Soares Isabel, Carneiro António Vaz
Serviço de Medicina I, Hospital de Egas Moniz, Lisboa.
Rev Port Cardiol. 2002 Oct;21(10):1191-8.
Intention-to-treat analysis is a technique used in randomized controlled trials (RCTs), where patients are compared--in terms of their final results--within the groups to which they were initially randomized, independently of receiving the allocated treatment, having dropped out of the study or having violated the initial protocol (for whatever reason). In other words, it constitutes an analysis of the results based on the treatment arm to which the patients belong due to the initial random allocation, and not on the treatment actually received (active or placebo). Intention-to-treat analysis permits the pragmatic evaluation of the benefit of a treatment change, and not the potential benefit in patients getting the pre-planned allocated treatment only. Full application of the intention-to-treat principle is only possible in those circumstances where all results from all patients are available. A significant number of RCTs state that they use intention-to-treat analysis, but the ways that violations of randomized allocation is handled varies considerably. Many trials present flaws in gathering primary data, and their methods of handling this problem are normally poor. Lastly, the intention-to-treat principle is frequently poorly described and applied. In this article we will present the importance, utilization, limitations and errors of intention-to-treat analysis.
意向性分析是一种用于随机对照试验（RCT）的技术，在该试验中，患者根据其最终结果在最初随机分配到的组内进行比较，而不考虑他们是否接受了分配的治疗、退出了研究或违反了初始方案（无论何种原因）。换句话说，它是基于患者因最初随机分配而所属的治疗组进行结果分析，而不是基于实际接受的治疗（活性治疗或安慰剂）。意向性分析允许对治疗改变的益处进行务实评估，而不仅仅是对仅接受预先计划分配治疗的患者的潜在益处进行评估。只有在所有患者的所有结果都可用的情况下，才能完全应用意向性原则。大量的随机对照试验表明它们使用意向性分析，但处理随机分配违规情况的方式差异很大。许多试验在收集原始数据方面存在缺陷，并且它们处理这个问题的方法通常很差。最后，意向性原则经常被描述和应用得很差。在本文中，我们将介绍意向性分析的重要性、应用、局限性和错误。
