整群随机对照设计在学校伤寒副伤寒综合干预项目中的应用研究

Application of Cluster Randomization Method on School Typhoid and Paratyphoid Comprehensive Intervention Program

目的以整群随机试验实现学校伤寒副伤寒综合干预项目的研究设计和实施应用,评价设计与应用效果。方法选择广西伤寒副伤寒高发区全州县为项目现场,采用整群随机试验方法确定干预组和对照组所需样本量。结果根据组群随机试验方法计算,共需要观察对象为28500人,以学校为单位,分为38个组群。根据组群的以往发病率、地理位置及性质(小学、中学、高中)分层配对,确定干预组分为19个组群共13563人,对照组为19个组群共14143人。对2组各主要混杂因子(学校性质、学生年龄与性别、学校卫生环境等)进行分析,2组之间总体相差不大,具有较好的均衡性与可比性。结论整群随机抽样法应用于伤寒、副伤寒学校干预试验研究,简单易行,能较好地控制组间混杂因子,但所需样本量较大。

Objective To describe the design and application of cluster randomized controlled method on school typhoid and paratyphoid comprehensive intervention program,and to assess the design of the study and analyze the effect of implementation.Methods According to simple size calculation of cluster-randomized trial to determine the sample size of intervention group and control group in Quanzhou county.Results According to simple size calculation,a total sample of 28 500 participants was needed and study schools were divided into 38 clusters.In practice,19 observation clusters with 13 563 participants and 19 control clusters with 14 143 participants were stratified and matched according to the previous typhoid and paratyphoid incidence,location,and type of school of cluster randomization into examination and control groups respectively.Comparing with confounding factors of two groups including type of school,age,sex,school health environment,etc.It was found that the ratio of differents of all confounding factors between two groups were comparable and balanceable.Conclusion It can better control the confounding factors between intervention group and control group by applying cluster-randomized method on the intervention program and the implementation of cluster randomization trial is simplicity,easy accepted and feasible,but it needed a big sample.