The proportion of never-smokers with non-small cell lung cancer (NSCLC) is increasing, but that in Korea has not been well addressed in a large population. We aimed to evaluate the proportion and clinical features of never-smokers with NSCLC in a large single institution. We analyzed clinical data of 1860 consecutive patients who were newly diagnosed with NSCLC between June 2011 and December 2014. Of the 1860 NSCLC patients, 707 (38.0%) were never-smokers. The proportions of women (83.7% vs. 5.6%) and adenocarcinoma (89.8% vs. 44.9%) were higher among never-smokers than among ever-smokers. Significantly more never-smokers were diagnosed at a younger median age (65 vs. 68 years, P < 0.001) and earlier stage (stage I–II, 44.5% vs. 38.9%, P = 0.015) compared with ever-smokers. Epidermal growth factor receptor mutations (57.8% vs. 24.4%, P < 0.001) and anaplastic lymphoma kinase rearrangements (7.8% vs. 2.8%, P < 0.001) were more common in never-smokers, whereas Kirsten rat sarcoma viral oncogene homolog mutations (5.8% vs. 9.6%, P = 0.021) were less frequently encountered in never-smokers than in ever-smokers. Never-smokers showed longer survival after adjusting for the favorable effects of younger age, female sex, adenocarcinoma histology, better performance status, early stage disease, being asymptomatic at diagnosis, received antitumor treatment, and the presence of driver mutations (hazard ratio, 0.624; 95% confidence interval, 0.460–0.848; P = 0.003). More than one-third of the Korean patients with NSCLC were never-smokers. NSCLC in never-smokers had different clinical characteristics and major driver mutations and resulted in longer overall survival compared with NSCLC in ever-smokers.

Background: All-cause mortality risk and causes of death in bronchiectasis patients have not been fully investigated. The aim of this study was to compare the mortality risk and causes of death between individuals with bronchiectasis and those without bronchiectasis. Methods: Patients with or without bronchiectasis determined based on chest computed tomography (CT) at one centre between 2005 and 2016 were enrolled. Among the patients without bronchiectasis, a control group was selected after applying additional exclusion criteria. We compared the mortality risk and causes of death between the bronchiectasis and control groups without lung disease. Subgroup analyses were also performed according to identification of Pseudomonas or non-tuberculous mycobacteria, airflow limitation, and smoking status. Results: Of the total 217,702 patients who underwent chest CT, 18,134 bronchiectasis patients and 90,313 non-bronchiectasis patients were included. The all-cause mortality rate in the bronchiectasis group was 1608.8 per 100,000 person-years (95% confidence interval (CI), 1531.5–1690.0), which was higher than that in the control group (133.5 per 100,000 person-years; 95% CI, 124.1–143.8; P < 0.001). The bronchiectasis group had higher all-cause (adjusted hazard ratio (aHR), 1.26; 95% CI, 1.09–1.47), respiratory (aHR, 3.49; 95% CI, 2.21–5.51), and lung cancer-related (aHR, 3.48; 95% CI, 2.33–5.22) mortality risks than the control group. In subgroup analysis, patients with airflow limitation and ever smokers showed higher all-cause mortality risk among bronchiectasis patients. Therefore, we observed significant interrelation between bronchiectasis and smoking, concerning the risks of all-cause mortality (P for multiplicative interaction, 0.030, RERI, 0.432; 95% CI, 0.097–0.769) and lung cancer-related mortality (RERI, 8.68; 95% CI, 1.631–15.736). Conclusion: Individuals with bronchiectasis had a higher risk of all-cause, respiratory, and lung cancer-related mortality compared to control group. The risk of all-cause mortality was more prominent in those with airflow limitation and in ever smokers.

