Use of data from nonrandomized trial designs in evidence reports: an application to treatment of pulmonary disease following spinal cord injury.

Evidence reports summarize the evidence pertaining to various health-related topics. Including evidence from nonrandomized studies into such reports involves a trade-off between availability and bias. We describe a general framework by which information from nonrandomized studies might be integrated reasonably into evidence reports and illustrate its application to a recent evidence report on preventing pulmonary complications among patients with spinal cord injury. The proposed framework, which is based upon the premise that producing a fair summary of the evidence requires only a level of evidence judged by clinical experts to be sufficient to the task at hand, may help focus scarce resources, strengthen the quality and documentation of decisions including evidence from nonrandomized studies, and suggest high-priority areas for future research.