Results from the multiple linear regression analysis with forced expiratory volume in 1 s (FEV1) after follow-up as primary end-point

CovariableIncrement or comparisonChanges in FEV1 after follow-up per unit change in covariable β95% CIp-value
Years in study+1 year−38 mL−60– −160.001
Baseline FEV1−10 mL−8.8 mL−8.6– −9.0<0.001
Smoking statusCurrent versus former−55 mL−77– −33<0.001
Age years+1 year−5 mL−7– −3<0.001
Height cm+1 cm+3 mL1–50.006
Pack-years+10 pack-years−10 mL−15– −5<0.001
Pi10 mm+1 mm−34 mL−56– −120.002
Perc15 Hounsfield Units10  Hounsfield Units lower−10 mL−15– −50.006
  • Pi10: square root of wall area of a 10-mm lumen perimeter; Perc15: 15th percentile method.