Reliability and validity of the Dutch adaptation of the Quebec Back Pain Disability Scale.

Abstract

The purposes of this study were to determine whether a Dutch translation of the Quebec Back Pain Disability Scale (QBPDS) retains the high levels of reliability and validity of the original English version and to determine whether it is therefore more practical to translate this scale, and possibly other scales, than to generate language- and culture-specific instruments. Subjects were 120 individuals with chronic low back pain. The QBPDS was filled out at the beginning of the study, after 1 week, and after 4 months. Reliability was determined by calculating Pearson correlation coefficients and intraclass correlation coefficients in addition to Cronbach's alpha and item-total correlation at the beginning of the study and after 4 months. Validity was examined by correlating the QBPDS scores to external criteria scores at a single point in time (cross-sectional) and over a period of time (longitudinal). Pearson and intraclass correlation coefficients for test-retest reliability were .90. Cronbach's alpha was .95. The cross-sectional construct validity coefficients were .80 (RDQ) and .70 (pain severity). The longitudinal construct validity coefficients were .60 (RDQ), .53 (pain severity), and .35 (course of the complaint). Our results support previous findings of the English and French versions of the QBPDS. Whether this instrument can be used as an evaluative instrument remains unknown.