大学生肺结核患者密切接触者结核分枝杆菌潜伏感染检测方法研究

A study of detection methods of latent Mycobacterium tuberculosis infection in close contacts of active tuberculosis patients among college students

目的探索大学生肺结核患者密切接触者结核分枝杆菌潜伏感染检测适宜方法,为我国结核病低疫情地区学校肺结核患者密切接触者筛查提供证据支持。方法根据上海市2019年各区结核病登记报告率水平(高、中、低),选取浦东新区、松江区、闵行区作为研究现场,在研究现场连续纳入2019学年所有大学一、二年级学生肺结核患者(指示病例)密切接触者作为研究对象。研究对象在常规学校肺结核疫情处置措施基础上,进行问卷调查及γ-干扰素释放试验(IGRA;采用QFT-GIT试剂盒)检测。共计767名完成基线问卷调查,其中,747名同时具有基线结核菌素皮肤试验(TST;采用BCG-PPD)及QFT检测结果。分析TST、QFT及TST-QFT联合检测的阳性率、成本效益、筛查效率,以及TST与QFT检测结果不一致的影响因素。结果QFT检测阳性率为5.0%(37/747),TST检测阳性率为17.1%(128/747),联合使用TST-QFT检测阳性率为4.0%(30/747)。单用QFT检测发现结核分枝杆菌潜伏感染者的例均费用最高(6218.9元),而TST-QFT联合检测的例均费用(3023.0元)相比于单用QFT检测降低51.4%。使用TST-QFT筛查24.9人可发现1例结核分枝杆菌潜伏感染者[筛查所需数量(NNS)为24.9],在无卡疤(NNS=7.3)、体质量指数<18.5(NNS=5.5)及吸烟人群(NNS=14.8)中,筛查效率更高。多因素logisitic回归分析显示,吸烟人群更易出现TST与QFT检测不一致的情况[TST(-)/QFT(+)vs TST(-)/QFT(-):aOR(95%CI)=10.99(1.76~68.54);TST(+)/QFT(-)vs TST(-)/QFT(-):aOR(95%CI)=1.98(1.13~3.49)]。结论在无法实现IGRA普查结核分枝杆菌潜伏感染情况下,推荐使用TST-IGRA两步筛查方法,尤其对无卡疤及体质量指数<18.5人群,可在一定程度上降低筛查成本,提高筛查效率;而吸烟人群,则建议直接行IGRA检测。

Objective This study aims to explore detection methods of latent Mycobacterium tuberculosis infection(LTBI)in close contacts of active tuberculosis patients among college students in Shanghai,to provide evidence for screening of close contacts of active tuberculosis patients in schools in areas with low prevalence of tuberculosis in China.Methods According to the different levels of reported incidence of tuberculosis in 2019 in Shanghai,we choose Pudong New Area,Songjiang District and Minhang District as study sites,close contacts of college active tuberculosis patients among the freshman/sophomore in three districts were continuously recruited as study subjects.In addition to routine screening methods,a questionnaire and interferon gamma release assay(IGRA,by QFT-GIT)were conducted in the subjects.Of the 767 close contacts who finished the baseline questionnaire,747 had both TST(by BCG-PPD)and QFT results.The positive rate,cost effectiveness and screening efficiency of TST,QFT and TST-QFT combined tests,as well as the influencing factors of the inconsistent of TST and QFT test results were analyzed.Results The positive rates were 5.0%(37/747)by QFT,17.1%(128/747)by TST and 4.0%(30/747)by TST-QFT combined test.The cost per case of LTBI detected by QFT alone was the highest(RMB 6218.9 yuan),while that by the combined use of TST-QFT reduced to 51.4%(RMB 3023.0 yuan).One LTBI could be found among 24.9 subjects by TST-QFT(numbers needed to screen(NNS)was 24.9),screening was more effective in those with no BCG scar(NNS=7.3),BMI<18.5(NNS=5.5)and smokers(NNS=14.8).Multivariate logistic regression analysis showed that inconsistent of TST and QFT detection(TST(-)/QFT(+)vs.TST(-)/QFT(-):aOR(95%CI)=10.99(1.76-68.54);TST(+)/QFT(-)vs.TST(-)/QFT(-):aOR(95%CI)=1.98(1.13-3.49))were more likely to be found in smokers.Conclusion When IGRA could not be widely used for LTBI detection,the TST-IGRA two-step method was recommended,especially in those without BCG scar and BMI<18.5.It could reduce the screening cost and improve the efficiency to a certain extent,while smokers are recommended to use IGRA test directly.