Research School of Population Health, Australian National University, Canberra, Australia.
Research School of Population Health, Australian National University, Canberra, Australia.
J Hosp Infect. 2018 Aug;99(4):453-460. doi: 10.1016/j.jhin.2017.12.014. Epub 2017 Dec 16.
Clostridium difficile infections occur frequently among hospitalized patients, with some infections acquired in hospital and others in the community. International guidelines classify cases as hospital-acquired if symptom onset occurs more than two days after admission. This classification informs surveillance and infection control, but has not been verified by empirical or modelling studies.
To assess current classification of C. difficile acquisition using a simulation model as a reference standard.
C. difficile transmission was simulated in a range of hospital scenarios. The sensitivity, specificity and precision of classifications that use cut-offs ranging from 0.25 h to 40 days were calculated. The optimal cut-off that correctly estimated the proportion of cases that were hospital acquired and the balanced cut-off that had equal sensitivity and specificity were identified.
The recommended two-day cut-off overestimated the incidence of hospital-acquired cases in all scenarios and by >100% in the base scenario. The two-day cut-off had good sensitivity (96%) but poor specificity (48%) and precision (52%) to identify cases acquired during the current hospitalization. A five-day cut-off was balanced, and a six-day cut-off was optimal in the base scenario. The optimal and balanced cut-offs were more than two days for nearly all scenarios considered (ranges: four to nine days and two to eight days, respectively).
Current guidelines for classifying C. difficile infections overestimate the proportion of cases acquired in hospital in all model scenarios. To reduce misclassification bias, an infection should be classified as being acquired prior to admission if symptoms begin within five days of admission.
艰难梭菌感染在住院患者中很常见，有些感染是在医院获得的，有些是在社区获得的。国际指南将症状出现于入院后超过两天的感染病例归类为医院获得性感染。这种分类方法为监测和感染控制提供了依据，但尚未通过实证或模型研究得到验证。
使用模拟模型作为参考标准，评估当前艰难梭菌感染的分类方法。
在一系列医院场景中模拟艰难梭菌的传播。计算了使用 0.25 小时至 40 天的时间间隔作为分类截止值的分类方法的灵敏度、特异性和精度。确定了正确估计医院获得性病例比例的最佳截止值和具有相等灵敏度和特异性的平衡截止值。
在所有场景中，推荐的两天截止值都高估了医院获得性病例的发生率，在基础场景中高估了 100%以上。两天截止值对识别当前住院期间获得的病例具有良好的灵敏度（96%），但特异性（48%）和精度（52%）较差。五天截止值是平衡的，在基础场景中六天截止值是最佳的。对于考虑的几乎所有场景，最佳和平衡截止值都超过两天（范围分别为四天至九天和两天至八天）。
目前用于分类艰难梭菌感染的指南在所有模型场景中都高估了医院获得性病例的比例。为了减少分类偏倚，如果症状在入院后五天内出现，应将感染归类为入院前获得。
