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. Author manuscript; available in PMC: 2016 Dec 1.
Published in final edited form as: Eur Respir J. 2015 Nov 5;46(6):1589–1597. doi: 10.1183/13993003.02377-2014

Table II.

Progression to COPD in Active Smokers with Normal Spirometry/Low DLCO vs Active Smokers with Normal Spirometry/Normal DLCO1

At end of evaluation period
Group2 % normal % with COPD
Normal spirometry, normal DLCO 97% (57/59) 3% (2/59)
Normal spirometry, low DLCO 78% (36/46) 22% (10/46)
p value3 0.009
1

Fifty-nine active smokers with normal spirometry/normal diffusion capacity, and 46 active smokers with normal spirometry/low diffusion capacity (DLCO) were followed over time with full lung function studies to determine the rate of progression to COPD.

2

Individuals with normal spirometry, lung volumes and normal DLCO were followed for 45±20 months. Individuals with normal spirometry, lung volumes but low DLCO were followed for 41±31months (p>0.4).

3

Chi-square.