Fig. 2

Studies reporting mortality in patients with mild COPD: Stavem et al. [61], Mannino et al. [62], Putcha et al. [63]. Inclusion criteria/study design: Stavem et al. [61], multivariate analysis of all-cause mortality over 26 years in an occupational cohort of men aged 40–59 years (data excluding all never-smokers), adjusted for age, smoking status, physical fitness, BMI, systolic blood pressure and serum cholesterol; Mannino et al. [62], multivariate analysis of all-cause mortality over 22 years in participants aged 25–74 years from the first National Health and Nutrition Examination Survey follow-up cohort, adjusted for lung function category, age, race, sex, education, smoking status, pack-years smoked, years since regularly smoked and BMI; Putcha et al. [63], all-cause mortality over 12.5 years in smokers aged 35–60 years with pre-bronchodilator FEV₁/FVC < 0.7 and FEV₁ 55–90% predicted from the Lung Health Study I and III cohorts, adjusted for age, gender, race, smoking status at Year 5, baseline FEV₁, pack-years smoked and randomisation group. BMI: body mass index; CI: confidence interval; COPD: chronic obstructive pulmonary disease; FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; GOLD: Global Initiative for Chronic Obstructive Lung Disease; HR, hazard ratio