Turkish adaptation, validity and reliability of the Total Disability Index questionnaire

Pain, especially chronic pain, is an important public health problem. Chronic low back pain is the most common chronic pain that causes activity limitation, and chronic neck pain is the second most common. In literature, there are studies that indicate that low back and neck pain trigger each other. Therefore, it is essential to evaluate the spine as a totally. This study aimed to adapt to Turkish and investigate its validity and reliability of the Total Disability Index (TDI) Questionnaire in individuals with chronic low back and/or neck pain. 77 individuals between the ages of 18-65 with low back and/or neck pain lasting for at least 3 months were included in the study. Internal consistency and test-retest analyses were used to determine the reliability of the TDI. Internal consistency was evaluated with the Cronbach Alpha value and test-retest analyses were evaluated with the Intraclass Correlation Coefficient. The validity of the TDI was evaluated with the convergent validity method. Pearson Correlation Analysis was used to assess the convergent validity of the relationship between TDI and the Functional Back Pain Scale (FBAS), Core Outcome Measure Index (COMI) - Neck, Short Form-36 (SF-36) Quality of Life Questionnaire. For all values p<0.05 was considered as significant. The Cronbach Alpha value was found to be 0.767 for the whole questionnaire. This value indicated that the questionnaire had a good internal consistency. While the Intraclass Correlation Coefficient ranged from 0.817 to 0.970, this result showed that the test-retest responses were good correlated. Consequencely, Pearson Correlation Analysis, TDI was found negatively very well correlated (r=-0.725, p<0.001) with FBAS; positively moderately correlated (r=0.550, p<0.001) with COMI-Neck; negatively well correlated (r=-0.671, p<0.001 / r=-0.636, p<0.001) with SF-36's physical function and pain sub-parameters; negatively moderately correlated (r=-0.505, p<0.001) with SF-36's physical role limitation sub-parameter; negatively weak moderately correlated (r=-0.346, p=0.002 / r=-0.372, p=0.001 / r=-0.332, p=0.003) with SF-36's emotional role limitation, social function and general health sub-parameters; negatively weakly correlated (r=-0.276, p=0.015 / r=0.202, p=0.078) with SF-36's energy and mental health sub-parameter.According to these results, it is valid and reliable to use the Turkish version of the TDI in individuals with low back and/or neck pain. TDI is a versatile questionnaire that is easy to understand and score, and can be answered quickly. For these reasons, we recommend using the Turkish version of the TDI to provide a holistic assessment of spine-related pain and disability, such as chronic low back and neck pain, in native speakers of Turkish.