Monash University, Melbourne, Victoria, Australia.
BMC Public Health. 2011 May 18;11:338. doi: 10.1186/1471-2458-11-338.
Interest in the use of emergency department (ED) data by syndromic surveillance systems to detect influenza outbreaks has been growing. Evaluations of these systems generally focus on events during influenza seasons. The aims of this study were to identify which emergency department disease codes best correlated with confirmed influenza cases and to determine if these same codes would be useful in the non-influenza season. The 2009 influenza pandemic in Victoria, Australia, provided further opportunity to examine the performance of the syndromic surveillance system during this event.
We undertook a retrospective analysis of data from the Victorian Department of Health's pilot syndromic surveillance programme, 'SynSurv'. SynSurv automatically captures patient information as it is entered by ED staff. This information includes patient demographics, their presenting symptoms and a preliminary diagnosis using ICD-10 coding. To determine which codes were best correlated with influenza notifications, weekly counts for each of the ICD-10 diagnosis codes ever used in the dataset were calculated and compared with the corresponding weekly count of confirmed influenza cases. Correlations between these codes and confirmed influenza cases in the non-influenza season were then undertaken. The data covered the period from July 2001 until August 2009 and included the 2009 influenza pandemic.
There was a marked increase in weekly counts of both laboratory-confirmed influenza cases and relevant ICD-10 codes during the influenza pandemic period. The increase in laboratory confirmed cases was more than four times greater than the previous highest number reported, in 2007, even though the influenza-like-illness activity in the community was considered comparable to 2003 and 2007. We found five ICD-10 codes to be moderately and significantly correlated with influenza cases. None of these codes was correlated with laboratory confirmed influenza notifications outside the influenza season, at least in part because of the small number of influenza cases notified during that period.
This study suggests that the choice of codes made by ED staff to record a case of influenza-like illness is influenced by their perceptions of how much influenza is circulating at the time. The ability of syndromic surveillance to detect outbreaks early may be impeded because case diagnosis is influenced by what ED staff believes to be occurring in the community.
使用急症室 (ED) 数据进行症候群监测系统来检测流感爆发的兴趣日益增长。这些系统的评估通常集中在流感季节的事件上。本研究的目的是确定哪些急诊疾病代码与确诊的流感病例相关性最好，并确定这些相同的代码在非流感季节是否有用。澳大利亚维多利亚州 2009 年流感大流行提供了进一步的机会，以检验在此期间症候群监测系统的性能。
我们对维多利亚州卫生部试点症候群监测计划“SynSurv”的数据进行了回顾性分析。SynSurv 自动捕获 ED 工作人员输入的患者信息。这些信息包括患者的人口统计学信息、他们的症状和使用 ICD-10 编码的初步诊断。为了确定哪些代码与流感通知相关性最好，我们计算了数据集内使用过的每个 ICD-10 诊断代码的每周计数，并将其与确诊流感病例的相应每周计数进行了比较。然后对这些代码与非流感季节确诊流感病例之间的相关性进行了研究。该数据涵盖了 2001 年 7 月至 2009 年 8 月的时间段，包括 2009 年流感大流行。
在流感大流行期间，实验室确诊的流感病例和相关的 ICD-10 代码的每周计数都有明显增加。实验室确诊病例的增加量是 2007 年报告的最高数字的四倍多，尽管社区的流感样疾病活动被认为与 2003 年和 2007 年相当。我们发现五个 ICD-10 代码与流感病例中度和显著相关。这些代码都与流感季节之外的实验室确诊流感通知不相关，至少部分原因是在此期间报告的流感病例数量较少。
本研究表明，ED 工作人员记录流感样疾病病例时选择的代码受到他们对当时流感传播程度的看法的影响。症候群监测系统提前检测到疫情的能力可能会受到阻碍，因为病例诊断受到 ED 工作人员对社区内发生情况的看法的影响。
