Emphysema predicts hospitalisation and incident airflow obstruction among older smokers: a prospective cohort study

PLoS One. 2014 Apr 3;9(4):e93221. doi: 10.1371/journal.pone.0093221. eCollection 2014.


Background: Emphysema on CT is common in older smokers. We hypothesised that emphysema on CT predicts acute episodes of care for chronic lower respiratory disease among older smokers.

Materials and methods: Participants in a lung cancer screening study age ≥ 60 years were recruited into a prospective cohort study in 2001-02. Two radiologists independently visually assessed the severity of emphysema as absent, mild, moderate or severe. Percent emphysema was defined as the proportion of voxels ≤ -910 Hounsfield Units. Participants completed a median of 5 visits over a median of 6 years of follow-up. The primary outcome was hospitalization, emergency room or urgent office visit for chronic lower respiratory disease. Spirometry was performed following ATS/ERS guidelines. Airflow obstruction was defined as FEV1/FVC ratio <0.70 and FEV1<80% predicted.

Results: Of 521 participants, 4% had moderate or severe emphysema, which was associated with acute episodes of care (rate ratio 1.89; 95% CI: 1.01-3.52) adjusting for age, sex and race/ethnicity, as was percent emphysema, with similar associations for hospitalisation. Emphysema on visual assessment also predicted incident airflow obstruction (HR 5.14; 95% CI 2.19-21.1).

Conclusion: Visually assessed emphysema and percent emphysema on CT predicted acute episodes of care for chronic lower respiratory disease, with the former predicting incident airflow obstruction among older smokers.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Aged
  • Aged, 80 and over
  • Airway Obstruction / diagnosis*
  • Airway Obstruction / etiology
  • Early Detection of Cancer
  • Female
  • Follow-Up Studies
  • Forced Expiratory Volume
  • Hospitalization / statistics & numerical data*
  • Humans
  • Lung Neoplasms / diagnosis*
  • Lung Neoplasms / etiology
  • Male
  • Middle Aged
  • Prospective Studies
  • Pulmonary Disease, Chronic Obstructive / diagnosis*
  • Pulmonary Disease, Chronic Obstructive / etiology
  • Pulmonary Emphysema / complications*
  • Respiratory Function Tests
  • Smoking / adverse effects*
  • Tomography, X-Ray Computed
  • Vital Capacity