We wished to determine whether excess COPD-related mortality in subjects with chronic mucus hypersecretion (CMH) could be explained by proneness to pulmonary infection.
Methods: 14,223 subjects of both sexes were followed for 10-12 years. Deaths with COPD as underlying or contributory cause (n = 214) were included and if death occurred in hospital, hospital records were obtained when possible (n = 101). From information regarding increased or purulent mucus, fever, leucocytosis and chest X-ray during hospital admission, death was classified as caused by pulmonary infection (n = 38), not caused by pulmonary infection (n = 51), or unclassifiable (n = 12).
Results: Of subjects reporting CMH, 54% died from pulmonary infection, whereas that was only the case for 28% of subjects without CMH (p < 0.01). Cox regression-analysis showed a strong inverse relationship between ventilatory function and COPD-related mortality. CMH was an independent predictor of death with pulmonary infection implicated (RR:3.5) but not of death without pulmonary infection (RR:0.9).
Conclusion: COPD-patients with CMH are more likely to die from pulmonary infection than COPD-patients without CMH.