Clinical Epidemiology Program, Veterans Affairs Medical Center, White River Junction, VT, USA; Department of Psychiatry, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.
Precision Health Economics, Oakland, CA, USA.
Vaccine. 2019 Mar 7;37(11):1484-1490. doi: 10.1016/j.vaccine.2019.01.063. Epub 2019 Feb 8.
Observational studies of the relative effectiveness of influenza vaccines are essential for public health decision making. Their estimates, however, are subject to bias due to unmeasured confounders. Instrumental variable (IV) methods can control for observed and unobserved confounders.
We used linked electronic medical record databases in the Veterans Health Administration (VHA) as well as Medicare administrative files to examine the relative vaccine effectiveness (rVE) of high-dose influenza vaccine (HD) versus standard-dose influenza vaccines (SD) in preventing hospitalizations among VHA-enrolled Veterans ≥65 years of age during 5 influenza seasons (2010-2011 through 2014-2015). Using multivariable IV Poisson regression modeling to address unmeasured confounding and bias, we analyzed the data by each season and through longitudinal analysis of all five seasons.
We included 3,638,924 person-influenza seasons of observation where 158,636 (4%) were among HD vaccine recipients and 3,480,288 (96%) were among SD vaccine recipients. Of the 1,728,562 Veterans, 1,702,824 (98.5%) were male and 1,299,412 (75%) were non-Hispanic white. Based on the longitudinal analysis of all five seasons, the IV-adjusted rVE estimate of HD vs. SD was 10% (95% CI, 8-12%) against all-cause hospitalization; 18% (95% CI, 15-21%) against cardiorespiratory-associated hospitalization; and 14% (95% CI, 6-22%) against influenza/pneumonia-associated hospitalization. The findings by season were similar.
Our analysis of VHA clinical data collected from approximately 1.7 million Veterans 65 years and older during five seasons demonstrates that high-dose influenza vaccine is more effective than standard-dose influenza vaccines in preventing influenza- or pneumonia-associated hospitalizations, cardiorespiratory hospitalizations, and all-cause hospitalizations.
观察性研究流感疫苗的相对有效性对于公共卫生决策至关重要。然而，由于无法测量的混杂因素，它们的估计值存在偏差。工具变量 (IV) 方法可以控制观察到的和未观察到的混杂因素。
我们使用退伍军人事务部 (VA) 的电子病历数据库和医疗保险管理档案，检查了高剂量流感疫苗 (HD) 与标准剂量流感疫苗 (SD) 之间的相对疫苗有效性 (rVE)，以预防在 5 个流感季节（2010-2011 年至 2014-2015 年）期间，VA 登记的 65 岁及以上退伍军人的住院治疗。使用多变量 IV 泊松回归模型来解决未测量的混杂和偏差，我们按每个季节和所有五个季节的纵向分析来分析数据。
我们包括了 3638924 个人-流感季节的观察，其中 158636 人（4%）接受了 HD 疫苗接种，3480288 人（96%）接受了 SD 疫苗接种。在 1728562 名退伍军人中，1702824 人（98.5%）为男性，1299412 人（75%）为非西班牙裔白人。根据所有五个季节的纵向分析，HD 与 SD 的 IV 调整 rVE 估计值为 10%（95%CI，8-12%），针对所有原因的住院治疗；18%（95%CI，15-21%）针对心肺相关住院治疗；14%（95%CI，6-22%）针对流感/肺炎相关住院治疗。各季节的结果相似。
我们对来自五个季节约 170 万 65 岁及以上退伍军人的 VA 临床数据进行的分析表明，高剂量流感疫苗比标准剂量流感疫苗更能有效预防流感或肺炎相关的住院治疗、心肺住院治疗和全因住院治疗。
