Unit of PharmacoEpidemiology & PharmacoEconomics (PE2), Department of Pharmacy, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands; Department of Epidemiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, Postbus 30 001, 9700 RB Groningen, the Netherlands.
Medical Research Council Biostatistics Unit, Institute of Public Health, University Forvie Site, Robinson Way, Cambridge. UK. CB2 0SR.
J Clin Epidemiol. 2014 Jul;67(7):734-44. doi: 10.1016/j.jclinepi.2014.02.009. Epub 2014 Apr 24.
To compare the performance of the bias-adjusted meta-analysis to the conventional meta-analysis assessing seasonal influenza vaccine effectiveness among community-dwelling elderly aged 60 years and older.
Systematic literature search revealed 14 cohort studies that met inclusion and exclusion criteria. Laboratory-confirmed influenza, influenza-like illness, hospitalization from influenza and/or pneumonia, and all-cause mortality were study outcomes. Potential biases were identified using bias checklists. The magnitude and uncertainty of biases were assessed by expert opinion. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using random effects model.
After incorporating biases, overall effect estimates regressed slightly toward no effect, with the largest relative difference between conventional and bias-adjusted ORs for laboratory-confirmed influenza (OR, 0.18; 95% CI: 0.01, 3.00 vs. OR, 0.23; 95% CI: 0.03, 2.04). In most of the studies, CIs widened reflecting uncertainties about the biases. The between-study heterogeneity reduced considerably with the largest reduction for all-cause mortality (I(2) = 4%, P = 0.39 vs. I(2) = 91%, P < 0.01).
This case study showed that after addressing potential biases influenza vaccine was still estimated effective in preventing hospitalization from influenza and/or pneumonia and all-cause mortality. Increasing the number of assessors and incorporating empirical evidence might improve the new bias-adjustment method.
比较偏倚调整的荟萃分析与传统荟萃分析评估 60 岁及以上社区居住老年人季节性流感疫苗有效性的性能。
系统文献检索揭示了 14 项符合纳入和排除标准的队列研究。实验室确诊的流感、流感样疾病、因流感和/或肺炎住院以及全因死亡率是研究结果。使用偏差检查表确定潜在偏差。通过专家意见评估偏差的大小和不确定性。使用随机效应模型计算合并的优势比（OR）和 95%置信区间（95%CI）。
在纳入偏差后，总体效应估计值略微向无效应回归，实验室确诊流感的传统和偏差调整 OR 之间的相对差异最大（OR，0.18；95%CI：0.01，3.00 与 OR，0.23；95%CI：0.03，2.04）。在大多数研究中，CI 变宽反映了对偏差的不确定性。研究间异质性大大降低，全因死亡率的降低最大（I²=4%，P=0.39 与 I²=91%，P<0.01）。
本案例研究表明，在解决潜在偏差后，流感疫苗仍被估计能有效预防因流感和/或肺炎住院以及全因死亡率。增加评估者的数量并纳入经验证据可能会改进新的偏差调整方法。
