• Tuberculosis and Respiratory Diseases
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• v.77 no.5
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• pp.209-214
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• 2014

Background: Bronchiectasis and asthma are different in many respects, but some patients have both conditions. Studies assessing the effect of bronchiectasis on asthma exacerbation are rare. The aim of this study is to investigate the effect of bronchiectasis on asthma exacerbation. Methods: We enrolled 2,270 asthma patients who were followed up in our hospital. Fifty patients had bronchiectasis and asthma. We selected fifty age- and sex-matched controls from the 2,220 asthma patients without bronchiectasis, and assessed asthma exacerbation and its severity based on the annual incidence of total asthma exacerbation, annual prevalence of steroid use, and frequency of emergency room visits and hospitalizations due to asthma exacerbation in each group. Results: Fifty patients (2.2%) had bronchiectasis and asthma. The annual incidence of asthma exacerbation was higher in patients with asthma and bronchiectasis than in patients with asthma alone ($1.08{\pm}1.68$ vs. $0.35{\pm}0.42$, p=0.004). The annual prevalence of steroid use ($0.9{\pm}1.54$ vs. $0.26{\pm}0.36$, p=0.006) and the frequency of emergency room visits ($0.46{\pm}0.84$ vs. $0.02{\pm}0.13$, p=0.001) due to asthma exacerbation were also higher in patients with asthma and bronchiectasis than in patients with asthma alone. Conclusion: Bronchiectasis is associated with difficult asthma control.

• Tuberculosis and Respiratory Diseases
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• v.70 no.5
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• pp.416-422
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• 2011

Background: Inhaled corticosteroids (ICSs) are the most essential medication for asthma control. Many reports suggest that the usage of ICSs improves not only the control of asthma symptoms but also prevents exacerbation. We investigated whether increases in ICS prescriptions are associated with decreases in asthma exacerbation in the clinical practice setting. Methods: We retrospectively analyzed the database of adult asthma patients who had visited a tertiary referral hospital, the Asan Medical Center between January 2000 and December 2009. The number of emergency department (ED) visits, admissions, intensive care unit (ICU) care, deaths, and ICS prescriptions were analyzed to evaluate the time trend of asthma exacerbation as a function of the ICS prescription rate during the ten years. Results: The numbers of ED visits, admissions, and episodes of ICU care decreased during the ten years (p<0.001, p=0.033, p=0.001, respectively) while the number of ICS prescriptions increased (p<0.001). We found a correlation between the number of ICS prescriptions and the number of ED visits, admissions, or ICU care. For these outcomes, the correlation coefficients were r=-0.952, p<0.001; r=-0.673, p=0.033; r=-0.948, p<0.001, respectively. Conclusion: The number of ICS prescriptions increased during the past ten years while the number of asthma exacerbations decreased. Our results also showed a negative correlation between the ICS prescription rate and asthma exacerbation in the clinical practice setting. In other words, an increase in ICS prescription may be a major cause of a decrease in asthma exacerbations.

• Clinical and Experimental Pediatrics
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• v.59 no.11
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• pp.432-439
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• 2016

Asthma is recognized as a complex disease resulting from interactions between multiple genetic and environmental factors. Accumulating evidence suggests that respiratory viral infections in early life constitute a major environmental risk factor for the development of childhood asthma. Respiratory viral infections have also been recognized as the most common cause of asthma exacerbation. The advent of molecular diagnostics to detect respiratory viruses has provided new insights into the role of human rhinovirus (HRV) infections in the pathogenesis of asthma. However, it is still unclear whether HRV infections cause asthma or if wheezing with HRV infection is simply a predictor of childhood asthma. Recent clinical and experimental studies have identified plausible pathways by which HRV infection could cause asthma, particularly in a susceptible host, and exacerbate disease. Airway epithelial cells, the primary site of infection and replication of HRV, play a key role in these processes. Details regarding the role of genetic factors, including ORMDL3, are beginning to emerge. This review discusses recent clinical and experimental evidence for the role of HRV infection in the development and exacerbation of childhood asthma and the potential underlying mechanisms that have been proposed.

