Reliability of the Norwegian version of PainDETECT: a test-retest study

Objectives: The PainDETECT Questionnaire (PD-Q) is a self-reported questionnaire aiming to assist in detecting neuropathic pain in individual patients. However, measurement properties of the Norwegian translated version should be examined, and the aim of the present study was to examine its test-retest reliability. Methods: A total of 107 patients were initially recruited to the study from physiotherapy clinics. After screening for inclusion- and exclusion criteria, 67 participants remained for examining reliability of separate items. They were to fill out the PD-Q twice at an interval of 14 days. Intraclass correlation coefficient (ICC) and standard error of measurement (SEM) of total scores, and Kappa statistics and percentage of agreement of separate items and screening data were used in the analysis. Results: Fifty-two participants filled out all items correctly, a prerequisite for determining the reliability of the total score and screening category. The ICC for the total score was 0.84 (95% confidence interval 0.73-0.91), SEM 2.5. The Kappa value for the screening category was 0.50 (95% confidence interval 0.31-0.69), and percentage of agreement 69%. Single items were found with reasonable to substantial reliability. Conclusion: The Norwegian version of the PD-Q showed good test-retest reliability for the total score, but only moderate reliability of the screening category classifying the likelihood of neuropathic pain. The high number of missing answers indicates that some guidance from a health care professional is needed when filling out the questionnaire.