Congenital diaphragmatic hernia: The role of multi-institutional collaboration and patient registries in supporting best practice.

Among congenital malformations, congenital diaphragmatic hernia (CDH) is distinguished by its relatively low occurrence rate, need for resource intensive, integrated multidisciplinary care, and widespread variation in practice and outcome. Although randomized controlled trials (RCTs) are considered the gold standard for generating evidence, they are poorly suited to the study of a condition like CDH due to challenges in illness severity adjustment, unpredictability in clinical course and the impact limitations of studying a single intervention at a time. An alternative to RCTs for comparative effectiveness research for CDH is the patient registry, which aggregates multi-institutional condition-specific patient level data into a large CDH-specific database for the dual purposes of collaborative research and quality improvement across participating sites. This article discusses patient registries from the perspective of structure, data collection and management, and privacy protection that guide the use of registry data to support collaborative, multidisciplinary research. Two CDH-specific registries are described as illustrative examples of the "value proposition" of registries in improving the evidence basis for best practices for CDH.