Centre for Health Informatics, Australian Institute of Health Innovation, Macquarie University, Sydney, NSW, 2109, Australia.
Syst Rev. 2018 Nov 17;7(1):195. doi: 10.1186/s13643-018-0856-9.
A number of methods for deciding when a systematic review should be updated have been proposed, yet little is known about whether systematic reviews are updated more quickly when new evidence becomes available. Our aim was to examine the timing of systematic review updates relative to the availability of new evidence.
We performed a retrospective analysis of the update timing of systematic reviews published in the Cochrane Database of Systematic Reviews in 2010 relative to the availability of new trial evidence. We compared the update timing of systematic reviews with and without signals defined by the completion or publication of studies that were included in the updates.
We found 43% (293/682) systematic reviews were updated before June 2017, of which 204 included an updated primary outcome meta-analysis (median update time 35.4 months; IQR 25.5-54.0), 38% (77/204) added new trials, and 4% (8/204) reported a change in conclusion. In the 171 systematic reviews with reconcilable trial reporting information, we did not find a clear difference in update timing (p = 0.05) between the 15 systematic reviews with a publication signal (median 25.3 months; IQR 15.3-43.5) and the 156 systematic reviews without a publication signal (median 34.4 months; IQR 25.1-52.2). In the 145 systematic reviews with reconcilable trial completion information, we did not find a difference in update timing (p = 0.33) between the 15 systematic reviews with a trial completion signal (median 26.0 months; IQR 19.3-49.5) and the 130 systematic reviews without a trial completion signal (median 32.4 months; IQR 24.1 to 46.0).
A minority of 2010 Cochrane reviews were updated before June 2017 to incorporate evidence from new primary studies, and very few updates led to a change in conclusion. We did not find clear evidence that updates were undertaken faster when new evidence was made available. New approaches for finding early signals that a systematic review conclusion is at risk of change may be useful in allocated resources to the updating of systematic reviews.
已经提出了许多用于确定何时应更新系统评价的方法，但对于新证据出现时系统评价是否会更快更新知之甚少。我们的目的是研究系统评价更新与新证据出现之间的时间关系。
我们对 2010 年发表在 Cochrane 系统评价数据库中的系统评价更新时间与新试验证据的可用性进行了回顾性分析。我们比较了有和没有信号的系统评价更新时间，这些信号是由更新中包含的研究完成或发表定义的。
我们发现 43%（293/682）的系统评价在 2017 年 6 月之前进行了更新，其中 204 个包含更新的主要结局荟萃分析（中位数更新时间为 35.4 个月；IQR 25.5-54.0），38%（77/204）添加了新试验，4%（8/204）报告了结论的改变。在 171 项具有可协调试验报告信息的系统评价中，我们没有发现更新时间（p=0.05）在有发表信号的 15 项系统评价（中位数 25.3 个月；IQR 15.3-43.5）和无发表信号的 156 项系统评价（中位数 34.4 个月；IQR 25.1-52.2）之间有明显差异。在 145 项具有可协调试验完成信息的系统评价中，我们没有发现更新时间（p=0.33）在有试验完成信号的 15 项系统评价（中位数 26.0 个月；IQR 19.3-49.5）和无试验完成信号的 130 项系统评价（中位数 32.4 个月；IQR 24.1 至 46.0）之间有差异。
在 2010 年的 Cochrane 综述中，只有少数（2017 年 6 月之前更新的）在更新时纳入了来自新的主要研究的证据，并且很少有更新导致结论的改变。我们没有发现明确的证据表明，当有新证据时，更新会更快地进行。寻找早期信号的新方法可能会有用，这些信号表明系统评价的结论有风险，从而可以将资源分配到系统评价的更新上。
