DISABILITY IN PATIENTS WITH CHRONIC NON-SPECIFIC LOW BACK PAIN: VALIDATION OF THE SLOVENE VERSION OF THE OSWESTRY DISABILITY INDEX

Aim: To validate the Slovene version of the Oswestry Disability Index. Method: A case series study of 129 adult patients with non-specific chronic low back pain attending a 10-day physical therapy programme. Visual Analog Pain Scale (VAS), Euroqol questionnaire (EQq), and Oswestry Disability Index (ODI) were used at the beginning and at the end of the physical therapy programme. Results: Cronbach's a of the Slovene ODI was 0.876 at the beginning of the physical therapy programme and 0.901 at the end of the programme. All items of the questionnaire loaded on the same factor. A significant positive correlation existed between the Slovene ODI and VAS, EQ-5D and EQ-VAS at the beginning of the physical therapy programme (r=0.630, p<0.001; r=0.657, p<0.001; r=-0.510, p<0.001, respectively), as well as at the end of the programme (r=0.491, p<0.001; r=0.725, p<0.001; r=-0.648, p<0.001, respectively). The difference between ODI scores obtained at the first and at the second interview was 2.7 +/- 5.2 (p<0.001), and the difference between ODI disability scores was 5.4 +/- 10.5 (p<0.001). The effect size of the Slovene ODI questionnaire was 0.30. Conclusions: The Slovene ODI questionnaire is a reliable and valid instrument for assessing outcomes of physical therapy in patients with chronic non-specific low back pain.