The relationship between COPD assessment test (CAT) scores and severity of airflow obstruction in stable COPD patients

Background COPD is a major cause of morbidity in smokers. The COPD assessment test (CAT) is a validated test for the evaluation of COPD impact on health status. Although CAT is not a diagnostic test and pulmonary function test (PFT) remains the important diagnostic test, its predictive value for evaluation of disease impact is weak. The purpose of this study was to determine the relationship between the CAT score and PFT in stable COPD. Method We evaluated 105 patients with stable COPD. Severity of airflow obstruction assessed by spirometry and classified by the Global initiative for Obstructive Lung Disease (GOLD) criteria. Then, the impact of COPD on health status was assessed by CAT. We statically compared interrelationship between CAT score, COPD stages, CAT groups and PFT. Results The mean age and mean period of smoking (p/y) were 59.60±11.93 SD and 35.43±15.33 SD respectively. The mean FEV1%predicted was 71.01±26.70 SD. The mean CAT score was 19.61±8.07 SD. Correlations between the severity of smoking by GOLD stages was significant (p=0.006). There was a significant difference between the FEV1%predicted and total CAT score(r= -0.55, p< 0.001). The comparison of mean FEV1%predicted with mean score of CAT groups 1, 2, 3, and 4 were significant (p