Respirology. 2019 Aug 19. doi: 10.1111/resp.13678. [Epub ahead of print]

Impact of chronic obstructive pulmonary disease on mortality: A large national cohort study.

Park HY¹, Kang D^2,3, Lee H⁴, Shin SH¹, Kang M², Kong S³, Rhee CK⁵, Cho J^2,3,6, Yoo KH⁷.

Author information

1

Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.

2

Center for Clinical Epidemiology, Samsung Medical Center, Seoul, Republic of Korea.

3

Department of Clinical Research Design and Evaluation, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea.

4

Division of Pulmonary Medicine and Allergy, Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea.

5

Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.

6

Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA.

7

Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Republic of Korea.

Abstract

BACKGROUND AND OBJECTIVE:

The global burden of chronic obstructive pulmonary disease (COPD) is increasing and COPD patients are at higher risk for all-cause mortality. We aimed to evaluate the impact of COPD on specific-cause mortality using national data.

METHODS:

This was nationwide retrospective cohort study of 340, 767 adults aged 40-84 years who lacked COPD diagnosis at baseline between 1 January 2003 and 31 December 2013. Incident COPD was defined by reference to COPD claim codes and prescription of COPD medication at least twice annually. Cox proportional hazard ratio (HR) for each cause of death in the COPD group was compared to that of the non-COPD group, with other causes of death accounted as the competing risk.

RESULTS:

All-cause mortality was higher in the COPD (2,978 per 100, 000 person-years) than the non-COPD group (629 per 100, 000 person-years) and adjusted HR was 1.41 (95% CI = 1.32, 1.50). The association was particularly strong for chronic lower airway disease (adjusted sub-HR = 9.67; 95% CI = 7.21, 12.96) and lung cancer (adjusted sub-HR = 3.16; 95% CI = 2.68, 3.71), and the association was stronger in those aged <60 years.

CONCLUSION:

In this large national cohort, COPD patients were at a statistically significant higher risk for all-cause mortality than those without COPD. They were more likely to die from chronic lower airway disease, lung cancer and pneumonia than subjects without COPD. The impact of COPD on specific mortalities was stronger in younger subjects.

© 2019 Asian Pacific Society of Respirology.

KEYWORDS:

chronic lower airway disease; chronic obstructive pulmonary disease; lung cancer; mortality