Background: Assessed dimensions of low back pain (LBP) vary in prevalence studies. This may explain the heterogeneity in frequency estimates. To standardize definitions of LBP, an English consensus with 28 experts from 12 countries developed the "Delphi Definitions of Low Back Pain Prevalence" (DOLBaPP). The optimal definition and the shorter minimal definition with the related questionnaires for online, paper, and face-to-face use and telephone surveys are suitable for population-based studies. The definitions have to be adapted to different languages and cultures to provide comparable frequency estimates. The objective was to culturally adapt and pre-test the English definitions and corresponding Delphi DOLBaPP questionnaire forms into German.

Methods: The German DOLBaPP adaptation was conducted using the systematic approach suggested by Beaton et al. A pre-test of the Delphi DOLBaPP optimal paper questionnaire including an additional evaluation form was conducted in a sample of 121 employees (mainly office workers). In order to evaluate the comprehensibility, usability, applicability, and completeness of the adapted questionnaire, response to the questionnaire and 6 closed evaluation questions were analyzed descriptively. Qualitative methods were used for the 3 open questions of the evaluation form.

Results: The cultural adaptation of the DOLBaPP for a German-speaking audience required little linguistic adaptation. Conceptual equivalence was difficult for the expression "low back pain". The expert committee considered the face validity of the pre-final version of the related Delphi DOLBaPP questionnaires as good. In the pre-test, most participants (95%) needed less than 5 minutes to fill in the optimal Delphi DOLBaPP questionnaire. They were generally positive regarding length, wording, diagram, and composition. All subjects with LBP (n = 61 out of 121 - 50.4%) answered the questions on functional limitation, sciatic pain, frequency and duration of symptoms as well as pain severity.

Conclusion: The results indicate that the cross-cultural German adaptation of the DOLBaPP Definitions and the corresponding questionnaires was successful. The definitions can be used in epidemiological studies to measure the prevalence of LBP. Some critical issues were raised regarding the general features of the Delphi DOLBaPP questionnaires. Future research is needed to evaluate these instruments.

This article is published in the Journal "BMC Musculoskeletal Disorders" 2014, 15:397.