ABSTRACT

As trachoma programs move towards eliminating trachoma as a public health problem, the number of surveys necessary to evaluate the status of trachomatous trichiasis (TT) increases. Currently, the World Health Organization endorses a district-level population-based prevalence survey for trachoma that involves a two-stage cluster design. We explored the validity of implementing this survey design in larger geographic areas to gain cost efficiencies. We evaluated the change in precision due to combining geographically contiguous and homogenous districts into single evaluation units (EUs) and modulating the sample size by running simulations on existing datasets. Preliminary findings from two opportunities in Tanzania show variability in the appropriateness in conducting this survey across larger geographies. These preliminary findings stress the importance of determining what is meant by homogeneity in terms of TT before combining multiple districts into a single EU.

摘要

随着沙眼项目朝着消除作为公共卫生问题的沙眼的方向发展，评估沙眼倒睫 (TT) 状况所需的调查数量也在增加。目前，世界卫生组织批准了一项涉及两阶段集群设计的地区级基于人群的沙眼流行率调查。我们探讨了在更大的地理区域实施这项调查设计以提高成本效益的有效性。我们评估了由于将地理上连续和同质的地区组合成单个评估单元 (EU) 并通过在现有数据集上运行模拟来调整样本大小而导致的精度变化。来自坦桑尼亚的两个机会的初步调查结果显示，在更大的地区开展这项调查的适当性存在差异。