Psychometric assessment of the Arabic version of the Dallas pain questionnaire in chronic low back pain patients

Abstract

Background
The Dallas Pain Questionnaire (DPQ) is an instrument designed to assess the impact of chronic pain on daily functioning. This study aimed to evaluate the reliability and validity of the Arabic DPQ in individuals with chronic low back pain.


Methods
A total of 114 patients with chronic low back pain were included. The Arabic DPQ underwent a standardized translation and cultural adaptation process. Principal component analysis with Varimax rotation was performed for exploratory structural analysis. Internal consistency was assessed using Cronbach’s alpha, and test–retest reliability was evaluated using the intraclass correlation coefficient. Measurement error was estimated using the standard error of measurement and smallest detectable change. Construct validity was examined through correlations with the Visual Analog Scale (VAS), Roland–Morris Disability Questionnaire (RMDQ), Bournemouth Questionnaire, and RAND-36 Health Survey (SF-36). Floor and ceiling effects were also assessed.


Results

Exploratory principal component analysis indicated a structure characterized by a dominant first component accounting for the majority of the variance (total variance explained: 83.3%), with a comparatively minor secondary component and notable item cross-loadings. The Arabic DPQ demonstrated excellent internal consistency (Cronbach’s alpha: 0.856–0.958) and strong test–retest reliability (intraclass correlation coefficient: 0.823–0.992). Standard error of measurement values ranged from 2.68 to 4.23, and smallest detectable change values ranged from 7.43 to 11.73; corresponding values for the composite score were 12.64 and 35.01, respectively. Significant positive correlations were observed with the VAS, RMDQ, and Bournemouth Questionnaire (
r
 = 0.745–0.860), whereas inverse correlations were observed with the SF-36 (
r
 = − 0.721 to − 0.883). No significant floor or ceiling effects were detected.



Conclusions
The findings suggest that the questionnaire primarily reflects a general construct of pain-related disability and may be most appropriately interpreted as an essentially unidimensional measure. Although the observed correlations supported the predefined hypotheses for convergent validity, they do not necessarily confirm construct distinctiveness.