Is easier the better in a feasibility study of questionnaires?

The diagnosis of gastroesophageal reflux disease (GERD) is primarily dependent upon symptoms reported by patients. Therefore, several types of questionnaires have been suggested for the diagnosis of GERD and assessment of treatment satisfaction. However, few of standardized questionnaires can be used in the clinical study restrictively due to the lack of validity, reliability and feasibility. The frequency scale for symptoms of GERD (FSSG) was developed by Kusano et al1 in 2004, based on Japanese studies of GERD. The FSSG is composed of twelve questions with cut off score of 8, and this method showed sensitivity of 62% and specificity of 59%. The FSSG is suitable for evaluating frequency of typical reflux symptoms. Quality of life and utility evaluation survey technology (QUEST) was suggested as a method of self-administered questionnaire for the diagnosis of GERD.2 The QUEST is comprised of 7 items and reports sensitivity of 70% and specificity of 46% at the cut-off score of 4. The QUEST includes more specified questions on the precipitating, exacerbating and relieving factors of GERD. In the previous comparative study of FSSG with QUEST, there was no difference in sensitivity, specificity and accuracy for GERD.3 Nonaka et al4 reported an interesting comparative study regarding the feasibility between 2 questionnaires, QUEST and FSSG. They measured the time taken to complete the questionnaire and counted the number of patients who asked any questions when they filled in the questionnaire. Completion for the QUEST took much longer than for the FSSG, and questions of QUEST were more complicated than those of FSSG. Based on these results, comparative study concluded the FSSG was a more convenient method for clinical use than the QUEST. Results of this study could demonstrate that simplicity is an important feature of a questionnaire and it should be considered critically in future studies. Nevertheless, I would like to make comments on this study. First, since time and number of patients asking questions are indirect parameters of feasibility, there are so many confounding factors such as educational status of subjects, the language of original questionnaire (translation into Japanese might be responsible for large number of characters and difficulty in understanding), introverted personality (do not want to ask questions) and so on. Therefore, it would be better to ask more direct questions, such as "which one do you like better" and "which questionnaire was easier to understand."5 Second, 2 questionnaires have quite different questions. QUEST focuses on influencing factors in GERD and FSSG emphasizes on symptom frequency. Therefore, although feasibility is important, considerations on types of questions are needed when we choose a questionnaire.