Table 1—

Demographics and baseline characteristics of analysis cohort

Subjects n5756
Age yrs64.5±8.5
Males74.6
Race
 White90.0
 Asian6.3
 Black1.6
 Unavailable2.0
Current smoker30.6
Smoking history pack-yrs48.7±27.9
Duration of COPD yrs9.8±8.3
BMI kg·m−226.0±5.1
SGRQ total score45.9±17.1
Pre-bronchodilator FEV1 % pred39.3±12.0
Post-bronchodilator FEV1 % pred47.6±12.6
GOLD stage
 Stage II: moderate46.6
 Stage III: severe44.7
 Stage IV: very severe8.8
Medication use
 Any respiratory medication93.1
 Short-acting β-agonists68.5
 Any long-acting bronchodilator60.5
 Inhaled steroids61.4
 Short-acting inhaled anticholinergics44.5
 Xanthines28.6
 Oxygen2.0
  • Data are presented as percentage of population or mean±sd, unless otherwise stated. COPD: chronic obstructive pulmonary disease; BMI: body mass index; SGRQ: St George’s Respiratory Questionnaire; FEV1: forced expiratory volume in one second; % pred: % predicted; GOLD: Global Initiative for Chronic Obstructive Lung Disease.