• Tuberculosis and Respiratory Diseases
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• v.59 no.5
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• pp.497-503
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• 2005

Backgrounds : The exacerbations of asthma and chronic obstructive pulmonary disease (COPD) have been suggested to be associated with respiratory tract viral infections (RTVIs). However, the rates of virus detection in previous studies have been quite variable, with lower rates for the exacerbation of COPD. Therefore, the virus detection of patients with exacerbation of asthma and COPD were investigated. Methods : 20 and 24 patients with exacerbation of asthma and COPD, respectively, were enrolled. Nasal and sputum samples were taken, and polymerase chain reaction (PCR) for rhinovirus and coronavirus and virus culture for influenza A, B, RSV and parainfluenza virus performed. Results : The mean $FEV_1/FVC$ in the exacerbation of asthma and COPD patients were 1.9/2.9 L (65.5%) and 1.1/2.6 L (42.3%), respectively. Respiratory virus was detected in 13 (65%) patients with exacerbation of asthma and rhinovirus was detected in 9. Coronavirus, influenza A, RSV and parainfluenza virus were detected in 2, 2, 1 and 1 patients with asthma. Among patients with exacerbation of COPD, a virus was detected in 14 (58.3%) patients, with rhinovirus, coronavirus and influenza A detected in 10, 3 and 4, respectively. Conclusions : This study suggested that RTVIs may have a role in the exacerbation of COPD as well as asthma.

• Tuberculosis and Respiratory Diseases
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• v.81 no.4
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• pp.289-298
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• 2018

Background: Obstructive airway disease patients with increased variability of airflow and incompletely reversible airflow obstruction are often categorized as having asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS). ACOS is heterogeneous with two sub-phenotypes: asthma-ACOS and COPD-ACOS. The objective of this study was to determine the difference in risk of exacerbation between the two sub-phenotypes of ACOS. Methods: A total of 223 patients exhibiting incompletely reversible airflow obstruction with increased variability (spirometrically defined ACOS) were enrolled. These patients were divided into asthma-ACOS and COPD-ACOS according to their physician's diagnosis and smoking history of 10 pack-years. Within-group comparisons were made for asthma-ACOS versus COPD-ACOS and light smokers versus heavy smokers. Results: Compared to patients with COPD-ACOS, patients with asthma-ACOS experienced exacerbation more often despite their younger age, history of light smoking, and better lung function. While the light-smoking group showed better lung function, they made unscheduled outpatient clinic visits more frequently. On multivariate analysis, asthma-ACOS and poor inhaler compliance were significantly associated with more than two unscheduled clinic visits during the previous year. Conclusion: Spirometrically defined ACOS includes heterogeneous subgroups with different clinical features. Phenotyping of ACOS by physician's diagnosis could be significant in predicting future risk of exacerbation.

• Kosin Medical Journal
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• v.33 no.2
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• pp.171-180
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• 2018

Objectives: We investigated whether asthma attacks in asthmatic children were caused by short-term exposure to particulate $matter(PM)_{2.5}$. Methods: Subjects were 411 patients who received inhalation therapy in National Fukuoka Hospital, from March to May 2013. All subjects were outpatients. We surveyed the air quality measurement results in the stations closest to the address of the patients. Data were used from the City of Fukuoka website data on air pollution. We carried out a case-crossover study and compared $PM_{2.5}$ concentration between 7 days after asthma attack occurred and the day asthma attack occurred and 1, 2 and 3 days before asthma attack occurred. Results: Highest hourly concentration of the day (OR 1.013, 95%CI 1.000-1.025) showed a significant association with 1 day before $PM_{2.5}$ concentration statistically. And 0-1 year-old infants were more vulnerable to the highest concentration of 1 day before $PM_{2.5}$ concentration(P < 0.05). Average concentration of $NO_2$ and $O_3$ and asthma attack also showed a significant association. Conclusions: Maximal daily $PM_{2.5}$ concentrations within 24 hours prior to the attack affect asthma exacerbation. 0-1 year-old infants are particularly vulnerable to $PM_{2.5}$ concentration. Asthma exacerbation is aggravated by $NO_2$ and $O_3$ concentration on the day of the asthma attack.

• Tuberculosis and Respiratory Diseases
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• v.85 no.1
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• pp.11-17
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• 2022

Background: In asthma, consistent control of chronic airway inflammation is crucial, and the use of asthma-controller medication has been emphasized. Our purpose in this study is to compare the incidence of acute exacerbation and healthcare costs related to the use of asthma-controller medication. Methods: By using data collected by the National Health Insurance Review and Assessment Service, we compared one-year clinical outcomes and medical costs from July 2014 to June 2015 (follow-up period) between two groups of patients with asthma who received different prescriptions for recommended asthma-controller medication (inhaled corticosteroids or leukotriene receptor antagonists) at least once from July 2013 to June 2014 (assessment period). Results: There were 51,757 patients who satisfied our inclusion criteria. Among them, 13,702 patients (26.5%) were prescribed a recommended asthma-controller medication during the assessment period. In patients using a recommended asthma-controller medication, the frequency of acute exacerbations decreased in the follow-up period, from 2.7% to 1.1%. The total medical costs of the controller group decreased during the follow-up period compared to the assessment period, from $3,772,692 to $1,985,475. Only 50.9% of patients in the controller group used healthcare services in the follow-up period, and the use of asthma-controller medication decreased in the follow-up period. Conclusion: Overall, patients using a recommended asthma-controller medication showed decreased acute exacerbation and reduced total healthcare cost by half.

