Although studies show that interest in complementary and alternative medicine (CAM) is growing throughout the world
[1–3], it is still difficult to find reliable data on the frequency of CAM use in, for example, specific diagnosis-related groups. This is partly because the reasons for using CAM vary considerably. Patients may use CAM as an alternative, i.e. instead of conventional therapy, or complementarily, and thus in addition to conventional treatments. The latter is often the case in oncology, and it is from this field that most published data is available
[4–7]. However, even in this well studied area, pooled data shows the frequency of CAM use to range from 25% to 50% within a given patient population, with the percentage being highly dependent on region and the measurement time frame
. By studying this data, the most significant reasons for data variations become evident: Firstly, a fixed definition of CAM is necessary, as some surveys include praying or relaxation techniques, for example
[9, 10], while others do not
. Depending on the definition of CAM, empirical data shows that CAM usage may range from 11% to 72% in the same patient group
Secondly, there is no standardized methodology for measuring CAM usage. Surveys may ask about lifetime usage
, or solely about usage during the trajectory of a specific disease
A systematic review of survey data on CAM usage in cancer patients shows that - apart from the measurement time frame - rates of CAM usage are also largely dependent on whether the participants were interviewed face-to-face or by means of a paper-pencil questionnaire, whether respondents were prompted by means of a list of CAM therapies, and whether surveys restricted CAM usage to particular CAM modalities
As a result of a complete lack of measurement standardization for CAM usage, the National Research Center in Complementary and Alternative Medicine (NAFKAM) in Norway carried out a workshop with the aim of developing a standardized questionnaire for measuring international CAM usage. Participants represented different countries (United States, Canada, Great Britain, Australia, Norway, Germany, Sweden and Denmark), came from a wide range of backgrounds (anthropology, sociology, nursing, health services, medicine, public health and pharmacy) and were specialists in different fields (survey design, cross-cultural research), and thus were able to develop a measurement instrument which covered both the most prominent types of CAM, as well as application methods in different countries, the I-CAM-Q
In order to improve data comparability, the next step was to translate the international questionnaire for use in different countries and languages, and to assess it’s performance.
The aim of the present study was to provide a German measurement instrument for CAM usage (I-CAM-G) which closely resembles the original English version, and to assess it’s performance in two potential samples for measuring CAM usage.
As this is the first attempt to adapt the international questionnaire for use in a non-English-speaking country, experiences gathered here may help others to develop different language versions.