Psychometric testing of the Impact of Event Scale-Chinese Version (IES-C) in oral cancer patients in Taiwan

Goals of work: No culturally relevant instrument exists to assess the impact of cancer on patients in Taiwan. Therefore, this two-phase study was undertaken to (1) develop a Chinese version of the Impact of Event Scale (IES), (2) examine its psychometric properties, and (3) use the IES-Chinese version (IES-C) to assess the impact of cancer in newly diagnosed oral cancer patients in Taiwan. Patients and methods: The psychometric properties of the 15-item IES-C were tested in 106 newly diagnosed oral cancer patients and analyzed by descriptive statistics, test-retest reliability, Pearson's correlation, and principal component analysis. Main results: The results showed that (1) the IES-C has satisfactory content validity and feasibility; (2) overall internal consistency (Cronbach's alpha) was 0.91 with values of 0.91 and 0.81 for intrusion and avoidance, respectively; (3) overall test-retest reliability (3-day interval) was 0.97; (4) two clearly identified factors explained 55.97% of the variance; (5) satisfactory construct validity was supported by both factor analysis and theoretically supported correlation analysis (significant correlations between the total IES-C and its subscales as well as anxiety and depression); and (6) oral cancer patients had relatively higher IES-C scores than previously reported. Conclusion: These results support the IES-C as an instrument with satisfactory psychometric properties and ease of use in clinical settings. They also suggest that more attention should be paid to the impact on patients of a new diagnosis of oral cancer. Further testing of the IES-C in different cancer populations is suggested to validate its psychometric properties.