The Nordic Cochrane Centre, Rigshospitalet, Department 7811, Blegdamsvej 9, 2100 Copenhagen Ø, Denmark.
The Nordic Cochrane Centre, Rigshospitalet, Department 7811, Blegdamsvej 9, 2100 Copenhagen Ø, Denmark.
J Clin Epidemiol. 2014 Sep;67(9):973-83. doi: 10.1016/j.jclinepi.2014.04.008. Epub 2014 Jun 25.
To examine the impact of not blinding outcome assessors on estimates of intervention effects in animal experiments modeling human clinical conditions.
We searched PubMed, Biosis, Google Scholar, and HighWire Press and included animal model experiments with both blinded and nonblinded outcome assessors. For each experiment, we calculated the ratio of odds ratios (ROR), that is, the odds ratio (OR) from nonblinded assessments relative to the corresponding OR from blinded assessments. We standardized the ORs according to the experimental hypothesis, such that an ROR <1 indicates that nonblinded assessor exaggerated intervention effect, that is, exaggerated benefit in experiments investigating possible benefit or exaggerated harm in experiments investigating possible harm. We pooled RORs with inverse variance random-effects meta-analysis.
We included 10 (2,450 animals) experiments in the main meta-analysis. Outcomes were subjective in most experiments. The pooled ROR was 0.41 (95% confidence interval [CI], 0.20, 0.82; I(2) = 75%; P < 0.001), indicating an average exaggeration of the nonblinded ORs by 59%. The heterogeneity was quantitative and caused by three pesticides experiments with very large observer bias, pooled ROR was 0.20 (95% CI, 0.07, 0.59) in contrast to the pooled ROR in the other seven experiments, 0.82 (95% CI, 0.57, 1.17).
Lack of blinding of outcome assessors in animal model experiments with subjective outcomes implies a considerable risk of observer bias.
检验在模拟人类临床情况的动物实验中，结局评估者未设盲对干预效果评估的影响。
我们检索了 PubMed、Biosis、Google Scholar 和 HighWire Press，并纳入了结局评估者设盲和未设盲的动物模型实验。对于每个实验，我们计算了比值比（ROR），即未设盲评估的优势比（OR）相对于设盲评估的相应 OR。我们根据实验假说对 OR 进行了标准化，使得 ROR<1 表示未设盲评估者夸大了干预效果，即研究可能获益的实验中夸大了获益，研究可能有害的实验中夸大了危害。我们采用Inverse Variance 随机效应荟萃分析对 ROR 进行了汇总。
我们纳入了 10 项（2450 只动物）主要荟萃分析实验。大多数实验的结局都是主观的。汇总的 ROR 为 0.41（95%置信区间[CI]，0.20，0.82；I²=75%；P<0.001），表明未设盲 OR 平均夸大了 59%。异质性是定量的，由三个农药实验引起，这些实验存在很大的观察者偏倚，汇总 ROR 为 0.20（95%CI，0.07，0.59），与其他七个实验的汇总 ROR 0.82（95%CI，0.57，1.17）形成对比。
在主观结局的动物模型实验中，结局评估者未设盲暗示着观察者偏倚的风险相当大。
