Background: Little information is available regarding medical utilization and cost in patients with overlap syndrome of chronic obstructive pulmonary disease (COPD) and asthma. The purpose of this study is to analyze medical utilization and cost in patients with overlap syndrome and to compare them to COPD patients without asthma. Methods: Using the 2009 Korean National Health Insurance (NHI) database, COPD patients were identified. Medical utilization and costs were also analyzed. Results: Of a total of 185,147 patients identified with COPD, 101,004 patients were classified with overlap syndrome of COPD and asthma and 84,143 patients with COPD without asthma. In 2009, the percentages of emergency room visits, admissions, and intensive care unit admissions were 14.6%, 30.5%, and 0.5%, respectively, in the patients with overlap syndrome group and 5.0%, 14.1%, and 0.2%, respectively, in the COPD patients without asthma group (p < 0.05 for all comparisons). The cost of medical utilization was 790 ± 71 US dollars per person and 3,373 ± 4,628 dollars per person for outpatient and inpatient services, respectively, in the patients with overlap syndrome and 413 ± 512 and 3,010 ± 5,013, respectively, in the COPD patients without asthma (p < 0.05 for all comparisons). Multiple linear regression showed that age, sex, overlap syndrome, hospitalization in the last year, low socioeconomic status, and type of hospital use were significant factors affecting medical utilization and cost. Conclusions: In patients with overlap syndrome, both medical utilization and cost were higher than in COPD patients without asthma.

Background and Objectives.Chronic obstructive pulmonary disease (COPD) is a complex disease characterized by airflow limitation. Although airway inflammation and oxidative stress are known to be important in the pathogenesis of COPD, the mechanism underlying airflow obstruction is not fully understood. Gene expression profiling of lung tissue was performed to define the molecular pathways that are dysregulated in COPD.Methods.RNA was isolated from lung tissues obtained from 98 subjects with COPD and 91 control subjects with normal spirometry. The RNA samples were processed with RNA-seq using the HiSeq 2000 system. Genes expressed differentially between the two groups were identified using Student’st-test.Results.After filtering for genes with zero counts and noncoding genes, 16,676 genes were evaluated. A total of 2312 genes were differentially expressed between the lung tissues of COPD and control subjects (false discovery rate correctedq<0.01). The expression of genes related to oxidative phosphorylation and protein catabolism was reduced and genes related to chromatin modification were dysregulated in lung tissues of COPD subjects.Conclusions. Oxidative phosphorylation, protein degradation, and chromatin modification were the most dysregulated pathways in the lung tissues of COPD subjects. These findings may have clinical and mechanistic implications in COPD.

Background: Gastroesophageal reflux disease (GERD) is one of the most common causes of chronic cough and a potential risk factor for exacerbation of chronic obstructive pulmonary disease (COPD). The aim of this study was to investigate the prevalence and risk factors of GERD in patients with COPD and association between GERD and COPD exacerbation. Methods: Data were collected from the National Health Insurance Database of Korea. The subjects were 40 years old and older, who had COPD as primary or secondary diagnosis codes and utilized health care resource to receive prescriptions of COPD medication at least twice in 2009. Univariate logistic regression was performed to understand the relationship between COPD and GERD, and multiple logistic regression analysis was performed with adjustment for several confounding factors. Results: The prevalence of GERD in COPD patients was 28% (39,987/141,057). Old age, female gender, medical aid insurance type, hospitalization, and emergency room (ER) visit were associated with GERD. Most of COPD medications except inhaled muscarinic antagonists were associated with GERD. The logistic regression analysis showed that the presence of GERD was associated with increased risk of hospitalization (OR 1.54, CI 1.50 to 1.58, p<0.001) and frequent ER visits (OR 1.55, CI 1.48 to 1.62, p<0.001). Conclusions: The prevalence of GERD in patients with COPD was high. Old age, female gender, medical aid insurance type, and many COPD medications except inhaled muscarinic antagonists were associated with GERD. The presence of GERD was associated with COPD exacerbation.

Cell therapy using stem cells has produced therapeutic benefits in animal models of COPD. Secretory mediators are proposed as one mechanism for stem cell effects because very few stem cells engraft after injection into recipient animals. Recently, nanovesicles that overcome the disadvantages of natural exosomes have been generated artificially from cells. We generated artificial nanovesicles from adipose-derived stem cells (ASCs) using sequential penetration through polycarbonate membranes. ASC-derived artificial nanovesicles displayed a 100 nm-sized spherical shape similar to ASC-derived natural exosomes and expressed both exosomal and stem cell markers. The proliferation rate of lung epithelial cells was increased in cells treated with ASC-derived artificial nanovesicles compared with cells treated with ASC-derived natural exosomes. The lower dose of ASC-derived artificial nanovesicles had similar regenerative capacity compared with a higher dose of ASCs and ASC-derived natural exosomes. In addition, FGF2 levels in the lungs of mice treated with ASC-derived artificial nanovesicles were increased. The uptake of ASC-derived artificial nanovesicles was inhibited by heparin, which is a competitive inhibitor of heparan sulfate proteoglycan that is associated with FGF2 signaling. Taken together, the data indicate that lower doses of ASC-derived artificial nanovesicles may have beneficial effects similar to higher doses of ASCs or ASC-derived natural exosomes in an animal model with emphysema, suggesting that artificial nanovesicles may have economic advantages that warrant future clinical studies.