiver operating characteristic(ROC)curve of H2S was drawn and diagnostic criteria of SBT was defined.Results A total of 300 subjects including 84 males and 216 females with age 17-32(21.6±2.4)years were enrolled from April 2019 to December 2019 and divided into two groups.Two hundred and three patients reported SIBO discomforts with 99(48.8%)LHMBT positive,while 38(39.2%)were LHMBT positive in 97 health controls.Rise of H2S at 90 min was positively related with that of hydrogen(r=0.516,P<0.01),and H2S levels at 90 min were positively correlated with methane(r=0.632,P<0.01).A rise in H2S of≥25.0 ppb or H2S levels≥62.5 ppb at 90 min during lactulose breath test was considered positive for SIBO,that sensitivity,specificity and accuracy were 66.4%,79.1%and 73.3%respectively.H2S levels were significantly related to the amount of Vitamin B12 intake(P=0.011).H2S-positive subjects exhibited a constipation-predominant pattern.Conclusion SBT is consistent with LHMBT,especially in constipation-predominant patients,which may provide a reference to the diagnosis of SIBO.