Floyd Sian, Sismanidis Charalambos, Yamada Norio, Daniel Rhian, Lagahid Jaime, Mecatti Fulvia, Vianzon Rosalind, Bloss Emily, Tiemersma Edine, Onozaki Ikushi, Glaziou Philippe, Floyd Katherine
London School of Hygiene & Tropical Medicine London, UK.
World Health Organization Geneva, Switzerland.
Emerg Themes Epidemiol. 2013 Sep 28;10(1):10. doi: 10.1186/1742-7622-10-10.
An unprecedented number of nationwide tuberculosis (TB) prevalence surveys will be implemented between 2010 and 2015, to better estimate the burden of disease caused by TB and assess whether global targets for TB control set for 2015 are achieved. It is crucial that results are analysed using best-practice methods.
To provide new theoretical and practical guidance on best-practice methods for the analysis of TB prevalence surveys, including analyses at the individual as well as cluster level and correction for biases arising from missing data.
TB prevalence surveys have a cluster sample survey design; typically 50-100 clusters are selected, with 400-1000 eligible individuals in each cluster. The strategy recommended by the World Health Organization (WHO) for diagnosing pulmonary TB in a nationwide survey is symptom and chest X-ray screening, followed by smear microscopy and culture examinations for those with an abnormal X-ray and/or TB symptoms. Three possible methods of analysis are described and explained. Method 1 is restricted to participants, and individuals with missing data on smear and/or culture results are excluded. Method 2 includes all eligible individuals irrespective of participation, through multiple missing value imputation. Method 3 is restricted to participants, with multiple missing value imputation for individuals with missing smear and/or culture results, and inverse probability weighting to represent all eligible individuals. The results for each method are then compared and illustrated using data from the 2007 national TB prevalence survey in the Philippines. Simulation studies are used to investigate the performance of each method.
A cluster-level analysis, and Methods 1 and 2, gave similar prevalence estimates (660 per 100,000 aged ≥ 10 years old), with a higher estimate using Method 3 (680 per 100,000). Simulation studies for each of 4 plausible scenarios show that Method 3 performs best, with Method 1 systematically underestimating TB prevalence by around 10%.
Both cluster-level and individual-level analyses should be conducted, and individual-level analyses should be conducted both with and without multiple missing value imputation. Method 3 is the safest approach to correct the bias introduced by missing data and provides the single best estimate of TB prevalence at the population level.
2010年至2015年期间将开展前所未有的大量全国性结核病患病率调查，以更好地估计结核病所致疾病负担，并评估是否实现了为2015年设定的全球结核病控制目标。至关重要的是要使用最佳实践方法对结果进行分析。
为结核病患病率调查分析的最佳实践方法提供新的理论和实践指导，包括个体层面和聚类层面的分析以及对缺失数据引起的偏差进行校正。
结核病患病率调查采用聚类抽样调查设计；通常选取50 - 100个聚类，每个聚类中有400 - 1000名符合条件的个体。世界卫生组织（WHO）推荐的在全国性调查中诊断肺结核的策略是症状和胸部X光筛查，随后对X光异常和/或有结核病症状者进行涂片显微镜检查和培养检查。描述并解释了三种可能的分析方法。方法1仅限于参与者，涂片和/或培养结果数据缺失的个体被排除。方法2通过多重缺失值插补纳入所有符合条件的个体，无论其是否参与。方法3仅限于参与者，对涂片和/或培养结果数据缺失的个体进行多重缺失值插补，并采用逆概率加权来代表所有符合条件的个体。然后使用菲律宾2007年全国结核病患病率调查的数据对每种方法的结果进行比较和说明。采用模拟研究来调查每种方法的性能。
聚类层面分析以及方法1和方法2得出的患病率估计值相似（每10万名10岁及以上人群中为660例），方法3得出的估计值更高（每10万名中为680例）。针对4种似然情景各自进行的模拟研究表明，方法3表现最佳，方法1系统性地低估结核病患病率约10%。
应同时进行聚类层面和个体层面的分析，个体层面分析应分别在有和没有多重缺失值插补的情况下进行。方法3是校正缺失数据引入偏差的最稳妥方法，并且能提供人群层面结核病患病率的最佳单一估计值。
