Mucus plugging and mucolytics in patients admitted with acute exacerbation of chronic obstructive pulmonary disease (COPD); investigating impact on short term mortality

<bold>Background:</bold> Although mucus plugging occluding medium to large sized airways in COPD is associated with increased long term all-cause mortality, acute exacerbations require further investigation, particularly where, despite reducing morbidity and improving quality of life, long-term use of mucolytics remains controversial. Objectives were (1) to quantify chest CT evidence of mucus plugging, (2) relate findings to mucolytics, and (3) investigate mucus plugging association with short term mortality. <bold>Methods:</bold> Retrospective review of 100 patients admitted with exacerbation of COPD (105 admissions). Comparative analysis by chi square (x2) and logistic regression, significant p<.05. <bold>Results:</bold> Mean (SD, range) age was 74.7 (10.5, 41-97) years with 54% male; mean FEV1/FVC 55% with FEV1 1.2(0.59, 0.4-3.6) litres at 49% predicted. 23 were on long term oxygen (LTOT). Mean stay was 6.3 (1-41) days. 24 died in the first 6 months. Where a historical or admission chest CT was available (n=82), 12 (15%) had mucus plugging with mucolytics prescribed to 6 (50%) compared to 32/70 (46%) without plugging (x2 0.057, NS). 9/56 (16%) with mucus plugging vs 3/26 (12%) without (x2 0.2921, NS) had emphysema and 3/13 (23%) vs 9/69 (13%) without (x2 1.016, NS) bronchiectasis. Regression investigating mortality at 6 months showed adverse outcomes for male sex, lower FEV1, and LTOT. <bold>Conclusions:</bold> 15% with acute COPD admissions have current or historical evidence of mucus plugging. Mucolytics are prescribed for 45% irrespective of prior CT radiology. Mortality (24%) at 6 months is high but not shown related to mucus plugging or reduced by mucolytics.