Reliability and Validity of the Korean Version of the Pain Disability Questionnaire

Objective To translate the English version of the Pain Disability Questionnaire (PDQ) into Korean and to investigate the reliability and validity of the Korean version of the PDQ (K-PDQ) in patients suffering chronic disabling musculoskeletal disorders (CDMDs). Methods The English version of the PDQ was translated into Korean. Ten patients with CDMDs were randomly selected for a pilot study to assess the comprehensibility of the pre-final version. One hundred and thirty-nine patients suffering from CDMDs for more than 3 months were enrolled in this study. Follow-up questionnaires were obtained to examine the test-retest reliability. Concurrent validity was evaluated by comparing the K-PDQ with the visual analogue scale (VAS). Construct validity was evaluated by comparing the K-PDQ with the brief form of the World Health Organization quality of life assessment instrument (WHOQOL-BREF) using Pearson correlation coefficient. Reliability was assessed using the intraclass correlation coefficient (ICC), and internal consistency was determined by Cronbach's alpha. Results Test-retest reliability was assessed in 70 patients, with an average time interval of 12 days. The ICC was 0.958 (p<0.001). Internal consistency reached Cronbach's alpha of 0.933 for the functional component and 0.870 for the psychosocial component. The correlation coefficient for the K-PDQ when compared with the VAS was 0.834 in the first assessment and 0.831 in the second assessment. All domains of the WHOQOL-BREF showed a significant negative correlation with the K-PDQ. Conclusion The K-PDQ is a reliable and valid instrument for measuring disability and can be used to assess disability and treatment outcomes in Korean patients with CDMD.