Gravel Jocelyn, Opatrny Lucie, Shapiro Stan
Division of Emergency Medicine, Department of Pediatrics, Sainte-Justine Hospital, and Department of Epidemiology and Biostatistics, McGill University, Montreal, Quebec, Canada. Graveljocelyn@ hotmail.com
Clin Trials. 2007;4(4):350-6. doi: 10.1177/1740774507081223.
Intention-to-treat (ITT) is an approach to the analysis of randomized controlled trials (RCT) in which patients are analyzed as randomized regardless of the treatment actually received.
To ascertain the proportion of RCT reporting the use of intention-to-treat and the accuracy of that report and to examine the distribution and analysis of missing data for the studies reporting an ITT analysis.
We conducted a cross-sectional literature review of RCTs reported in 10 medical journals in 2002. All articles were assessed using a standardized form. Two evaluators independently reviewed a 10% sample of articles to assess reliability. Subsequently, one evaluator reviewed the remaining articles. The proportion of articles reporting the use of ITT was calculated. Among these, the proportion of articles that ;analyzed patients as randomized' and the proportion and analysis of missing data were evaluated using standardized definitions.
Of the 403 articles, 249 (62%) reported the use of ITT. Among these, available patients were clearly analyzed as randomized in 192 (77%). Authors used a modified ITT in 23 (9%); clearly violated a major component of ITT in 17 (7%), and the approach used was unclear in 17 (7%). More than 60% of articles had missing data in their primary analysis. Few articles reported a strategy for missing data. The main reason for missing data was loss to follow-up.
A single evaluator evaluated most articles, but the high concordance obtained during the inter-rater evaluation suggests that the assessments were consistent. In addition, the small spectrum of journals limits generalizability. Finally, there could be a difference between what was reported and what was performed.
This study emphasizes that authors use the label ;intention-to-treat' quite differently. The most common use refers to the analysis of all available subjects as randomized regardless of the missing data aspect.
意向性分析（ITT）是一种用于分析随机对照试验（RCT）的方法，即无论患者实际接受何种治疗，均按随机分组情况进行分析。
确定报告使用意向性分析的随机对照试验的比例及其报告的准确性，并检查报告进行意向性分析的研究中缺失数据的分布和分析情况。
我们对2002年10种医学期刊上报道的随机对照试验进行了横断面文献综述。所有文章均使用标准化表格进行评估。两名评估人员独立审查了10%的文章样本以评估可靠性。随后，一名评估人员审查了其余文章。计算报告使用意向性分析的文章比例。在这些文章中，使用标准化定义评估“按随机分组情况分析患者”的文章比例以及缺失数据的比例和分析情况。
在403篇文章中，249篇（62%）报告使用了意向性分析。其中，192篇（77%）对可获得的患者按随机分组情况进行了明确分析。23篇（9%）作者使用了改良的意向性分析；17篇（7%）明显违反了意向性分析的一个主要组成部分，17篇（7%）所采用的方法不明确。超过60%的文章在其主要分析中有缺失数据。很少有文章报告处理缺失数据的策略。缺失数据的主要原因是失访。
大多数文章由一名评估人员评估，但在评估人员间评估过程中获得的高一致性表明评估是一致的。此外，期刊范围较小限制了普遍性。最后，报告的内容与实际执行的内容可能存在差异。
本研究强调作者对“意向性分析”这一标签的使用差异很大。最常见的用法是将所有可获得的受试者按随机分组情况进行分析，而不考虑缺失数据方面。
