Factors that influence practitioners' interpretations of evidence from alternative medicine trials: a factorial vignette experiment embedded in a national survey.

Over the past decade, the National Institutes of Health has sponsored rigorous scientific research on complementary and alternative medicines (CAM) (1). Yet little is known about how data from that research have been translated into clinical care, which depends on healthcare practitioners, both CAM and conventional medicine, taking an interest in and keeping an open mind about new research data that may be of clinical consequence. Keeping an open mind may be particularly difficult for practitioners whose training and experience have strongly influenced their beliefs about what constitutes a legitimate treatment. Prior cross-sectional studies suggest that physicians’ self-reported willingness to recommend a specific CAM practice depends on their prior beliefs about the efficacy of the practice, the reputation of journals in which data on that practice are reported, whether the practice is requested by a patient, and whether or not the patient’s condition is refractory to other more conventional medicine measures.(3–5) Physicians may be more open to herbs, vitamins, supplements and other “biologically based” CAM modalities than they are to energy therapies and other practices whose effects are less explicable from the biomedical paradigm.(6) Resch et al demonstrated the potential for reviewer bias against CAM in scientific review manuscripts.(7) They found that reviewers’ ratings of the importance of the manuscript and their verdict about acceptance or rejection were significantly higher for the “orthodox” remedy. However, little is known about how physicians’ prior beliefs may influence their interpretations and clinical translation of scientific data from clinical trials of CAM. (8) This study uses experimental vignettes to examine the impact of contextual features on conventional medicine and CAM practitioners’ interpretations of research evidence from hypothetical clinical studies of CAM. It was designed to test four hypotheses that arose from our assessment of physician survey data, from commentaries surrounding the publication of several major CAM trials in 2005–2006, as well as from focus groups we conducted: First, conventional medicine practitioners would be less likely to either rate a particular CAM practice as effective, or be willing to recommend it, if the practice is less obviously “biologically based”—even after being presented with new scientific evidence for the efficacy of the CAM practice. Second, conventional medicine practitioners’ willingness to recommend CAM therapies would be determined in part by contextual factors such as the prestige of the journal in which positive research findings are reported, whether a patient requests the therapy, and whether a patient has suffered chronic, refractory symptoms. Third, these factors would exert little influence on physicians’ interpretations of evidence showing inefficacy, because of strong prior propensity to reject such therapies. Finally, we hypothesized that CAM practitioners in our study (acupuncturists and naturopaths) would be much more likely than physicians to rate different CAM practices as effective and legitimate, even after considering evidence for the inefficacy of those practices.