A Validation Study for the Korean Version of Chronic Obstructive Pulmonary Disease Assessment Test (CAT)

Background: Health status measure is not only important for clinical research studies but also for clinical practices of chronic obstructive pulmonary disease (COPD) patients. The objective of this study is to evaluate the validity of the Korean Version of COPD Assessment Test (CAT) in primary care clinics as well as in referral hospitals. Methods: Smokers or ex-smokers, aged 40 years or older, with a smoking history of >10 pack-years; and a COPD diagnosis in the past 6 months or more, were recruited from 4 primary care clinics and 2 referral hospitals. Demographic, medical, and spirometry data was collected from patients who completed the CAT and St. George Respiratory Questionnaire (SGRQ), and had their dyspnea been assessed. The primary endpoint was the correlation between of the Korean version of CAT with SGRQ in patients with COPD. Results: A total 100 patients were enrolled. The mean age and smoking amounts were $69.2{\pm}8.4$ years and $40.6{\pm}22.3$ pack-years, respectively. Sixty-seven percent of the patients reported at least one exacerbation in the past year. The mean CAT score was $16.9{\pm}8.0$. The internal consistency assessed by Cronbach's alpha was 0.85. The CAT score was positively correlated with the SGRQ score (r=0.76, p<0.0001) and each component of SGRQ: symptoms, activity and impacts; r=0.68, r=0.61, and r=0.72, respectively (all p<0.0001). These positive correlations were preserved in the different groups (r=0.86, p<0.0001 in primary care clinic group; r=0.69, p<0.0001 in hospital group). The CAT score was also positively correlated to the Medical Research Council dyspnoea scale (r=0.46, p<0.0001). Conclusion: The Korean version of CAT had good internal consistency and showed good correlations with SGRQ. It can be used for assessing the impacts of COPD on the patient's health including primary care setting.