Pragmatic controlled clinical trials in primary care: the struggle between external and internal validity.
Pragmatic controlled clinical trials in primary care: the struggle between external and internal validity.
复制标题
DOI：
10.1186/1471-2288-3-28
复制
发表时间：
2003-12-22
影响因子：
4
通讯作者：
Seguin R
中科院分区：
文献类型：
--
作者：
Godwin M;Ruhland L;Casson I;MacDonald S;Delva D;Birtwhistle R;Lam M;Seguin R
卫生保健干预措施的对照临床试验要么是解释性的，要么是务实的。解释性试验测试干预是否有效;也就是说，它是否可以在理想情况下产生有益的影响。实用性试验测量有效性;它们测量真实的临床实践中有益效果的程度。在语用测试中，需要在外部效度（结果的可概括性）和内部效度（结果的可靠性或准确性）之间取得平衡。解释性试验旨在通过确保严格控制干预以外的所有变量来最大限度地提高内部效度。实用主义的尝试寻求最大限度的外部效度，以确保结果可以推广。然而，实用主义试验的危险是，内部有效性可能会过度妥协，以确保普遍性的努力。我们正在进行两项关于初级保健高血压管理干预措施的实用随机对照试验。我们描述了试验的设计和处理外部和内部有效性的竞争需求所采取的步骤。外部有效性最大限度地有几个排除标准，并允许在解释干预和管理决策的灵活性。在这些非盲试验中，通过分组随机化减少污染偏倚，通过随机化前收集基线数据减少观察者和评估偏倚，使用24小时动态血压监测仪自动进行结局评估，并对数据分析设盲，从而最大限度地提高内部有效性。在社区实践中进行的临床试验为研究者提供了与保持内部效度（结果的可靠性）和外部效度（可推广性）之间的平衡有关的困难的方法选择。试图达到方法学纯度可能导致临床无意义的结果，而试图达到完全的普遍性可能导致无效和不可靠的结果。在两者之间实现创造性的张力是至关重要的。
Controlled clinical trials of health care interventions are either explanatory or pragmatic. Explanatory trials test whether an intervention is efficacious; that is, whether it can have a beneficial effect in an ideal situation. Pragmatic trials measure effectiveness; they measure the degree of beneficial effect in real clinical practice. In pragmatic trials, a balance between external validity (generalizability of the results) and internal validity (reliability or accuracy of the results) needs to be achieved. The explanatory trial seeks to maximize the internal validity by assuring rigorous control of all variables other than the intervention. The pragmatic trial seeks to maximize external validity to ensure that the results can be generalized. However the danger of pragmatic trials is that internal validity may be overly compromised in the effort to ensure generalizability. We are conducting two pragmatic randomized controlled trials on interventions in the management of hypertension in primary care. We describe the design of the trials and the steps taken to deal with the competing demands of external and internal validity. External validity is maximized by having few exclusion criteria and by allowing flexibility in the interpretation of the intervention and in management decisions. Internal validity is maximized by decreasing contamination bias through cluster randomization, and decreasing observer and assessment bias, in these non-blinded trials, through baseline data collection prior to randomization, automating the outcomes assessment with 24 hour ambulatory blood pressure monitors, and blinding the data analysis. Clinical trials conducted in community practices present investigators with difficult methodological choices related to maintaining a balance between internal validity (reliability of the results) and external validity (generalizability). The attempt to achieve methodological purity can result in clinically meaningless results, while attempting to achieve full generalizability can result in invalid and unreliable results. Achieving a creative tension between the two is crucial.