Use of complementary and alternative medicine among patients: classification criteria determine level of use.

BACKGROUND AND OBJECTIVES Self-reported use of complementary and alternative medicine (CAM) among patients varies widely between studies, possibly because the definition of a CAM user is not comparable. This makes it difficult to compare studies. The aim of this study is to present a six-level model for classifying patients' reported exposure to CAM. Prayer, physical exercise, special diets, over-the-counter products/CAM techniques, and personal visits to a CAM practitioner are successively removed from the model in a reductive fashion. METHODS By applying the model to responses given by Norwegian patients with cancer, we found that 72% use CAM if the user was defined to include all types of CAM. This proportion was reduced successively to only 11% in the same patient group when a CAM user was defined as a user visiting a CAM practitioner four or more times. When considering a sample of 10 recently published studies of CAM use among patients with breast cancer, we found 98% use when the CAM user was defined to include all sorts of CAM. This proportion was reduced successively to only 20% when a CAM user was defined as a user of a CAM practitioner. CONCLUSIONS We recommend future surveys of CAM use to report at more than one level and to clarify which intensity level of CAM use the report is based on.