Department of Medicine (Geriatrics), Dalhousie University, Halifax, Nova Scotia, Canada.
Canadian Center for Vaccinology, IWK Health Centre and Nova Scotia Health Authority, Dalhousie University, Halifax, Nova Scotia, Canada.
Infect Control Hosp Epidemiol. 2020 May;41(5):499-504. doi: 10.1017/ice.2020.22. Epub 2020 Mar 9.
Older adults often have atypical presentation of illness and are particularly vulnerable to influenza and its sequelae, making the validity of influenza case definitions particularly relevant. We sought to assess the performance of influenza-like illness (ILI) and severe acute respiratory illness (SARI) criteria in hospitalized older adults.
Prospective cohort study.
The Serious Outcomes Surveillance Network of the Canadian Immunization Research Network undertakes active surveillance for influenza among hospitalized adults.
Data were pooled from 3 influenza seasons: 2011/12, 2012/13, and 2013/14. The ILI and SARI criteria were defined clinically, and influenza was laboratory confirmed. Frailty was measured using a validated frailty index.
Of 11,379 adult inpatients (7,254 aged ≥65 years), 4,942 (2,948 aged ≥65 years) had laboratory-confirmed influenza. Their median age was 72 years (interquartile range [IQR], 58-82) and 52.6% were women. The sensitivity of ILI criteria was 51.1% (95% confidence interval [CI], 49.6-52.6) for younger adults versus 44.6% (95% CI, 43.6-45.8) for older adults. SARI criteria were met by 64.1% (95% CI, 62.7-65.6) of younger adults versus 57.1% (95% CI, 55.9-58.2) of older adults with laboratory-confirmed influenza. Patients with influenza who were prefrail or frail were less likely to meet ILI and SARI case definitions.
A substantial proportion of older adults, particularly those who are frail, are missed by standard ILI and SARI case definitions. Surveillance using these case definitions is biased toward identifying younger cases, and does not capture the true burden of influenza. Because of the substantial fraction of cases missed, surveillance definitions should not be used to guide diagnosis and clinical management of influenza.
老年人的疾病表现常常不典型，且特别容易感染流感及其并发症，因此流感病例定义的准确性尤为重要。我们旨在评估流感样疾病（ILI）和严重急性呼吸道感染（SARI）标准在住院老年人中的应用效果。
前瞻性队列研究。
加拿大免疫研究网络的严重后果监测网络对住院成人中的流感进行主动监测。
数据来自三个流感季节（2011/12、2012/13 和 2013/14 年）的汇总。ILI 和 SARI 标准通过临床定义，流感通过实验室确认。采用经过验证的脆弱性指数来衡量脆弱性。
在 11379 名成年住院患者中（≥65 岁 7254 人），有 4942 人（≥65 岁 2948 人）实验室确诊为流感。他们的中位年龄为 72 岁（四分位距 [IQR]，58-82），52.6%为女性。对于年轻患者，ILI 标准的敏感性为 51.1%（95%置信区间 [CI]，49.6-52.6），而对于老年患者为 44.6%（95% CI，43.6-45.8）。SARI 标准在 64.1%（95% CI，62.7-65.6）的年轻患者和 57.1%（95% CI，55.9-58.2）的老年患者中得到满足，这些患者的流感经实验室确诊。患有流感的虚弱前期或虚弱患者不太可能符合 ILI 和 SARI 病例定义。
标准的 ILI 和 SARI 病例定义会遗漏相当一部分老年患者，尤其是那些脆弱的患者。使用这些病例定义进行监测会偏向于识别年轻病例，而不能捕捉到流感的真实负担。由于大量病例被遗漏，监测定义不应用于指导流感的诊断和临床管理。
