Validation of the Japanese Version of Comorbid Conditions Questionnaire (CCQ-J) and Recent Physical Symptoms Questionnaire (RPSQ-J)

Objective The comorbid conditions questionnaire (CCQ) and the recent physical symptoms questionnaire (RPSQ) have been validated in the US for the evaluation of comorbid physical conditions in patients with irritable bowel syndrome (IBS). A lack of instruments to assess somatization in Japanese subjects with IBS warrants development of the Japanese versions of these questionnaires. The purpose of this study was to validate the Japanese versions created, the CCQ-J and RPSQ-J. Methods and Patients Study 1 was carried out to verify the test-retest reliability and internal consistency of the CCQ-J and RPSQ-J in 49 patients with functional bowel disorder. Study 2 was performed to confirm the construct validities of these questionnaires compared to the Cornell Medical Index (CMI) in 120 patients with psychosomatic symptoms (assigned to the somatoform disorder, anxiety disorder, depressive disorder, or IBS group) and 22 healthy subjects. Results In Study 1, high reproducibility and high intraclass correlation coefficients were demonstrated for these questionnaires. In Study 2, total score on the CMI was significantly associated with score on the CCQ-J and on the RPSQ-J in the IBS group. The proportion of patients with chronic back pain was significantly higher in the IBS group than in controls (27.3% vs. 18.5%, p<0.05). Conclusion The CCQ-J and RPSQ-J are valid and reliable instruments for evaluating comorbid conditions in Japanese patients with IBS. Further studies are needed to confirm the direct cross-cultural comparison of the impact of somatization in IBS between different countries.