Supporting the clinical use of the ICF in Japan – development of the Japanese version of the simple, intuitive descriptions for the ICF Generic-30 set, its operationalization through a rating reference guide, and interrater reliability study

Background The World Health Organization developed the International Classification of Functioning, Disability, and Health (ICF) in 2001 and has been in the process of implementing it in clinics since then. Current international efforts to implement ICF in rehabilitation clinics include the implementation of ICF Core Sets and the development of simple, intuitive descriptions for the ICF Generic-30 Set (also called Rehabilitation Set). The present study was designed to operationalize these ICF tools for clinical practice in Japan. This work included 1) the development of the Japanese version of the simple, intuitive descriptions for the ICF Generic-30 Set, 2) the development of a rating reference guide for Activity and Participation categories, and 3) the examination of the interrater reliability of rating Activity and Participation categories. Methods The Japanese version of the simple, intuitive descriptions for the ICF Generic-30 Set was developed following the process employed to develop the Chinese and Italian versions. For further operationalization of this ICF Set in practice, a rating reference guide was developed. The development of the rating reference guide involved the following steps: 1) a trial of rating patients by several raters, 2) cognitive interviewing of the raters to analyse the thinking process involved in rating, 3) drafting of the rating reference guide, and 4) review by ICF specialists to confirm consistency with the original ICF concepts. After the rating reference guide was developed, interrater reliability of the rating with the reference guide was determined. Interrater reliability was examined using weighted kappa statistics with linear weight. Results Through the pre-defined process, the Japanese version of the simple, intuitive descriptions for 30 categories of the ICF Generic-30 Set and the rating reference guides for 21 Activity and Participation categories were successfully developed. The weighted kappa statistics ranged from 0.61 to 0.85, showing substantial to excellent agreement of the ratings between raters. Conclusions The present study demonstrates that ICF categories can be translated into clinical practice. Collaboration between clinicians and researchers would further enhance the implementation of the ICF in Japan.