Patient-reported outcomes in studies of complementary and alternative medicine: problems, solutions, and future directions.

Patient-reported outcome (PRO) measures are frequently used to assess therapeutic efficacy and effectiveness of complementary and alternative medicine (CAM). Although CAM investigators are increasingly making use of valid, self-report instruments to assess patient-relevant outcomes, the sheer number of available instruments poses challenges. Two of the more pressing issues are discussed: the lack of guidance for selecting measures and the limited attention paid to the clinical meaningfulness of PRO results. Solutions are offered that may support selection and standardization of outcome measures for future CAM studies. This includes testing of tools from the National Institutes of Health's Patient-Reported Outcomes Measurement Information System (PROMIS). Increased standardization of outcome measurement in CAM studies will allow for more cross-study comparisons and facilitate the statistical pooling of results, ultimately leading to a more informative evidence base.