Clinical role of the chronic obstructive pulmonary disease assessment test in prediction of the response to treatment for exacerbations

Background: The chronic obstructive pulmonary disease (COPD) assessment test (CAT) is a validated, eight-item questionnaire used to quantify the health status of patients. The aim of this study was to evaluate the usefulness of the CAT questionnaire as a tool to assess the response to treatment in acute exacerbations of COPD in an outpatient setting. Methods: A multicenter, phase 3 randomized controlled trial was conducted previously to examine the efficacy and safety of oral zabofloxacin for the treatment of COPD exacerbations. In the present post hoc analysis of the original study, patients with COPD exacerbation were categorized as responders or non-responders according to the respiratory symptoms persisting on day 10 (visit 3) of treatment. The CAT questionnaire was completed daily by patients at home from the initial visit to the second visit on day 5. Subsequently, the questionnaire was completed in the presence of a physician on days 10 (visit 3) and 36 (visit 4). Multivariate regression analysis was performed to determine the association between CAT scores and the therapeutic response. Results: The CAT scores decreased more rapidly in responders compared to non-responders during the first 5 days (23.320.4 vs. 23.522). Among responders, patients with higher severity of illness also revealed higher CAT scores on the first day of an exacerbation (mild, 19.8; moderate, 21.4; severe, 23.8; very severe, 28.6). Multivariate analysis revealed that a change in the CAT score during the first 3 days influenced the therapeutic response. A significant decrease in scores in the domains of sputum production, chest tightness, and activities of daily living was seen among responders. Conclusion: Early improvement in CAT scores may be associated with a more favorable response to the treatment of COPD exacerbations.