Medical Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
J Clin Epidemiol. 2013 Apr;66(4):361-366.e4. doi: 10.1016/j.jclinepi.2012.11.005. Epub 2013 Feb 4.
Although observational studies provide useful descriptive and correlative information, their role in the evaluation of medical interventions remains contentious. There has been no systematic evaluation of authors' attitudes toward their own nonrandomized studies and how often they recommend specific medical practices.
We reviewed all original articles of nonrandomized studies published in 2010 in New England Journal of Medicine, Lancet, Journal of the American Medical Association, and Annals of Internal Medicine. We classified articles based on whether authors recommend a medical practice and whether they state that a randomized trial is needed to support their recommendation. We also examined the types of logical extrapolations used by authors who did advance recommendations.
Of the 631 original articles published in 2010, 298 (47%) articles were eligible observational studies. In 167 (56%) of 298 studies, authors recommended a medical practice based on their results. Only 24 (14%) of 167 studies stated that a randomized controlled trial (RCT) should be done to validate the recommendation, whereas the other 143 articles made a total of 149 logical extrapolations to recommend specific medical practices. Recommendations without a call for a randomized trial were most common in studies of modifiable factors (59%), but they were also common in studies reporting incidence or prevalence (51%), studies examining novel tests (41%), and association studies of nonmodifiable factors (32%).
The authors of observational studies often extrapolate their results to make recommendations concerning a medical practice, typically without first calling for a RCT.
尽管观察性研究提供了有用的描述性和相关性信息，但它们在评估医学干预措施方面的作用仍存在争议。目前还没有系统地评估作者对自己非随机研究的态度，以及他们推荐特定医疗实践的频率。
我们回顾了 2010 年在《新英格兰医学杂志》、《柳叶刀》、《美国医学会杂志》和《内科学年鉴》上发表的所有非随机研究的原始文章。我们根据作者是否推荐医疗实践以及是否说明需要进行随机试验来支持他们的建议，对文章进行分类。我们还检查了提出建议的作者使用的逻辑推断类型。
在 2010 年发表的 631 篇原始文章中，有 298 篇（47%）是合格的观察性研究。在 298 项研究中，有 167 项（56%）作者根据研究结果推荐了一种医疗实践。在这 167 项研究中，只有 24 项（14%）表明需要进行随机对照试验（RCT）来验证该建议，而其他 143 项研究共进行了 149 次逻辑推断，以推荐特定的医疗实践。没有呼吁进行随机试验的建议在可改变因素的研究中最为常见（59%），但在报告发病率或患病率的研究（51%）、检查新试验的研究（41%）以及不可改变因素的关联研究中也很常见（32%）。
观察性研究的作者经常推断他们的结果以提出有关医疗实践的建议，通常不首先呼吁进行 RCT。
