Psychometric Validation of the Dampness Syndrome Scale of Chinese Medicine for People in China

Dampness syndrome is a basic syndrome of many major and chronic diseases. Early screening and identification of dampness syndrome are important. The Dampness Syndrome Scale of Chinese Medicine (DSSCM) was developed to measure the occurrence and severity of dampness syndrome. The measurement characteristics of the DSSCM should be further validated. The objective of this study is to evaluate the reliability and validity of the DSSCM based on a cross-sectional survey.

The development of DSSCM was based on the traditional Chinese medicine (TCM) theory, expert consensus and clinical investigations. Participants were recruited from Guangdong Provincial Hospital of Chinese Medicine and Guangzhou Cadre Health Management Center in Guangdong Province, China. All participants completed the baseline questionnaire and DSSCM. The reliability of the DSSCM was evaluated by internal consistency reliability and test-retest reliability. The factor structure was tested with confirmatory factor analysis (CFA), while discriminant validity was evaluated by calculating the difference between the total score of the DSSCM and its four dimensions for participants with or without dampness syndrome. We used a clinician's diagnosis of dampness syndrome as a criterion to evaluate the criterion validity. Multivariate regression analysis was used to analyze the associations among gender, age, height, and weight and dampness syndrome.

A total of 880 participants were enrolled for psychometric validation and 869 participants were included in the final analyses after exclusion. The mean age of the participants was 42.62±12.86 years. The Cronbach's alpha coefficients for the four dimensions of the DSSCM were 0.809, 0.891, 0.816 and 0.780. The ICCs for the four dimensions of the DSSCM were 0.806, 0.674, 0.780 and 0.760. For validity, the results showed that the DSSCM had good content validity, discriminant validity and criterion validity. For the CFA, the root mean square error of approximation (RMSEA) was 0.091; the standardized root mean square residual (SRMR) was 0.074; the comparative fit index (CFI) was 0.766; and the Tucker-Lewis index (TLI) was 0.745. Weight was found to be associated with the total scores of the DSSCM and its three dimensions.

The DSSCM has good reliability and validity to support its use as a tool for assessing the severity of dampness syndrome. This study provides empirical evidence for future updates to the DSSCM.