Evaluation of the COPD Assessment Test and GOLD patient types: a cross-sectional analysis

BACKGROUND The COPD Assessment Test (CAT) has been recently developed to quantify COPD impact in routine practice. However, no relationship with other measures in the Global Initiative for Obstructive Lung Disease (GOLD) strategy has been evaluated. The present study aimed to evaluate the relationship of the CAT with other GOLD multidimensional axes, patient types, and the number of comorbidities. METHODS This was a cross-sectional analysis of the Clinical presentation, diagnosis, and course of chronic obstructive pulmonary disease (On-Sint) study. The CAT score was administered to all participants at the inclusion visit. A GOLD 2011 strategy consisting of modified Medical Research Council scale (MRC) scores was devised to study the relationship between the CAT, and GOLD 2011 axes and patient types. The relationship with comorbidities was assessed using the Charlson comorbidity index, grouped as zero, one to two, and three or more. RESULTS The CAT questionnaire was completed by 1,212 patients with COPD. The CAT maintained a relationship with all the three axes, with a ceiling effect for dyspnea and no distinction between mild and moderate functional impairment. The CAT score increased across GOLD 2011 patient types A-D, with similar scores for types B and C. Within each GOLD 2011 patient type, there was a considerably wide distribution of CAT values. CONCLUSION Our study indicates a correlation between CAT and the GOLD 2011 classification axes as well as the number of comorbidities. The CAT score can help clinicians, as a complementary tool to evaluate patients with COPD within the different GOLD patient types.