Abstract
BACKGROUND: Validated instruments collecting data on health-related resource use are lacking, but required, for example, to investigate predictors of healthcare use or for health economic evaluation.The objective of the study was to develop, test and refine a questionnaire collecting data on health-related resource use and expenditure in patients with diabetes. METHODS: The questionnaire was tested in 43 patients with diabetes mellitus types 1 and 2 in Germany. Response behaviour suggestive of problems with questions (item non-response, request for clarification, comments, inadequate answer, "don't know") was systematically registered. Cognitive interviews focusing on information retrieval and comprehension problems were carried out. RESULTS: Many participants had difficulties answering questions pertaining to frequency of visits to the general practitioner (26%), time spent receiving healthcare services (39%), regular medication currently taken (35%) and out of pocket expenditure on medication (42%). These difficulties seem to result mainly from poor memory. A number of comprehension problems were established and relevant questions were revised accordingly. CONCLUSION: The questionnaire on health-related resource use and expenditure for use in diabetes research in Germany was developed and refined after careful testing. Ideally, the questionnaire should be externally validated for different modes of administration and recall periods within a variety of populations.