Naval Health Research Center, 140 Sylvester Rd, San Diego, CA 92106, USA.
BMC Infect Dis. 2012 Jun 7;12:129. doi: 10.1186/1471-2334-12-129.
Rapid influenza diagnosis is important for early identification of outbreaks, effective management of high-risk contacts, appropriate antiviral use, decreased inappropriate antibiotic use and avoidance of unnecessary laboratory testing. Given the inconsistent performance of many rapid influenza tests, clinical diagnosis remains integral for optimizing influenza management. However, reliable clinical diagnostic methods are not well-established. This study assesses predictors of influenza, and its various subtypes, in a broad population at the point of care, across age groups, then evaluates the performance of clinical case definitions composed of identified predictors.
Respiratory specimens and demographic and clinical data were obtained from 3- to 80-year-old US military family members presenting for care with influenza-like illness (ILI) from November 2007 to April 2008. Molecular and virus isolation techniques were used to detect and subtype influenza viruses. Associations between influenza diagnosis and demographic/clinical parameters were assessed by logistic regression, including influenza type and subtype analyses. The predictive values of multiple combinations of identified clinical predictors (case definitions), and the Centers for Disease Control and Prevention (CDC) ILI case definition, were estimated.
Of 789 subjects, 220 (28%) had laboratory-confirmed influenza (51 A(H1), 46 A(H3), 19 A(unsubtypeable), 67 B, 1 AB coinfection), with the proportion of influenza A to B cases highest among 6- to 17-year-olds (p = 0.019). Independent predictors of influenza included fever, cough, acute onset, body aches, and vaccination status among 6- to 49-year-olds, only vaccination among 3- to 5-year-olds, and only fever among 50- to 80-year-olds. Among 6- to 49-year-olds, some clinical case definitions were highly sensitive (100.0%) or specific (98.6%), but none had both parameters over 60%, though many performed better than the CDC ILI case definition (sensitivity 37.7%, 95% confidence interval 33.6-41.9% in total study population).
Patterns of influenza predictors differed across age groups, with most predictors identified among 6- to 49-year-olds. No combination of clinical and demographic predictors served as a reliable diagnostic case definition in the population and influenza season studied. A standardized clinical case definition combined with a point-of-care laboratory test may be the optimal rapid diagnostic strategy available.
快速流感诊断对于早期识别暴发、有效管理高危接触者、合理使用抗病毒药物、减少不必要的抗生素使用以及避免不必要的实验室检测至关重要。鉴于许多快速流感检测的性能不一致，临床诊断仍然是优化流感管理的重要组成部分。然而，可靠的临床诊断方法尚未得到很好的确立。本研究评估了在不同年龄段的广泛人群中，在护理点对流感及其各种亚型的预测因素，并评估了由确定的预测因素组成的临床病例定义的性能。
从 2007 年 11 月至 2008 年 4 月，从美国军事家庭成员中收集了 3 至 80 岁出现流感样疾病（ILI）的呼吸道标本以及人口统计学和临床数据。使用分子和病毒分离技术检测和亚型流感病毒。通过 logistic 回归评估流感诊断与人口统计学/临床参数之间的关联，包括流感类型和亚型分析。估计了多种确定的临床预测因素（病例定义）以及疾病控制和预防中心（CDC）ILI 病例定义的组合的预测值。
在 789 名受试者中，有 220 名（28%）经实验室确认为流感（51 株 A(H1)、46 株 A(H3)、19 株未定型、67 株 B、1 株 AB 共感染），6 至 17 岁人群中流感 A 与 B 病例的比例最高（p=0.019）。6 至 49 岁人群中流感的独立预测因素包括发热、咳嗽、急性发作、身体疼痛和疫苗接种状态，3 至 5 岁人群中仅与疫苗接种相关，50 至 80 岁人群中仅发热。在 6 至 49 岁人群中，一些临床病例定义具有很高的敏感性（100.0%）或特异性（98.6%），但没有一个参数超过 60%，尽管许多参数的性能优于 CDC ILI 病例定义（总研究人群中的敏感性为 37.7%，95%置信区间为 33.6-41.9%）。
不同年龄组流感预测因素的模式不同，大多数预测因素在 6 至 49 岁人群中确定。在研究的人群和流感季节中，没有任何临床和人口统计学预测因素的组合可以作为可靠的诊断病例定义。结合床边实验室检测的标准化临床病例定义可能是目前可用的最佳快速诊断策略。
