Gilca Rodica, De Serres Gaston, Skowronski Danuta, Boivin Guy, Buckeridge David L
Institut National de Santé Publique du Québec, Quebec, PQ, Canada.
Am J Epidemiol. 2009 Oct 1;170(7):925-36. doi: 10.1093/aje/kwp195. Epub 2009 Aug 13.
Public policy regarding influenza has been based largely on the burden of hospitalization estimated through ecologic studies applying increasingly sophisticated statistical methods to administrative databases. None are known to have been validated by observational studies. The authors illustrated how 6 commonly applied statistical methods estimate virus-attributable hospitalization of children 6-23 months of age and compared the estimates with results obtained from a prospective study using virologic assessment. The proportions of pneumonia and influenza and of bronchiolitis hospitalizations attributable to respiratory syncytial virus and/or influenza were derived by using Serfling regression, periseason differences, Poisson regression with log link, negative binomial regression with identity link, and a Box-Jenkins transfer function. No method provided accurate or consistent estimates for both viruses and outcomes. Virus-attributable hospitalization estimates varied widely between statistical methods and between seasons, with greater between-season variation for admissions attributed to influenza compared with respiratory syncytial virus. Sophistication of statistical methods may have been interpreted as assurance that results are more accurate. Without validation against epidemiologic data, with viral etiology confirmed in individual patients, the accuracy of statistical methods in ecologic studies is simply not known. Until these methods are validated, their methodological limitations should be made explicit and proxy estimates used cautiously in guiding public policy.
关于流感的公共政策很大程度上基于通过对行政数据库应用日益复杂的统计方法进行生态学研究估算出的住院负担。目前尚无已知的研究通过观察性研究进行验证。作者阐述了6种常用统计方法如何估算6至23个月大儿童的病毒所致住院情况，并将这些估算结果与通过病毒学评估的前瞻性研究结果进行比较。使用塞尔弗林回归、季节差异、对数链接的泊松回归、恒等链接的负二项回归以及Box-Jenkins传递函数，得出了归因于呼吸道合胞病毒和/或流感的肺炎、流感以及细支气管炎住院比例。没有一种方法能对两种病毒和结局都提供准确或一致的估算。病毒所致住院估算在统计方法之间以及季节之间差异很大，与呼吸道合胞病毒相比，流感所致入院的季节间差异更大。统计方法的复杂性可能被解读为结果更准确的保证。在没有根据个体患者病毒病因得到确认的流行病学数据进行验证的情况下，生态学研究中统计方法的准确性根本无法得知。在这些方法得到验证之前，应明确其方法学局限性，并在指导公共政策时谨慎使用替代估算。
