Development of a Phlegm Pattern Questionnaire for Functional Dyspepsia and Analysis of Its Reliability and Validity

Abstract

Objectives The aim of this study was to develop a Phlegm Pattern Questionnaire for Functional Dyspepsia (PPQ-FD) by modifying a previously developed Phlegm Pattern Questionnaire (PPQ) and to verify its reliability and validity. Further objectives were to obtain the optimal cut-off value for the PPQ-FD for standardization and for clinical use. Methods The PPQ-FD was developed by extracting the major symptoms of the phlegm pattern in functional dyspepsia and by using the Delphi method to administer a requested importance survey to experts. The reliability, validity, and optimal cut-off value of the PPQ-FD were analyzed by enrolling a total of 60 subjects in this study. Thirty patients were diagnosed with both functional dyspepsia and phlegm pattern and thirty patients were diagnosed with only functional dyspepsia. All participants were requested to fill out the PPQ-FD. Results No statistically significant differences were detected in the two groups for sex distribution, age, or body mass index. Five of the survey questions negatively affected its reliability; therefore, we decided to exclude those five questions on further inspection. The Cronbach’s α coefficient of the revised PPQ-FD was 0.853, and clinical validity was verified. Construct validity was analyzed by factor analysis and identified four factors. Statistically significant positive correlations were found between the revised PPQ-FD and other dyspepsia scales, such as the SQDQ, SSQD, VAS, NDI-K, and FD-QoL scales. The VAS had particularly strong positive correlations with the PPQ-FD. Conclusions The PPQ-FD developed in this study has fundamental reliability and validity for use as a pattern-diagnosis questionnaire. The PPQ-FD can help to diagnose the phlegm pattern in patients with functional dyspepsia. Keywords: phlegm, functional dyspepsia, pattern identification, questionnaire, reliability, validity