From: Analyzing networks of phenotypes in complex diseases: methodology and applications in COPD
Variables (abbreviation) | Descriptions/Comments |
---|---|
FEV1 (% predicted FEV1) | Observed FEV1 (liters)/predicted FEV1 (liters), with predicted valued from Hankinson reference equations |
Emphysema (Emph) | % Emphysema at -950 Hounsfield units(HU) |
Emphysema Distribution (EmphDist) | Log ratio of emphysema at -950 HU in the upper 1/3 of lung fields compared to the lower 1/3 of lung fields |
Gas Trapping (GasTrap) | Air trapping at -856HU on expiratory chest CT scan |
Airway Wall Area (Pi10) | Square root of the wall area of a hypothetical 10 mm internal perimeter airway |
Exacerbation frequency (ExacerFreq) | Number of COPD exacerbations during the year before study enrollment |
Six minute walk distance (6MWD) | Measure of exercise capacity |
BMI | Body Mass Index |
Age | In years |
Pack-Years (PackYear) | One pack-year is defined as smoking one pack (20 cigarettes) per day for one year |