F. I. Proctor Foundation, 513 Parnassus Avenue, Med Sci S309, Box 0412, University of California, San Francisco, San Francisco, CA 94143-0412, USA.
Invest Ophthalmol Vis Sci. 2012 Jan 25;53(1):235-40. doi: 10.1167/iovs.11-8493.
Although trachoma control programs frequently use the World Health Organization (WHO) simplified grading system for trachoma to monitor the clinical response after repeated mass azithromycin treatments, the programmatic relevance of this evaluation after multiple rounds of antibiotic treatments is unclear.
Three rounds of annual mass azithromycin were distributed to 12 villages in Ethiopia. Twelve months after the third treatment, children were assessed for follicular trachomatous inflammation (TF) and intense trachomatous inflammation (TI) using the WHO simplified grading system and for ocular chlamydial infection using DNA-based and RNA-based tests. Test characteristics for predicting chlamydial infection were computed assuming a chlamydial RNA-based gold standard. As a secondary analysis, test characteristics were also assessed using a latent class analysis.
The prevalence of RNA evidence of ocular chlamydia was 7.1% (95% confidence interval [CI], 2.7-17.4). A DNA-based test and TF had sensitivities of 61.0% (95% CI, 47.1-73.3) and 65.9% (95% CI, 41.6-83.9), specificities of 100% (95% CI, 99.3-100) and 67.5% (95% CI, 61.0-73.5), and positive predictive values of 100% (95% CI, 86.3-100) and 13.4% (95% CI, 5.5-29.3) compared with an RNA-based gold standard. The latent class analysis confirmed that the RNA-based test was a reasonable choice for a gold standard, with a sensitivity of 100% (95% CI, 67.1-100) and specificity of 99.6% (95% CI, 98.1-100).
Basing treatment decisions after mass azithromycin distributions on the WHO simplified grading system will maximize the treatment of infected persons compared with a DNA-based test but will also result in more uninfected persons being treated. The RNA-based test was considerably more sensitive, and almost equivalently specific, compared with a DNA-based test. (ClinicalTrials.gov number, NCT00322972.).
尽管沙眼控制项目常使用世界卫生组织（WHO）简化的沙眼分级系统来监测重复使用阿奇霉素大规模治疗后的临床反应，但在多次使用抗生素治疗后，这种评估在项目中的相关性尚不清楚。
在埃塞俄比亚的 12 个村庄中，每年进行三轮阿奇霉素的大规模分发。第三次治疗后 12 个月，使用 WHO 简化分级系统评估儿童滤泡性沙眼炎症（TF）和强烈的沙眼炎症（TI），并使用基于 DNA 和 RNA 的检测评估眼部衣原体感染。假设使用基于 RNA 的衣原体检测作为金标准，计算了用于预测衣原体感染的检测特征。作为二次分析，还使用潜在类别分析评估了检测特征。
眼部衣原体 RNA 证据的流行率为 7.1%（95%置信区间 [CI]，2.7-17.4）。基于 DNA 的检测和 TF 的敏感性分别为 61.0%（95% CI，47.1-73.3）和 65.9%（95% CI，41.6-83.9），特异性分别为 100%（95% CI，99.3-100）和 67.5%（95% CI，61.0-73.5），阳性预测值分别为 100%（95% CI，86.3-100）和 13.4%（95% CI，5.5-29.3），与基于 RNA 的金标准相比。潜在类别分析证实，基于 RNA 的检测是金标准的合理选择，敏感性为 100%（95% CI，67.1-100），特异性为 99.6%（95% CI，98.1-100）。
与基于 DNA 的检测相比，在大规模阿奇霉素分发后，根据 WHO 简化分级系统做出治疗决策将使受感染人群的治疗最大化，但也会导致更多未感染人群接受治疗。与基于 DNA 的检测相比，基于 RNA 的检测具有更高的敏感性，几乎相同的特异性。（临床试验注册号：NCT00322972.）
