Association of impulse oscillometry and spirometry with COPD exacerbations

<bold>Background:</bold> Impulse oscillometry (IOS) may add information to spirometry for assessing COPD. This study aims to evaluate the association of COPD exacerbations with the parameters obtained with IOS. <bold>Methods:</bold> The study included 73 COPD patients diagnosed according to GOLD criteria (age 67.8 ± 14.4 years, 27 [37%] females, GOLD A: 9 [12.3%], B: 35 [47.9%] and E: 29 [39.7%]). <bold>Results:</bold> FEV1 and IOS parameters showed good associations with the history of exacerbations (Table 1). Table 1: <table-wrap><object-id>erj;64/suppl_68/PA389/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></td><td>FEV1%*</td><td>R5%*</td><td>X5%*</td><td>R5-20%*</td></tr><tr><td><bold>All exacerbations</bold></td><td></td><td></td><td></td><td></td></tr><tr><td>0 (38, 52%)</td><td>58 (39-72)</td><td>148 (116-200)</td><td>407 (227-708)</td><td>342 (142-661)</td></tr><tr><td>1 (20, 27.4%)</td><td>50 (37-64)</td><td>171 (131-214)</td><td>550 (401-1241)</td><td>404 (173-610)</td></tr><tr><td>2 (15, 20.5%)</td><td>34 (21-43)</td><td>195 (148-269)</td><td>853 (431-2665)</td><td>787 (362-1024)</td></tr><tr><td></td><td><italic>p = 0.001</italic></td><td><italic>p = 0.080</italic></td><td><italic>p = 0.017</italic></td><td><italic>p = 0.033</italic></td></tr><tr><td><bold>Severe exacerbation</bold></td><td></td><td></td><td></td><td></td></tr><tr><td>no (47, 64.4%)</td><td>53 (39-65)</td><td>151 (116-200)</td><td>423 (242-738)</td><td>362 (144-697)</td></tr><tr><td>yes (26, 35.6%)</td><td>37 (29-62)</td><td>171 (140-245)</td><td>810 (425-1702)</td><td>517 (302-797)</td></tr><tr><td></td><td><italic>p = 0.038</italic></td><td><italic>p = 0.093</italic></td><td><italic>p = 0.003</italic></td><td><italic>NS</italic></td></tr></tbody></table></table-wrap> *median (IQR 25-75) In the ROC curve analysis (Figure 1), X5 had the largest AUC for a history of at least one severe exacerbation (AUC [95% CI]: FEV1% 0.646 [0.506 – 0.786], R5% 0.626 [0.490 – 0.761], X5% 0.712 [0.583 – 0.840], R5-20% 0.602 [0.467 – 0.736]). Figure 1: <fig><object-id>erj;64/suppl_68/PA389/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig> <bold>Conclusions:</bold> IOS measurements show similar associations to spirometry with a history of COPD exacerbations, although there may be a better association of IOS (especially X5) with severe exacerbations of COPD.