Three hundred and fourteen low back pain patients completed the Korean version of the Oswestry Disability Questionnaire (KODQ) and the Rasch analysis was then applied to identify the inappropriate items and to determine ODQ item difficulties according to a subject's characteristics. For women and youths, the 'sex life' item showed misfit statistics, whereas for older subjects it was the 'pain intensity' and 'standing' items. Also, in the acute low back group the 'pain intensity', 'standing' and 'sex life' items showed misfit statistics. For all subjects, the most difficult item was 'pain intensity', whereas the easiest item was 'walking'. But for the older and acute groups 'lifting' was the most difficult item and for those who have a visual analogue scale score of 3 or less 'sitting' was the most difficult item. These results show that differential item functioning is present in several items according to sex, age, acute and chronic pain, and VAS score. This study may be useful for adjusting the KODQ item difficulties for low back pain patients with different characteristics

• 김경모(연세대학교 대학원 재활학과) | Gyoung-mo Kim
• 박소연(전주대학교 대체의학대학 물리치료학과) | So-yeon Park 통신저자
• 이충휘(연세대학교 보건과학대학 물리치료학과, 연세대학교 보건환경대학원 인간공학치료학과) | Chung-hwi Yi