Validity of the COPD assessment test translated into local languages for Asian patients

Our objective was to evaluate the validity of the COPD Assessment Test (CAT), translated locally, for measuring the health status of patients in Asian countries.

A pooled analysis of cross-sectional studies from Indonesia, Korea, Vietnam, and Hong Kong was performed. Smokers or ex-smokers, aged ≥ 40 years, with a smoking history of ≥ 10 pack-years and a COPD diagnosis in the past 6 months or more were recruited. Demographic, smoking, and COPD history and spirometry data were collected from patients who completed the CAT or St. George's Respiratory Questionnaire (SGRQ) and had their dyspnea assessed.

The study included 333 patients with mean age of 69 ± 9 years and smoking history of 38 ± 25 pack-years; 82% had ceased smoking. One-third suffered from cardiovascular comorbidities, 72% reported at least one exacerbation in the past year, and 82% recorded at least moderate health impairment (CAT scores ≥ 10 units). The CAT score was positively correlated with the SGRQ score (r = 0.72, P < .001) and Medical Research Council (MRC) dyspnea score (r = 0.50, P < .001) and poorly correlated with the FEV1 (r = -0.23, P < .001) and number of exacerbations in the past year (r = 0.11, P = .04). The relationships between the CAT score and SGRQ score, MRC dyspnea score, or FEV1 did not differ between countries (P value for interaction term = 0.76, 0.75, and 0.06, respectively).

The CAT correlated well with the SGRQ and MRC dyspnea score in all countries, and the relationship did not differ between countries despite varying patient characteristics. This suggests that a CAT score in one of these countries has the same clinical significance as the same score in another.