A valid cross-culturally adapted simplified Chinese version of the Quebec Back Pain Disability Scale.

OBJECTIVE

To evaluate the reliability and validity of the simplified Chinese version of the Quebec Back Pain Disability Scale (SC-QDS).

STUDY DESIGN AND SETTING

The QDS was translated and cross-culturally adapted into SC following international guidelines. The SC-QDS was completed by 114 patients with low back pain (LBP) and 65 healthy controls, along with the SC Oswestry Disability Index (SC-ODI) and visual analogue scale (VAS). Psychometric evaluation included homogeneity and reproducibility by internal consistency and test-retest reliability and construct validity by calculating the Pearson's correlation coefficients among QDS, SC-ODI, and VAS. Discriminative validity was determined by student's t-test.

RESULTS

SC-QDS scores were well distributed, with no floor or ceiling effects. Internal consistency was excellent (Cronbach α 0.976). The items and overall SC-QDS were correlated (r=0.640-0.898 and P<0.0001). Intraclass correlation coefficient of test-retest reliability was excellent (0.987, 95% confidence interval: 0.978-0.992). Construct validity was confirmed by high correlation of SC-QDS and SC-ODI (r=0.901 and P<0.0001) and VAS (r=0.770 and P<0.0001) scores, as was discriminative validity by significantly different SC-QDS scores for patients with LBP and controls (46.3 ± 19.9 vs. 14.6 ± 8.5 and P<0.0001).

CONCLUSIONS

The SC-QDS has good internal consistency, test-retest reliability, and construct and discriminative validity. The SC-QDS is appropriate for clinical and research uses with Chinese-speaking patients with LBP in mainland China.