Construction of a traditional Chinese medicine syndrome-specific outcome measure: the Kidney Deficiency Syndrome questionnaire (KDSQ)

BACKGROUND Development of Traditional Chinese Medicine (TCM) syndrome-specific outcome measures is needed for the evaluation of TCM syndrome-specific therapies. We constructed a Kidney Deficiency Syndrome Questionnaire (KDSQ) for the evaluation of the common TCM syndromes Kidney-Yin Deficiency Syndrome (KDS-Yin) and Kidney-Yang Deficiency Syndrome (KDS-Yang) in middle-aged women with menopausal symptoms. METHODS KDS-Yin and KDS-Yang were traditionally defined by expert opinion were validated by exploratory factor analysis (EFA) and structural equation modeling (SEM). Content validity was tested by EFA on a sample of 236 women from a seminar and SEM on another sample of 321 women from a postal survey. Other psychometric properties were tested on 292 women from the seminar at baseline and two systematically selected sub-samples: 54 who reported no changes in discomforts 11-12 days after the baseline and 31 who reported changes in discomforts 67-74 days after the baseline. All participants completed the KDSQ, the Greene Climacteric Scale and the standard 12-item Short Form Health Survey. RESULTS The EFA and SEM established the measurement models of KDS-Yin and KDS-Yang supporting content validity of the KDSQ. Internal consistency was good (Cronbach's Alpha >0.70). Construct validity was supported by theoretically-derived levels of correlation with the established external measures. Test-retest reliability was strong (ICC(agreement): KDS-Yin, 0.94; KDS-Yang, 0.93). The KDSQ was responsive to changes over time as tested by effect size and longitudinal validity. CONCLUSIONS The KDSQ was a valid and reliable measure for KDS-Yin and KDS-Yang in Hong Kong Chinese middle-aged women with menopausal symptoms.