• Tuberculosis and Respiratory Diseases
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• v.86 no.3
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• pp.151-157
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• 2023

The introduction of inhaled corticosteroids (ICS) for the management of asthma has led to a decrease in acute exacerbation of asthma. However, there are concerns regarding the safety of long-term ICS use, particularly pneumonia. Growing evidence indicates that ICS use is associated with an increased risk of pneumonia in patients with chronic obstructive pulmonary disease, whereas the risk in patients with asthma remains unclear. This review discusses the effect of ICS on pneumonia among patients with asthma to update the existing literature. Asthma is associated with an increased risk of pneumonia. Several hypotheses have been proposed to explain this association, including that asthma impairs the clearance of bacteria owing to chronic inflammation. Therefore, controlling airway inflammation with ICS may prevent the occurrence of pneumonia in asthma. In addition, two meta-analyses investigating randomized control trials showed that ICS use was associated with a protective effect against pneumonia in asthma.

• Tuberculosis and Respiratory Diseases
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• v.79 no.3
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• pp.111-120
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• 2016

Asthma is a prevalent and serious health problem in Korea. Recently, the Korean Asthma Guideline has been updated by The Korean Academy of Tuberculosis and Respiratory Diseases (KATRD) in an effort to improve the clinical management of asthma. This guideline focuses on adult patients with asthma and aims to deliver up to date scientific evidence and recommendations to general physicians for the management of asthma. For this purpose, this guideline was updated following systematic review and meta-analysis of recent studies and adapting some points of international guidelines (Global Initiative for Asthma [GINA] report 2014, National Asthma Education and Prevention Program [NAEPP] 2007, British Thoracic Society [BTS/SIGN] asthma guideline 2012, and Canadian asthma guideline 2012). Updated issues include recommendations derived using the population, intervention, comparison, and outcomes (PICO) model, which produced 20 clinical questions on the management of asthma. It also covers a new definition of asthma, the importance of confirming various airflow limitations with spirometry, the epidemiology and the diagnostic flow of asthma in Korea, the importance and evidence for inhaled corticosteroids (ICS) and ICS/formoterol as a single maintenance and acute therapy in the stepwise management of asthma, assessment of severity of asthma and management of exacerbation, and an action plan to cope with exacerbation. This guideline includes clinical assessments, and treatment of asthma-chronic obstructive pulmonary disease overlap syndrome, management of asthma in specific conditions including severe asthma, elderly asthma, cough variant asthma, exercise-induced bronchial contraction, etc. The revised Korean Asthma Guideline is expected to be a useful resource in the management of asthma.

• IMMUNE NETWORK
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• v.21 no.4
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• pp.26.1-26.28
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• 2021

Asthma exacerbations are a major cause of intractable morbidity, increases in health care costs, and a greater progressive loss of lung function. Asthma exacerbations are most commonly triggered by respiratory viral infections, particularly with human rhinovirus (hRV). Respiratory viral infections are believed to affect the expression of indoleamine 2,3-dioxygenase (IDO), a limiting enzyme in tryptophan catabolism, which is presumed to alter asthmatic airway inflammation. Here, we explored the detailed role of IDO in the progression of asthma exacerbations using a mouse model for asthma exacerbation caused by hRV infection. Our results reveal that IDO is required to prevent neutrophilic inflammation in the course of asthma exacerbation caused by an hRV infection, as corroborated by markedly enhanced Th17- and Th1-type neutrophilia in the airways of IDO-deficient mice. This neutrophilia was closely associated with disrupted expression of tight junctions and enhanced expression of inflammasome-related molecules and mucin-inducing genes. In addition, IDO ablation enhanced allergen-specific Th17- and Th1-biased CD4⁺ T-cell responses following hRV infection. The role of IDO in attenuating Th17- and Th1-type neutrophilic airway inflammation became more apparent in chronic asthma exacerbations after repeated allergen exposures and hRV infections. Furthermore, IDO enzymatic induction in leukocytes derived from the hematopoietic stem cell (HSC) lineage appeared to play a dominant role in attenuating Th17- and Th1-type neutrophilic inflammation in the airway following hRV infection. Therefore, IDO activity in HSC-derived leukocytes is required to regulate Th17- and Th1-type neutrophilic inflammation in the airway during asthma exacerbations caused by hRV infections.