[Development of a patient-reported outcome scale for stable chronic obstructive pulmonary disease and its clinical applicability].

Objective: To develop a patient-reported outcome (PRO) scale for patients with stable chronic obstructive pulmonary disease (sCOPD) and to study its clinical applicability in traditional Chinese medicine (TCM).

Methods: According to standardized procedures, the test version of PRO scale for sCOPD (sCOPD-PRO scale) was developed based on the theory of "unity of body and spirit" and was used to test 324 patients selected from six clinical centers. Five methods were used to analyze the items; the reliability, validity and responsiveness of the remaining items of the scale were evaluated.

Results: (1) sCOPD-PRO consisted of 23 items after item analysis, and according to the content of each item, these items could be grouped into four domains, namely, lung and kidney deficiency symptom, spleen deficiency symptom, functional activities and emotional impact. (2) Cronbach's alpha coefficient for sCOPD-PRO scale was more than 0.75 in four domains and total scores. (3) sCOPD-PRO scale and St. George's Respiratory Questionnaire (SGRQ) were moderately correlated or highly correlated in corresponding domains: the correlation coefficient between the total score of sCOPD-PRO scale and the total score of SGRQ was 0.72 (P<0.01), the correlation coefficient between functional activities domain of sCOPD-PRO scale and activity domain of SGRQ was 0.77 (P<0.01), and the correlation coefficient between emotional impact domain of sCOPD-PRO scale and impact domain of SGRQ was 0.51 (P<0.01). Factor analysis revealed that four factors could explain 65.06% of the total variance. (4) The four domains and total scores of sCOPD-PRO scale were significantly different before and after intervention in TCM group and Western medicine group (P<0.01); moreover, the effect size and standardized response mean of two groups were more than 0.4.

Conclusion: The development process and method of sCOPD-PRO scale, which is based on the theories of "unity of body and spirit", are standard, and the reliability, validity and responsiveness of the scale are sound and can be relied upon for sCOPD clinical efficacy evaluation of TCM.