Etter Jean-François, Stapleton John
Faculty of Medicine, Institute of Social and Preventive Medicine, University of Geneva, Switzerland.
J Clin Epidemiol. 2009 Aug;62(8):831-7. doi: 10.1016/j.jclinepi.2008.09.015. Epub 2009 Jan 6.
To study variations in the number of times trials of nicotine replacement therapy (NRT) were cited, and which characteristics of trials predicted the number of citations and the impact factors of journals in which articles were published.
We used all 105 randomized controlled trials in the Cochrane review of NRT for smoking cessation. We obtained impact factors from the Journal Citation Reports and the number of citations from ISI Web of Knowledge and Google Scholar.
Trials were cited from 0 to 632 times (median 23 times). Trials were cited more often when results were statistically significant than when they were not (median=41 vs. 17 times, P<0.001), and when impact factors were higher (10.2 more citations per impact factor point, P<0.001). Patch trials were cited more often than gum trials (median=29 vs. 17 times, P=0.001), and trials funded by the pharmaceutical industry were cited more often than other trials (median=28 vs. 16.5 times, P=0.001). Trials with statistically significant results were published in journals with higher impact factors than trials with nonsignificant results (median impact factor=2.80 vs. 1.81, P=0.011).
Citations were biased toward trials with positive results and toward trials published in high-impact-factor journals.
研究尼古丁替代疗法（NRT）试验被引用次数的变化情况，以及试验的哪些特征能够预测被引用次数和发表文章的期刊的影响因子。
我们使用了Cochrane系统评价中关于NRT戒烟的所有105项随机对照试验。我们从《期刊引证报告》中获取影响因子，并从科学网和谷歌学术中获取被引用次数。
试验被引用次数从0到632次不等（中位数为23次）。与无统计学意义的试验相比，有统计学意义的试验被引用的频率更高（中位数分别为41次和17次，P<0.001），且影响因子越高被引用次数越多（每增加一个影响因子点多被引用10.2次，P<0.001）。贴片试验比口香糖试验被引用的频率更高（中位数分别为29次和17次，P=0.001），由制药行业资助的试验比其他试验被引用的频率更高（中位数分别为28次和16.5次，P=0.001）。有统计学意义结果的试验发表在影响因子高于无统计学意义结果试验的期刊上（中位数影响因子分别为2.80和1.81，P=0.011）。
引用偏向于有阳性结果的试验以及发表在高影响因子期刊上的试验。
