Development of a valid and reliable phlegm pattern questionnaire.

Objectives: The present study was conducted to examine the reliability and validity of a Phlegm Pattern Questionnaire (PPQ) that was developed within the context of Traditional Chinese Medicine.

Methods: A total of 292 normal subjects and 61 inpatients were asked to complete the PPQ. Among the 292 normal subjects, 73 college students were additionally asked to complete the Profile of Mood States (POMS) and the Chalder Fatigue Scale (CFS). Three (3) clinicians determined whether the 61 inpatients exhibited the Phlegm Pattern (PP). The authors estimated the internal consistency and construct validity for the PPQ using data from the normal and inpatient subjects. The POMS and CFS data were used to evaluate the concurrent validity of the PPQ. PPQ data and the clinicians' diagnoses of the inpatient subjects were used to estimate the sensitivity and specificity and to define the optimum cut-off point of the PPQ.

Results: The PPQ had satisfactory internal consistency (α=0.902 in normal subjects, α=0.919 in inpatient subjects) and concurrent validity, with significant correlations between the total score of the PPQ and all of the POMS and CFS subscales. In a test of construct validity using principal component analysis, a total of six factors were extracted, and the overall variance explained by all factors was 58.9%. In the test of discriminant validity using receiver operating characteristic curve analysis, the sensitivity, specificity, and area under the curve were 83.78%, 83.33%, and 0.860, respectively. The optimum cut-off level was defined as five points.

Conclusions: These results suggest that the PPQ is a reliable and valid self-rating instrument for estimating the severity of PP.