Cross-cultural adaptation and validation of simplified Chinese version of the Waddell Disability Index for patients with nonspecific low back pain in Mainland China

The current study aimed to translate the Waddell Disability Index (WDI) in a cross-cultural fashion, and evaluate the reliability and validity of the adapted simplified Chinese version (SC-WDI) for patients with nonspecific low back pain (LBP). The cross-cultural adaptation of the SC-WDI was conducted following international guidelines. The reliability and validity of the SC-WDI was assessed in a prospective observational study. The test–retest reliability was assessed by comparing the results of the first and final SC-WDI scales, 3 days interval. The discriminative, concurrent, and construct validity of the cross-cultural adapted questionnaire was evaluated. The relationship between the SC-WDI with SC-Oswestry Disability Index, SC-Roland-Morris Disability Questionnaire and visual analogue scale was assessed using the correlation coefficients. SPSS 18.0 (Chicago, IL) was used for statistical analysis. Two hundred eighty patients with LBP were included in current study. The mean age of participants was 48.4 years (range 25–82), and the mean disease duration was 1.3 years (range 0.5–24). The mean BMI was 24.6 ± 2.2. No floor or ceiling effects were noted for the SC-WDI. Cronbach’s α for the total scale of was excellent with the value of 0.821. The intraclass correlation coefficient values of total SC-WDI was 0.74, which reflected a satisfactory test–retest reliability. SC-WDI had a good discriminative validity. It also indicated that the SC-WDI had a good concurrent criterion validity (R = 0.681, 0.704, and 0.615, respectively) and construct validity with SC-Oswestry Disability Index, SC-Roland-Morris Disability Questionnaire, and visual analogue scale (all P values of < .0001). The SC-WDI demonstrated a good acceptability, score distribution, internal consistency, test–retest reliability and validity. It has high sensitivity in evaluating the HRQOL. Therefore, it is was considered as a satisfactory tool for evaluating HRQOL of Chinese patients with LBP.