Identification worsening patterns in the CAT Questionnaire during a severe exacerbation of COPD

<bold>Introduction:</bold> During a COPD exacerbation, symptom worsening may not be uniform. The aim of this study is to identify different patterns of worsening using the COPD Assessment Test (CAT) questionnaire. <bold>Methods:</bold> Observational study of patients admitted due to a COPD exacerbation between 2021 and 2023. Clinical characteristics of patients were collected, and the CAT questionnaire was administered twice, referring to the time of admission (exacerbation CAT) and the two months prior to admission (stable CAT). Worsening patterns were identified using discriminant analysis. <bold>Results:</bold> Fifty patients were included, of whom 30 (60%) were males. The mean age was 70.5 years (SD 9.6). The mean FEV1 was 1.17 L (SD 0.46) and 46.7% (SD 0.8). The stable CAT score was 13.5 (IQR 7-19), and the exacerbation CAT score was 25 (IQR 17.5-30), p<0.001. Three patterns were identified: those with more cough and sputum (cluster 1), those with more dyspnea and activity limitation (cluster 2), and those with worse sleep quality and less energy (cluster 3). Table 1. Clinical characteristics according to worsening patterns. <table-wrap><object-id>erj;64/suppl_68/PA396/TB1</object-id><object-id>T1</object-id><object-id>TB1</object-id><table><colgroup><col></col><col></col><col></col><col></col><col></col></colgroup><tbody><tr><td>Characteristics</td><td>Cluster 1 (n=34)</td><td>Cluster 2 (n=11)</td><td>Cluster 3 (n=5)</td><td>p-Value</td></tr><tr><td>Male, n (%)</td><td>21 (61.8)</td><td>6 (54.5)</td><td>3 (60.0)</td><td>0.914</td></tr><tr><td>Age, year (SD)</td><td>72 (8)</td><td>68 (13)</td><td>68 (10)</td><td>0.499</td></tr><tr><td>Weight, kg (SD)</td><td>72 (17)</td><td>74 (13)</td><td>71 (17)</td><td>0.905</td></tr><tr><td>Height, m (SD)</td><td>1.64 (0.07)</td><td>1.63 (0.10)</td><td>1.61 (0.10)</td><td>0.679</td></tr><tr><td>FEV1, L (SD)</td><td>1.20 (0.50)</td><td>1.11 (0.39)</td><td>1.08 (0.24)</td><td>0.788</td></tr><tr><td>FEV1pp, % (SD)</td><td>47 (17)</td><td>47 (17)</td><td>42 (7)</td><td>0.787</td></tr></tbody></table></table-wrap> <bold>Conclusions:</bold> Three patterns of worsening were identified, although patients are not clinically distinguishable during the stable phase.