Wedzicha discusses the study by Labaki and coauthors on causes of death related to lung function impairment in former or current smokers from the COPDgene (Genetic Epidemiology of COPD) study. The study has recruited subjects with COPD of all severities. A total of 10,132 subjects were included, among whom 2,200 deaths occurred; they were followed for 10.1 years and divided into those with normal spirometry, a group with preserved ratio impaired spirometry (PRISm), and then Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1 and 2 and GOLD 3 and 4 groups. Data on causes of death were available on just over 75% of the deaths, and these were adjudicated after review of death certificates, medical records, and next-of-kin interviews. Analysis of the missing mortality data suggested that those subjects had clinical features similar to those of subjects with mortality causes documented.