Confirming the theoretical structure of the Japanese version of the McGill Pain Questionnaire in chronic pain

Abstract

Objective: Based upon a tripartite theoretical model of pain, the Pain Rating Index of the McGill Pain Questionnaire continues to be one of the most frequently used instruments to measure clinical pain. However, differences in languages and cultural backgrounds have hindered its wide use and standardization in Japan. Although a number of exploratory factor analytic studies have failed to consistently support the theoretical structure of the instrument, a few previous confirmatory factor analytic studies did statistically support the a priori model. The purpose of this study was to test the theoretical structure of a Japanese version of the McGill Pain Questionnaire, which followed a format similar to the original questionnaire, through a confirmatory factor analysis.

Design: This study used confirmatory factor analysis on prospectively collected data from consecutive outpatients with chronic pain at a university hospital to test the hypothesis regarding the theoretical structure of the Japanese McGill Pain Questionnaire.

Results and conclusion: The first 16 Pain Rating Index subclass scores were subjected to confirmatory factor analysis procedures that yielded a well-fitting final model that explained 91% of the covariance in the observed data. The results approximately supported the hypothesis that the sensory, affective, and evaluative subscales of the Pain Rating Index are representative of the multidimensionality of the pain experience with minimal overlap but could not disregard relatively high intercorrelations among those subscales similar to the original McGill Pain Questionnaire. It is suggested that the theoretical structure of the McGill Pain Questionnaire is approximately kept in the Japanese McGill Pain Questionnaire used in this study. Therefore, the translation-based Japanese McGill Pain Questionnaire used in this study adequately permits comparison of studies from English-speaking and non-English-speaking populations, thus facilitating the first step toward international research exchange and communications.