Development and evaluation of a Traditional Chinese Medicine syndrome questionnaire for measuring sub-optimal health status in China

OBJECTIVE: Sub-optimal health status (SHS), in which a person's mind and body exists in a low-quality state of being between disease and health, has become a public health problem that cannot be ignored in China. SHS measurement presents a challenge to the academic fields. We developed and evaluated a questionnaire from the perspective of traditional Chinese medicine (TCM) that embodies the features of TCM syndrome diagnosis for measuring SHS in China. METHODS: The construction of the theoretical framework of the questionnaire was based on a literature review, an expert questionnaire survey and group interviews. The subscales and questionnaire items were screened through a pilot study using statistical means and qualitative analysis. Reliability tests that were used included test-retest reliability, Cronbach's a coefficient, split-half reliability; validity tests included content validity, criterion validity, discrimination validity and construct validity. RESULTS: The final questionnaire, the SHSQ-50, included 50 five-class quantifiable items that encompassed nine subscales: liver stagnation syndrome, liver-Qi deficiency syndrome, spleen-Qi deficiency syndrome, liver-fire syndrome, heart-fire syndrome, stomach-fire syndrome, heart-Qi deficiency syndrome, lung-Qi deficiency syndrome and dampness syndrome. Questionnaires were completed by 268 of the 288 SHS subjects (93.0%) and by 86 of the 94 healthy subjects (91.5%). The Cronbach a coefficients, split-half coefficients and stability coefficients ranged from 0.70 to 0.95, 0.67 to 0.87 and 0.88 to 0.98, respectively, for the overall scores and subscales. The Wilcoxon rank test showed statistically significant differences in the subscales and overall scores between the SHS group and the healthy group (P < 0.01). Twelve factors with an eigenvalue greater than one were extracted by factor analysis and merged into nine factors, for which the cumulative contribution rate was 63.63%. The nine factors were corresponded to the overall structure of the questionnaire. CONCLUSION: The SHSQ-50 is a reliable and valid instrument for measuring TCM syndrome diagnosis of SHS in China.