Chronic obstructive pulmonary disease (COPD) is often heterogeneous in its presentation and prognosis, and neither pulmonary function tests nor CT alone are always adequate to characterize a patient’s disease. a study has found.
In a paper published in CHEST, Jinkyeong Park, MD, PhD, of Dongguk University Ilsan Hospital in Goyang, South Korea, and colleagues looked at data from 9,080 subjects enrolled in the COPDGene study, an observational cohort of longtime smokers with and without COPD. By assessing visually defined patterns of emphysema with quantitative imaging features and spirometry data, the researchers identified 10 distinct subtypes of COPD (including no disease) and noted significant differences in mortality and progression among them.
Dr. Park and colleagues found that patients in the subgroups with quantitative but no visual emphysema and those with visual but not quantitative emphysema represented unique groups with mild COPD that were both at risk for progression – but with likely different underlying mechanisms. Current smokers, women, and whites were more common among subjects showing visually defined emphysema without quantitative evidence. “Many of the subjects in the visual-only emphysema subtype have areas of low lung density due to emphysema masked by smoking-induced lung inflammation,” the researchers wrote.
Overall 5-year mortality differed significantly among the groups (P less than .01) and was highest in the three groups with moderate to severe centrilobular emphysema. Patients with paraseptal and moderate to severe centrilobular emphysema showed substantial progression of emphysema over 5 years, compared with individuals with no CT abnormality (P less than .05).
“These results suggest that the combination of visual and quantitative CT features, which may reflect different underlying pathobiological processes in COPD, may provide a superior approach to classify individuals with COPD, compared to the use of visual or quantitative CT features alone,” the researchers wrote.
The study received funding from the National Heart, Lung and Blood Institute. Three of the study’s coauthors reported conflicts of interest in the form of patent applications or financial support from pharmaceutical firms. The COPDGene Project receives pharmaceutical industry and U.S. government support.
SOURCE: Park J et al. CHEST. 2019 Jul 5. doi:10:1016/j.chest.2019.06.15.