Background: Since the Global Initiative for Chronic Obstructive Lung Disease (GOLD) groups A-D were introduced, the lung function changes according to group have been evaluated rarely. Objective: We investigated the rate of decline in annual lung function in patients categorized according to the 2014 GOLD guidelines. Methods: Patients with COPD included in the Korean Obstructive Lung Disease (KOLD) prospective study, who underwent yearly postbronchodilator spirometry at least three times, were included. The main outcome was the annual decline in postbronchodilator forced expiratory volume in 1 second (FEV₁), which was analyzed by random-slope and random-intercept mixed linear regression. Results: A total 175 participants were included. No significant postbronchodilator FEV₁ decline was observed between the groups (-34.4±7.9 [group A]; -26.2±9.4 [group B]; -22.7±16.0 [group C]; and -24.0±8.7 mL/year [group D]) (P=0.79). The group with less symptoms (-32.3±7.2 vs -25.0±6.5 mL/year) (P=0.44) and the low risk group (-31.0±6.1 vs -23.6±7.7 mL/year) (P=0.44) at baseline showed a more rapid decline in the postbronchodilator FEV₁, but the trends were not statistically significant. However, GOLD stages classified by FEV₁ were significantly related to the annual lung function decline. Conclusion: There was no significant difference in lung function decline rates according to the GOLD groups. Prior classification using postbronchodilator FEV₁ predicts decline in lung function better than does the new classification.

Background Smoking has been considered an important risk factor for idiopathic pulmonary fibrosis (IPF) incidence. However, there are no population-based large-scale studies demonstrating the effects of smoking on the development of IPF. We aimed to evaluate the effect of smoking on IPF development using a nationwide population-based cohort. Methods Using the Korean National Health Information Database, we enrolled individuals who had participated in the health check-up service between 2009 and 2012. Participants having a prior diagnosis of IPF were excluded. The history of smoking status and quantity was collected by a questionnaire. We identified all cases of incident IPF through 2016 on the basis of ICD-10 codes for IPF and medical claims. Cox proportional hazards models were used to calculate the adjusted HR (aHR) of the development of IPF. Results A total of 25 113 individuals (0.11%) with incident IPF were identified out of 23 242 836 participants registered in the database. The risk of IPF was significantly higher in current and former smokers than in never smokers, with an aHR of 1.66 (95% CI 1.61 to 1.72) and 1.42 (95% CI 1.37 to 1.48), respectively. Current smokers had a higher risk of IPF than former smokers (aHR 1.17, 95% CI 1.13 to 1.21). The risk of IPF development increased as the smoking intensity and duration increased. Conclusion Smoking significantly increased the risk of IPF development. Current smokers had a higher risk of IPF than former smokers. A dose–response relationship was observed between smoking and the development of IPF.

This study aimed to estimate the prevalence of gestational diabetes mellitus (GDM) and use of anti-diabetic medications for patients with GDM in Korea, using data of the period 2007–2011 from the Health Insurance Review and Assessment (HIRA) database, which includes the claims data of 97% of the Korean population. We used the Healthcare Common Procedure Coding System codes provided by the HIRA to identify women with delivery in the HIRA database between 2009 and 2011. GDM was defined according to ICD-10 codes, and patients with pre-existing diabetes between January 1, 2007 and pregnancy were excluded. A Poisson regression was performed to evaluate the trends in annual prevalence rates. The annual numbers of deliveries in 2009–2011 were 479,160 in 2009, 449,747 in 2010, and 377,374 in 2011. The prevalence of GDM during that period was 7.5% in 2009–2011: 5.7% in 2009, 7.8% in 2010, and 9.5% in 2011. The age-stratified analysis showed that the prevalence of GDM was highest in women aged 40–44 years, at 10.6% in 2009–2011, and that the annual prevalence significantly increased even in young women aged 20–29 years during that period (P < 0.05). More than 95% of the patients with GDM did not take any anti-diabetic medication. Among the anti-diabetic medications prescribed for patients with GDM, insulin was most commonly prescribed (for >98% of the patients with GDM on medication). The prevalence of GDM in Korean women recently reached 5.7–9.5% in recent years. This represents a public health concern that warrants proper screening and medical care for GDM in women during the childbearing years.